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DOI: 10.1055/a-2175-1271
Iterative Assembly of Chiral Alcohols Utilizing CMMP-Mediated Mitsunobu Reactions
This work was supported by Grants-in-Aid from the JSPS KAKENHI (20K06955 and 23K06062) and Mitsubishi Tanabe Pharma Award in Synthetic Organic Chemistry, Japan.
Abstract
An iterative assembly of chiral alcohol building blocks is reported utilizing cyanomethylene trimethylphosphorane (CMMP)-mediated Mitsunobu reactions. 1,3-Benzodithiole tetraoxide (BDT) was used as the platform to prepare long-chain saturated compounds with multiple stereocenters en route to polyisoprenoid natural products. Selectively protected chiral 1,3-butanediols played a key role in iterative chain elongation for the construction of 1,5-dimethyl branched arrays with high stereocontrol.
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Key words
Mitsunobu reaction - BDT - chiral alcohols - stereochemistry - polyisoprenoids - CMMP - desulfonylationMitsunobu reaction is the dehydrative condensation of alcohols and acidic pronucleophiles under a redox system using a combination of diazocarboxylate and phosphines.[1] This reaction is conveniently used for the syntheses of biologically active compounds because the preactivation of alcohols is not required.[2] In addition, Mitsunobu reaction involves a stereochemical inversion of alcohols under mild and neutral conditions. However, the reaction is limited by low acidity of the pronucleophiles.[3] For the reaction with pronucleophiles having pK a values of >11, the product yields are generally lower. To overcome this drawback, our laboratory developed stabilized phosphorane reagents[4] for the Mitsunobu reaction. These reagents mediate the reaction using pronucleophiles with pK a values of up to 23 with satisfactory yields. We previously reported that the alkylation of phenylsulfonylacetonitrile as an active methylene compound with 2-octanol using a combination of azo reagents such as diethyl azodicarboxylate (DEAD) or tetramethylazodicarboxamide (TMAD)[5] with phosphines led to poor results.[6] By contrast, the phosphorane reagents, particularly cyanomethylene trimethylphosphorane (CMMP),[7] afforded the product in a high yield (Scheme [1]A).
In this study, 1,3-benzodithiole tetraoxide (BDT, 1)[8] with pK a of 13 is utilized as a potential platform for the assembly of chiral alcohols, which serves as a useful methylene building block.[9] [10] Upon treatment with CMMP, the monoalkylation of 1 with R1OH afforded I. Further alkylation of I with R2OH yielded II, and the subsequent reductive cleavage of the BDT unit furnished the methylene-linked coupling product III (Scheme [1]B).[11] Utilizing this method for iterative Mitsunobu reactions,[12] biologically active compounds with multiple stereogenic centers can be prepared. Consequently, polyisoprenoids sharing 1,5-syn methyl-branched arrays on their long-saturated chains,[13] such as mycoketide[14] and vitamin E,[15] can be systematically synthesized (Scheme [1]C). This method provides an alternative to the existing approaches that involve asymmetric high-pressure hydrogenation or conjugate addition of methyl anions of unsaturated substrates.
We initiated our study with the alkylation of 1 using commercially available (S)-2-octanol (2, >99% ee, 1.1 equiv). The reaction proceeded by treatment with CMMP (1.4 equiv) in toluene (0.1 M) at 100 °C to give the monoalkylated product 3 in 98% yield. The product was obtained in 99% ee by the stereochemical inversion of alcohol 2. In this case, the homo-dialkylated product was not obtained. Second alkylation was performed using 3-phenyl-1-propanol (4) under the same conditions to give 5 in 91% yield. These reactions were also performed in a one-pot operation via the successive addition of two different alcohols to 1 (96% yield) (Scheme [2]).
The iterative synthesis[16] via the assembly of chiral alcohols utilizes both enantiomers of 1,3-butanediol (6), which are commercially available in optically pure forms. Additionally, either primary or secondary hydroxy groups in the diol could be selectively protected. Treatment of (S)-6 (99% ee) with TBSCl and imidazole gave secondary alcohol 7, whereas treatment with p-anisaldehyde in the presence of TsOH afforded the intermediary cyclic acetal as a single diastereomer, which was regioselectively reduced by DIBAL to give primary alcohol 8 (Scheme [3]).[17]
Next, we investigated the construction of chiral 1,5-dimethyl building blocks. Starting with monoalkylated product 3, chiral primary alcohol (S)-8 was used for the second alkylation to give 9 in good yield. The reductive cleavage of 9 using magnesium in MeOH[18] provided 1,5-anti substituted compound 10. By contrast, upon treatment of 3 with (R)-8, diastereomeric 1,5-syn dimethyl substituted product 12 was obtained (Scheme [4]).
We further investigated the Mitsunobu alkylation using secondary alcohols to synthesize chiral 1,3-dimethyl-substituted compounds, which are typically found in deoxypolypropionate natural products.[19] Using compound 3, the reaction with secondary alcohol (S)-7 proceeded with stereoinversion promoted by CMMP. The steric hindrance in the reaction required an excess amount of CMMP (3 equiv) and elevated temperature (120 °C) to perform the second alkylation step. Dialkylated compound 13 was obtained in 64% yield with the recovery of starting material 3 (23%). The reductive cleavage of BDT, followed by the removal of the TBS group furnished 1,3-anti alcohol 15, whereas 1,3-syn alcohol 18 was also prepared by reacting with (R)-7. In 13C NMR, the chemical shifts of C3 and C5 methyl groups in 15 and 18 are clearly distinguished. The spectroscopic data of 18 are in good agreement with the reported data.[20] Notably, we previously reported that double alkylations on acyclic phenylsulfonylacetonitrile with secondary alcohols failed, in contrast to the successful alkylations involving the rigid cyclic structure of 1 (Scheme [5]).[7a] [21]
As an extension of the CMMP-mediated Mitsunobu reaction, we utilized the iterative Mitsunobu reactions on BDT (1) to prepare the long-chain saturated compounds with multiple stereocenters (Scheme [6]). Two differently protected alcohols with either PG1 or PG2 underwent stepwise alkylation with BDT to give A. When the PG2 group was selectively cleaved, the resultant alcohol B was utilized for further alkylation. Mono-alkylated product D was then subjected to the reaction with alcohol B to give product E, and subsequent desulfonylations and deprotections afforded diol G. When the PG1 group in A was removed, alcohol C reacted with D to give F. After final manipulations, regioisomeric diol H was thus obtained.
Taking these findings into account, BDT (1) was reacted with (S)-7 (99% ee) to give monoalkylated product 19 with stereochemical inversion (97% ee). Second alkylation was performed with (S)-8 to afford 20. These reactions were performed in one pot to give dialkylated product 20 in high yield. The subsequent reductive cleavage of BDT gave 1,5-anti dimethyl compound 21 (Scheme [7]).
The absolute stereochemistry of 19 was determined by comparison with the optical rotation of a derivative of a known compound. The Mitsunobu alkylation of 1 with (S)-7, followed by second alkylation with an excess amount of methanol afforded 22 in 98% yield (one pot). The subsequent desulfonylation of 22 under standard conditions did not give the desired product. After changing the protecting group from the TBS to BOM group, the reductive desulfonylation of 24 was performed to give 25. By contrast, commercially available (S)-3-methyl-1-pentanol (26) was protected by the BOM group to afford 25. The sign of the optical rotation of 25 obtained from 1 {[α]D 20 +4.3 (c 1.0, CHCl3)} matched that obtained from 26 {[α]D 20 +6.7 (c 1.0, CHCl3)}, confirming the stereochemical inversion in the Mitsunobu reaction (Scheme [8]).
Next, we examined a further elaboration of the Mitsunobu reaction for the synthesis of three stereocenters-bearing compound. The TBS group in dialkylated compound 20 was cleaved by TBAF to give alcohol 27, which was then subjected to the CMMP-mediated Mitsunobu reaction using compound 19 with one stereocenter, resulting in further alkylation in 75% yield. After the reductive cleavage of two molecules of BDT in 28, trimethyl substituted product 29 was obtained (Scheme [9]).
When 27 was reacted with 30, which was prepared by 1 and (S)-8 under Mitsunobu conditions, product 32 with a 1,7-dimethyl branch was obtained after reductive desulfonylation (Scheme [10]).
