Alkylation Reactions with Alkylsulfonium Salts

Abstract

The application of alkylsulfonium salts as alkyl-transfer reagents in organic synthesis has reemerged over the past few years. Numerous heteroatom- and carbon-centered nucleophiles, alkenes, arenes, alkynes, organometallic reagents, and others are readily alkylated by alkylsulfonium salts under mild conditions. The reactions feature convenience, high efficiency, readily accessible and structurally diversified alkylation reagents, good functional group tolerance, and a wide range of substrate types, allowing the facile synthesis of various useful organic molecules from commercially available building blocks. This review summarizes alkylation reactions using either isolated or in situ formed alkylsulfonium salts via nucleophilic substitution, transition-metal-catalyzed reactions, and photoredox processes.

1 Introduction

2 General Methods for the Synthesis of Alkylsulfonium Salts

3 Electrophilic Alkylation Using Alkylsulfonium Salts

4 Transition-Metal-Catalyzed Alkylation Using Alkylsulfonium Salts

5 Photoredox-Catalyzed Alkylation Using Alkylsulfonium Salts

6 Conclusion

Introduction

Sulfonium salts are widely present in functional materials, natural products, and bioactive molecules.[1] [2] [3] They have a positive charge on the sulfur centers bearing three C–S bonds and show rich reactivity due to their structural diversity, being one of the most important class of organosulfur(IV) species.[1] The selective cleavage of C–S bonds in sulfonium salts is of fundamental significance. Alkylsulfonium salts represent a subclass of sulfonium(IV) salts, containing at least one ‘alkyl-S⁺’ fragment in their structures, and have played an important role in materials and life sciences (Figure [1]).[3] Sulfonium polymers, prepared from methylation of sulfur-containing compounds in light oil with iodomethane and AgBF₄ during desulfurization, were used as thermal latent initiators for the cationic ring-opening polymerization of epoxides.[3a] [b] The properties of alkylsulfonium salts as photoacid generators under UV/visible-light irradiation were also described.[3c] [d] Alkylsulfonium-containing zwitterionic polymers, synthesized by controlled RAFT polymerization and subsequent modification, exhibited low cytotoxicities and were demonstrated to be superior protein stabilizers compared to dimethylsulfoniopropionate and other conventional stabilizers.[3e] The ROS-responsive polysulfoniums that degrade into uncharged sulfide fragments by intracellular reactive oxygen species (ROS) can efficiently dissociate and release DNA for gene expression, which deliver the suicide gene to intraperitoneal tumors in vivo, eliciting high anticancer activity.[3f] S-Adenosylmethionine (SAM) is the biological methyl donor in most cases sustaining a wide range of biological processes, including gene expression, protein modification, lipid biosynthesis, and many other metabolic pathways.[4]

In the fields of organic chemistry, alkylsulfonium salts have drawn increasing attention because they can serve as versatile reagents or intermediates to offer simple, effective, and selective access to target structures, including the late-stage modification of complex molecules (Figure [1]).[5] Alkylsulfonium salts have been generally used as precursors of sulfur ylides for the synthesis of diverse organic scaffolds through the Johnson–Corey–Chaykovsky reaction, cyclization, rearrangement, and cross-coupling.[5] Perfluoroalkyl(diaryl)sulfonium salts, the fluorinated version of alkyl(diaryl)sulfonium salts, are well-known electrophilic perfluoroalkylation agents (e.g., Yagupolskii–Umemoto reagents), achieving a large number of useful methods for introducing perfluoroalkyl groups into organic compounds.[6] The dealkylative functionalization of alkylsulfonium salts has also been explored to conveniently afford elegant sulfides.[7] Inspired by the biological relevance of triorganosulfonium salts as alkylating reagents,[4] alkylation using alkylsulfonium salts has flourished over the past few years and has become one of the major focuses for synthetic chemists. Although a series of reviews have highlighted transformations of sulfoniums as cross-coupling partners or intermediates to form valuable compounds, the use of alkylsulfonium salts as alkyl-transfer reagents via C–S bond cleavage has not yet been systematically summarized in the literature.[1c] ^, [5`] [c] [d] [e] [f] [g] [h] [i] [j] [k] [l] ^, [8]

Considering the advances of alkylation with alkylsulfonium salts in recent years, it would be indispensable to provide a short review of the findings in the field. For the sake of convenience, we have summarized the alkylation reactions of alkylsulfonium salts in this article and organized them in three parts according to their possible reaction mechanisms: electrophilic alkylation, transition-metal-catalyzed alkylation, and photoredox-catalyzed alkylation. To aid the readers, the representative synthetic methods of alkylsulfonium salts as well as the selectivity of alkylation reactions with alkylsulfonium salts containing three different C–S bonds are also discussed in this review. Thanks to the significant structural diversity and unique aspects of alkylsulfonium salts, developing general, efficient, and selective alkylation methods with alkylsulfonium salts is a challenging task in organic synthesis. Alkylation using alkylsulfonium salts is still one of the least acknowledged research fields in sulfur chemistry. We anticipate that this review will help new researchers to quickly develop an understanding of the subject and will stimulate further interest from the synthetic community to survey the new reactivity and application of alkylsulfonium salts.

General Methods for the Synthesis of Alkylsulfonium Salts

In most cases, alkylsulfonium salts are prepared from the substitution reactions of sulfides with alkyl halides, alcohols, and esters, the interrupted Pummerer reactions of activated sulfoxides with arenes, alkenes, and alkynes, or the addition of thianthrene radical cations with alkenes (Figure [2]).[1] [5] [8] [9] The in situ generation of alkylsulfonium salts from the addition of aryne intermediates with alkyl sulfides or the assembly of sulfide radical cations with alkyl radicals has also been demonstrated in sulfide-participated alkylation reactions.[1] [5] [8] [9] It should be mentioned that unstable alkylsulfonium salts are generally synthesized at low temperatures. Moreover, sulfur ylides undergoing protonation, alkylation, or combination with other electrophiles at the negative α-carbon centers form alkylsulfonium intermediates that are powerful alkylation reagents for diverse nucleophiles in one-pot procedures.[5]

Electrophilic Alkylation Using Alkylsulfonium Salts

It is well known that S-adenosylmethionine (SAM) is an efficient electrophilic methylation reagent in most biological processes because of the electron-deficient nature of the sulfonium group, which can react with various N-, O-, and S-nucleophiles, unsaturated carbons, and halide ions via typical S_N2 displacement.[4] Nature also employs enzymes to catalyze the methylation of non-nucleophilic substrates with SAM via radical mechanisms, leading to transformations relevant to nucleic acid and protein modification, and to the biosynthesis of vitamins, coenzymes, and antibiotics. Taking a lesson from SAM as a powerful alkylation agent, trimethylsulfonium salts, trialkylsulfonium salts, dialkyl(aryl)sulfonium salts, and alkyl(diaryl)sulfonium salts have been comprehensively utilized to alkylate a variety of nucleophiles such as (thio)phenols, alcohols, thiols, amines, acids, 1,3-dicarbonyls, enolates, phosphine, Grignard reagents, alkyllithiums, azides, hydrides, halides, and others via S_N2 reactions under transition-metal-free conditions (Figure [3a]).[10] The formation of sulfurane intermediates followed by reductive elimination, intramolecular substitution, or ionic fragmentation to afford alkylated products were also observed in the reactions with hard nucleophiles (e.g., n-butyllithium, enolate, carboxylate, and phenolate anions) (Figure [3b]).[10`] [h] [i] Furthermore, the S_N1 mechanism was suggested for the reactions of alkyltetrathiafulvalenium intermediates with several nucleophiles (Figure [3b]).[11] It should be noted that the selective alkylation with alkylsulfonium salts bearing three different alkyl groups and the selective alkylation of nucleophiles containing more than one reactive site with certain alkylsulfonium salts is highly sought after (Figure [3c]).

Selective Alkylation with Acyclic and Cyclic Alkylsulfonium Salts

Selective alkylation is a long-term challenge in organic chemistry. Yamaguchi and co-workers found that uridine, thymidine, guanosine, inosine, theophylline, and 2-pyridone were methylated by [Me₃S]F or [BuSMe₂]F in DMF at 90–100 °C to give the corresponding N-methylated products in good yields. The counteranion of trimethylsulfonium had a big influence on the methylation as [Me₃S]F converted uridine into 3-methyluridine quantitatively, whereas [Me₃S]I did not react with uridine. Treatment of guanosine (1) with [Me₃S]F formed 1-methylguanosine (2a) in 67% yield, while the similar reaction with [Me₃S]I provided 7-methylguanosine (2b) in 54% yield (Scheme [1]).[12] The difference in the selectivity of methylation might be attributed to the hydrogen bonding between the fluoride anion and amide/imide groups in the substrates, which increased the nucleophilicity of the groups and enhanced the attack of sulfonium cations.

In 2020, Shi and co-workers developed a selective d ₃-methylation of complex molecules bearing several reactive sites with 5-(methyl-d ₃)-5H-dibenzothiophen-5-ium triflate (DMTT, 3) (Scheme [2]).[13a] The reagent behaved as an analogue of SAM and was synthesized from dibenzothiophene and methyl-d ₃ formate by following a TfOH-promoted S-alkylation procedure reported by Tsuchida (Scheme [2a]).[9h] DMTT had very different reactivity from other commonly used d ₃-methylation reagents [CD₃I and (CD₃)₂SO₄] because of the steric hindrance of the leaving group, and exhibited better chemoselectivity than CD₃I and (CD₃)₂SO₄ in the d ₃-methylation of 4-amino-2-hydroxybenzoic acid (4) to give methyl-d ₃ 4-amino-2-hydroxybenzoate (5) (Scheme [2b]).[13a] Reactions of primary amines with DMTT in the presence of 10 mol% Ni(OAc)₂·4H₂O selectively formed N,N-dimethyl-d ₃ products in moderate to good yields, avoiding the overmethylation that frequently occurs in the direct methylation of primary amines with iodomethane to afford quaternary ammonium salts.[13a] This d ₃-methylation proceeded smoothly under mild conditions with high-level deuterium incorporation and was applicable to the late-stage modification of pharmaceuticals with excellent functional group compatibility (Scheme [2c]). In 2021, the same research group reported the use of DMTT as a d ₂-methylene source in the synthesis of α-deuterated boronates through a sulfur ylide mediated 1,2-migration reaction.[13b] Such boron-initiated, sulfur ylide mediated migration processes were similarly explored in detail by Aggarwal and others.[13`] [d] [e] [f] [g]

In 1976, Eliel and co-workers found that the nucleophilic attack of 1-methyltetrahydrothiophenium (8a) (five-membered ring) by sodium azide or methanethiolate afforded the ring-opening products with small amounts of methylated products, while the similar reactions with 1-methyltetrahydro-2H-thiopyranium iodide (8b) (six-membered ring) gave largely the methylated products accompanied by minor ring-opening products (Scheme [3a]).[14] The α-substituents on tetrahydrothiophenium also had an impact on the regioselectivity of alkylation. Treatment of 1,2-dimethyltetrahydrothiophenium iodide (8c) with azide or methanethiolate and reaction of 1,2,6-trimethyltetrahydrothiophenium iodide (8d) with methanethiolate provided mainly or nearly entirely methylated product by displacement at the exocyclic methyl moiety.[14] The S_N2 reaction mechanism together with the strain of the five-membered ring might explain the different selectivity of these systems.[14] Taylor and co-workers investigated the reactions of thietane (9) with benzyl halides, yielding 3-halopropyl benzyl sulfides 11 via ring opening of 1-benzylthietanium halide­ intermediates 10 (Scheme [3b]).[15] Different from the reactions of 9 with iodomethane and other halides giving no products or complex mixtures of polysulfides, a variety of 3-bromopropyl benzyl sulfides 11 were successfully synthesized in good to excellent yields by heating 9 and benzyl halides in the presence or absence of solvent.[15] Závada and co-workers reported that reactions of 4-alkyl-4,5-dihydro-3H-dinaphtho[2,1-c:1′,2′-e]thiepin-4-ium 13 with a range of N-, S-, Se-, O-, and C-nucleophiles afforded the corresponding ring-opened bidentate products 14 and/or dealkylative product 12, which was dependent upon the counteranions of the sulfoniums (Scheme [3c]).[16] In most instances, iodide caused the formation of 12, while perchlorate, tetraphenylborate, and tetrafluoroborate favored the production of 14. Alkylation of racemic 12 with iodomethane was a reversible process and required very large excess of iodomethane (about 50-fold) to complete the reaction. This difficulty was overcome by using a non-nucleophilic counteranion (e.g., ^–BPh₄, ^–ClO₄, or ^–BF₄) as the reactions with equimolar methyl perchlorate and Et₃O⁺BF₄ ^– afforded alkylsulfonium salts in nearly quantitative yields.[16]

A synthetic route to α-aminoboronic acids 19 as inhibitors of serine proteases using electrophilic alkylsulfonium side chains was developed by Kettner and co-workers (Scheme [4]).[17a] BrCH₂CHF₂, BrCH₂CO₂ t-Bu, and CH₂=CHCO₂Me reacted with the anion of (phenylthio)methaneboronate 15 to give substituted boronates 16, which were converted into the corresponding alkylsulfonium ions 17 by treatment with iodomethane. Simultaneous substitution of the active sulfonium intermediates 17 with iodide formed α-iodo derivatives 18, which underwent amination to afford the expected α-aminoboronic acids 19. This method was particularly advantageous for compounds with functionalities that were sensitive under basic conditions.[17a] Earlier it was reported that there was a chemical equilibrium between alkyl sulfide and alkyl halide, from which the most stable sulfonium salt would be formed.[17b] The use of a large excess of iodomethane was beneficial for the generation of 17 in this reaction.[17a]

Thiiranium intermediates 23 are highly reactive three-membered alkylsulfonium salts that have been widely examined with diverse nucleophiles to furnish a large family of α-functionalized sulfides 24 (Scheme [5]).[1a] [18] These sulfonium intermediates are usually in situ generated from the reactions of electrophilic alkyl- or arylthiolation reagents 20 with alkenes 21 or the intramolecular nucleophilic attack of the sulfur atoms in sulfides 22 at the electron-deficient carbon centers bearing an appropriate leaving group. The regioselectivity of ring opening of thiiraniums 23 is dramatically dependent upon the nature of the nucleophile (^–Nu) and the substituents (R² and R³) attached to the three-membered ring.[1a] [18] Since this is an extensive topic, we do not intend to discuss this in detail here, but instead refer the interested reader to reviews on recent achievements in the synthesis and reactivity of thiiranium salts.[18]

Iyoda and co-workers reported that the alkylation of tetramethylammonium­ pentacarbonyl(1-oxyalkylidene)metalates 27 with alkyl(diphenyl)sulfonium salts 26 permits a simple synthesis of Fischer-type chromium, molybdenum, and tungsten (alkoxy)carbene complexes 28 with diverse functionalized alkyl groups (Scheme [6a]).[19] The reactions proceeded smoothly to give the corresponding (alkoxy)carbene complexes 28 in good to high yields. Alkyl(diphenyl)sulfonium tetrafluoroborates 26 were readily prepared from the reactions of alkyl halides 25 with Ph₂S in the presence of AgBF₄. The competitive alkylation of 27a with 26a and 26b showed that the secondary isopropyl(diphenyl)sulfonium salt 26b was more reactive than the primary methyl(diphenyl)sulfonium salt 26a (Scheme [6b]),[19] which implied that the mechanism of this alkylation might involve participation of an S–O sulfurane intermediate 26′ rather than a simple S_N2 pathway since the relative reactivities of methyl, ethyl, and isopropyl halides in S_N2 reactions are often found to be methyl > ethyl > isopropyl (Scheme [6b]). The formation of 26′ via an electron-transfer process could explain the unusual reactivity of the alkylsulfonium salts towards 27a.[19]

Synthesis of β-Lactams, Azetidines, and Furanones through Alkylsulfonium Salts

The stereoselective construction of the β-lactam ring in the synthesis of carbapenem antibiotics is a difficult synthetic task.[20a] In 1993, Naito and co-workers provided a practical method for the chiral synthesis of cis- and trans-β-lactams using the combination of the stereoselective Michael­ addition of thiophenol to α,β-unsaturated carbonyls and subsequent intramolecular substitution of the in situ formed sulfonium group, which was successfully applied to the formal preparation of carbapenem antibiotic 31 (Scheme [7a]).[20a] Initially, stereospecific reaction of thiols with α,β-unsaturated carboxylic acid derivatives 29-I, followed by aminolysis with alkoxyamine hydrochloride and S-alkylation with iodomethane in the presence of silver perchlorate, afforded alkylsulfonium salts 29-III, which then underwent smooth lactamization through intramolecular displacement of the sulfonium group with O-alkylhydroxamate in the presence of potassium carbonate to give β-lactam 30 with high stereoselectivity. In 2015, Jamison and co-workers reported that enantiopure 2-alkylazetidines 33 could be straightforwardly synthesized via consecutive processes including regioselective Ni-catalyzed cross-coupling of organozinc reagents with an aziridine 32-I bearing a phenylthio group, methylation of the phenylthio group to form a sulfonium moiety, and nucleophilic intramolecular substitution under basic conditions (Scheme [7b]).[20b] This sequence tolerated a range of organozinc reagents, giving the products in good overall yields and with excellent selectivity.