For a further chain elongation, alcohol 27 was reacted with 1 to give 33, possessing an additional alkylation site. The compound was combined with secondary alcohol 34, which was derived from the dialkylated compound 20 by oxidative cleavage of p-methoxybenzyl (PMB) group by 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ), to furnish product 35 in 96% yield. After reductive cleavage of three BDT groups, tetramethyl substituted product 36 was obtained (Scheme [11]).
In conclusion, we have successfully developed an iterative assembly of chiral alcohols utilizing the CMMP-mediated Mitsunobu reaction. This method will allow us to synthesize polyisoprenoid natural products. Further studies along these lines are currently underway in our laboratory.
All experiments dealing with air- and moisture-sensitive compounds were conducted under an atmosphere of dry argon. THF, toluene, MeOH, DMF, and CH2Cl2 (anhydrous; Kanto Chemical Co., Inc.) were used as received. For TLC analysis, Merck pre-coated plates (silica gel 60 F254, Art 5715, 0.25 mm) were used. For column chromatography, silica gel 60 N (Spherical, 63–210 μm, Kanto Chemical Co., Inc.) was used. Optical rotations were measured with a JASCO P-2300 polarimeter. Melting points were determined on a Büchi B-545 apparatus and are uncorrected. IR spectra were recorded using a JASCO Model FTIR-410 spectrophotometer. 1H NMR and 13C NMR spectra were measured on a Bruker Avance III HD-500 spectrometer (500 MHz/125 MHz). High-resolution mass spectra (HRMS) were recorded with a JEOL JMS-700 (EI/CI), Waters SYNAPT G2-Si HDMS (ESI), or a JEOL SpiralTOF JMS-S3000 mass spectrometers (MALDI). High-performance liquid chromatography (HPLC) was performed using a Jasco UV-2070 plus for UV/Vis detector and a PU-980 for HPLC pump.
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Mitsunobu Reaction; Product 3; Typical Procedure A
A mixture of BDT (1; 207 mg, 0.950 mmol) and alcohol (S)-2 (138 μL, 1.06 mmol) in toluene (8.0 mL) was evacuated and backfilled with argon. To this mixture was added CMMP (152 mg, 1.32 mmol). After stirring at 100 °C for 21 h, the mixture was cooled to rt. The volatiles were removed in vacuo and the residue was purified by silica-gel column chromatography (hexane/EtOAc 5:1) to give product 3; yield: 309 mg (98%); white solid; mp 94–96 °C; Rf = 0.29 (hexane/EtOAc 2:1); [α]D 23 +15.1 (c 1.01, CHCl3).
HPLC (Chiralpak IA, 4.6 mm × 250 mm, UV 210 nm, hexane/i-PrOH (9:1), flow 1.0 mL/min), t R = 15.5 min (minor), t R = 16.5 min (major).
IR (ATR): 2928, 1328, 1176, 1124 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.90 (t, J = 6.7 Hz, 3 H), 1.25–1.44 (m, 7 H), 1.41 (d, J = 6.7 Hz, 3 H), 1.47–1.56 (m, 1 H), 1.57–1.66 (m, 1 H), 1.93–2.02 (m, 1 H), 2.75–2.84 (m, 1 H), 4.21 (d, J = 10.8 Hz, 1 H), 7.88–7.92 (m, 2 H), 7.99–8.03 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 14.0, 15.9, 22.6, 25.4, 29.0, 30.1, 31.6, 32.7, 78.5, 122.3, 122.4, 134.97, 134.98, 137.91, 137.92.
HRMS (EI): m/z calcd for C15H22O4S2 [M]+: 330.0960; found: 330.0957.
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Product 5
According to Typical Procedure A, product 5 was obtained from 3 and 4 as a colorless solid; yield: 370 mg (91%); mp 132–133 °C; Rf = 0.44 (hexane/EtOAc 2:1); [α]D 23 +12.8 (c 1.03, CHCl3).
IR (ATR): 2925, 1459, 1312, 1150, 1116, 757, 697, 557 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.89 (t, J = 6.9 Hz, 3 H), 1.24 (d, J = 6.8 Hz, 3 H), 1.23–1.42 (m, 8 H), 1.46–1.56 (m, 3 H), 1.75–1.83 (m, 1 H), 2.23–2.35 (m, 2 H), 2.55 (t, J = 7.6 Hz, 2 H), 2.84–2.92 (m, 1 H), 7.02 (d, J = 7.1 Hz, 2 H), 7.12–7.16 (m, 1 H), 7.19–7.24 (m, 2 H), 7.82–7.87 (m, 2 H), 7.93–7.98 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 14.1, 14.4, 22.6, 24.9, 27.4, 27.8, 29.0, 31.6, 31.7, 34.0, 36.2, 83.2, 121.8, 121.9, 126.0, 128.2, 128.3, 135.0 (× 2), 137.96, 138.05, 140.5.
HRMS (EI): m/z calcd for C24H32O4S2 [M]+: 448.1742; found: 448.1743.
For a one-pot procedure, a mixture of BDT (1; 174 mg, 0.795 mmol) and alcohol (S)-2 (114 mg, 0.877 mmol) in toluene (8.0 mL) was evacuated and backfilled with argon (× 3). To the mixture was added CMMP (132 mg, 1.15 mmol) and stirred at 100 °C for 24 h. After cooling to rt, alcohol 4 (135 mg, 0.991 mmol) was added and the mixture was evacuated and backfilled with argon (× 3). To the mixture was added CMMP (141 mg, 1.22 mmol) and stirred at 100 °C for 24 h. After cooling to rt, the volatiles were removed in vacuo and the residue was purified by silica gel column chromatography (hexane/acetone 5:1) to give product 5; yield: 343 mg (96%).
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(S)-4-(tert-Butyldimethylsilyloxy)butan-2-ol (7)
To a solution of (S)-1,3-butanediol (6; 1.04 g, 11.5 mmol) and imidazole (1.63 g, 23.9 mmol) in DMF (15 mL) was added TBSCl (1.86 g, 12.3 mmol) at 0 °C. After stirring at rt for 2 h, the reaction was quenched with sat. aq NH4Cl at 0 °C. The products were extracted with Et2O (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 4:1) gave product 7 as a colorless oil; yield: 2.35 g (93%); Rf = 0.55 (hexane/EtOAc 7:3); [α]D 21 –4.3 (c 1.0, CHCl3).
IR (ATR): 3374, 2929, 1471, 1254, 1084, 829, 773 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.08 (s, 6 H), 0.91 (s, 9 H), 1.19 (d, J = 6.3 Hz, 3 H), 1.59–1.71 (m, 2 H), 3.38 (br s, 1H ), 3.79–3.84 (m, 1 H), 3.87–3.91 (m, 1 H), 3.99–4.05 (m, 1 H).
13C NMR (125 MHz, CDCl3): δ = –5.60, –5.55, 18.1, 23.3, 25.8, 39.9, 62.8, 68.3.
HRMS (CI): m/z calcd for C10H23O2Si [M – H]+: 203.1462; found 203.1486.
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(S)-3-(4-Methoxybenzyloxy)butan-1-ol (8)
To a solution of 1,3-butanediol (6; 1.07 mL, 12.0 mmol) and anisaldehyde (1.22 μL, 10.0 mmol) in toluene (25 mL) was added TsOH·H2O (95 mg, 0.50 mmol) at 0 °C. After stirring under reflux conditions for 10 h, the reaction was quenched with sat. aq NaHCO3 at 0 °C. The products were extracted with EtOAc (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 9:1) gave the corresponding cyclic acetal as a colorless oil; yield: 1.49 g (71%); Rf = 0.53 (hexane/EtOAc 8:2); [α]D 22 +1.5 (c 1.0, CHCl3).
IR (ATR): 2969, 1517, 1374, 1245, 1104, 1031, 826 cm–1.
1H NMR (500 MHz, CDCl3): δ = 1.30 (d, J = 6.3 Hz, 3 H), 1.49–1.58 (m, 1 H), 1.75–1.83 (m, 1 H), 3.79 (s, 3 H), 3.89–3.99 (m, 2 H), 4.21–4.25 (m, 1 H), 5.46 (s, 1 H), 6.88 (d, J = 8.8 Hz, 2 H), 7.42 (d, J = 8.8 Hz, 2 H).
13C NMR (125 MHz, CDCl3): δ = 21.8, 32.9, 55.3, 67.0, 73.3, 101.2, 113.6, 127.4, 131.4, 159.9.
HRMS (EI): m/z calcd for C12H15O3 [M – H]+: 207.1016; found 207.1021.
To a solution of the cyclic acetal (1.49 g, 7.13 mmol) in CH2Cl2 (24 mL) was added DIBAL (1.02 M in hexane, 14.0 mL, 14.3 mmol) at 0 °C. After stirring at this temperature for 1.5 h, the reaction was carefully quenched with aq 1 M HCl at 0 °C. The products were extracted with CH2Cl2 (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 75:25) gave product 8 as a colorless oil; yield: 1.41 g (94%); Rf = 0.19 (hexane/EtOAc 7:3); [α]D 22 +55.7 (c 1.00, CHCl3).
IR (ATR): 3366, 2931, 1513, 1245, 1032, 820 cm–1.
1H NMR (500 MHz, CDCl3): δ = 1.24 (d, J = 6.2 Hz, 3 H), 1.73–1.78 (m, 2 H), 3.71–3.81 (m, 3 H), 3.80 (s, 3 H), 4.37 (d, J = 11.3 Hz, 1 H), 4.57 (d, J = 11.3 Hz, 1 H), 6.88 (d, J = 8.7 Hz, 2 H), 7.26 (d, J = 8.7 Hz, 2 H).
13C NMR (125 MHz, CDCl3): δ = 19.3, 38.7, 55.3, 61.09, 70.1, 74.4, 113.9, 129.3, 130.4, 159.2.
HRMS (CI): m/z calcd for C12H18O3 [M]+: 210.1250; found 210.1258.
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Product 9
According to Typical Procedure A, product 9 was obtained from 3 and (S)-8 as a colorless oil; yield: 108 mg (76%); Rf = 0.38 (hexane/EtOAc 2:1); [α]D 19 +10.1 (c 1.10, CHCl3).
IR (ATR): 2929, 1513, 1464, 1326, 1247, 1156, 1034 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.90 (t, J = 6.8 Hz, 3 H), 1.06 (d, J = 6.2 Hz, 3 H), 1.25 (d, J = 6.7 Hz, 3 H), 1.26–1.44 (m, 10 H), 1.46–1.55 (m, 1 H), 1.80–1.89 (m, 1 H), 2.14–2.23 (m, 1 H), 2.39–2.48 (m, 1 H), 2.85–2.94 (m, 1 H), 3.35–3.42 (m, 1 H), 3.79 (s, 3 H), 4.29 (d, J = 11.4 Hz, 1 H), 4.38 (d, J = 11.4 Hz, 1 H), 6.84 (d, J = 8.6 Hz, 2 H), 7.20 (d, J = 8.6 Hz, 2 H), 7.84–7.89 (m, 2 H), 7.93–7.98 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 14.0, 14.3, 19.2, 22.6, 23.9, 27.4, 29.0, 29.5, 31.66, 31.68, 34.0, 55.2, 69.5, 73.5, 83.2, 113.7, 121.8, 122.0, 129.2, 130.7, 135.0 (× 2), 137.9, 138.0, 159.1.
HRMS (EI): m/z calcd for C27H38O6S2 [M]+: 522.2110; found: 522.2113.
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Reductive Desulfonylation; Product 10; Typical Procedure B
To a mixture of compound 9 (105 mg, 0.200 mmol) and MeOH (5.0 mL) was added activated Mg (117 mg, 4.82 mmol). After stirring at 80 °C for 16 h, the mixture was cooled to rt. The reaction was quenched with aq 1 M HCl at 0 °C. The products were extracted with hexane (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 20:1) gave product 10 as a colorless oil; yield: 36.2 mg (56%); Rf = 0.78 (hexane/EtOAc 2:1); [α]D 17 +23.1 (c 1.04, CHCl3).
IR (ATR): 2925, 1513, 1463, 1246, 1038, 820, 507 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.84 (d, J = 6.6 Hz, 3 H), 0.88 (t, J = 7.0 Hz, 3 H), 1.03–1.11 (m, 2 H), 1.17 (d, J = 6.1 Hz, 3 H), 1.19–1.33 (m, 12 H), 1.34–1.44 (m, 2 H), 1.51–1.59 (m, 1 H), 3.44–3.52 (m, 1 H), 3.80 (s, 3 H), 4.39 (d, J = 11.4 Hz, 1 H), 4.49 (d, J = 11.4 Hz, 1 H), 6.87 (d, J = 8.6 Hz, 2 H), 7.27 (d, J = 8.6 Hz, 2 H).
13C NMR (125 MHz, CDCl3): δ = 14.1, 19.65, 19.66, 22.7, 23.0, 27.0, 29.7, 32.0, 32.7, 36.95, 37.08, 37.09, 55.3, 69.9, 74.6, 113.7, 129.2, 131.3, 159.0.
HRMS (EI): m/z calcd for C21H36O2 [M]+: 320.2715; found: 320.2718.
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Product 11
According to Typical Procedure A, product 11 was obtained from 3 and (R)-8 as a colorless oil; yield: 188 mg (88%); Rf = 0.47 (hexane/EtOAc 2:1); [α]D 23 –5.2 (c 1.05, CHCl3).
IR (ATR): 2929, 1513, 1327, 1155, 1034, 754, 570 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.89 (t, J = 6.7 Hz, 3 H), 1.06 (d, J = 6.2 Hz, 3 H), 1.22–1.42 (m, 10 H), 1.28 (d, J = 6.7 Hz, 3 H), 1.46–1.53 (m, 1 H), 1.75–1.83 (m, 1 H), 2.11–2.20 (m, 1 H), 2.42–2.51 (m, 1 H), 2.86–2.93 (m, 1 H), 3.35–3.42 (m, 1 H), 3.79 (s, 3 H), 4.29 (d, J = 11.4 Hz, 1 H), 4.38 (d, J = 11.4 Hz, 1 H), 6.85 (d, J = 8.6 Hz, 2 H), 7.21 (d, J = 8.6 Hz, 2 H), 7.85–7.90 (m, 2 H), 7.95–7.99 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 14.1, 14.4, 19.2, 22.6, 24.0, 27.4, 29.1, 29.6, 31.67, 31.70, 34.0, 55.3, 69.6, 73.6, 83.2, 113.7, 121.89, 121.94, 129.3, 130.7, 134.96, 134.98, 138.02, 138.05, 159.1.
HRMS (EI): m/z calcd for C27H38O6S2 [M]+: 522.2104; found: 522.2111.
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Product 12
According to Typical Procedure B, product 12 was obtained from 11 as a colorless oil; yield: 60.2 mg (53%); Rf = 0.66 (hexane/EtOAc 9:1); [α]D 22 –4.6 (c 0.60, CHCl3).
IR (ATR): 2924, 1512, 1463, 1246, 1038, 820 cm–1.
1H NMR (500 MHz, CDCl3) δ = 0.84 (d, J = 6.6 Hz, 3 H), 0.88 (t, J = 6.8 Hz, 3 H), 1.04–1.12 (m, 2 H), 1.17 (d, J = 6.1 Hz, 3 H), 1.20–1.42 (m, 14 H), 1.53–1.61 (m, 1 H), 3.45–3.52 (m, 1 H), 3.80 (s, 3 H), 4.39 (d, J = 11.4 Hz, 1 H), 4.49 (d, J = 11.4 Hz, 1 H), 6.87 (d, J = 8.6 Hz, 2 H), 7.27 (d, J = 8.6 Hz, 2 H).
13C NMR (125 MHz, CDCl3) δ = 14.1, 19.7 (× 2), 22.7, 23.0, 27.0, 29.7, 31.9, 32.7, 36.98, 37.03, 37.08, 55.3, 69.9, 74.5, 113.7, 129.2, 131.3, 159.0.
HRMS (EI): m/z calcd for C21H36O2 [M]+: 320.2710; found: 320.2716.
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Product 13
According to Typical Procedure A, product 13 was obtained from 3 and (S)-7 as a colorless oil; yield: 213 mg (64%); Rf = 0.43 (hexane/EtOAc 2:1); [α]D 19 +2.3 (c 0.96, CHCl3).