In 2016, Kawano and co-workers disclosed the synthesis of 5-alkoxyfuran-3(2H)-ones 35 from the intramolecular cyclization of 3-(alkoxycarbonyl)-2-oxopropyl(diphenyl)sulfonium salts 37 in the presence of t-BuOK (Scheme [8a]).[21a] Similarly, intramolecular cyclization of (4-aryl-2,4-dioxobutyl)methylphenylsulfonium salts 39 derived from 1-arylethanone 38 produced a family of 5-arylfuran-3(2H)-ones 40 in excellent yields under ambient conditions (Scheme [8a]).[21b] When ethyl 4-chloroacetoacetate (34a) and ethyl 4-bromoacetoacetate (34b) were subjected to the optimal conditions, 35a was observed as a minor product and the dimerization product 36 was the major product (Scheme [8a]).[21a] These results indicated that a bulky diphenylsulfonio group was very important for the cyclization as substrates bearing smaller leaving groups (e.g., Cl, Br) underwent intermolecular S_N2 reactions. This strategy also enabled a one-pot preparation of 5-alkoxy-4-alkylfuran-3(2H)-ones 41 from sulfoniums 37 via alkylation with alkyl halides followed by intramolecular cyclization, showing a wide substrate scope and good functional group tolerance (Schemes 8b and 8c).[21a] In addition, halogenative intramolecular cyclization of 37 with NXS (X = Br, I) conveniently furnished a variety of 4-bromo- or 4-iodo-substituted 5-alkoxyfuran-3(2H)-ones 42 as useful synthetic building blocks in good to high yields.[21c] Acylative intramolecular cyclization of alkylsulfonium salts 44 by in situ formation of a mixed anhydride between carboxylic acid 43 and trifluoroacetic anhydride (TFAA) in the presence of N-methylimidazole, followed by sequential acylation and cyclization, was extensively explored, which provided various 2-substituted 4-oxo-4,5-dihydrofuran-3-carboxylates 45 in good yields (Scheme [8c]).[21d]

Ring-Opening Alkylation with Cyclic Alkyl(aryl)sulfonium Salts

The ring-opening reactions of cyclic alkyl(aryl)sulfonium salts constitute effective methods for introducing alkylthio groups into organic molecules (Scheme [9]). This strategy was favorably applied in the three-component cascade reactions of aryne precursors, cyclic sulfides, and nucleophiles (HNu).[22] [23] [24] In 2016, Hoye and co-workers revealed the reaction of alkyl sulfide 47 with aryne 46, thermally generated by the hexadehydro-Diels–Alder (HDDA) cycloisomerization of tetrayne 51, produced an aryl anion bearing o-sulfonium moiety that underwent intramolecular proton transfer to form an S-aryl sulfur ylide 48 (Schemes 9a and 9b).[22] This species was trapped via sigmatropic shift or rearrangement to form sulfides 49 or protonated by weak acids (HNu) to produce alkylsulfonium intermediates. In the reactions of cyclic alkyl sulfides, Nu^– [derived from weak acids (HNu)] was incorporated into the product 50 by ring opening.[22] In 2018, Xu and Tan reported a three-component cascade reaction of o-(trimethylsilyl)aryl triflates 53, cyclic sulfides 54, and C-, N-, O-, or S-nucleophiles 55 through the aryne-activated ring-opening process under mild conditions, giving structurally diverse sulfides in good yields (Scheme [9c]).[23a] Independently, He and co-workers disclosed a similar three-component reaction of aryne precursors 56, four- to six-membered sulfides 57, and divergent nucleophiles 58, including inorganic salts (e.g., KF, KCl, KBr and KSCN), silylated reagents (e.g., TMSCN, TMSN₃, TMSCl), and water (Scheme [9d]).[23b] Likewise, Lewis and co-workers described the synthesis of azulenyl sulfides by ring-opening reactions of azulenylsulfonium salts with the thiophenol anion and amines.[24] These strategies allowed convenient syntheses of a large number of useful alkyl aryl sulfides for future applications.[22] [23] [24]

Alkylsulfonium-Mediated C–F Functionalization

In 2021, Young and co-workers reported that frustrated Lewis pair (FLP) catalyzed monoselective C–F activation of polyfluorocarbons 59 at geminal or distal sites with tris(perfluorophenyl)borane [B(C₆F₅)₃] and tetrahydrothiophene (THT) formed 1-(fluoro)alkyltetrahydrothiophenium intermediates 60 in excellent yields (Scheme [10]).[25] Different from the previous ring opening processes, these cyclic sulfonium salts 60 reacted with nucleophiles through substitution of THT to afford a range of divergent products 61.[25] THT was found to be a superior base working as FLP partner in this C–F activation in terms of reactivity, product yield, and selectivity.

Synthesis and Alkylation of Dicationic Alkylthianthrenium Salts

Alkenes are also important synthons to prepare alkylsulfonium salts.[26] [27] In 1979, Shine and co-workers found that thianthrene and phenoxathiin radical cation perchlorates 63, prepared in situ from the chemical oxidation of thianthrene and phenoxathiin, respectively, could facilely react with a number of alkenes 62 to form alkanedisulfonium diperchlorates 64 in excellent yields (Scheme [11a]).[26a] Thianthrene radical cation perchlorate (TT^•+ClO₄ ^–) reacted with cyclohexene (62a) to give 1,2-bis(thianthren-5-ium-5-yl)cyclohexane diperchlorate 64a.[26b] The outcomes of the reactions of 1,2-bis(thianthren-5-ium-5-yl)cycloalkane diperchlorates 64a,b with ^–CN, I^–, and ^–SPh in dimethyl sulfoxide or ethanol indicated that they have a trans-1,2 structure and could undergo S_N2 substitution and E2 elimination at room temperature (Scheme [11b]).[26] Although addition of TT^•+ClO₄ ^– to 62a gave trans-1,2-bis(thianthren-5-ium-5-yl)alkane diperchlorate 64a, reaction of TT^•+ClO₄ ^– with cyclooctene afforded only cis-monoadduct 65, 1,2-(thianthrene-5,10-diium-5,10-diyl)cyclooctane diperchlorate.[26c] Similar monoadducts were obtained when TT^•+BF₄ ^–, TT^•+SbF₆ ^–, and TT^•+PF₆ ^– added to cyclooctene. Interestingly, addition of TT^•+ to cyclopentene (62b) and cycloheptene provided mixtures of mono- and bisadducts 64 and 65. The proportions of monoadducts obtained in the initial stage of the reactions varied with the size of cycloalkenes 62.[26d] Bis- and monoadducts were also obtained in the addition of TT^•+ClO₄ ^– to acyclic alkenes, and the relative amounts again changed with the structures of alkenes.[26d] The monoadducts 65 afforded 1-(thianthren-5-ium-5-yl)cycloalkenes 66 by loss of a proton. In both bis- and monoadducts of acyclic alkenes, the configuration of the alkene was retained.[26d]

A convenient method for electrochemical synthesis of mono- and bis(thianthrenium) salts was demonstrated by Wayner and co-workers.[27a] The selectivity for the mono- or bis(thianthrenium) adduct was proposed to be governed by the oxidation potential of the distonic radical cation intermediate. In 2021, Wickens and co-workers reported that terminal alkenes 73 were electrochemically transformed into metastable dicationic sulfonium intermediates 74 and 75 that underwent aziridination with primary amines 76 under basic conditions to afford a range of N-alkylaziridines 77 (Scheme [12]).[27b] Since the oxidative alkene activation was decoupled from the aziridination step, a wide range of oxidatively sensitive amines were used as coupling partners for aziridination. This methodology streamlined the synthesis of important complex amines, including medicinally relevant molecules (e.g., 77a), and was extended to other conversions, such as direct diamination of alkenes to give 78 without additional base under the aziridination conditions, formation of dihalogenated product 79 by treatment with halides, and construction of vinyl nitrile 80 with addition of potassium cyanide.[27b]

Synthesis of β,γ-Unsaturated Amines through Alkylsulfonium Intermediates

In 2003, Mukaiyama and co-workers explored a sulfonium-mediated method for the preparation of β,γ-unsaturated amines 83 from 1,1-disubstituted and 1,1,2-trisubstituted alkenes 81 in good yields (Scheme [13a]).[28a] The reactions started with the formation of α,β-unsaturated diphenylsulfonium triflates 85 from alkenes 81 and diphenyl(triflyloxy)sulfonium triflate (84), followed by C=C bond migration in 85 to give allylsulfonium triflates 86 with the primary or secondary amines 82, and successive nucleophilic substitution of 86 with 82 to afford the desired products 83. In contrast, the reactions of styrenes with 84 under similar conditions afforded 2-arylvinyl(diphenyl)sulfonium triflates, which were treated with primary amines to give 2-arylaziridines in high yields.[28b] Likewise, Du, Xu, and Li disclosed a sulfonium-mediated allylic C–H amination of terminal olefins 87 with amines 88, probably involving conversion of the secondary carbocations to the primary carbocations or the primary triflates, which was driven by intramolecular electrostatic repulsion in dicationic intermediates (Scheme [13b]).[29a] The reaction of 84 with allylbenzene (87a) initially gives a secondary carbocation 92, which is converted into secondary triflate 93 or an allylsulfonium salt 94 followed by S_N2 reaction or both S_N2 and elimination reactions with amine to afford the minor product 89a (path a). Alternatively, 92 might rearrange through a phenonium ion 95 to form a primary carbocation 96, a primary triflate 97, or an allylsulfonium salt 98, which react with amine to afford the major product 90a (path b). Interestingly, the same reaction with primary amine provided azetidine 91 by double S_N2 attacks. The product distributions varied dramatically depending on the amine and alkene substrates.[29a] In addition, transition-metal-free allylic C–H arylation, epoxidation, and aziridination of alkenes with the respective electrophiles were investigated.[29b] The reactions involved addition of 84 to olefins, deprotonation of sulfonium intermediates under basic conditions, and condensation of the in situ generated allyl sulfur ylides with arylboronic acids, aldehydes, and aldimines, to give allylic functionalized products in good yields,[29b] which were mechanistically different from the previous aminations.

Alkylsulfonium-Mediated MBH Reactions and Their Extension

The Morita–Baylis–Hillman (MBH) reaction is a well-known named reaction that permits α-functionalization of alkenes with electron-withdrawing groups.[30a] Employment of an oxophilic Lewis acid and a sulfide (Lewis base) to form a key β-sulfonium intermediate allowed the reaction to be compatible with more active Michael acceptors and to a wider range of terminal electrophiles (Scheme [14]).[10e] ^, [30`] [c] [d] [e] [f] [g] [h] [i] In 1998, Kataoka and co-workers reported that a combination of dimethyl sulfide with TiCl₄ effected a MBH reaction between acrylonitrile, methyl acrylate, or phenyl vinyl sulfone and aldehyde at room temperature.[30j,k] The reactions might involve a β-sulfonium-TiCl₄-stabilized enolate 100 which is generated by conjugate addition of dimethyl sulfide to the TiCl₄-activated Michael acceptor, despite the fact that exceptions were also found in some cases.[30a] [j] In 2002, Goodman and co-workers disclosed that Et₂O·BF₃ together with THT moderately sustained the MBH reaction of methyl vinyl ketone (MVK, 104).[30l] When the reaction was quenched with aqueous acid, allylsulfonium salt 106 was isolated, which provided compelling evidence for the intermediacy of sulfonium species. In 1993, Kim and co-workers revealed that β-sulfonium silyl enol ethers 108 were generated by treatment of the corresponding enone or enal with TBSOTf and dimethyl sulfide at low temperatures.[10e] MBH-type reaction of the β-sulfonium silyl enol ether of cyclohexenone 108a with acetal 109 and TMSOTf, followed by treatment with DBU, afforded O-methylated MBH-adduct 110.[10e] [30b] [m] In 2006, Metzner and co-workers modified Kim’s procedure with Hünig’s base, TBSOTf, and THT, allowing in situ enolization of the β-sulfonium-β′-OMe intermediate and giving the MBH adducts by an aqueous quenching.[30b] Remarkably, β-sulfonium silyl enol ethers 108 underwent facile nucleophilic substitution at the β-position with various nucleophiles including Grignard reagents, the sodium salt of dimethyl malonate, tributyltin azide, tributyltin hydride, enamine, piperidine, triphenylphosphine, and pyridine to form the respective enol silyl ethers in good yields (Scheme [14b]).[10e] These reactions had an increased scope of terminal electrophiles over the tertiary amine-/phosphine-catalyzed conditions and were superior for reactive Michael acceptors. Besides, Kim and co-workers harnessed α-alkoxysulfonium salts 112 by reaction of aliphatic diethyl acetal 111 with TMSOTf and dimethyl sulfide at –78 °C.[30n] This salt was treated with a variety of nucleophiles (e.g., Grignard reagents, CH₂=CHCH₂TMS, silyl enol ethers, CH₂=CHCH₂SnBu₃, and PhSLi) to afford the corresponding adducts 114 in good yields.

Radical-Polar Crossovers Involving Alkyltetrathiafulvalenium Intermediates

Tetrathiafulvalene (TTF) was developed as a reliable radical-polar crossover (RPC) catalyst by Murphy and co-workers due to its excellent electron-donor ability in the reductive transformation of arenediazonium salts 115 through alkylsulfonium intermediates 118 (Scheme [15]).[11] In these reactions, the TTF radical cation 117 and aryl radical 116 were first generated from TTF and arenediazonium salts 115 via a single electron transfer (SET) process. Cyclization of the aryl radicals bearing adjacent C=C bonds 116, followed by coupling of the newly formed carbon radicals with the TTF radical cation, formed the key alkylsulfonium intermediates 118. These salts 118 participated in S_N1 reactions with nucleophiles including water, alcohols, and acetonitrile to afford a series of functionalized bi- and tricyclic ring systems 119 (Scheme [15b]).[11] However, when tetrathiafulvalenium salt 118a reacted with azide, diethyl malonate, and KOH, unexpected products (e.g., 120) via fragmentation of the tetrathiafulvalenium rings or addition of nucleophile to the central C=C bond of the tetrathiafulvalenium moiety were obtained (Scheme [15c]).[11i]

Synthesis of α-Heterosubstituted Ketones via α-Carbonyl Sulfonium Salts

A one-pot, transition-metal-free procedure for the synthesis of α-heterosubstituted ketones 123 through sulfonium-mediated difunctionalization of aryl-substituted internal alkynes 121 was described by Li, Du, and co-workers in 2019 (Scheme [16a]).[31a] Initially, 121 attacks Tf₂O-activated sulfoxide 84 to form a sulfonium vinyl triflate intermediate 124,[31] which undergoes hydrolysis to give an α-sulfonium ketone 125.[31a] Subsequent substitution of 125 with various nitrogen, oxygen, sulfur, and halogen nucleophiles 122 provides different types of α-substituted ketones 123. The preliminary catalytic asymmetric variant of the reaction gave the desired product with moderate yield and er value (Scheme [16b]).[31a] In 2020, Li and co-workers expanded the reaction scope to both internal and terminal arylalkynes under relatively weak basic conditions using potassium acetate as both base and nucleophile to furnish α-acetoxy ketones, avoiding the unwanted elimination process for terminal alkynes.[31b] Sun, Li, and co-workers disclosed a catalytic asymmetric approach for the synthesis of chiral α-amino ketones 129 with excellent efficiency and enantioselectivity from α-carbonyl sulfonium ylides 126 and amines 128 by a protonation-amination sequence involving an α-carbonyl sulfonium intermediate 127.[32a] The reaction was extended to α-amino esters by varying the chiral catalysts 130. Mechanistic studies indicated that the enantioselectivity of the reaction was controlled by dynamic kinetic resolution in the rate-determining amination step rather than the initial protonation step. Furthermore, the cleavage of the non-ylidic S–C bond of alkyl(aryl)sulfonium ylides was explored.[32b] The ylides served as alkyl cation precursors under acidic conditions and allowed alkylation of alcohols, acids, amines, amides, 2-mercaptobenzothiazole, and electron-rich arenes. If the reaction of alcohols or phenols was performed under alkaline conditions, the cleavage of the S–aryl bond occurred to form O-arylated compounds.[32b] This protocol had excellent compatibility of a wide variety of substrates including carbohydrates.