IR (ATR): 2927, 1326, 1153, 1096, 834, 774, 587 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.04 (s, 3 H), 0.05 (s, 3 H), 0.876 (t, J = 7.1 Hz, 3 H), 0.882 (s, 9 H), 1.16 (d, J = 6.4 Hz, 3 H), 1.22 (d, J = 6.7 Hz, 3 H), 1.19–1.39 (m, 8 H), 1.45–1.54 (m, 2 H), 1.68–1.76 (m, 1 H), 1.82–1.92 (m, 1 H), 2.08–2.17 (m, 1 H), 2.84–2.92 (m, 1 H), 2.99–3.07 (m, 1 H), 3.65–3.75 (m, 2 H), 7.84–7.87 (m, 2 H), 7.92–7.97 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.43, –5.38, 14.1, 15.6, 16.1, 22.6, 25.9, 28.7, 29.1, 31.7, 32.2, 33.1, 35.3, 35.7, 61.2, 86.5, 121.5 (× 2), 134.8 (× 2), 138.7 (× 2).
HRMS (ESI): m/z calcd for C25H45O5SiS2 [M + H]+: 517.2478; found: 517.2479.
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Product 14
According to Typical Procedure B, product 14 was obtained from 13 as a colorless oil; yield: 37.9 mg (68%); Rf = 0.85 (hexane/EtOAc 9:1); [α]D 18 –12.2 (c 0.32, CHCl3).
IR (ATR): 2923, 1463, 1257, 1093, 1016, 801 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.05 (s, 6 H), 0.81 (d, J = 6.6 Hz, 3 H), 0.83 (d, J = 6.6 Hz, 3 H), 0.89 (s, 9 H), 1.00–1.13 (m, 3 H), 1.19–1.37 (m, 13 H), 1.42–1.70 (m, 3 H), 3.58–3.69 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.28, –5.25, 14.1, 19.47, 19.54, 22.7, 26.0, 26.7, 27.0, 29.7, 30.0, 32.0, 37.9, 40.8, 44.9, 61.4.
HRMS (ESI): m/z calcd for C19H42OSi [M]+: 314.3005; found: 314.3008.
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(3S,5R)-3,5-dimethylundecan-1-ol (15)
To a solution of silyl ether 14 (85.5 mg, 0.271 mmol) in THF (2.7 mL) was added TBAF (540 μL, 1.0 M in THF solution, 0.54 mmol) at 0 °C. After stirring for 1 h at this temperature, the reaction was quenched with aq 1 M HCl. The products were extracted with EtOAc (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 85:15) gave alcohol 15 as a colorless oil; yield: 42.4 mg (78%); Rf = 0.34 (hexane/EtOAc 4:1); [α]D 21 –30.7 (c 0.097, CHCl3).
IR (ATR): 3281, 2922, 1457, 1377, 1055, 774 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.83 (d, J = 6.6 Hz, 3 H), 0.86 (d, J = 6.6 Hz, 3 H), 0.88 (t, J = 6.8 Hz, 3 H), 1.02–1.15 (m, 3 H), 1.19–1.33 (m, 9 H), 1.35–1.43 (m, 1 H), 1.44–1.51 (m, 1 H), 1.52–1.59 (m, 1 H), 1.60–1.69 (m, 1 H), 3.64–3.73 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 14.1, 19.37, 19.41, 22.7, 26.8, 27.0, 29.6, 30.0, 31.9, 37.9, 40.8, 44.9, 61.2.
HRMS (CI): m/z calcd for C13H27O [M – H]+: 199.2056; found: 199.2062.
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Product 16
According to Typical Procedure A, product 16 was obtained from 3 and (R)-7 as a colorless oil; yield: 65.9 mg (79%); Rf = 0.55 (hexane/ EtOAc 2:1); [α]D 21 +4.6 (c 1.0, CHCl3).
IR (ATR): 2928, 1330, 1255, 1153, 1096, 834, 775, 584 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.03 (s, 3 H), 0.04 (s, 3 H), 0.85 (t, J = 7.1 Hz, 3 H), 0.87 (s, 9 H), 1.15–1.32 (m, 7 H), 1.23 (d, J = 6.8 Hz, 3 H), 1.36 (d, J = 6.9 Hz, 3 H), 1.36–1.51 (m, 2 H), 1.55–1.73 (m, 2 H), 2.02–2.12 (m, 1 H), 2.83–2.93 (m, 1 H), 2.97–3.06 (m, 1 H), 3.70 (t, J = 6.8 Hz, 2 H), 7.84–7.88 (m, 2 H), 7.92–7.97 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.42, –5.39, 14.0, 15.7, 16.1, 18.2, 22.5, 25.9, 28.1, 29.0, 31.6, 32.5, 35.4, 35.6, 61.5, 86.3, 121.3, 121.6, 134.78, 134.80, 138.6, 138.7.
HRMS (ESI): m/z calcd for C25H44O5SiS2Na [M + Na]+: 539.2297; found: 539.2297.
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Product 17
According to Typical Procedure B, product 17 was obtained from 16 as a colorless oil; yield: 29.0 mg (73%); Rf = 0.85 (hexane/EtOAc 9:1); [α]D 22 +0.9 (c 0.83, CHCl3).
IR (ATR): 2926, 1462, 1253, 1095, 833 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.05 (s, 6 H), 0.83 (d, J = 6.6 Hz, 3 H), 0.85 (d, J = 6.6 Hz, 3 H), 0.88 (t, J = 7.1 Hz, 3 H), 0.89 (s, 9 H), 0.91–0.97 (m, 1 H), 1.00–1.08 (m, 1 H), 1.17–1.34 (m, 11 H), 1.44–1.52 (m, 1 H), 1.52–1.77 (m, 2 H), 3.55–3.69 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.29, –5.25, 14.1, 20.2, 20.4, 22.7, 25.96, 26.00, 26.8, 26.9, 29.7, 29.9, 32.0, 36.9, 39.8, 45.3, 61.4.
HRMS (CI): m/z calcd for C19H42OSi [M]+: 314.3005; found: 314.2979.
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(3R,5R)-3,5-Dimethylundecan-1-ol (18)
To a solution of silyl ether 17 (23.9 mg, 0.0759 mmol) in THF (1.5 mL) was added TBAF (150 μL, 1.0 M in THF solution, 0.15 mmol) at 0 °C. After stirring for 1 h at this temperature, the reaction was quenched with aq 1 M HCl. The products were extracted with EtOAc (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 4:1) gave alcohol 18 as a colorless oil; yield: 9.3 mg (61%); Rf = 0.38 (hexane/EtOAc 4:1); [α]D 21 +7.6 (c 0.096, CHCl3).
IR (ATR): 3299, 2923, 1457, 1377, 1054 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.85 (d, J = 6.6 Hz, 3 H), 0.88 (t, J = 7.0 Hz, 3 H), 0.89 (d, J = 6.5 Hz, 3 H), 0.93–1.08 (m, 2 H), 1.18–1.36 (m, 11 H), 1.44–1.53 (m, 1 H), 1.57–1.69 (m, 2 H), 3.62–3.74 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 14.1, 20.20, 20.22, 22.7, 26.87, 26.89, 29.7, 30.0, 31.9, 36.8, 39.8, 45.3, 61.2.
HRMS (CI): m/z calcd for C13H27O [M – H]+: 199.2056; found: 199.2065.
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Product 19
According to Typical Procedure A, product 19 was obtained from 1 and (S)-7 as a white solid; yield: 679 mg (84%); mp 124–125 °C; Rf = 0.21 (hexane/EtOAc 2:1); [α]D 22 +2.1 (c 1.04, CHCl3).
HPLC (Chiralpak IA, 4.6 mm × 250 mm, UV 210 nm, hexane/i-PrOH (9:1), flow 1.0 mL/min), t R = 15.5 min (minor), t R = 16.5 min (major).
IR (ATR): 2931, 1326, 1255, 1178, 1124, 835, 762, 565 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.08 (d, J =5.9 Hz, 6 H), 0.89 (s, 9 H), 1.45 (d, J = 6.8 Hz, 3 H), 1.80–1.88 (m, 1 H), 2.16–2.24 (m, 1 H), 2.93–3.03 (m, 1 H), 3.79–3.90 (m, 2 H), 4.48 (d, J = 10.3 Hz, 1 H), 7.87–7.92 (m, 2 H), 7.99–8.03 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.5, 15.6, 18.2, 25.9, 28.2, 34.9, 59.7, 78.5, 122.3, 122.4, 135.0 (× 2), 137.95, 137.97.
HRMS (CI): m/z calcd for C17H29O5S2Si [M + H]+: 405.1226; found: 405.1220.
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Product 20
According to Typical Procedure A, product 20 was obtained from 19 and (S)-8 as a colorless oil; yield: 305 mg (93%); Rf = 0.37 (hexane/EtOAc 2:1); [α]D 17 –0.26 (c 1.13, CHCl3).
IR (ATR): 2930, 1513, 1328, 1247, 1155, 1092, 833, 773, 717, 568 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.07 (s, 3 H), 0.08 (s, 3 H), 0.91 (s, 9 H), 1.08 (d, J = 6.2 Hz, 3 H), 1.25 (d, J = 6.7 Hz, 3 H), 1.40–1.48 (m, 2 H), 1.51–1.60 (m, 1 H), 2.08–2.16 (m, 1 H), 2.18–2.28 (m, 1 H), 2.40–2.49 (m, 1 H), 3.01–3.09 (m, 1 H), 3.37–3.44 (m, 1 H), 3.74–3.82 (m, 2 H), 3.80 (s, 3 H), 4.31 (d, J = 11.4 Hz, 1 H), 4.39 (d, J = 11.4 Hz, 1 H), 6.85 (d, J = 8.6 Hz, 2 H), 7.21 (d, J = 8.6 Hz, 2 H), 7.85–7.90 (m, 2 H), 7.95–7.99 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.40, –5.38, 14.9, 19.2, 24.0, 25.9, 29.5, 31.2, 34.4, 55.3, 61.0, 69.6, 73.5, 82.9, 113.8, 121.9, 122.0, 129.3, 130.7, 135.0 (× 2), 137.9, 138.0, 159.1.
HRMS (ESI): m/z calcd for C29H44O7S2SiNa [M + Na]+: 619.2190; found: 619.2195.
For a one-pot procedure, a mixture of BDT (1; 439 mg, 2.01 mmol) and alcohol (S)-7 (428 mg, 2.09 mmol) in toluene (15 mL) was evacuated and backfilled with argon (× 3). To the mixture was added CMMP (331 mg, 2.88 mmol) and stirred at 100 °C for 24 h. After cooling to rt, alcohol (S)-8 (537 mg, 2.56 mmol) was added, and the mixture was evacuated and backfilled with argon (× 3). To the mixture was added CMMP (382 mg, 3.32 mmol) and stirred at 100 °C for 24 h. After cooling to rt, the volatiles were removed in vacuo and the residue was purified by silica gel column chromatography (hexane/EtOAc 5:1) to give product 20; yield: 1.10 g (92%).
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Product 21
According to Typical Procedure B, product 21 was obtained from 20 as a colorless oil; yield: 63.9 mg (52%); Rf = 0.70 (hexane/EtOAc 2:1); [α]D 18 +1.1 (c 0.35, CHCl3).
IR (ATR): 2927, 1513, 1463, 1246, 1089, 833, 773 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.05 (s, 6 H), 0.86 (d, J = 6.5 Hz, 3 H), 0.89 (s, 9 H), 1.07–1.14 (m, 1 H), 1.17 (d, J = 6.2 Hz, 3 H), 1.23–1.46 (m, 5 H), 1.49–1.59 (m, 3 H), 3.44–3.51 (m, 1 H), 3.58–3.68 (m, 2 H), 3.80 (s, 3 H), 4.39 (d, J = 11.4 Hz, 1 H), 4.49 (d, J = 11.4 Hz, 1 H), 6.87 (d, J = 8.6 Hz, 2 H), 7.26 (d, J = 8.6 Hz, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.27, –5.25, 18.3, 19.6, 22.9, 26.0, 29.5, 36.9, 37.2, 40.0, 55.3, 61.5, 69.9, 74.6, 113.7, 129.2, 131.3, 159.0.
HRMS (ESI): m/z calcd for C23H42O3SiNa [M + Na]+: 417.2801; found: 417.2801.
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Product 22
A mixture of BDT (1; 222 mg, 1.02 mmol) and TBS-alcohol (S)-7 (227 mg, 1.11 mmol) in toluene (11 mL) was evacuated and backfilled with argon (× 3). To the mixture was added CMMP (195 mg, 1.66 mmol) and stirred at 100 °C for 23 h. After cooling to rt, MeOH (0.32 mL, 7.9 mmol) was added, and the mixture was evacuated and backfilled with argon (× 3). To the mixture was added CMMP (183 mg, 1.59 mmol) and stirred at 80 °C for 20 h. After cooling to rt, the volatiles were removed in vacuo and the residue was purified by silica gel column chromatography (hexane/acetone 8:2) to give product 22; yield: 416 mg (98%); mp 144–145 °C; Rf = 0.47 (hexane/acetone 7:3); [α]D 21 –24.5 (c 0.20, CHCl3).
IR (ATR): 2929, 1320, 1254, 1155, 1103, 994, 833, 770, 715, 558, 516 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.086 (s, 3 H), 0.088 (s, 3 H), 0.91 (s, 9 H), 1.33 (d, J = 6.7 Hz, 3 H), 1.44–1.52 (m, 1 H), 1.69 (s, 3 H), 2.12–2.20 (m, 1 H), 3.09–3.17 (m, 1 H), 3.81 (dd, J = 7.0, 6.2 Hz, 2 H), 7.86–7.90 (m, 2 H), 7.97–8.01 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.39, –5.37, 13.6, 14.5, 18.2, 25.9, 29.5, 34.1, 60.7, 80.7, 123.00, 123.04, 134.98, 134.99, 135.7, 135.8.
HRMS (ESI): m/z calcd for C18H30O5SiS2Na [M + Na]+: 441.1202; found: 441.1203.
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Product 23
To a solution of silyl ether 22 (75.7 mg, 0.181 mmol) in THF (1.8 mL) was added TBAF (0.22 mL, 1.0 M in THF solution, 0.22 mmol) at 0 °C. After stirring for 1 h at this temperature, the reaction was quenched with aq 1 M HCl. The products were extracted with EtOAc (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/acetone 6:4) gave alcohol 23 as a white solid; yield: 52.5 mg (95%); mp 184.7–185.1 °C; Rf = 0.16 (hexane/acetone 7:3); [α]D 20 +0.58 (c 0.50, CHCl3).
IR (ATR): 3434, 2884, 1315, 1152, 1042, 853, 770, 711, 567, 518 cm–1.
1H NMR (500 MHz, CDCl3): δ = 1.35 (d, J = 6.7 Hz, 3 H), 1.47 (t, J = 5.7 Hz, 1 H), 1.52–1.60 (m, 1 H), 1.70 (s, 3 H), 2.16–2.23 (m, 1 H), 3.18 (ddq, J = 10.9, 2.0, 6.7 Hz, 1 H), 3.78–3.91 (m, 2 H), 7.88–7.92 (m, 2 H), 7.99–8.03 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 13.5, 14.4, 29.1, 34.2, 60.1, 80.5, 123.06, 123.13, 135.09, 135.13, 135.6, 135.7.
HRMS (ESI): m/z calcd for C12H16O5S2Na [M + Na]+: 327.0337; found: 327.0334.
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Product 24
To a solution of alcohol 23 (132 mg, 0.432 mmol) in CH2Cl2 (4.0 mL) was successively added i-Pr2NEt (110 μL, 0.64 mmol) and benzyloxymethyl chloride (BOMCl; 70 μL, 0.51 mmol) at 0 °C. After stirring for 21 h at 30 °C, the reaction was quenched with aq 1 M HCl. The products were extracted with CH2Cl2 (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 7:3) gave product 24 as a colorless oil; yield: 176 mg (96%); Rf = 0.41 (hexane/EtOAc 6:4); [α]D 22 –1.2 (c 1.02, CHCl3).
IR (ATR): 2880, 1444, 1328, 1156, 1107, 1025, 743, 712, 556 cm–1.
1H NMR (500 MHz, CDCl3): δ = 1.33 (d, J = 6.7 Hz, 3 H), 1.50–1.58 (m, 1 H), 1.69 (s, 3 H), 2.24–2.33 (m, 1 H), 3.13–3.21 (m, 1 H), 3.73–3.80 (m, 2 H), 4.62 (d, J = 11.8 Hz, 1 H), 4.65 (d, J = 11.8 Hz, 1 H), 4.78 (d, J = 11.4 Hz, 1 H), 4.80 (d, J = 11.4 Hz, 1 H), 7.26–7.31 (m, 1 H), 7.33–7.39 (m, 4 H), 7.86–7.91 (m, 2 H), 7.97–8.02 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 13.5, 14.1, 29.7, 31.0, 64.9, 69.6, 80.6, 94.5, 123.04, 123.06, 127.7, 128.0, 128.4, 135.05, 135.06, 135.61, 135.68, 137.9.