Indole Functionalization through Alkylsulfonium Intermediates

Indoles bearing functional groups are often found as key structures in biologically active natural products and pharmaceuticals.[33] In 2011, Kawasaki and co-workers reported the sulfonium-mediated functionalization of indole derivatives 131 with methanol at the 2α-position in the presence of sulfoxide and trifluoroacetic anhydride (Scheme [17a]).[33`] [b] [c] The active thionium species 134 were derived in situ from the alkyl or aryl sulfoxide and TFAA. In addition to methanol, other carbon- and heteroatom-nucleophiles 132 were also directly introduced into 131 to form 133 in excellent yields.[33`] [b] [c] Similarly, a one-pot sulfonium-mediated synthesis of homo- and heterodimeric pyrroloindolines 140 was developed by combination of DMSO and Tf₂O (Scheme [17b]).[33d] Intramolecular cyclization of tryptamine with DMSO/Tf₂O, followed by substitution with indoles or anilines, produced C3a-nitrogen-linked pyrroloindolines, including several bioactive alkaloids.[33d] [e] The use of 2,3-dihydrotryptamine instead of anilines in the same reaction enabled easy access to 3a-(indol-1-yl)pyrroloindoline and a concise synthesis of (±)-psychotriasine.[33e] In 2016, the enantioselective synthesis of C3a-substituted pyrroloindolines from tryptamine utilizing C ₂-symmetric chiral sulfoxides was accomplished in a one-pot procedure, the synthetic utility of which was demonstrated by the facile total synthesis of (+)-psychotriasine.[33f] Moreover, the total synthesis of (+)-gliocladin C was implemented on the basis of a 3a-(indol-3-yl)pyrroloindoline structure that was built by sulfonium-promoted cross-coupling of a tryptophan derivative with indole in the presence of dialkyl sulfoxide and Tf₂O.[33g] Likewise, the sulfonium-triggered direct C2-functionalization of indoles 141 with different kinds of nucleophiles 142 was explored (Scheme [17c]).[33h] Reaction of 141 with the in situ formed sulfonium salt from DMSO/Tf₂O generates iminium species 144, which is attacked by 142 followed by elimination of dimethyl sulfide, to afford the corresponding C2-substituted indole derivatives 143 in good to high yields.

Alkylation of Alkenes and Arenes via Allyl- or Allenylsulfonium Salts

In 2009, Yorimitsu, Oshima, and co-workers found that reaction of 2-(2,2,2-trifluoroethylidene)-1,3-dithiane monoxide with allylsilanes, Tf₂O, and 2,6-di-tert-butylpyridine through allylsulfonium intermediates afforded β-allylated ketene dithioacetals in good yields (Scheme [18a]).[5d] [34a] The specific C–C bond formation with γ-substituted allylsilanes at the α-position suggested the intervention of [3,3]-sigmatropic rearrangement of an allylsulfonium intermediate 149. Initially, an activated sulfonium species 147 is formed in the interrupted Pummerer reaction wherein allylsilane 148 attacks the sulfur atom to generate an allyl(alkenyl)sulfonium salt 149. Subsequently, 149 undergoes [3,3]-sigmatropic rearrangement followed by deprotonation to yield the final product 151. This valuable interrupted Pummerer reaction/[3,3]-sigmatropic rearrangement sequence was extended to the ortho-selective C–H alkylation of aryl sulfoxides (Scheme [18b]).[34`] [c] [d] [e] [f] Procter and co-workers disclosed a general method for the metal-free ortho-allylation of aryl and heteroaryl sulfoxides 152 with allylsilanes 153 and Tf<sub>2</sub>O or TFAA as an activator.[34b] [c] Pyrrole and pyrazole sulfoxides underwent a heterocycle-accelerated interrupted Pummerer reaction and thio-Claisen rearrangement to form ortho-allylated products, showing complete regiospecificity with regard to both coupling partners.[34c] In a similar manner, sulfoxide-directed metal-free ortho-propargylation of aromatics and heteroaromatics 156 through an interrupted Pummerer/allenyl thio-Claisen rearrangement enabled propargylic carbon nucleophiles to be added ortho to sulfur atoms on the aromatic or heteroaromatic rings 159.[34`] [e] [f] This cross-coupling procedure was operationally simple and completely selective for products of propargylation over allenylation.

Benzothiophenes represent important scaffolds that are widely found in biological molecules and organic materials. By employing the interrupted Pummerer reaction to capture and deliver allyl- or propargylsilanes 160 or 161, Procter and co-workers accomplished a metal- and directing-group-free preparation of C3-alkylated benzothiophenes 163 from benzothiophene S-oxides 162 under mild conditions (Scheme [18b]).[34g] The method had a broad substrate scope and provided various medicinally relevant C3-arylated products, giving greater diversity in important benzothiophenes. Notably, C2-allylated and C2-propargylated benzothiophenes 165 were also synthesized by a cascade sequence involving interrupted Pummerer reaction of 3-substituted benzothiophene S-oxides 164 with 160 or 161, [3,3]-sigmatropic rearrangement of the in situ formed allyl- or allenylsulfonium salts, and 1,2-migration of the 3,3-disubstituted benzothiophenium intermediates.[34h] The facile [3,3]-sigmatropic rearrangement and 1,2-migration process ensured complete regioselectivity and tolerated a range of reactive functional groups in both coupling partners. Furthermore, Procter and co-workers reported a dual vicinal functionalization of electron-rich heteroarenes (e.g., 166) via an interrupted Pummerer cross-coupling of allyl or propargyl sulfoxides (e.g., 167) with subsequent charge-accelerated [3,3]-sigmatropic rearrangement of the corresponding sulfonium intermediates (e.g., 168), providing biologically relevant C3-sulfanylated and C2-allylated or -allenylated heterocycles (e.g., 169) under mild conditions.[34i] Analogously, a metal-free twofold C–H annulation via an interrupted Pummerer reaction/[3,3]-sigmatropic rearrangement/cyclization sequence was harnessed for the preparation of benzothiophenes (e.g., 175) from non-prefunctionalized arenes 170 and allyl sulfoxides (e.g., 171).[34j] This procedure was particularly effective for the synthesis of polyaromatic benzothiophenes from non-prefunctionalized polyaromatic hydrocarbons (PAHs).

Transition-Metal-Catalyzed Alkylation Using­ Alkylsulfonium Salts

Cu-Catalyzed Alkylation with Allylsulfonium Salts

Because of the electron-deficient nature of sulfur(IV) centers, sulfonium salts easily undergo oxidative addition with transition metals, working as pseudohalides in transition-metal-catalyzed cross-coupling reactions.[8] In 1983, Julia and co-workers disclosed that the transition-metal-free alkylation of carboxylate salts with alkylsulfonium salts showed little dependence upon the substituents attached to the sulfur atoms, while the reactions with allylsulfonium salts in the presence of copper(I) salts were greatly accelerated and selectively transfer the unsaturated residues.[35a] [b] Prenyl sulfonium salts 176, which reacted very efficiently at the α-position without copper salts to form primary esters 178, gave exclusively tertiary esters 179 with a catalytic amount of copper bromide (Scheme [19a]).[35a] Similarly, reactions of tetrabutylammonium dihydrogenphosphate with terpenic allylsulfonium salts gave the corresponding primary terpenic allyl phosphates in fair to moderate yields, whereas the Cu-catalyzed reactions led to the production of tertiary allyl phosphates.[35b] It was demonstrated that the copper(I) catalyst dramatically changes the regioselectivity of the reactions of allylsulfonium salts with nucleophiles.[35] This regioselectivity is probably controlled by forming the reactive π-allyl- or σ-allylcopper intermediate which predominantly undergoes nucleophilic attack at the most substituted carbon sites, yielding the tertiary esters.[35a] [b] Later the strategy was favorably employed by Lipton and co-workers in the one-step synthesis of 1,1-dimethylallyl esters of N-protected amino acids 182 using dimethyl(prenyl)sulfonium tetrafluoroborate (176a) in conjunction with catalytic amount of CuBr (Scheme [19b]).[35c] [d] Sulfonium salt 176a was prepared from prenyl alcohol (180) and dimethyl sulfide in the presence of tetrafluoroboric acid. The alkylation was complete within several hours and afforded 182 in excellent yields and with high regioselectivity. These 1,1-dimethylallyl-protected amino acids were useful materials in the synthesis of tripeptide esters and others.[35c] [d]

Pd- or Ni-Catalyzed Alkylation with Diverse Alkylsulfonium­ Salts

In 1997, Srogl, Liebeskind, and Allred reported the first palladium- and nickel-catalyzed benzylation of organoboron, -tin, and -zinc reagents 185 with a variety of 1-benzyltetrahydrothiophenium salts 184, affording the corresponding benzylated products 186 in moderate to good yields (Scheme [20]).[36] Benzyl- and heterobenzylsulfonium salts 184 were readily synthesized from benzyl alcohols or halides 183 and tetrahydrothiophene. It is worth noting that this pioneering work played an indispensable role in stimulating the rapid development of cross-coupling reactions of sulfonium salts in the last decade.[8]

In 2013, Li and co-workers reported a Pd-catalyzed methylation of terminal alkynes 187 with dimethylsulfonium ylide 188 as a methyl source, yielding a number of methyl-functionalized internal alkynes 189 through a C(sp)–C(sp³) bond formation process (Scheme [21a]).[37] In 2018, Novák and co-workers found that alkyldibenzothiophenium salts 191 were suitable alkylation reagents in the palladium-catalyzed direct ortho-C–H alkylation of acetanilide and aromatic urea derivatives 190, which enabled the transfer of methyl and other alkyl groups (e.g., ethyl, propyl, phenethyl and carboxymethylene groups) from sulfoniums to the aniline derivatives under mild conditions (Scheme [21b]).[38] In a similar manner, Shi and co-workers accomplished a Pd-catalyzed C–H methylation of directing group substituted arenes with 5-(methyl-d ₃)-5H-dibenzothiophen-5-ium triflate (DMTT).[13a] Using pyridyl as a directing group, the ortho-bis(d ₃-methylation) was achieved, leading to the dimethylated product, while using acetylamino as a directing group and reducing the number of equivalents of DMTT, the mono-d ₃-methylation product was detected with only trace amount of ortho-bis(d ₃-methylation) product.[13a] The drug molecules (e.g., phenacetin) were also modified by this method, furnishing the d ₃-methylated products with high deuterium incorporation.

In 2021, Wang, Zhou, Yu, and co-workers disclosed an interrupted Pummerer/Pd-catalyzed ring opening/fluorination strategy for the C–H fluoroalkylthiolation of alkenes 193 with cyclic alkyl sulfoxide 194 and Tf₂O (Scheme [22a]).[39] The reaction proceeds through an in situ generated cycloalkyl(vinyl)sulfonium intermediate 195, which undergoes Pd-catalyzed ring-opening/fluorination with CsF via selective aliphatic C–S bond cleavage to afford the fluoroalkylthiolated alkene derivatives 196 under an air atmosphere. Since a small amount of the target product was formed in the absence of the catalyst, nucleophilic ring-opening fluorination could not be excluded.[39] This protocol featured broad substrate scopes and good functional group tolerance, showing potential for the synthesis of diverse fluoroalkylthiolated N-heterocycles. The substituent and ring-size effects from sulfonium salts had a big impact on the fluorination (Scheme [22b]).[39] Reaction of sulfonium 197 with CsF under the standard conditions gave a mixture of two fluoroalkylthiolated products 198a/198b, which revealed that the sterically hindered C(sp³)–S bond is much easier to cleave. Treatment of dimethylsulfonium salt 199 with CsF gave methylthiolated alkene 200 in 91% yield with methyl fluoride as the major byproduct. In the case of decyl(methyl)sulfonium salt 201, the cleavage of two different C(sp³)–S bonds occurs to form 202a (16%) and 202b (34%), respectively, as well as 193a (31%). Methyl fluoride, decyl methyl sulfide (RSMe), and decyl triflate were also detected or presumed according to the GC-MS analysis. Interestingly, the standard reaction of methyl(phenyl)sulfonium salt 203 with CsF predominantly provided 204 (41%) and 193a (52%) with PhSMe and PhOTf but not phenyl fluoride. These results suggested that the Me–S bond is easier to cleave than the long-chain alkyl–S bonds, and the Ph–S bond is much easier to cleave than the Me–S bond without occurrence of fluoroarylation under the Pd-catalyzed conditions.[39]

In addition, Yorimitsu and co-workers reported a nickel-catalyzed Negishi-type reaction of trialkylsulfonium salts 206 with arylzinc reagents 207 in the presence of cyclohexanethiol (CySH) (Scheme [23]).[40a] The transformation was applicable to the one-pot alkylation of 207 with dialkyl sulfides 205 by combining S-methylation with MeOTf. The alkylation using alkyl(dimethyl)sulfonium salts proceeds selectively via cleavage of the [C_alkyl–SMe₂]⁺ bonds. The outcomes of the reaction with trialkylsulfonium triflate 206a bearing three different alkyl groups indicates that the formation of the most stable carbon-centered radicals through C–S bond cleavage by SET from low-valent nickel species 209 to sulfoniums was preferred in the reactions (Schemes 23b and 23c). The intermediacy of radical species was also confirmed by the radical clock experiment.[40a] Further studies showed that CySH might assist the C–S bond cleavage and the recombination of radical species (Scheme [23c]).[40a] Tentatively, reduction of Ni(II) precatalyst followed by comproportionation in the presence of the CyS^– anion generates a Ni(I)–SCy species 209, the single election transfer of which to trialkylsulfonium triflate forms an alkyl radical and a Ni(II) intermediate 210. Then, recombination of the radical and Ni(II) 210 affords an alkyl-Ni(III) cation 211, which might be trapped by another CyS^– anion to generate 212. Finally, transmetalation of 212 with 207 yields alkyl(aryl)Ni(III) complex 213 that undergoes reductive elimination to afford 208 and regenerate 209. The alkyl(aryl)Ni(III) species 213 was also possibly derived from transmetalation of 211 with 207 without proceeding through 212.[40a] It was noted that Procter and co-workers had previously reported an interrupted Pummerer process using tetrahydrothiophene S-oxide and styrenes to form alkenyl(alkyl)sulfonium salts, which underwent Ni-catalyzed Negishi cross-coupling with a range of organozinc partners to afford di-, tri-, and tetrasubstituted alkenes in moderate to good yields.[40b] This interrupted Pummerer activation and sulfonium salt formation could be extended to arene and alkyne systems as well.

Photoredox-Catalyzed Alkylation Using Alkylsulfonium Salts

In 2013, Fensterbank, Goddard, Ollivier, and co-workers reported the pioneering application of a triarylsulfonium salt as an alternative aryl radical source in organic synthesis under photocatalytic conditions.[41a] Aryl radicals derived from photoinitiated homolytic reduction of triarylsulfoniums by single electron transfer could participate in C–C bond formation with alkenes. Since 2019, the groups of Ritter, Procter, Wang, and others have contributed greatly to this area, accomplishing convenient and efficient arylation methods for the late-stage functionalization of complex molecules with diverse arylsulfonium salts.[41`] [c] [d] [e] [f] [g] [h] [i] Despite these advances, sulfonium salts that undergo SET processes have been mainly limited to the formation of aryl radicals.[8d] Although several chemical, electrochemical, and photoredox methods were developed to initiate the one-electron reduction of alkylsulfonium salts to stabilized alkyl radicals in the last half of the 20th century,[42–44] the generation of alkyl radicals, especially the non-stabilized ones, from alkylsulfonium salts is still a big challenge. Recently, the emergence of visible-light photoredox catalysis has offered possibilities for the SET-induced transformations of alkylsulfonium salts under mild conditions, wherein various non-stabilized alkyl radicals were effectively generated as key intermediates or coupling partners for synthetically useful transformations.[45] [46] [47] [48]

Transition-Metal-Catalyzed Photoredox Alkylation­

In 2019, Yorimitsu and co-workers reported a visible-light-mediated radical benzylation of alkenes 215 with 1-benzyltetrahydrothiophenium salts 214 using fac-Ir(ppy)₃ as a photocatalyst to give allylbenzenes 216 in good yields (Scheme [24a]).[45] The reaction allowed coupling of various benzylsulfoniums and alkenes and tolerated a range of functional groups such as halogen, ester, and cyano groups. The choice of a suitable counteranion for benzylsulfonium salts was an important issue for the alkylation.[45] The transformation possibly involves the following processes (Scheme [24a]): (1) photoexcited catalyst (PC*) reduces benzylsulfonium 214 to generate benzyl radical 217 and dialkyl sulfide, (2) addition of 217 to alkene 215a produces a new carbon radical 218, (3) single electron transfer from 218 to the oxidized photocatalyst (PC^+•) forms a cation 219, and (4) deprotonation of 219 affords the product 216a.