HRMS (ESI): m/z calcd for C20H24O6S2 [M]+: 424.1009; found: 424.1016.
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Product 25
According to Typical Procedure B, product 25 was obtained from 24 as a colorless oil; yield: 48.3 mg (54%); Rf = 0.47 (hexane/acetone 9:1); [α]D 22 +4.3 (c 1.0, CHCl3).
IR (ATR): 2926, 1455, 1378, 1109, 1041, 734, 696 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.88 (t, J = 7.5 Hz, 3 H), 0.89 (d, J = 6.6 Hz, 3 H), 1.12–1.22 (m, 1 H), 1.32–1.43 (m, 2 H), 1.45–1.54 (m, 1 H), 1.60–1.68 (m, 1 H), 3.57–3.66 (m, 2 H), 4.60 (s, 2 H), 4.76 (s, 2 H), 7.26–7.31 (m, 1 H), 7.32–7.37 (m, 4 H).
13C NMR (125 MHz, CDCl3): δ = 11.3, 19.1, 29.5, 31.4, 36.3, 66.3, 69.3, 94.6, 127.6, 127.9, 128.4, 138.0.
HRMS (EI): m/z calcd for C14H22O2 [M]+: 222.1614; found: 222.1619.
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Product 27
To a solution of silyl ether 20 (615 mg, 1.03 mmol) in THF (25 mL) was added TBAF (3.2 mL, 1.0 M in THF solution, 3.2 mmol) at 0 °C. After stirring for 1 h at rt, the reaction was quenched with aq 1 M HCl. The products were extracted with EtOAc (× 3) and the combined extracts were washed with brine, and dried (MgSO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 2:1→1:1) gave alcohol 27 as a colorless oil; yield: 433 mg (87%); Rf = 0.39 (CHCl3/MeOH 9:1); [α]D 23 +1.6 (c 0.35, CHCl3).
IR (ATR): 3398, 2925, 1325, 1247, 1154, 1043, 719, 569 cm–1.
1H NMR (500 MHz, CDCl3): δ = 1.09 (d, J = 6.2 Hz, 3 H), 1.25 (d, J = 7.0 Hz, 3 H), 1.40–1.51 (m, 2 H), 1.54–1.63 (m, 1 H), 2.09–2.18 (m, 1 H), 2.20–2.28 (m, 1 H), 2.40–2.48 (m, 1 H), 3.06–3.14 (m, 1 H), 3.37–3.45 (m, 1 H), 3.69–3.82 (m, 2 H), 3.80 (s, 3 H), 4.29 (d, J = 11.4 Hz, 1 H), 4.42 (d, J = 11.4 Hz, 1 H), 6.86 (d, J = 8.7 Hz, 2 H), 7.22 (d, J = 8.7 Hz, 2 H), 7.87–7.91 (m, 2 H), 7.96–8.00 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 14.9, 19.3, 24.0, 29.5, 30.8, 34.7, 55.3, 60.3, 69.8, 73.7, 82.7, 113.8, 121.9, 122.1, 129.4, 130.6, 135.08, 135.13, 137.8, 137.9, 159.1.
HRMS (EI): m/z calcd for C23H30O7S2 [M]+: 482.1433; found: 482.1436.
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Product 28
According to Typical Procedure A, product 28 was obtained from 27 and 19 as a white solid; yield: 145 mg (75%); mp 148–151 °C; Rf = 0.62 (hexane/EtOAc 1:1); [α]D 20 +2.7 (c 1.0, CHCl3).
IR (ATR): 2930, 1442, 1329, 1247, 1155, 832, 751, 557 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.08 (d, J = 0.8 Hz, 6 H), 0.91 (s, 9 H), 0.96 (d, J = 6.1 Hz, 3 H), 1.10–1.30 (m, 3 H), 1.20 (d, J = 6.7 Hz, 3 H), 1.37 (d, J = 6.8 Hz, 3 H), 1.50–1.58 (m, 1 H), 1.71–1.78 (m, 1 H), 1.87–2.00 (m, 2 H), 2.04–2.13 (m, 1 H), 2.37–2.48 (m, 2 H), 2.71–2.79 (m, 1 H), 3.05–3.14 (m, 1 H), 3.23–3.32 (m, 1 H), 3.76–3.83 (m, 2 H), 3.81 (s, 3 H), 4.25 (d, J = 11.4 Hz, 1 H), 4.34 (d, J = 11.4 Hz, 1 H), 6.90 (d, J = 8.6 Hz, 2 H), 7.18 (d, J = 8.6 Hz, 2 H), 7.69 (dd, J = 7.6, 7.5 Hz, 1 H), 7.77 (dd, J = 7.6, 7.5 Hz, 1 H), 7.84–7.99 (m, 6 H).
13C NMR (125 MHz, CDCl3): δ = –5.39, –5.37, 14.0, 14.9, 18.3, 19.1, 23.7, 25.9, 26.2, 26.7, 29.3, 31.1, 34.5, 34.6, 55.3, 61.0, 69.6, 73.1, 82.3, 82.8, 113.8, 121.8, 121.98, 122.00, 122.3, 129.3, 130.6, 134.9, 135.1, 137.5, 137.7, 137.97, 138.00, 159.2.
HRMS (MALDI): m/z calcd for C40H56O11SiS4Na [M + Na]+: 891.2367; found: 891.2373.
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Product 29
According to Typical Procedure B, product 29 was obtained from 28 as a colorless oil; yield: 18.4 mg (57%); Rf = 0.73 (hexane/EtOAc 5:1); [α]D 22 +3.1 (c 0.55, CHCl3).
IR (ATR): 2927, 1513, 1462, 1375, 1247, 1090, 833, 774 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.05 (s, 6 H), 0.84 (d, J = 6.6 Hz, 3 H), 0.87 (d, J = 6.6 Hz, 3 H), 0.89 (s, 9 H), 1.04–1.12 (m, 2 H), 1.17 (d, J = 6.2 Hz, 3 H), 1.20–1.45 (m, 9 H), 1.45–1.60 (m, 5 H), 3.48 (q, J = 6.2 Hz, 1 H), 3.58–3.68 (m, 2 H), 3.80 (s, 3 H), 4.39 (d, J = 11.4 Hz, 1 H), 4.49 (d, J = 11.4 Hz, 1 H), 6.87 (d, J = 8.7 Hz, 2 H), 7.27 (d, J = 8.7 Hz, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.27, –5.26, 18.3, 19.7, 19.8, 23.0, 24.4, 26.0, 29.5, 32.8, 37.0, 37.1, 37.4, 37.5, 40.0, 55.3, 61.5, 69.9, 74.6, 113.7, 129.2, 131.3, 159.0.
HRMS (MALDI): m/z calcd for C28H52O3SiNa [M + Na]+: 487.3577; found: 487.3578.
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Product 30
According to Typical Procedure A, product 30 was obtained from 1 and (S)-8 as a colorless oil; yield: 378 mg (92%); Rf = 0.29 (hexane/EtOAc 2:1); [α]D 21 +12.6 (c 1.02, CHCl3).
IR (ATR): 2935, 1513, 1443, 1329, 1245, 1164, 1123, 1031, 762, 562, 517 cm–1.
1H NMR (500 MHz, CDCl3): δ = 1.27 (d, J = 6.2 Hz, 3 H), 1.86–2.02 (m, 2 H), 2.34–2.52 (m, 2 H), 3.62–3.70 (m, 1 H), 3.78 (s, 3 H), 4.41 (d, J = 11.3 Hz, 1 H), 4.45 (t, J = 7.2 Hz, 1 H), 4.56 (d, J = 11.3 Hz, 1 H), 6.87 (d, J = 8.6 Hz, 2 H), 7.29 (d, J = 8.6 Hz, 2 H), 7.88–7.92 (m, 2 H), 7.99–8.04 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 18.7, 19.3, 32.2, 55.2, 70.1, 73.0, 73.8, 113.9, 122.6 (× 2), 129.4, 130.4, 135.1 (× 2), 137.78, 137.84, 159.2.
HRMS (ESI): m/z calcd for C19H22O6S2 [M]+: 410.0858; found: 410.0856.