In 2020, Novák and co-workers developed a Ni/Ir-catalyzed photoredox system for the synthesis of benzylpyrrolidine derivatives 222 from benzylsulfonium salts 220 and N-Boc-proline 221 with extrusion of CO₂ (Scheme [24b]).[46] The reaction enabled the one-step synthesis of 2-benzylpyrrolidines from inexpensive starting materials via C(sp³)–C(sp³) bond formation, which are of high interest in the field of medicinal chemistry. The dual photocatalyzed reaction from deprotonated N-Boc-proline to photoexcited Ir(III) species, producing the N-Boc-pyrrolidine radical and an Ir(II) intermediate.[46] Meantime, oxidative addition of benzylsulfonium with Ni(0) derived from NiCl₂ forms a benzyl–Ni(II) complex, which intercepts the pyrrolidine radical to provide an alkyl(benzyl)Ni(III) species. Reductive elimination of alkyl(benzyl)Ni(III) affords the desired product and expels a Ni(I) intermediate. Finally, another SET process occurs to reduce Ni(I) to Ni(0) and oxidize Ir(II) to Ir(III), which regenerates both catalysts.[46]

In 2021, Shi, Lu, and co-workers found that SET-induced fragmentation and transformation of alkylthianthrenium salts under photo- and thermoinduced conditions, especially under mild photoredox systems, generated non-stabilized alkyl radicals for C–B and C–C bond formation (Scheme [25]).[47] Alkylthianthrenium salts were demonstrated as suitable electrophiles for borylation, heteroarylation, alkylation, alkenylation, and alkynylation with different substrates bearing a large range of functional groups under photochemical conditions. The formation of an electron-donor-accepter (EDA) complex among alkylthianthrenium salt 223, bis(catecholato)diboron (B₂cat₂), and N,N-dimethylacetamide (DMA) was a key to the photoinduced alkyl borylation.[47] On the other hand, the thermoinduced construction of alkylboronates 224 from 223 and B₂cat₂ was promoted by Lewis base (Et₃N) (Scheme [25a]). Moreover, the Ir-catalyzed photoredox reaction enabled transfer of alkyl radicals from alkylthianthrenium 223a to alkenes (e.g., 225), arenes (e.g., 227), and other radical accepters (e.g., 229) to build C–C bonds via radical addition and C–H functionalization (Scheme [25b]). Also in 2021, Shi, Lu, and co-workers expanded the photoredox method to the Cu-catalyzed Sonogashira cross-couplings of 223 with alkynes 231 (Scheme [25c]).[48] Diverse alkylthianthrenium salts were successfully employed in the reactions with great functional group tolerance, affording various alkylalkynes 232 in moderate to good yields. The sensitive C–X (X = Cl, Br, I) bonds that were poorly tolerated in conventional approaches were compatible in this reaction. These alkylthianthrenium reagents could be further used in Cu-catalyzed Kumada reactions.[48]

Transition-Metal-Free Photoredox-Catalyzed Alkylation

Ohmiya, Nagao, and co-workers reported a visible-light-mediated sulfide-catalyzed decarboxylative C(sp³)–O bond formation between alcohol, amide, or thiol nucleophiles 234 and tertiary or secondary alkyl carboxylic acid derived redox active esters 233 via an alkylsulfonium intermediate 242 (Scheme [26a]).[49a] [b] In these reactions, the sulfide radical cation 240 and alkyl radical 241 are first generated from an EDA complex 239 of 233 and organosulfide catalyst 236a. Then, radical-radical coupling of 240 and 241 or single-electron oxidation of 241 by 240 followed by complexation forms 242, which undergoes nucleophilic substitution to afford a variety of ethers, sulfides, and N-alkyl-substituted amides 237 (Schemes 26a and 26b). This strategy could be applied to the N-alkylation of azoles 235.[49c] The protocol was also amenable to the vicinal difunctionalization of alkenes 243, enabling the assembly of various nitrogen, oxygen, and halogen nucleophiles 244 with 243 and 233 into highly functionalized C(sp³)-rich motifs 245 (Scheme [26c]).[49d] The catalytic cycle of the reaction begins similarly with the photoinduced SET within an EDA complex composed of sulfide 236b and 233, which is then coupled with vinylarene 243 to form a benzylsulfonium intermediate. Finally, the benzylsulfonium salt is intercepted by 244 to afford the bifunctionalized products 245. Notably, these reactions did not require transition metals, external oxidants/reductants, and strong acids, featuring advantages such as mildness, high functional group tolerance, applicability to various heteroatom nucleophiles, and ability to the synthesis of drug-like molecules.[49]

Conclusion

Recent years have witnessed a reemergence of alkylsulfonium salts serving as valuable alkyl-transfer reagents. These salts have intrigued chemists in the fields of synthesis, materials, and life sciences because of their diversiform structures and rich chemistry. Sulfonium compounds that have been successfully used in alkylation reactions include alkyl(diaryl)-, dialkyl(aryl)-, and trialkylsulfonium salts. They are usually employed in purely isolated forms or in situ generated unseparated forms, undergoing nucleophilic substitution, transition-metal-catalyzed reactions, and photoredox transformation via single-electron reduction to convert a large number of N-, O-, S-, C-nucleophiles, alkenes, arenes, alkynes, organometallic reagents, and others into the corresponding alkylated products in an operationally simple and efficient manner. The sulfonium-participated alkylation featured convenience, mildness, non-volatile alkylation reagents, structurally diversified and readily accessible alkylsulfonium salts, good functional group tolerance, and a wide range of substrates, enabling facile construction of various useful organic molecules from commercially available starting materials.

While numerous synthetic methods have been explored based on alkylsulfonium salts, the alkylations using alkylsulfoniums as the coupling partners are still lacking in comparison with arylations using arylsulfonium salts.[5] [8] Thus, continuous efforts are needed to develop novel catalytic systems and structurally diversified alkylsulfonium salts. The ingenious combination of alkylsulfonium salts with transition-metal catalysis, photoredox methods, electrochemical synthesis, mechanochemistry, and green chemistry would provide future driving forces for advances in alkylation reactions. The regioselective C–S bond cleavage of alkylsulfonium salts bearing different alkyl groups, as well as the chemoselective alkylation of nucleophiles containing several reactive sites with certain alkylsulfonium, are highly sought after and remain challenges at present. The enantioselective alkylation with alkylsulfonium salts is another upcoming issue for chemists. The efficient preparation of diversiform alkylsulfonium salts would also be similarly concentrated as this could benefit alkylation and synthesis of complex molecules. Since alkylsulfonium salts are promising cross-coupling partners for many substrates, this review will hopefully inspire more researchers to participate in and contribute to or use sulfonium chemistry for alkylation. The merits of alkylsulfonium salts over alkyl halides in coupling reactions has future potential in terms of efficiency, scope, and mechanisms. It is anticipated that the use of alkylsulfonium salts as common reagents will enrich the chemist’s synthetic toolkit.[50]

Conflict of Interest

The authors declare no conflict of interest.

• References

• 1a Stirling CJ. M, Patai S. The Chemistry of the Sulfonium Group, Part 1 and Part 2. John Wiley and Sons; New York: 1981
  Search in Google Scholar
• 1b Fernández I, Khiar N. Arylsulfonium Salts and Derivatives . In Science of Synthesis, Vol. 31a. Ramsden CA. Thieme; Stuttgart: 2007: 1001
  Search in Google Scholar
• 1c Kaiser D, Klose I, Oost R, Neuhaus J, Maulide N. Chem. Rev. 2019; 119: 8701
  CrossrefPubMedSearch in Google Scholar
• 2a Huang Y, Gao Y, He W, Wang Z, Li W, Lin A, Xu J, Tanabe G, Muraoka O, Wu X, Xie W. Angew. Chem. Int. Ed. 2019; 58: 6400
  CrossrefPubMedSearch in Google Scholar
• 2b Quadri M, Stokes C, Gulsevin A, Felts AC. J, Abboud KA, Papke RL, Horenstein NA. J. Med. Chem. 2017; 60: 7928
  CrossrefPubMedSearch in Google Scholar

Selected examples:
• 3a Shimomura O, Tomita I, Endo T. J. Polym. Sci., Part A: Polym. Chem. 2001; 39: 3928
  CrossrefSearch in Google Scholar
• 3b Shiraishi Y, Tachibana K, Hirai T, Komasawa I. Ind. Eng. Chem. Res. 2002; 41: 5554
  CrossrefSearch in Google Scholar
• 3c Nakano K, Iwasa S, Maeda K, Hasegawa E. J. Photopolym. Sci. Technol. 2001; 14: 357
  CrossrefSearch in Google Scholar
• 3d Wu X, Malval J, Wan D, Jin M. Dyes Pigm. 2016; 132: 128
  CrossrefSearch in Google Scholar
• 3e Imamura R, Mori H. Biomacromolecules 2019; 20: 904
  CrossrefPubMedSearch in Google Scholar
• 3f Zhu D, Yan H, Liu X, Xiang J, Zhou Z, Tang J, Liu X, Shen Y. Adv. Funct. Mater. 2017; 27: 1606826
  CrossrefSearch in Google Scholar
• 3g Matsumoto H, Matsuda T, Miyazaki Y. Chem. Lett. 2000; 29: 1430
  CrossrefSearch in Google Scholar
• 3h Kaneko S, Kumatabara Y, Shimizu S, Maruoka K, Shirakawa S. Chem. Commun. 2017; 53: 119
  CrossrefPubMedSearch in Google Scholar
• 3i Yi L, Shi J, Gao S, Li S, Niu C, Xi Z. Tetrahedron Lett. 2009; 50: 759
  CrossrefSearch in Google Scholar
• 4a Zhang Q, van der Donk WA, Liu W. Acc. Chem. Res. 2012; 45: 555
  CrossrefPubMedSearch in Google Scholar
• 4b Salvatore F, Borek E, Zappia V, Williams-Ashman HG, Schlenk F. The Biochemistry of Adenosylmethionine . Columbia University Press; New York: 1977
  Search in Google Scholar
• 5a Oost R, Neuhaus JD, Merad J, Maulide N. Modern Ylide Chemistry . In Structure and Bonding, Vol. 177. Gessner VH. Springer; Cham: 2017: 73-115
  Search in Google Scholar
• 5b Lu L.-Q, Li T.-R, Wang Q, Xiao W.-J. Chem. Soc. Rev. 2017; 46: 4135
  CrossrefPubMedSearch in Google Scholar
• 5c Lin J.-H, Xiao J.-C. Acc. Chem. Res. 2020; 53: 1498
  CrossrefPubMedSearch in Google Scholar
• 5d Yanagi T, Nogi K, Yorimitsu H. Tetrahedron Lett. 2018; 59: 2951
  CrossrefSearch in Google Scholar
• 5e Zhang Y, Wang J. Coord. Chem. Rev. 2010; 254: 941
  CrossrefSearch in Google Scholar
• 5f Liu Y, Ling Y, Ge H, Lu L, Shen Q. Chin. J. Chem. 2021; 39: 1667
  CrossrefSearch in Google Scholar
• 5g Jana S, Guo Y, Koenigs RM. Chem. Eur. J. 2021; 27: 1270
  Search in Google Scholar
• 5h Yorimitsu H. Chem. Rec. 2017; 17: 1156
  CrossrefPubMedSearch in Google Scholar
• 5i Shafir A. Tetrahedron Lett. 2016; 57: 2673
  CrossrefSearch in Google Scholar
• 5j Meng L, Zeng J, Wan Q. Synlett 2018; 29: 148
  Thieme ConnectSearch in Google Scholar
• 5k Li P. Synlett 2021; 32: 1275
  Thieme ConnectSearch in Google Scholar
• 5l Zhang L, Hu M, Peng B. Synlett 2019; 30: 2203
  Thieme ConnectSearch in Google Scholar

Selected paper and reviews:
• 6a Ni C, Hu M, Hu J. Chem. Rev. 2015; 115: 765
  CrossrefPubMedSearch in Google Scholar
• 6b Wang S.-M, Han J.-B, Zhang C.-P, Qin H.-L, Xiao J.-C. Tetrahedron 2015; 71: 7949
  CrossrefSearch in Google Scholar
• 6c Zhang C. Org. Biomol. Chem. 2014; 12: 6580
  CrossrefPubMedSearch in Google Scholar
• 6d Prakash GK. S, Weber C, Chacko S, Olah GA. Org. Lett. 2007; 9: 1863
  CrossrefPubMedSearch in Google Scholar
• 6e Lu S.-L, Qin W.-B, Liu J.-J, Huang Y.-Y, Wong HN. C, Liu G.-K. Org. Lett. 2018; 20: 6925
  CrossrefPubMedSearch in Google Scholar
• 6f Melngaile R, Veliks J. Synthesis 2021; 53: 4549
  Thieme ConnectSearch in Google Scholar
• 6g Koike T, Akita M. Acc. Chem. Res. 2016; 49: 1937
  CrossrefPubMedSearch in Google Scholar

Selected examples:
• 7a Wang D, Carlton CG, Tayu M, McDouall JJ. W, Perry GJ. P, Procter DJ. Angew. Chem. Int. Ed. 2020; 59: 15918
  CrossrefPubMedSearch in Google Scholar
• 7b Faizi DJ, Davis AJ, Meany FB, Blum SA. Angew. Chem. Int. Ed. 2016; 55: 14286
  CrossrefPubMedSearch in Google Scholar
• 7c Luo K, Yang W.-C, Wei K, Liu Y, Wang J.-K, Wu L. Org. Lett. 2019; 21: 7851
  CrossrefPubMedSearch in Google Scholar
• 7d Yang K, Zhang H, Niu B, Tang T, Ge H. Eur. J. Org. Chem. 2018; 5520
  Crossref
• 7e Zhang Q, Liu X, Xin X, Zhang R, Liang Y, Dong D. Chem. Commun. 2014; 50: 15378
  CrossrefPubMedSearch in Google Scholar
• 7f Leypold M, D’Angelo KA, Movassaghi M. Org. Lett. 2020; 22: 8802
  CrossrefPubMedSearch in Google Scholar
• 7g Zhang L, Nagaraju S, Paplal B, Lin Y, Liu S. Eur. J. Org. Chem. 2021; 1365
  Crossref
• 7h Kawashima H, Yanagi T, Wu C.-C, Nogi K, Yorimitsu H. Org. Lett. 2017; 19: 4552
  CrossrefPubMedSearch in Google Scholar
• 7i Zhang Z, He P, Du H, Xu J, Li P. J. Org. Chem. 2019; 84: 4517
  CrossrefPubMedSearch in Google Scholar
• 8a Lou J, Wang Q, Wu P, Wang H, Zhou Y.-G, Yu Z. Chem. Soc. Rev. 2020; 49: 4307
  CrossrefPubMedSearch in Google Scholar
• 8b Kozhushkov SI, Alcarazo M. Eur. J. Inorg. Chem. 2020; 2020: 2486
  CrossrefPubMedSearch in Google Scholar
• 8c Fan R, Tan C, Liu Y, Wei Y, Zhao X, Liu X, Tan J, Yoshida H. Chin. Chem. Lett. 2021; 32: 299
  CrossrefSearch in Google Scholar
• 8d Péter Á, Perry GJ. P, Procter DJ. Adv. Synth. Catal. 2020; 362: 2135
  CrossrefSearch in Google Scholar
• 8e Tian Z.-Y, Hu Y.-T, Teng H.-B, Zhang C.-P. Tetrahedron Lett. 2018; 59: 299
  CrossrefSearch in Google Scholar
• 8f Otsuka S, Nogi K, Yorimitsu H. Top. Curr. Chem. 2018; 376: 13
  CrossrefPubMedSearch in Google Scholar
• 8g Yorimitsu H. Chem. Rec. 2021; 21: 1
  CrossrefPubMedSearch in Google Scholar

Selected examples:
• 9a Bosshard H. Helv. Chim. Acta 1972; 55: 37
  CrossrefSearch in Google Scholar
• 9b Braun H, Amann A. Angew. Chem. Int. Ed. Engl. 1975; 14: 755
  CrossrefSearch in Google Scholar
• 9c Tanikaga R, Hiraki Y, Ono N, Kaji A. J. Chem. Soc., Chem. Commun. 1980; 41
  Crossref
• 9d Shiraishi Y, Taki Y, Hirai T, Komasawa I. Ind. Eng. Chem. Res. 2001; 40: 1213
  CrossrefSearch in Google Scholar
• 9e Song H.-X, Wang S.-M, Wang X.-Y, Han J.-B, Gao Y, Jia S.-J, Zhang C.-P. J. Fluorine Chem. 2016; 192: 131
  CrossrefPubMedSearch in Google Scholar
• 9f Tian Z.-Y, Zhang C.-P. Chem. Commun. 2019; 55: 11936
  CrossrefPubMedSearch in Google Scholar
• 9g Altundas B, Kumar CV. S, Fleming FF. ACS Omega 2020; 5: 13384
  CrossrefPubMedSearch in Google Scholar
• 9h Miyatake K, Yamamoto K, Endo K, Tsuchida E. J. Org. Chem. 1998; 63: 7522
  CrossrefPubMedSearch in Google Scholar

Selected pioneer works:
• 10a Yamauchi K, Tanabe T, Kinoshita M. J. Org. Chem. 1979; 44: 638
  CrossrefSearch in Google Scholar
• 10b Badet B, Julia M, Ramirez-Muñoz M. Synthesis 1980; 926
  Thieme Connect
• 10c Coward JK, Sweet WD. J. Org. Chem. 1971; 36: 2337
  CrossrefSearch in Google Scholar
• 10d Garst ME, McBride BJ. J. Org. Chem. 1983; 48: 1362
  CrossrefSearch in Google Scholar
• 10e Kim S, Park JH, Kim YG, Lee JM. J. Chem. Soc., Chem. Commun. 1993; 1188
  Crossref
• 10f Liu B, Shine HJ. J. Phys. Org. Chem. 2001; 14: 81
  CrossrefSearch in Google Scholar
• 10g Umemura K, Matsuyama H, Watanabe N, Kobayashi M, Kamigata N. J. Org. Chem. 1989; 54: 2374
  CrossrefSearch in Google Scholar
• 10h Matsuyama H, Nakamura T, Kamigata N. J. Org. Chem. 1989; 54: 5218
  CrossrefSearch in Google Scholar
• 10i Umemura K, Matsuyama H, Kamigata N. Bull. Chem. Soc. Jpn. 1990; 63: 2593
  CrossrefSearch in Google Scholar
• 10j Umemura K, Matsuyama H, Kobayashi M, Kamigata N. Bull. Chem. Soc. Jpn. 1989; 62: 3026
  CrossrefSearch in Google Scholar
• 10k Uyehara T, Ohnuma T, Saito T, Kato T, Yoshida T, Takahashi K. J. Chem. Soc., Chem. Commun. 1981; 127
  Crossref
• 10l Kobayashi M, Umemura K, Matsuyama H. Chem. Lett. 1987; 16: 327
  CrossrefSearch in Google Scholar
• 10m Butte W, Eilers J, Kirsch M. Anal. Lett. 1982; 15: 841
  CrossrefSearch in Google Scholar
• 10n Trost BM, Schinski WL, Chen F, Mantz IB. J. Am. Chem. Soc. 1971; 93: 676
  CrossrefSearch in Google Scholar
• 10o Laali KK, Chun J.-H, Okazaki T. J. Org. Chem. 2007; 72: 8383
  CrossrefPubMedSearch in Google Scholar
• 10p Dorn H. Angew. Chem. Int. Ed. Engl. 1967; 6: 371
  CrossrefSearch in Google Scholar
• 10q Hyne JB, Golinkin HS. Can. J. Chem. 1963; 41: 3139
  CrossrefSearch in Google Scholar
• 10r Cooper KA, Dhar ML, Hughes ED, Ingold CK, MacNulty BJ, Woolf LI. J. Chem. Soc. 1948; 2043
  Crossref
• 10s Pickersgill IF, Marchington AP, Rayner CM. J. Chem. Soc., Chem. Commun. 1994; 2597
  Crossref
• 10t Takuwa T, Onishi JY, Matsuo J.-I, Mukaiyama T. Chem. Lett. 2004; 33: 8
  CrossrefSearch in Google Scholar
• 11a Lampard C, Murphy JA, Lewis N. J. Chem. Soc., Chem. Commun. 1993; 295
  Crossref
• 11b Fletcher RJ, Lampard C, Murphy JA, Lewis N. J. Chem. Soc., Perkin Trans. 1 1995; 623
  Crossref
• 11c Kizil M, Lampard C, Murphy JA. Tetrahedron Lett. 1996; 37: 2511
  CrossrefSearch in Google Scholar
• 11d Murphy JA, Rasheed F, Roome SJ, Lewis N. Chem. Commun. 1996; 737
  Crossref
• 11e Murphy JA, Rasheed F, Roome SJ, Scott KA, Lewis N. J. Chem. Soc., Perkin Trans. 1 1998; 2331
  Crossref
• 11f Patro B, Merrett M, Murphy JA, Sherrington DC, Morrison MG. J. T. Tetrahedron Lett. 1999; 40: 7857
  CrossrefSearch in Google Scholar
• 11g Patro B, Merrett MC, Makin SD, Murphy JA, Parkes KE. B. Tetrahedron Lett. 2000; 41: 421
  CrossrefSearch in Google Scholar
• 11h Bashir N, Murphy JA. Chem. Commun. 2000; 46: 627
  CrossrefSearch in Google Scholar
• 11i Callaghan O, Franck X, Murphy JA. Chem. Commun. 1997; 1923
  Crossref
• 12 Yamauchi K, Hisanaga Y, Kinoshita M. Synthesis 1980; 852
  Thieme Connect
• 13a Wang M, Zhao Y, Zhao Y, Shi Z. Sci. Adv. 2020; 6: eaba0946
  CrossrefPubMedSearch in Google Scholar
• 13b Zhang Z, Wen J, Wang M, Yan C.-G, Shi Z. Green Synth. Catal. 2021; 2: 275
  CrossrefSearch in Google Scholar
• 13c Aggarwal VK, Harvey JN, Robiette R. Angew. Chem. Int. Ed. 2005; 44: 5468
  CrossrefPubMedSearch in Google Scholar
• 13d Aggarwal VK, Fang GY, Schmidt AT. J. Am. Chem. Soc. 2005; 127: 1642
  CrossrefPubMedSearch in Google Scholar
• 13e Fang GY, Wallner OA, Di Blasio N, Ginesta X, Harvey JN, Aggarwal VK. J. Am. Chem. Soc. 2007; 129: 14632
  CrossrefPubMedSearch in Google Scholar
• 13f Fang GY, Aggarwal VK. Angew. Chem. Int. Ed. 2007; 46: 359
  CrossrefPubMedSearch in Google Scholar
• 13g He Z, Song F, Sun H, Huang Y. J. Am. Chem. Soc. 2018; 140: 2693
  CrossrefPubMedSearch in Google Scholar
• 14 Eliel EL, Hutchins RO, Mebane R, Willer RL. J. Org. Chem. 1976; 41: 1052
  CrossrefSearch in Google Scholar
• 15 Palmer DC, Taylor EC. J. Org. Chem. 1986; 51: 846
  CrossrefSearch in Google Scholar
• 16 Stará IG, Starý I, Tichý M, Závada J, Fiedler P. J. Org. Chem. 1994; 59: 1326
  CrossrefSearch in Google Scholar
• 17a Jagannathan S, Forsyth TP, Kettner CA. J. Org. Chem. 2001; 66: 6375
  CrossrefPubMedSearch in Google Scholar
• 17b Ray FE, Levine R. J. Org. Chem. 1937; 2: 267
  CrossrefSearch in Google Scholar

Selected literature:
• 18a Denmark SE, Vogler T. Chem. Eur. J. 2009; 15: 11737
  CrossrefPubMedSearch in Google Scholar
• 18b Sromek AW, Gevorgyan V. Top. Curr. Chem. 2007; 274: 77
  CrossrefSearch in Google Scholar
• 18c Smit WA, Caple R, Smoliakova IP. Chem. Rev. 1994; 94: 2359
  CrossrefSearch in Google Scholar
• 18d Adams, E. J.; Oscarson, S. Dimethyl(methylthio)sulfonium Tetrafluoroborate, In e-EROS Encyclopedia of Reagents for Organic Synthesis [Online]; Wiley & Sons, Posted October 15, 2005.
• 18e Denmark SE, Collins WR, Cullen MD. J. Am. Chem. Soc. 2009; 131: 3490
  CrossrefPubMedSearch in Google Scholar
• 18f Trost BM, Shibata T. J. Am. Chem. Soc. 1982; 104: 3225
  CrossrefSearch in Google Scholar
• 18g Denmark SE, Jaunet A. J. Am. Chem. Soc. 2013; 135: 6419
  CrossrefPubMedSearch in Google Scholar
• 18h Roth A, Denmark SE. J. Am. Chem. Soc. 2019; 141: 13767
  CrossrefPubMedSearch in Google Scholar
• 18i Lin S, Jacobsen EN. Nat. Chem. 2012; 4: 817
  CrossrefPubMedSearch in Google Scholar
• 18j Luo J, Zhu Z, Liu Y, Zhao X. Org. Lett. 2015; 17: 3620
  CrossrefPubMedSearch in Google Scholar
• 18k An R, Liao L, Liu X, Song S, Zhao X. Org. Chem. Front. 2018; 5: 3557
  CrossrefSearch in Google Scholar
• 18l Shen F, Lu L, Shen Q. Chem. Sci. 2020; 11: 8020
  CrossrefPubMedSearch in Google Scholar
• 18m Tang M, Han S, Huang S, Huang S, Xie L.-G. Org. Lett. 2020; 22: 9729
  CrossrefPubMedSearch in Google Scholar
• 19a Matsuyama H, Nakamura T, Iyoda M. Chem. Lett. 1994; 23: 1537
  CrossrefSearch in Google Scholar
• 19b Matsuyama H, Nakamura T, Iyoda M. J. Org. Chem. 2000; 65: 4796
  CrossrefPubMedSearch in Google Scholar
• 20a Miyata O, Fujiwara Y, Ninomiya I, Naito T. J. Chem. Soc., Perkin Trans. 1 1993; 2861
  Crossref
• 20b Jensen KL, Nielsen DU, Jamison TF. Chem. Eur. J. 2015; 21: 7379
  CrossrefPubMedSearch in Google Scholar
• 21a Inagaki S, Ukaku M, Chiba A, Takahashi F, Yoshimi Y, Morita T, Kawano T. J. Org. Chem. 2016; 81: 8363
  CrossrefPubMedSearch in Google Scholar
• 21b Inagaki S, Saito K, Suto S, Aihara H, Sugawara A, Tamura S, Kawano T. J. Org. Chem. 2018; 83: 13834
  CrossrefPubMedSearch in Google Scholar
• 21c Inagaki S, Nakazato M, Fukuda N, Tamura S, Kawano T. J. Org. Chem. 2017; 82: 5583
  CrossrefPubMedSearch in Google Scholar
• 21d Inagaki S, Sato A, Sato H, Tamura S, Kawano T. Tetrahedron Lett. 2017; 58: 4872
  CrossrefSearch in Google Scholar
• 22 Chen J, Palani V, Hoye TR. J. Am. Chem. Soc. 2016; 138: 4318
  CrossrefPubMedSearch in Google Scholar
• 23a Zheng T, Tan J, Fan R, Su S, Liu B, Tan C, Xu K. Chem. Commun. 2018; 54: 1303
  CrossrefPubMedSearch in Google Scholar
• 23b Jian H, Wang Q, Wang W.-H, Li Z.-J, Gu C.-Z, Dai B, He L. Tetrahedron 2018; 74: 2876
  CrossrefSearch in Google Scholar
• 24 López-Alled CM, Martin FJ. O, Chen K.-Y, Kociok-Köhn G, James TD, Wenk J, Lewis SE. Tetrahedron 2020; 76: 131700
  CrossrefSearch in Google Scholar
• 25 Gupta R, Mandal D, Jaiswal AK, Young RD. Org. Lett. 2021; 23: 1915
  CrossrefPubMedSearch in Google Scholar
• 26a Shine HJ, Bandlish BK, Mani SR, Padilla AG. J. Org. Chem. 1979; 44: 915
  CrossrefSearch in Google Scholar
• 26b Iwai K, Shine HJ. J. Org. Chem. 1981; 46: 271
  CrossrefSearch in Google Scholar
• 26c Lee WK, Liu B, Park CW, Shine HJ, Guzman-Jimenez IY, Whitmire KH. J. Org. Chem. 1999; 64: 9206
  CrossrefSearch in Google Scholar
• 26d Qian D.-Q, Shine HJ, Guzman-Jimenez IY, Thurston JH, Whitmire KH. J. Org. Chem. 2002; 67: 4030
  CrossrefPubMedSearch in Google Scholar
• 27a Houmam A, Shukla D, Kraatz H.-B, Wayner DD. M. J. Org. Chem. 1999; 64: 3342
  CrossrefPubMedSearch in Google Scholar
• 27b Holst DE, Wang DJ, Kim MJ, Guzei IA, Wickens ZK. Nature 2021; 596: 74
  CrossrefPubMedSearch in Google Scholar
• 28a Yamanaka H, Matsuo J, Kawana A, Mukaiyama T. Chem. Lett. 2003; 32: 626
  CrossrefSearch in Google Scholar
• 28b Matsuo J.-I, Yamanaka H, Kawana A, Mukaiyama T. Chem. Lett. 2003; 32: 392
  CrossrefSearch in Google Scholar
• 29a Zhang Z, Du H, Xu J, Li P. Chem. Commun. 2016; 52: 11547
  CrossrefPubMedSearch in Google Scholar
• 29b Luo H, Hu G, Li P. J. Org. Chem. 2019; 84: 10569
  CrossrefPubMedSearch in Google Scholar
• 30a McGarrigle EM, Myers EL, Illa O, Shaw MA, Riches SL, Aggarwal VK. Chem. Rev. 2007; 107: 5841
  CrossrefPubMedSearch in Google Scholar
• 30b Rao JS, Brière J.-F, Metzner P, Basavaiah D. Tetrahedron Lett. 2006; 47: 3553
  CrossrefSearch in Google Scholar
• 30c Myers EL, de Vries JG, Aggarwal VK. Angew. Chem. Int. Ed. 2007; 46: 1893
  CrossrefPubMedSearch in Google Scholar
• 30d Kinoshita H, Osamura T, Kinoshita S, Iwamura T, Watanabe S.-I, Kataoka T, Tanabe G, Muraoka O. J. Org. Chem. 2003; 68: 7532
  CrossrefPubMedSearch in Google Scholar
• 30e Basavaiah D, Muthukumaran K, Sreenivasulu B. Synlett 1999; 1249
  Thieme Connect
• 30f Bauer T, Tarasiuk J. Tetrahedron: Asymmetry 2001; 12: 1741
  CrossrefSearch in Google Scholar
• 30g Park J, Kawatkar S, Kim J.-H, Boons G.-J. Org. Lett. 2007; 9: 1959
  CrossrefPubMedSearch in Google Scholar
• 30h Kataoka T, Iwama T, Kinoshita H, Tsujiyama S, Tsurukami Y, Iwamura T, Watanabe S. Synlett 1999; 197
  Thieme Connect
• 30i Kataoka T, Iwama T, Tsujiyama S.-I, Kanematsu K, Iwamura T, Watanabe S.-I. Chem. Lett. 1999; 28: 257
  CrossrefSearch in Google Scholar
• 30j Kataoka T, Iwama T, Tsujiyama S.-I, Iwamura T, Watanabe S.-I. Tetrahedron 1998; 54: 11813
  CrossrefSearch in Google Scholar
• 30k Kataoka T, Iwama T, Tsujiyama S.-I. Chem. Commun. 1998; 197
  Crossref
• 30l Walsh LM, Winn CL, Goodman JM. Tetrahedron Lett. 2002; 43: 8219
  CrossrefSearch in Google Scholar
• 30m Lee K, Kim H, Miura T, Kiyota K, Kusama H, Kim S, Iwasawa N, Lee PH. J. Am. Chem. Soc. 2003; 125: 9682
  CrossrefPubMedSearch in Google Scholar
• 30n Kim S, Lee BS, Park JH. Bull. Korean Chem. Soc. 1993; 14: 654
  Search in Google Scholar
• 31a Zhang Z, Luo Y, Du H, Xu J, Li P. Chem. Sci. 2019; 10: 5156
  CrossrefPubMedSearch in Google Scholar
• 31b Zhang Z, Li P. Tetrahedron Lett. 2020; 61: 151707
  CrossrefSearch in Google Scholar
• 31c Nenajdenko VG, Vertelezkij PV, Balenkova ES. Synthesis 1997; 351
  Thieme Connect
• 31d Fernández-Salas JA, Eberhart AJ, Procter DJ. J. Am. Chem. Soc. 2016; 138: 790
  CrossrefPubMedSearch in Google Scholar
• 31e Hu G, Xu J, Li P. Org. Chem. Front. 2018; 5: 2167
  CrossrefSearch in Google Scholar
• 32a Guo W, Luo Y, Sung HH.-Y, Williams ID, Li P, Sun J. J. Am. Chem. Soc. 2020; 142: 14384
  CrossrefPubMedSearch in Google Scholar
• 32b Fang J, Li T, Ma X, Sun J, Cai L, Chen Q, Liao Z, Meng L, Zeng J, Wan Q. Chin. Chem. Lett. 2021; in press, DOI:
  Crossref
• 33a Kawasaki T, Suzuki H, Sakata I, Nakanishi H, Sakamoto M. Tetrahedron Lett. 1997; 38: 3251
  CrossrefSearch in Google Scholar
• 33b Higuchi K, Tayu M, Kawasaki T. Chem. Commun. 2011; 47: 6728
  CrossrefPubMedSearch in Google Scholar
• 33c Tayu M, Higuchi K, Inaba M, Kawasaki T. Org. Biomol. Chem. 2013; 11: 496
  CrossrefPubMedSearch in Google Scholar
• 33d Tayu M, Higuchi K, Ishizaki T, Kawasaki T. Org. Lett. 2014; 16: 3613
  CrossrefPubMedSearch in Google Scholar
• 33e Tayu M, Ishizaki T, Higuchi K, Kawasaki T. Org. Biomol. Chem. 2015; 13: 3863
  CrossrefPubMedSearch in Google Scholar
• 33f Tayu M, Suzuki Y, Higuchi K, Kawasaki T. Synlett 2016; 27: 941
  Thieme ConnectSearch in Google Scholar
• 33g Tayu M, Hui Y, Takeda S, Higuchi K, Saito N, Kawasaki T. Org. Lett. 2017; 19: 6582
  CrossrefPubMedSearch in Google Scholar
• 33h Tayu M, Nomura K, Kawachi K, Higuchi K, Saito N, Kawasaki T. Chem. Eur. J. 2017; 23: 10925
  CrossrefPubMedSearch in Google Scholar
• 34a Yoshida S, Yorimitsu H, Oshima K. Org. Lett. 2009; 11: 2185
  CrossrefPubMedSearch in Google Scholar
• 34b Eberhart AJ, Imbriglio JE, Procter DJ. Org. Lett. 2011; 13: 5882
  CrossrefPubMedSearch in Google Scholar
• 34c Eberhart AJ, Cicoira C, Procter DJ. Org. Lett. 2013; 15: 3994
  CrossrefPubMedSearch in Google Scholar
• 34d Eberhart AJ, Procter DJ. Angew. Chem. Int. Ed. 2013; 52: 4008
  CrossrefPubMedSearch in Google Scholar
• 34e Eberhart AJ, Shrives HJ, Álvarez E, Carrër A, Zhang Y, Procter DJ. Chem. Eur. J. 2015; 21: 7428
  CrossrefPubMedSearch in Google Scholar
• 34f Eberhart AJ, Shrives H, Zhang Y, Carrër A, Parry AV. S, Tate DJ, Turner ML, Procter DJ. Chem. Sci. 2016; 7: 1281
  CrossrefPubMedSearch in Google Scholar
• 34g Shrives HJ, Fernández-Salas JA, Hedtke C, Pulis AP, Procter DJ. Nat. Commun. 2017; 8: 14801
  CrossrefPubMedSearch in Google Scholar
• 34h He Z, Shrives HJ, Fernández-Salas JA, Abengózar A, Neufeld J, Yang K, Pulis AP, Procter DJ. Angew. Chem. Int. Ed. 2018; 57: 5759
  CrossrefPubMedSearch in Google Scholar
• 34i Šiaučiulis M, Sapmaz S, Pulis AP, Procter DJ. Chem. Sci. 2018; 9: 754
  CrossrefPubMedSearch in Google Scholar
• 34j Yan J, Pulis AP, Perry GJ. P, Procter DJ. Angew. Chem. Int. Ed. 2019; 58: 15675
  CrossrefPubMedSearch in Google Scholar
• 35a Badet B, Julia M, Ramirez-Munoz M, Sarrazin A. Tetrahedron 1983; 39: 3111
  CrossrefSearch in Google Scholar
• 35b Julia M, Mestdagh H, Rolando C. Tetrahedron 1986; 42: 3841
  CrossrefSearch in Google Scholar
• 35c Sedighi M, Çalimsiz S, Lipton MA. J. Org. Chem. 2006; 71: 9517
  CrossrefPubMedSearch in Google Scholar
• 35d Hostetler MA, Lipton MA. J. Org. Chem. 2018; 83: 7762
  CrossrefPubMedSearch in Google Scholar
• 36 Srogl J, Allred GD, Liebeskind LS. J. Am. Chem. Soc. 1997; 119: 12376
  CrossrefSearch in Google Scholar
• 37 Liu Y.-Y, Yang X.-H, Huang X.-C, Wei W.-T, Song R.-J, Li J.-H. J. Org. Chem. 2013; 78: 10421
  CrossrefPubMedSearch in Google Scholar
• 38 Simkó DC, Elekes P, Pázmándi V, Novák Z. Org. Lett. 2018; 20: 676
  CrossrefPubMedSearch in Google Scholar
• 39 He Y, Huang Z, Ma J, Huang F, Lin J, Wang H, Xu B.-H, Zhou Y.-G, Yu Z. Org. Lett. 2021; 23: 6110
  CrossrefPubMedSearch in Google Scholar
• 40a Minami H, Nogi K, Yorimitsu H. Synlett 2021; 32: 1542
  Thieme ConnectSearch in Google Scholar
• 40b Aukland MH, Talbot FJ. T, Fernández-Salas JA, Ball M, Pulis AP, Procter DJ. Angew. Chem. Int. Ed. 2018; 57: 9785
  CrossrefPubMedSearch in Google Scholar
• 41a Donck S, Baroudi A, Fensterbank L, Goddard J.-P, Ollivier C. Adv. Synth. Catal. 2013; 355: 1477
  CrossrefSearch in Google Scholar
• 41b Berger F, Plutschack MB, Riegger J, Yu W, Speicher S, Ho M, Frank N, Ritter T. Nature 2019; 567: 223
  CrossrefPubMedSearch in Google Scholar
• 41c Ye F, Berger F, Jia H, Ford J, Wortman A, Borgel J, Genicot C, Ritter T. Angew. Chem. Int. Ed. 2019; 58: 14615
  CrossrefPubMedSearch in Google Scholar
• 41d Sang R, Korkis SE, Su W, Ye F, Engl PS, Berger F, Ritter T. Angew. Chem. Int. Ed. 2019; 58: 16161
  CrossrefPubMedSearch in Google Scholar
• 41e Engl PS, Haering AP, Berger F, Berger G, Perez-Bitrian A, Ritter T. J. Am. Chem. Soc. 2019; 141: 13346
  CrossrefPubMedSearch in Google Scholar
• 41f Huang C, Feng J, Ma R, Fang S, Lu T, Tang W, Du D, Gao J. Org. Lett. 2019; 21: 9688
  CrossrefPubMedSearch in Google Scholar
• 41g Li J, Chen J, Sang R, Ham W.-S, Plutschack MB, Berger F, Chabbra S, Schnegg A, Genicot C, Ritter T. Nat. Chem. 2020; 12: 56
  CrossrefPubMedSearch in Google Scholar
• 41h Aukland MH, Siauciulis M, West A, Perry GJ. P, Procter DJ. Nat. Catal. 2020; 3: 163
  CrossrefSearch in Google Scholar
• 41i Wu J, Wang Z, Chen X.-Y, Wu Y, Wang D, Peng Q, Wang P. Sci. China: Chem. 2020; 63: 336
  CrossrefSearch in Google Scholar
• 42a van Bergen TJ, Kellogg RM. J. Am. Chem. Soc. 1976; 98: 1962
  CrossrefPubMedSearch in Google Scholar
• 42b Beak P, Sullivan TA. J. Am. Chem. Soc. 1982; 104: 4450
  CrossrefSearch in Google Scholar
• 42c Kataoka T, Tsutsumi K, Kano K, Mori K, Miyake M, Yokota M, Shimizu H, Hori M. J. Chem. Soc., Perkin Trans. 1 1990; 3017
  Crossref
• 42d Kataoka T, Iwama T, Shimizu H, Hori M. Phosphorus, Sulfur Silicon Relat. Elem. 1992; 67: 169
  CrossrefSearch in Google Scholar