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Product 31
According to Typical Procedure A, product 31 was obtained from 27 and 30 as a colorless oil; yield: 287 mg (82%); mp 82.7–83.4 °C; Rf = 0.27 (hexane/EtOAc 1:1); [α]D 21 +5.3 (c 1.0, CHCl3).
IR (ATR): 2966, 1512, 1327, 1244, 1154, 1031, 820, 718, 569 cm–1.
1H NMR (500 MHz, CDCl3): δ = 1.04 (d, J = 6.2 Hz, 3 H), 1.24 (d, J = 6.2 Hz, 3 H), 1.28 (d, J = 6.8 Hz, 3 H), 1.29–1.38 (m, 2 H), 1.63–1.74 (m, 1 H), 1.78–1.87 (m, 1 H), 1.87–1.97 (m, 1 H), 2.04–2.15 (m, 2 H), 2.21–2.52 (m, 5 H), 2.81–2.90 (m, 1 H), 3.31–3.38 (m, 1 H), 3.54–3.62 (m, 1 H), 3.78 (s, 3 H), 3.79 (s, 3 H), 4.27 (d, J = 11.5 Hz, 1 H), 4.40 (d, J = 11.5 Hz, 2 H), 4.49 (d, J = 11.5 Hz, 1 H), 6.84 (d, J = 8.6 Hz, 2 H), 6.89 (d, J = 8.6 Hz, 2 H), 7.20 (d, J = 8.6 Hz, 2 H), 7.24 (d, J = 8.6 Hz, 2 H), 7.84–7.91 (m, 4 H), 7.92–8.02 (m, 4 H).
13C NMR (125 MHz, CDCl3): δ = 14.3, 19.1, 19.5, 24.0, 24.5, 25.5, 26.9, 29.4, 29.6, 34.6, 55.25, 55.30, 69.6, 69.8, 73.1, 74.1, 79.1, 82.6, 113.7, 113.8, 122.0, 122.1, 122.9, 123.0, 129.2, 129.4, 130.6, 130.9, 135.08, 135.10, 135.12, 135.2, 136.4, 136.5, 137.7, 137.8, 159.0, 159.2.
HRMS (MALDI): m/z calcd for C42H50O12S4Na [M + Na]+: 897.2077; found: 897.2084.
#
Product 32
According to Typical Procedure B, product 32 was obtained from 31 as a colorless oil; yield: 24.4 mg (31%); Rf = 0.39 (hexane/EtOAc 9:1); [α]D 20 +3.4 (c 0.54, CHCl3).
IR (ATR): 2928, 1512, 1463, 1245, 1034, 820 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.84 (d, J = 6.6 Hz, 3 H), 1.03–1.11 (m, 2 H), 1.17 (d, J = 6.1 Hz, 6 H), 1.20–1.46 (m, 13 H), 1.52–1.62 (m, 2 H), 3.44–3.52 (m, 2 H), 3.79 (s, 6 H), 4.39 (d, J = 11.4 Hz, 2 H), 4.49 (d, J = 11.4 Hz, 2 H), 6.86 (d, J = 8.6 Hz, 4 H), 7.26 (d, J = 8.6 Hz, 4 H).
13C NMR (125 MHz, CDCl3): δ = 19.6, 19.7, 23.0, 25.6, 27.1, 30.1, 32.7, 36.7, 36.95, 37.06, 37.09, 55.3, 69.89, 69.91, 74.6, 113.7, 129.14, 129.15, 131.3, 159.0.
HRMS (MALDI): m/z calcd for C30H46O4 [M]+: 470.3396; found: 470.3405.
#
Product 33
According to Typical Procedure A, product 33 was obtained from 27 and 1 as a white foam; yield: 242 mg (91%); mp 89–90 °C; Rf = 0.31 (hexane/EtOAc 1:1); [α]D 20 +16.5 (c 1.02, CHCl3).
IR (ATR): 1327, 1247, 1157, 1033, 759, 717, 571 cm–1.
1H NMR (500 MHz, CDCl3): δ = 1.08 (d, J = 6.2 Hz, 3 H), 1.35 (d, J = 6.8 Hz, 3 H), 1.36–1.43 (m, 2 H), 1.78–1.87 (m, 1 H), 2.11–2.30 (m, 2 H), 2.38–2.56 (m, 3 H), 2.95–3.03 (m, 1 H), 3.36–3.43 (m, 1 H), 3.79 (s, 3 H), 4.29 (d, J = 11.5 Hz, 1 H), 4.41–4.46 (m, 2 H), 6.88 (d, J = 8.6 Hz, 2 H), 7.23 (d, J = 8.6 Hz, 2 H), 7.88–8.06 (m, 8 H).
13C NMR (125 MHz, CDCl3): δ = 14.4, 19.2, 21.2, 24.0, 28.3, 29.7, 34.4, 55.3, 69.6, 73.1, 73.4, 82.4, 113.8, 122.0, 122.2, 122.6, 122.7, 129.5, 130.6, 135.17, 135.20, 135.24, 137.6, 137.7, 137.8, 159.1.
HRMS (MALDI): m/z calcd for C30H34O10S4Na [M + Na]+: 705.0927; found: 705.0928.
#
Product 34
To a mixture of PMB ether 20 (235 mg, 0.393 mmol) in CH2Cl2 (7.2 mL) and pH 7 phosphate buffer (0.8 mL) was added DDQ (99.5 mg, 0.438 mmol) at 0 °C. After stirring for 1.5 h at this temperature, the reaction was quenched with sat. aq NaHCO3. The products were extracted with CH2Cl2 (× 3) and the combined extracts were washed with brine, and dried (Na2SO4). Concentration and purification by silica gel column chromatography (hexane/EtOAc 8:2→6:4) gave alcohol 34 as a white solid; yield: 181 mg (96%); mp 109–110 °C; Rf = 0.22 (hexane/EtOAc 6:4); [α]D 22 –2.0 (c 0.50, CHCl3).
IR (ATR): 2929, 1331, 1255, 1154, 1099, 832, 767, 718, 561, 516 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.07 (s, 3 H), 0.08 (s, 3 H), 0.90 (s, 9 H), 1.09 (d, J = 6.2 Hz, 3 H), 1.25 (br d, J = 5.0 Hz, 1 H), 1.29 (d, J = 6.7 Hz, 3 H), 1.31–1.45 (m, 2 H), 1.57–1.65 (m, 1 H), 2.08–2.16 (m, 1 H), 2.30–2.38 (m, 1 H), 2.48–2.56 (m,1 H), 3.02–3.10 (m, 1 H), 3.66–3.73 (m, 1 H), 3.75–3.81 (m, 2 H), 7.87–7.91 (m, 2 H), 7.95–8.00 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.41, –5.38, 14.9, 18.3, 23.4, 24.5, 25.9, 31.3, 32.6, 34.4, 60.9, 67.8, 82.9, 121.9, 122.0, 135.1 (× 2), 137.9, 138.0.
HRMS (MALDI): m/z calcd for C21H36O6SiS2Na [M + Na]+: 499.1615; found: 499.1600.
#
Product 35
According to Typical Procedure A, product 35 was obtained from 33 and 34 as a white solid; yield: 273 mg (96%); mp 137 °C (dec.); Rf = 0.32 (hexane/acetone 6:4); [α]D 23 +28.0 (c 0.50, CHCl3).
IR (ATR): 2930, 1329, 1248, 1155, 1107, 835, 761, 702, 560, 517 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.08 (s, 3 H), 0.09 (s, 3 H), 0.91 (s, 9 H), 0.94 (d, J = 6.1 Hz, 3 H), 1.02 (d, J = 6.5 Hz, 3 H), 1.04–1.25 (m, 4 H), 1.28 (d, J = 6.8 Hz, 3 H), 1.36 (d, J = 6.7 Hz, 3 H), 1.48–1.57 (m, 1 H), 1.60–1.69 (m, 1 H), 1.69–1.95 (m, 4 H), 2.05–2.22 (m, 2 H), 2.38–2.47 (m, 2 H), 2.58–2.67 (m, 1 H), 2.73–2.82 (m, 1 H), 3.06–3.15 (m, 1 H), 3.22–3.30 (m, 1 H), 3.77–3.81 (m, 2 H), 3.82 (s, 3 H), 4.25 (d, J = 11.5 Hz, 1 H), 4.34 (d, J = 11.5 Hz, 1 H), 6.90 (d, J = 8.6 Hz, 2 H), 7.18 (d, J = 8.6 Hz, 2 H), 7.68–8.02 (m, 12 H).