Selected examples:
• 43a Saeva FD, Morgan BP. J. Am. Chem. Soc. 1984; 106: 4121
  CrossrefSearch in Google Scholar
• 43b Andrieux CP, Robert M, Saeva FD, Savéant J.-M. J. Am. Chem. Soc. 1994; 116: 7864
  CrossrefSearch in Google Scholar
• 43c Ghanimi A, Simonet J. New J. Chem. 1997; 21: 257
  Search in Google Scholar
• 44a Hedstrand DM, Kruizinga WH, Kellogg RM. Tetrahedron Lett. 1978; 17: 1255
  CrossrefSearch in Google Scholar
• 44b van Bergen TJ, Hedstrand DM, Kruizinga WH, Kellogg RM. J. Org. Chem. 1979; 44: 4953
  CrossrefSearch in Google Scholar
• 44c Saeva FD, Breslin DT, Luss HR. J. Am. Chem. Soc. 1991; 113: 5333
  CrossrefSearch in Google Scholar
• 44d Wang X, Saeva FD, Kampmeier JA. J. Am. Chem. Soc. 1999; 121: 4364
  CrossrefSearch in Google Scholar
• 44e Kampmeier JA, Hoque AK. M. M, Saeva FD, Wedegaertner DK, Thomsen P, Ullah S, Krake J, Lund T. J. Am. Chem. Soc. 2009; 131: 10015
  CrossrefPubMedSearch in Google Scholar
• 45 Otsuka S, Nogi K, Rovis T, Yorimitsu H. Chem. Asian J. 2019; 14: 532
  CrossrefPubMedSearch in Google Scholar
• 46 Varga B, Gonda Z, Tóth BL, Kotschy A, Novák Z. Eur. J. Org. Chem. 2020; 1466
  Crossref
• 47 Chen C, Wang Z.-J, Lu H, Zhao Y, Shi Z. Nat. Commun. 2021; 12: 4526
  CrossrefPubMedSearch in Google Scholar
• 48 Chen C, Wang M, Lu H, Zhao B, Shi Z. Angew. Chem. Int. Ed. 2021; 60: 21756
  CrossrefPubMedSearch in Google Scholar
• 49a Shibutani S, Kodo T, Takeda M, Nagao K, Tokunago N, Sasaki Y, Ohimiya H. J. Am. Chem. Soc. 2020; 142: 1211
  CrossrefPubMedSearch in Google Scholar
• 49b Nakagawa M, Nagao K, Ikeda Z, Reynolds M, Ibáñez I, Wang J, Tokunaga N, Sasaki Y, Ohmiya H. ChemCatChem 2021; 13: 3930
  CrossrefSearch in Google Scholar
• 49c Kobayashi R, Shibutani S, Nagao K, Ikeda Z, Wang J, Ibáñez I, Reynolds M, Sasaki Y, Ohmiya H. Org. Lett. 2021; 23: 5415
  CrossrefPubMedSearch in Google Scholar
• 49d Shibutani S, Nagao K, Ohmiya H. Org. Lett. 2021; 23: 1798
  CrossrefPubMedSearch in Google Scholar

Examples of use of aryl alkyl sulfonium salts as arylation reagents rather than alkylation ones:
• 50a Wang S.-M, Wang X.-Y, Qin H.-L, Zhang C.-P. Chem. Eur. J. 2016; 22: 6542
  CrossrefPubMedSearch in Google Scholar
• 50b Wang X.-Y, Song H.-X, Wang S.-M, Yang J, Qin H.-L, Jiang X, Zhang C.-P. Tetrahedron 2016; 72: 7606
  CrossrefSearch in Google Scholar
• 50c Wang S.-M, Song H.-X, Wang X.-Y, Liu N, Qin H.-L, Zhang C.-P. Chem. Commun. 2016; 52: 11893
  CrossrefPubMedSearch in Google Scholar
• 50d Tian Z.-Y, Wang S.-M, Jia S.-J, Song H.-X, Zhang C.-P. Org. Lett. 2017; 19: 5454
  CrossrefPubMedSearch in Google Scholar
• 50e See ref. 9f.
• 50f Ming X.-X, Wu S, Tian Z.-Y, Song J.-W, Zhang C.-P. Org. Lett. 2021; 23: 6795
  CrossrefPubMedSearch in Google Scholar
• 50g Minami H, Otsuka S, Nogi K, Yorimitsu H. ACS Catal. 2018; 8: 579
  CrossrefSearch in Google Scholar
• 50h Zhao J.-N, Kayumov M, Wang D.-Y, Zhang A. Org. Lett. 2019; 21: 7303
  CrossrefPubMedSearch in Google Scholar

Corresponding Author

Publication History

Received: 30 September 2021

Accepted after revision: 25 October 2021

Accepted Manuscript online:
25 October 2021

Article published online:
12 January 2022

© 2021. Thieme. All rights reserved

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

• References

• 1a Stirling CJ. M, Patai S. The Chemistry of the Sulfonium Group, Part 1 and Part 2. John Wiley and Sons; New York: 1981
  Search in Google Scholar
• 1b Fernández I, Khiar N. Arylsulfonium Salts and Derivatives . In Science of Synthesis, Vol. 31a. Ramsden CA. Thieme; Stuttgart: 2007: 1001
  Search in Google Scholar
• 1c Kaiser D, Klose I, Oost R, Neuhaus J, Maulide N. Chem. Rev. 2019; 119: 8701
  CrossrefPubMedSearch in Google Scholar
• 2a Huang Y, Gao Y, He W, Wang Z, Li W, Lin A, Xu J, Tanabe G, Muraoka O, Wu X, Xie W. Angew. Chem. Int. Ed. 2019; 58: 6400
  CrossrefPubMedSearch in Google Scholar
• 2b Quadri M, Stokes C, Gulsevin A, Felts AC. J, Abboud KA, Papke RL, Horenstein NA. J. Med. Chem. 2017; 60: 7928
  CrossrefPubMedSearch in Google Scholar

Selected examples:
• 3a Shimomura O, Tomita I, Endo T. J. Polym. Sci., Part A: Polym. Chem. 2001; 39: 3928
  CrossrefSearch in Google Scholar
• 3b Shiraishi Y, Tachibana K, Hirai T, Komasawa I. Ind. Eng. Chem. Res. 2002; 41: 5554
  CrossrefSearch in Google Scholar
• 3c Nakano K, Iwasa S, Maeda K, Hasegawa E. J. Photopolym. Sci. Technol. 2001; 14: 357
  CrossrefSearch in Google Scholar
• 3d Wu X, Malval J, Wan D, Jin M. Dyes Pigm. 2016; 132: 128
  CrossrefSearch in Google Scholar
• 3e Imamura R, Mori H. Biomacromolecules 2019; 20: 904
  CrossrefPubMedSearch in Google Scholar
• 3f Zhu D, Yan H, Liu X, Xiang J, Zhou Z, Tang J, Liu X, Shen Y. Adv. Funct. Mater. 2017; 27: 1606826
  CrossrefSearch in Google Scholar
• 3g Matsumoto H, Matsuda T, Miyazaki Y. Chem. Lett. 2000; 29: 1430
  CrossrefSearch in Google Scholar
• 3h Kaneko S, Kumatabara Y, Shimizu S, Maruoka K, Shirakawa S. Chem. Commun. 2017; 53: 119
  CrossrefPubMedSearch in Google Scholar
• 3i Yi L, Shi J, Gao S, Li S, Niu C, Xi Z. Tetrahedron Lett. 2009; 50: 759
  CrossrefSearch in Google Scholar
• 4a Zhang Q, van der Donk WA, Liu W. Acc. Chem. Res. 2012; 45: 555
  CrossrefPubMedSearch in Google Scholar
• 4b Salvatore F, Borek E, Zappia V, Williams-Ashman HG, Schlenk F. The Biochemistry of Adenosylmethionine . Columbia University Press; New York: 1977
  Search in Google Scholar
• 5a Oost R, Neuhaus JD, Merad J, Maulide N. Modern Ylide Chemistry . In Structure and Bonding, Vol. 177. Gessner VH. Springer; Cham: 2017: 73-115
  Search in Google Scholar
• 5b Lu L.-Q, Li T.-R, Wang Q, Xiao W.-J. Chem. Soc. Rev. 2017; 46: 4135
  CrossrefPubMedSearch in Google Scholar
• 5c Lin J.-H, Xiao J.-C. Acc. Chem. Res. 2020; 53: 1498
  CrossrefPubMedSearch in Google Scholar
• 5d Yanagi T, Nogi K, Yorimitsu H. Tetrahedron Lett. 2018; 59: 2951
  CrossrefSearch in Google Scholar
• 5e Zhang Y, Wang J. Coord. Chem. Rev. 2010; 254: 941
  CrossrefSearch in Google Scholar
• 5f Liu Y, Ling Y, Ge H, Lu L, Shen Q. Chin. J. Chem. 2021; 39: 1667
  CrossrefSearch in Google Scholar
• 5g Jana S, Guo Y, Koenigs RM. Chem. Eur. J. 2021; 27: 1270
  Search in Google Scholar
• 5h Yorimitsu H. Chem. Rec. 2017; 17: 1156
  CrossrefPubMedSearch in Google Scholar
• 5i Shafir A. Tetrahedron Lett. 2016; 57: 2673
  CrossrefSearch in Google Scholar
• 5j Meng L, Zeng J, Wan Q. Synlett 2018; 29: 148
  Thieme ConnectSearch in Google Scholar
• 5k Li P. Synlett 2021; 32: 1275
  Thieme ConnectSearch in Google Scholar
• 5l Zhang L, Hu M, Peng B. Synlett 2019; 30: 2203
  Thieme ConnectSearch in Google Scholar

Selected paper and reviews:
• 6a Ni C, Hu M, Hu J. Chem. Rev. 2015; 115: 765
  CrossrefPubMedSearch in Google Scholar
• 6b Wang S.-M, Han J.-B, Zhang C.-P, Qin H.-L, Xiao J.-C. Tetrahedron 2015; 71: 7949
  CrossrefSearch in Google Scholar
• 6c Zhang C. Org. Biomol. Chem. 2014; 12: 6580
  CrossrefPubMedSearch in Google Scholar
• 6d Prakash GK. S, Weber C, Chacko S, Olah GA. Org. Lett. 2007; 9: 1863
  CrossrefPubMedSearch in Google Scholar
• 6e Lu S.-L, Qin W.-B, Liu J.-J, Huang Y.-Y, Wong HN. C, Liu G.-K. Org. Lett. 2018; 20: 6925
  CrossrefPubMedSearch in Google Scholar
• 6f Melngaile R, Veliks J. Synthesis 2021; 53: 4549
  Thieme ConnectSearch in Google Scholar
• 6g Koike T, Akita M. Acc. Chem. Res. 2016; 49: 1937
  CrossrefPubMedSearch in Google Scholar

Selected examples:
• 7a Wang D, Carlton CG, Tayu M, McDouall JJ. W, Perry GJ. P, Procter DJ. Angew. Chem. Int. Ed. 2020; 59: 15918
  CrossrefPubMedSearch in Google Scholar
• 7b Faizi DJ, Davis AJ, Meany FB, Blum SA. Angew. Chem. Int. Ed. 2016; 55: 14286
  CrossrefPubMedSearch in Google Scholar
• 7c Luo K, Yang W.-C, Wei K, Liu Y, Wang J.-K, Wu L. Org. Lett. 2019; 21: 7851
  CrossrefPubMedSearch in Google Scholar
• 7d Yang K, Zhang H, Niu B, Tang T, Ge H. Eur. J. Org. Chem. 2018; 5520
  Crossref
• 7e Zhang Q, Liu X, Xin X, Zhang R, Liang Y, Dong D. Chem. Commun. 2014; 50: 15378
  CrossrefPubMedSearch in Google Scholar
• 7f Leypold M, D’Angelo KA, Movassaghi M. Org. Lett. 2020; 22: 8802
  CrossrefPubMedSearch in Google Scholar
• 7g Zhang L, Nagaraju S, Paplal B, Lin Y, Liu S. Eur. J. Org. Chem. 2021; 1365
  Crossref
• 7h Kawashima H, Yanagi T, Wu C.-C, Nogi K, Yorimitsu H. Org. Lett. 2017; 19: 4552
  CrossrefPubMedSearch in Google Scholar
• 7i Zhang Z, He P, Du H, Xu J, Li P. J. Org. Chem. 2019; 84: 4517
  CrossrefPubMedSearch in Google Scholar
• 8a Lou J, Wang Q, Wu P, Wang H, Zhou Y.-G, Yu Z. Chem. Soc. Rev. 2020; 49: 4307
  CrossrefPubMedSearch in Google Scholar
• 8b Kozhushkov SI, Alcarazo M. Eur. J. Inorg. Chem. 2020; 2020: 2486
  CrossrefPubMedSearch in Google Scholar
• 8c Fan R, Tan C, Liu Y, Wei Y, Zhao X, Liu X, Tan J, Yoshida H. Chin. Chem. Lett. 2021; 32: 299
  CrossrefSearch in Google Scholar
• 8d Péter Á, Perry GJ. P, Procter DJ. Adv. Synth. Catal. 2020; 362: 2135
  CrossrefSearch in Google Scholar
• 8e Tian Z.-Y, Hu Y.-T, Teng H.-B, Zhang C.-P. Tetrahedron Lett. 2018; 59: 299
  CrossrefSearch in Google Scholar
• 8f Otsuka S, Nogi K, Yorimitsu H. Top. Curr. Chem. 2018; 376: 13
  CrossrefPubMedSearch in Google Scholar
• 8g Yorimitsu H. Chem. Rec. 2021; 21: 1
  CrossrefPubMedSearch in Google Scholar

Selected examples:
• 9a Bosshard H. Helv. Chim. Acta 1972; 55: 37
  CrossrefSearch in Google Scholar
• 9b Braun H, Amann A. Angew. Chem. Int. Ed. Engl. 1975; 14: 755
  CrossrefSearch in Google Scholar
• 9c Tanikaga R, Hiraki Y, Ono N, Kaji A. J. Chem. Soc., Chem. Commun. 1980; 41
  Crossref
• 9d Shiraishi Y, Taki Y, Hirai T, Komasawa I. Ind. Eng. Chem. Res. 2001; 40: 1213
  CrossrefSearch in Google Scholar
• 9e Song H.-X, Wang S.-M, Wang X.-Y, Han J.-B, Gao Y, Jia S.-J, Zhang C.-P. J. Fluorine Chem. 2016; 192: 131
  CrossrefPubMedSearch in Google Scholar
• 9f Tian Z.-Y, Zhang C.-P. Chem. Commun. 2019; 55: 11936
  CrossrefPubMedSearch in Google Scholar
• 9g Altundas B, Kumar CV. S, Fleming FF. ACS Omega 2020; 5: 13384
  CrossrefPubMedSearch in Google Scholar
• 9h Miyatake K, Yamamoto K, Endo K, Tsuchida E. J. Org. Chem. 1998; 63: 7522
  CrossrefPubMedSearch in Google Scholar

Selected pioneer works:
• 10a Yamauchi K, Tanabe T, Kinoshita M. J. Org. Chem. 1979; 44: 638
  CrossrefSearch in Google Scholar
• 10b Badet B, Julia M, Ramirez-Muñoz M. Synthesis 1980; 926
  Thieme Connect
• 10c Coward JK, Sweet WD. J. Org. Chem. 1971; 36: 2337
  CrossrefSearch in Google Scholar
• 10d Garst ME, McBride BJ. J. Org. Chem. 1983; 48: 1362
  CrossrefSearch in Google Scholar
• 10e Kim S, Park JH, Kim YG, Lee JM. J. Chem. Soc., Chem. Commun. 1993; 1188
  Crossref
• 10f Liu B, Shine HJ. J. Phys. Org. Chem. 2001; 14: 81
  CrossrefSearch in Google Scholar
• 10g Umemura K, Matsuyama H, Watanabe N, Kobayashi M, Kamigata N. J. Org. Chem. 1989; 54: 2374
  CrossrefSearch in Google Scholar
• 10h Matsuyama H, Nakamura T, Kamigata N. J. Org. Chem. 1989; 54: 5218
  CrossrefSearch in Google Scholar
• 10i Umemura K, Matsuyama H, Kamigata N. Bull. Chem. Soc. Jpn. 1990; 63: 2593
  CrossrefSearch in Google Scholar
• 10j Umemura K, Matsuyama H, Kobayashi M, Kamigata N. Bull. Chem. Soc. Jpn. 1989; 62: 3026
  CrossrefSearch in Google Scholar
• 10k Uyehara T, Ohnuma T, Saito T, Kato T, Yoshida T, Takahashi K. J. Chem. Soc., Chem. Commun. 1981; 127
  Crossref
• 10l Kobayashi M, Umemura K, Matsuyama H. Chem. Lett. 1987; 16: 327
  CrossrefSearch in Google Scholar
• 10m Butte W, Eilers J, Kirsch M. Anal. Lett. 1982; 15: 841
  CrossrefSearch in Google Scholar
• 10n Trost BM, Schinski WL, Chen F, Mantz IB. J. Am. Chem. Soc. 1971; 93: 676
  CrossrefSearch in Google Scholar
• 10o Laali KK, Chun J.-H, Okazaki T. J. Org. Chem. 2007; 72: 8383
  CrossrefPubMedSearch in Google Scholar
• 10p Dorn H. Angew. Chem. Int. Ed. Engl. 1967; 6: 371
  CrossrefSearch in Google Scholar
• 10q Hyne JB, Golinkin HS. Can. J. Chem. 1963; 41: 3139
  CrossrefSearch in Google Scholar
• 10r Cooper KA, Dhar ML, Hughes ED, Ingold CK, MacNulty BJ, Woolf LI. J. Chem. Soc. 1948; 2043
  Crossref
• 10s Pickersgill IF, Marchington AP, Rayner CM. J. Chem. Soc., Chem. Commun. 1994; 2597
  Crossref
• 10t Takuwa T, Onishi JY, Matsuo J.-I, Mukaiyama T. Chem. Lett. 2004; 33: 8
  CrossrefSearch in Google Scholar
• 11a Lampard C, Murphy JA, Lewis N. J. Chem. Soc., Chem. Commun. 1993; 295
  Crossref
• 11b Fletcher RJ, Lampard C, Murphy JA, Lewis N. J. Chem. Soc., Perkin Trans. 1 1995; 623
  Crossref
• 11c Kizil M, Lampard C, Murphy JA. Tetrahedron Lett. 1996; 37: 2511
  CrossrefSearch in Google Scholar
• 11d Murphy JA, Rasheed F, Roome SJ, Lewis N. Chem. Commun. 1996; 737
  Crossref
• 11e Murphy JA, Rasheed F, Roome SJ, Scott KA, Lewis N. J. Chem. Soc., Perkin Trans. 1 1998; 2331
  Crossref
• 11f Patro B, Merrett M, Murphy JA, Sherrington DC, Morrison MG. J. T. Tetrahedron Lett. 1999; 40: 7857
  CrossrefSearch in Google Scholar
• 11g Patro B, Merrett MC, Makin SD, Murphy JA, Parkes KE. B. Tetrahedron Lett. 2000; 41: 421
  CrossrefSearch in Google Scholar
• 11h Bashir N, Murphy JA. Chem. Commun. 2000; 46: 627
  CrossrefSearch in Google Scholar
• 11i Callaghan O, Franck X, Murphy JA. Chem. Commun. 1997; 1923
  Crossref
• 12 Yamauchi K, Hisanaga Y, Kinoshita M. Synthesis 1980; 852
  Thieme Connect
• 13a Wang M, Zhao Y, Zhao Y, Shi Z. Sci. Adv. 2020; 6: eaba0946
  CrossrefPubMedSearch in Google Scholar
• 13b Zhang Z, Wen J, Wang M, Yan C.-G, Shi Z. Green Synth. Catal. 2021; 2: 275
  CrossrefSearch in Google Scholar
• 13c Aggarwal VK, Harvey JN, Robiette R. Angew. Chem. Int. Ed. 2005; 44: 5468
  CrossrefPubMedSearch in Google Scholar
• 13d Aggarwal VK, Fang GY, Schmidt AT. J. Am. Chem. Soc. 2005; 127: 1642
  CrossrefPubMedSearch in Google Scholar
• 13e Fang GY, Wallner OA, Di Blasio N, Ginesta X, Harvey JN, Aggarwal VK. J. Am. Chem. Soc. 2007; 129: 14632
  CrossrefPubMedSearch in Google Scholar
• 13f Fang GY, Aggarwal VK. Angew. Chem. Int. Ed. 2007; 46: 359
  CrossrefPubMedSearch in Google Scholar
• 13g He Z, Song F, Sun H, Huang Y. J. Am. Chem. Soc. 2018; 140: 2693
  CrossrefPubMedSearch in Google Scholar
• 14 Eliel EL, Hutchins RO, Mebane R, Willer RL. J. Org. Chem. 1976; 41: 1052
  CrossrefSearch in Google Scholar
• 15 Palmer DC, Taylor EC. J. Org. Chem. 1986; 51: 846
  CrossrefSearch in Google Scholar
• 16 Stará IG, Starý I, Tichý M, Závada J, Fiedler P. J. Org. Chem. 1994; 59: 1326
  CrossrefSearch in Google Scholar
• 17a Jagannathan S, Forsyth TP, Kettner CA. J. Org. Chem. 2001; 66: 6375
  CrossrefPubMedSearch in Google Scholar
• 17b Ray FE, Levine R. J. Org. Chem. 1937; 2: 267
  CrossrefSearch in Google Scholar

Selected literature:
• 18a Denmark SE, Vogler T. Chem. Eur. J. 2009; 15: 11737
  CrossrefPubMedSearch in Google Scholar
• 18b Sromek AW, Gevorgyan V. Top. Curr. Chem. 2007; 274: 77
  CrossrefSearch in Google Scholar
• 18c Smit WA, Caple R, Smoliakova IP. Chem. Rev. 1994; 94: 2359
  CrossrefSearch in Google Scholar
• 18d Adams, E. J.; Oscarson, S. Dimethyl(methylthio)sulfonium Tetrafluoroborate, In e-EROS Encyclopedia of Reagents for Organic Synthesis [Online]; Wiley & Sons, Posted October 15, 2005.
• 18e Denmark SE, Collins WR, Cullen MD. J. Am. Chem. Soc. 2009; 131: 3490
  CrossrefPubMedSearch in Google Scholar
• 18f Trost BM, Shibata T. J. Am. Chem. Soc. 1982; 104: 3225
  CrossrefSearch in Google Scholar
• 18g Denmark SE, Jaunet A. J. Am. Chem. Soc. 2013; 135: 6419
  CrossrefPubMedSearch in Google Scholar
• 18h Roth A, Denmark SE. J. Am. Chem. Soc. 2019; 141: 13767
  CrossrefPubMedSearch in Google Scholar
• 18i Lin S, Jacobsen EN. Nat. Chem. 2012; 4: 817
  CrossrefPubMedSearch in Google Scholar
• 18j Luo J, Zhu Z, Liu Y, Zhao X. Org. Lett. 2015; 17: 3620
  CrossrefPubMedSearch in Google Scholar
• 18k An R, Liao L, Liu X, Song S, Zhao X. Org. Chem. Front. 2018; 5: 3557
  CrossrefSearch in Google Scholar
• 18l Shen F, Lu L, Shen Q. Chem. Sci. 2020; 11: 8020
  CrossrefPubMedSearch in Google Scholar
• 18m Tang M, Han S, Huang S, Huang S, Xie L.-G. Org. Lett. 2020; 22: 9729
  CrossrefPubMedSearch in Google Scholar
• 19a Matsuyama H, Nakamura T, Iyoda M. Chem. Lett. 1994; 23: 1537
  CrossrefSearch in Google Scholar
• 19b Matsuyama H, Nakamura T, Iyoda M. J. Org. Chem. 2000; 65: 4796
  CrossrefPubMedSearch in Google Scholar
• 20a Miyata O, Fujiwara Y, Ninomiya I, Naito T. J. Chem. Soc., Perkin Trans. 1 1993; 2861
  Crossref
• 20b Jensen KL, Nielsen DU, Jamison TF. Chem. Eur. J. 2015; 21: 7379
  CrossrefPubMedSearch in Google Scholar
• 21a Inagaki S, Ukaku M, Chiba A, Takahashi F, Yoshimi Y, Morita T, Kawano T. J. Org. Chem. 2016; 81: 8363
  CrossrefPubMedSearch in Google Scholar
• 21b Inagaki S, Saito K, Suto S, Aihara H, Sugawara A, Tamura S, Kawano T. J. Org. Chem. 2018; 83: 13834
  CrossrefPubMedSearch in Google Scholar
• 21c Inagaki S, Nakazato M, Fukuda N, Tamura S, Kawano T. J. Org. Chem. 2017; 82: 5583
  CrossrefPubMedSearch in Google Scholar
• 21d Inagaki S, Sato A, Sato H, Tamura S, Kawano T. Tetrahedron Lett. 2017; 58: 4872
  CrossrefSearch in Google Scholar
• 22 Chen J, Palani V, Hoye TR. J. Am. Chem. Soc. 2016; 138: 4318
  CrossrefPubMedSearch in Google Scholar
• 23a Zheng T, Tan J, Fan R, Su S, Liu B, Tan C, Xu K. Chem. Commun. 2018; 54: 1303
  CrossrefPubMedSearch in Google Scholar
• 23b Jian H, Wang Q, Wang W.-H, Li Z.-J, Gu C.-Z, Dai B, He L. Tetrahedron 2018; 74: 2876
  CrossrefSearch in Google Scholar
• 24 López-Alled CM, Martin FJ. O, Chen K.-Y, Kociok-Köhn G, James TD, Wenk J, Lewis SE. Tetrahedron 2020; 76: 131700
  CrossrefSearch in Google Scholar
• 25 Gupta R, Mandal D, Jaiswal AK, Young RD. Org. Lett. 2021; 23: 1915
  CrossrefPubMedSearch in Google Scholar
• 26a Shine HJ, Bandlish BK, Mani SR, Padilla AG. J. Org. Chem. 1979; 44: 915
  CrossrefSearch in Google Scholar
• 26b Iwai K, Shine HJ. J. Org. Chem. 1981; 46: 271
  CrossrefSearch in Google Scholar
• 26c Lee WK, Liu B, Park CW, Shine HJ, Guzman-Jimenez IY, Whitmire KH. J. Org. Chem. 1999; 64: 9206
  CrossrefSearch in Google Scholar
• 26d Qian D.-Q, Shine HJ, Guzman-Jimenez IY, Thurston JH, Whitmire KH. J. Org. Chem. 2002; 67: 4030
  CrossrefPubMedSearch in Google Scholar
• 27a Houmam A, Shukla D, Kraatz H.-B, Wayner DD. M. J. Org. Chem. 1999; 64: 3342
  CrossrefPubMedSearch in Google Scholar
• 27b Holst DE, Wang DJ, Kim MJ, Guzei IA, Wickens ZK. Nature 2021; 596: 74
  CrossrefPubMedSearch in Google Scholar
• 28a Yamanaka H, Matsuo J, Kawana A, Mukaiyama T. Chem. Lett. 2003; 32: 626
  CrossrefSearch in Google Scholar
• 28b Matsuo J.-I, Yamanaka H, Kawana A, Mukaiyama T. Chem. Lett. 2003; 32: 392
  CrossrefSearch in Google Scholar
• 29a Zhang Z, Du H, Xu J, Li P. Chem. Commun. 2016; 52: 11547
  CrossrefPubMedSearch in Google Scholar
• 29b Luo H, Hu G, Li P. J. Org. Chem. 2019; 84: 10569
  CrossrefPubMedSearch in Google Scholar
• 30a McGarrigle EM, Myers EL, Illa O, Shaw MA, Riches SL, Aggarwal VK. Chem. Rev. 2007; 107: 5841
  CrossrefPubMedSearch in Google Scholar
• 30b Rao JS, Brière J.-F, Metzner P, Basavaiah D. Tetrahedron Lett. 2006; 47: 3553
  CrossrefSearch in Google Scholar
• 30c Myers EL, de Vries JG, Aggarwal VK. Angew. Chem. Int. Ed. 2007; 46: 1893
  CrossrefPubMedSearch in Google Scholar
• 30d Kinoshita H, Osamura T, Kinoshita S, Iwamura T, Watanabe S.-I, Kataoka T, Tanabe G, Muraoka O. J. Org. Chem. 2003; 68: 7532
  CrossrefPubMedSearch in Google Scholar
• 30e Basavaiah D, Muthukumaran K, Sreenivasulu B. Synlett 1999; 1249
  Thieme Connect
• 30f Bauer T, Tarasiuk J. Tetrahedron: Asymmetry 2001; 12: 1741
  CrossrefSearch in Google Scholar
• 30g Park J, Kawatkar S, Kim J.-H, Boons G.-J. Org. Lett. 2007; 9: 1959
  CrossrefPubMedSearch in Google Scholar
• 30h Kataoka T, Iwama T, Kinoshita H, Tsujiyama S, Tsurukami Y, Iwamura T, Watanabe S. Synlett 1999; 197
  Thieme Connect
• 30i Kataoka T, Iwama T, Tsujiyama S.-I, Kanematsu K, Iwamura T, Watanabe S.-I. Chem. Lett. 1999; 28: 257
  CrossrefSearch in Google Scholar
• 30j Kataoka T, Iwama T, Tsujiyama S.-I, Iwamura T, Watanabe S.-I. Tetrahedron 1998; 54: 11813
  CrossrefSearch in Google Scholar
• 30k Kataoka T, Iwama T, Tsujiyama S.-I. Chem. Commun. 1998; 197
  Crossref
• 30l Walsh LM, Winn CL, Goodman JM. Tetrahedron Lett. 2002; 43: 8219
  CrossrefSearch in Google Scholar
• 30m Lee K, Kim H, Miura T, Kiyota K, Kusama H, Kim S, Iwasawa N, Lee PH. J. Am. Chem. Soc. 2003; 125: 9682
  CrossrefPubMedSearch in Google Scholar
• 30n Kim S, Lee BS, Park JH. Bull. Korean Chem. Soc. 1993; 14: 654
  Search in Google Scholar
• 31a Zhang Z, Luo Y, Du H, Xu J, Li P. Chem. Sci. 2019; 10: 5156
  CrossrefPubMedSearch in Google Scholar
• 31b Zhang Z, Li P. Tetrahedron Lett. 2020; 61: 151707
  CrossrefSearch in Google Scholar
• 31c Nenajdenko VG, Vertelezkij PV, Balenkova ES. Synthesis 1997; 351
  Thieme Connect
• 31d Fernández-Salas JA, Eberhart AJ, Procter DJ. J. Am. Chem. Soc. 2016; 138: 790
  CrossrefPubMedSearch in Google Scholar
• 31e Hu G, Xu J, Li P. Org. Chem. Front. 2018; 5: 2167
  CrossrefSearch in Google Scholar
• 32a Guo W, Luo Y, Sung HH.-Y, Williams ID, Li P, Sun J. J. Am. Chem. Soc. 2020; 142: 14384
  CrossrefPubMedSearch in Google Scholar
• 32b Fang J, Li T, Ma X, Sun J, Cai L, Chen Q, Liao Z, Meng L, Zeng J, Wan Q. Chin. Chem. Lett. 2021; in press, DOI:
  Crossref
• 33a Kawasaki T, Suzuki H, Sakata I, Nakanishi H, Sakamoto M. Tetrahedron Lett. 1997; 38: 3251
  CrossrefSearch in Google Scholar
• 33b Higuchi K, Tayu M, Kawasaki T. Chem. Commun. 2011; 47: 6728
  CrossrefPubMedSearch in Google Scholar
• 33c Tayu M, Higuchi K, Inaba M, Kawasaki T. Org. Biomol. Chem. 2013; 11: 496
  CrossrefPubMedSearch in Google Scholar
• 33d Tayu M, Higuchi K, Ishizaki T, Kawasaki T. Org. Lett. 2014; 16: 3613
  CrossrefPubMedSearch in Google Scholar
• 33e Tayu M, Ishizaki T, Higuchi K, Kawasaki T. Org. Biomol. Chem. 2015; 13: 3863
  CrossrefPubMedSearch in Google Scholar
• 33f Tayu M, Suzuki Y, Higuchi K, Kawasaki T. Synlett 2016; 27: 941
  Thieme ConnectSearch in Google Scholar
• 33g Tayu M, Hui Y, Takeda S, Higuchi K, Saito N, Kawasaki T. Org. Lett. 2017; 19: 6582
  CrossrefPubMedSearch in Google Scholar
• 33h Tayu M, Nomura K, Kawachi K, Higuchi K, Saito N, Kawasaki T. Chem. Eur. J. 2017; 23: 10925
  CrossrefPubMedSearch in Google Scholar
• 34a Yoshida S, Yorimitsu H, Oshima K. Org. Lett. 2009; 11: 2185
  CrossrefPubMedSearch in Google Scholar
• 34b Eberhart AJ, Imbriglio JE, Procter DJ. Org. Lett. 2011; 13: 5882
  CrossrefPubMedSearch in Google Scholar
• 34c Eberhart AJ, Cicoira C, Procter DJ. Org. Lett. 2013; 15: 3994
  CrossrefPubMedSearch in Google Scholar
• 34d Eberhart AJ, Procter DJ. Angew. Chem. Int. Ed. 2013; 52: 4008
  CrossrefPubMedSearch in Google Scholar
• 34e Eberhart AJ, Shrives HJ, Álvarez E, Carrër A, Zhang Y, Procter DJ. Chem. Eur. J. 2015; 21: 7428
  CrossrefPubMedSearch in Google Scholar
• 34f Eberhart AJ, Shrives H, Zhang Y, Carrër A, Parry AV. S, Tate DJ, Turner ML, Procter DJ. Chem. Sci. 2016; 7: 1281
  CrossrefPubMedSearch in Google Scholar
• 34g Shrives HJ, Fernández-Salas JA, Hedtke C, Pulis AP, Procter DJ. Nat. Commun. 2017; 8: 14801
  CrossrefPubMedSearch in Google Scholar
• 34h He Z, Shrives HJ, Fernández-Salas JA, Abengózar A, Neufeld J, Yang K, Pulis AP, Procter DJ. Angew. Chem. Int. Ed. 2018; 57: 5759
  CrossrefPubMedSearch in Google Scholar
• 34i Šiaučiulis M, Sapmaz S, Pulis AP, Procter DJ. Chem. Sci. 2018; 9: 754
  CrossrefPubMedSearch in Google Scholar
• 34j Yan J, Pulis AP, Perry GJ. P, Procter DJ. Angew. Chem. Int. Ed. 2019; 58: 15675
  CrossrefPubMedSearch in Google Scholar
• 35a Badet B, Julia M, Ramirez-Munoz M, Sarrazin A. Tetrahedron 1983; 39: 3111
  CrossrefSearch in Google Scholar
• 35b Julia M, Mestdagh H, Rolando C. Tetrahedron 1986; 42: 3841
  CrossrefSearch in Google Scholar
• 35c Sedighi M, Çalimsiz S, Lipton MA. J. Org. Chem. 2006; 71: 9517
  CrossrefPubMedSearch in Google Scholar
• 35d Hostetler MA, Lipton MA. J. Org. Chem. 2018; 83: 7762
  CrossrefPubMedSearch in Google Scholar
• 36 Srogl J, Allred GD, Liebeskind LS. J. Am. Chem. Soc. 1997; 119: 12376
  CrossrefSearch in Google Scholar
• 37 Liu Y.-Y, Yang X.-H, Huang X.-C, Wei W.-T, Song R.-J, Li J.-H. J. Org. Chem. 2013; 78: 10421
  CrossrefPubMedSearch in Google Scholar
• 38 Simkó DC, Elekes P, Pázmándi V, Novák Z. Org. Lett. 2018; 20: 676
  CrossrefPubMedSearch in Google Scholar
• 39 He Y, Huang Z, Ma J, Huang F, Lin J, Wang H, Xu B.-H, Zhou Y.-G, Yu Z. Org. Lett. 2021; 23: 6110
  CrossrefPubMedSearch in Google Scholar
• 40a Minami H, Nogi K, Yorimitsu H. Synlett 2021; 32: 1542
  Thieme ConnectSearch in Google Scholar
• 40b Aukland MH, Talbot FJ. T, Fernández-Salas JA, Ball M, Pulis AP, Procter DJ. Angew. Chem. Int. Ed. 2018; 57: 9785
  CrossrefPubMedSearch in Google Scholar
• 41a Donck S, Baroudi A, Fensterbank L, Goddard J.-P, Ollivier C. Adv. Synth. Catal. 2013; 355: 1477
  CrossrefSearch in Google Scholar
• 41b Berger F, Plutschack MB, Riegger J, Yu W, Speicher S, Ho M, Frank N, Ritter T. Nature 2019; 567: 223
  CrossrefPubMedSearch in Google Scholar
• 41c Ye F, Berger F, Jia H, Ford J, Wortman A, Borgel J, Genicot C, Ritter T. Angew. Chem. Int. Ed. 2019; 58: 14615
  CrossrefPubMedSearch in Google Scholar
• 41d Sang R, Korkis SE, Su W, Ye F, Engl PS, Berger F, Ritter T. Angew. Chem. Int. Ed. 2019; 58: 16161
  CrossrefPubMedSearch in Google Scholar
• 41e Engl PS, Haering AP, Berger F, Berger G, Perez-Bitrian A, Ritter T. J. Am. Chem. Soc. 2019; 141: 13346
  CrossrefPubMedSearch in Google Scholar
• 41f Huang C, Feng J, Ma R, Fang S, Lu T, Tang W, Du D, Gao J. Org. Lett. 2019; 21: 9688
  CrossrefPubMedSearch in Google Scholar
• 41g Li J, Chen J, Sang R, Ham W.-S, Plutschack MB, Berger F, Chabbra S, Schnegg A, Genicot C, Ritter T. Nat. Chem. 2020; 12: 56
  CrossrefPubMedSearch in Google Scholar
• 41h Aukland MH, Siauciulis M, West A, Perry GJ. P, Procter DJ. Nat. Catal. 2020; 3: 163
  CrossrefSearch in Google Scholar
• 41i Wu J, Wang Z, Chen X.-Y, Wu Y, Wang D, Peng Q, Wang P. Sci. China: Chem. 2020; 63: 336
  CrossrefSearch in Google Scholar
• 42a van Bergen TJ, Kellogg RM. J. Am. Chem. Soc. 1976; 98: 1962
  CrossrefPubMedSearch in Google Scholar
• 42b Beak P, Sullivan TA. J. Am. Chem. Soc. 1982; 104: 4450
  CrossrefSearch in Google Scholar
• 42c Kataoka T, Tsutsumi K, Kano K, Mori K, Miyake M, Yokota M, Shimizu H, Hori M. J. Chem. Soc., Perkin Trans. 1 1990; 3017
  Crossref
• 42d Kataoka T, Iwama T, Shimizu H, Hori M. Phosphorus, Sulfur Silicon Relat. Elem. 1992; 67: 169
  CrossrefSearch in Google Scholar

Selected examples:
• 43a Saeva FD, Morgan BP. J. Am. Chem. Soc. 1984; 106: 4121
  CrossrefSearch in Google Scholar
• 43b Andrieux CP, Robert M, Saeva FD, Savéant J.-M. J. Am. Chem. Soc. 1994; 116: 7864
  CrossrefSearch in Google Scholar
• 43c Ghanimi A, Simonet J. New J. Chem. 1997; 21: 257
  Search in Google Scholar
• 44a Hedstrand DM, Kruizinga WH, Kellogg RM. Tetrahedron Lett. 1978; 17: 1255
  CrossrefSearch in Google Scholar
• 44b van Bergen TJ, Hedstrand DM, Kruizinga WH, Kellogg RM. J. Org. Chem. 1979; 44: 4953
  CrossrefSearch in Google Scholar
• 44c Saeva FD, Breslin DT, Luss HR. J. Am. Chem. Soc. 1991; 113: 5333
  CrossrefSearch in Google Scholar
• 44d Wang X, Saeva FD, Kampmeier JA. J. Am. Chem. Soc. 1999; 121: 4364
  CrossrefSearch in Google Scholar
• 44e Kampmeier JA, Hoque AK. M. M, Saeva FD, Wedegaertner DK, Thomsen P, Ullah S, Krake J, Lund T. J. Am. Chem. Soc. 2009; 131: 10015
  CrossrefPubMedSearch in Google Scholar
• 45 Otsuka S, Nogi K, Rovis T, Yorimitsu H. Chem. Asian J. 2019; 14: 532
  CrossrefPubMedSearch in Google Scholar
• 46 Varga B, Gonda Z, Tóth BL, Kotschy A, Novák Z. Eur. J. Org. Chem. 2020; 1466
  Crossref
• 47 Chen C, Wang Z.-J, Lu H, Zhao Y, Shi Z. Nat. Commun. 2021; 12: 4526
  CrossrefPubMedSearch in Google Scholar
• 48 Chen C, Wang M, Lu H, Zhao B, Shi Z. Angew. Chem. Int. Ed. 2021; 60: 21756
  CrossrefPubMedSearch in Google Scholar
• 49a Shibutani S, Kodo T, Takeda M, Nagao K, Tokunago N, Sasaki Y, Ohimiya H. J. Am. Chem. Soc. 2020; 142: 1211
  CrossrefPubMedSearch in Google Scholar
• 49b Nakagawa M, Nagao K, Ikeda Z, Reynolds M, Ibáñez I, Wang J, Tokunaga N, Sasaki Y, Ohmiya H. ChemCatChem 2021; 13: 3930
  CrossrefSearch in Google Scholar
• 49c Kobayashi R, Shibutani S, Nagao K, Ikeda Z, Wang J, Ibáñez I, Reynolds M, Sasaki Y, Ohmiya H. Org. Lett. 2021; 23: 5415
  CrossrefPubMedSearch in Google Scholar
• 49d Shibutani S, Nagao K, Ohmiya H. Org. Lett. 2021; 23: 1798
  CrossrefPubMedSearch in Google Scholar

Examples of use of aryl alkyl sulfonium salts as arylation reagents rather than alkylation ones:
• 50a Wang S.-M, Wang X.-Y, Qin H.-L, Zhang C.-P. Chem. Eur. J. 2016; 22: 6542
  CrossrefPubMedSearch in Google Scholar
• 50b Wang X.-Y, Song H.-X, Wang S.-M, Yang J, Qin H.-L, Jiang X, Zhang C.-P. Tetrahedron 2016; 72: 7606
  CrossrefSearch in Google Scholar
• 50c Wang S.-M, Song H.-X, Wang X.-Y, Liu N, Qin H.-L, Zhang C.-P. Chem. Commun. 2016; 52: 11893
  CrossrefPubMedSearch in Google Scholar
• 50d Tian Z.-Y, Wang S.-M, Jia S.-J, Song H.-X, Zhang C.-P. Org. Lett. 2017; 19: 5454
  CrossrefPubMedSearch in Google Scholar
• 50e See ref. 9f.
• 50f Ming X.-X, Wu S, Tian Z.-Y, Song J.-W, Zhang C.-P. Org. Lett. 2021; 23: 6795
  CrossrefPubMedSearch in Google Scholar
• 50g Minami H, Otsuka S, Nogi K, Yorimitsu H. ACS Catal. 2018; 8: 579
  CrossrefSearch in Google Scholar
• 50h Zhao J.-N, Kayumov M, Wang D.-Y, Zhang A. Org. Lett. 2019; 21: 7303
  CrossrefPubMedSearch in Google Scholar