13C NMR (125 MHz, CDCl3): δ = –5.40, –5.37, 13.8, 13.9, 14.9, 18.3, 19.0, 23.6, 25.9, 26.2, 26.6, 29.2, 31.0, 34.3, 34.4, 34.5, 55.3, 60.9, 69.6, 72.9, 82.0, 82.1, 82.8, 113.8, 121.7, 121.92, 121.95, 122.01, 122.36, 122.42, 129.4, 130.5, 134.94, 134.98, 135.04, 135.14, 135.17, 137.4, 137.5, 137.69, 137.71, 138.0, 138.1, 159.2.
HRMS (MALDI): m/z calcd for C51H68O15SiS6Na [M + Na]+: 1163.2544; found: 1163.2537.
#
Product 36
According to Typical Procedure B, product 36 was obtained from 35 as a colorless oil; yield: 41.3 mg (33%); Rf = 0.50 (hexane/Et2O 9:1); [α]D 20 +2.9 (c 0.53, CHCl3).
IR (ATR): 2926, 1462, 1247, 1092, 833, 774 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.05 (s, 6 H), 0.84 (d, J = 6.6 Hz, 6 H), 0.87 (d, J = 6.6 Hz, 3 H), 0.89 (s, 9 H), 1.01–1.12 (m, 4 H), 1.17 (d, J = 6.1 Hz, 3 H), 1.19–1.45 (m, 16 H), 1.49–1.60 (m, 3 H), 3.45–3.52 (m, 1 H), 3.57–3.68 (m, 2 H), 3.80 (s, 3 H), 4.39 (d, J = 11.4 Hz, 1 H), 4.49 (d, J = 11.4 Hz, 1 H), 6.87 (d, J = 8.6 Hz, 2 H), 7.26 (d, J = 8.6 Hz, 2 H).
13C NMR (125 MHz, CDCl3): δ = –5.27, –5.25, 18.3, 19.66, 19.76, 19.78, 23.0, 24.4, 24.5, 26.0, 29.5, 32.78, 32.80, 37.0, 37.1, 37.3, 37.40, 37.44, 37.46, 39.95, 40.02, 55.3, 61.5, 69.9, 74.6, 113.7, 129.1, 131.3, 159.0.
HRMS (MALDI): m/z calcd for C33H62O3SiNa [M + Na]+: 557.4360; found: 557.4370.
#
#
Conflict of Interest
The authors declare no conflict of interest.
Supporting Information
- Supporting information for this article is available online at https://doi-org.accesdistant.sorbonne-universite.fr/10.1055/a-2175-1271.
- Supporting Information
-
References
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Corresponding Authors
Publication History
Received: 13 August 2023
Accepted after revision: 13 September 2023
Accepted Manuscript online:
13 September 2023
Article published online:
26 October 2023
© 2023. Thieme. All rights reserved
Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany
-
References
- 1a Mitsunobu O. Synthesis 1981; 1
- 1b But TY. S, Toy PH. Chem. Asian J. 2007; 2: 1340
- 1c Swamy KC. K, Kumar NN. B, Balaraman E, Kumar KV. P. P. Chem. Rev. 2009; 109: 2551
- 1d Fletcher S. Org. Chem. Front. 2015; 2: 739
- 2 Dryzhakov M, Richmond E, Moran J. Synthesis 2016; 48: 935
- 3 Itô S, Tsunoda T. Pure Appl. Chem. 1999; 71: 1053
- 4a Tsunoda T, Ozaki F, Itô S. Tetrahedron Lett. 1994; 35: 5081
- 4b Tsunoda T, Nagaku M, Nagino C, Kawamura Y, Ozaki F, Hioki H, Itô S. Tetrahedron Lett. 1995; 36: 2531
- 5 Tsunoda T, Otsuka J, Yamamiya Y, Itô S. Chem. Lett. 1994; 23: 539
- 6 Tsunoda T, Itô S. J. Synth. Org. Chem. Jpn. 1997; 55: 631
- 7a Tsunoda T, Nagino C, Oguri M, Itô S. Tetrahedron Lett. 1996; 37: 2459
- 7b Tsunoda T, Uemoto K, Ohtani T, Kaku H, Itô S. Tetrahedron Lett. 1999; 40: 7359
- 7c Sakamoto I, Kaku H, Tsunoda T. Chem. Pharm. Bull. 2003; 51: 474
- 7d Hwang J.-T. Cyanomethylenetrimethylphosphorane, Encyclopedia of Reagents for Organic Synthesis. Wiley;
- 8a Kündig EP, Cunningham AF. Tetrahedron 1988; 44: 6855
- 8b Zhang S, Li J, Zhao S, Wang W. Tetrahedron Lett. 2010; 51: 1766
- 8c Zheng H, Li Z, Jing J, Xue X.-S, Cheng J.-P. Angew. Chem. Int. Ed. 2021; 60: 9401
- 9 Trost BM, Kalnmals CA. Chem. Eur. J. 2019; 25: 11193
- 10a Shing TK. M, Li L, Narkunan K. J. Org. Chem. 1997; 62: 1617
- 10b Takacs JM, Xu Z, Jiang X.-t, Leonov AP, Theriot GC. Org. Lett. 2002; 4: 3843
- 10c Prakash GK. S, Chacko S, Alconcel S, Stewart T, Mathew T, Olah GA. Angew. Chem. Int. Ed. 2007; 46: 4933
- 11 Nájera C, Yus M. Tetrahedron 1999; 55: 10547
- 12a Shiozaki H, Miyahara M, Otsuka K, Miyako K, Honda A, Takasaki Y, Takamizawa S, Tukada H, Ishikawa Y, Sakai R, Oikawa M. Org. Lett. 2018; 20: 3403
- 12b Irie R, Miyahara M, Nakamura S, Honda A, Sakai R, Oikawa M. J. Nat. Prod. 2020; 83: 2769
- 13a Eguchi T, Terachi T, Kakinuma K. J. Chem. Soc., Chem. Commun. 1994; 137
- 13b Li N.-S, Piccirilli JA. Tetrahedron 2013; 69: 9633
- 13c Van Summeren RP, Reijmer SJ. W, Feringa BL, Minnaard AJ. Chem. Commun. 2005; 1387
- 13d Ruiz J, Oger P, Soulére L, Popowycz F. J. Org. Chem. 2021; 86: 9396
- 14a Van Summeren RP, Moody DB, Feringa BL, Minnaard AJ. J. Am. Chem. Soc. 2006; 128: 4546
- 14b Li N.-S, Scharf L, Adams EJ, Piccirilli JA. J. Org. Chem. 2013; 78: 5970
- 14c Andringa RL. H, de Kok NA. W, Driessen AJ. M, Minnaard AJ. Angew. Chem. Int. Ed. 2021; 60: 17497
- 15a Netscher T. Vitam. Horm. 2007; 76: 155
- 15b Eggersdorfer M, Laudert D, Létinois U, McClymont T, Medlock J, Netscher T, Bonrath W. Angew. Chem. Int. Ed. 2012; 51: 12960
- 15c Kundu S, Sarkar D. J. Heterocycl. Chem. 2023; 60: 345
- 16a Burns M, Essafi S, Bame JR, Bull SP, Webster MP, Balieu S, Dale JW, Butts CP, Harvey JN, Aggarwal VK. Nature 2014; 513: 183
- 16b Bootwicha T, Feilner JM, Myers EL, Aggarwal VK. Nat. Chem. 2017; 9: 896
- 17a Breuilles P, Oddon G, Uguen D. Tetrahedron Lett. 1997; 38: 6607
- 17b Krishna PR, Prabhakar S. Tetrahedron Lett. 2013; 54: 3788
- 18a Brown AC, Carpino LA. J. Org. Chem. 1985; 50: 1749
- 18b Huang B.-q, Chen Y, Zhang X.-j, Yan M. Eur. J. Org. Chem. 2021; 3015
- 18c Pan P, Chen L, Zhang X.-j, Yan M. Tetrahedron 2021; 96: 132371
- 19a Hanessian S, Giroux S, Mascitti V. Synthesis 2006; 1057
- 19b ter Horst B, Feringa BL, Minnaard AJ. Chem. Commun. 2010; 46: 2535
- 19c Holzheimer M, Buter J, Minnaard AJ. Chem. Rev. 2021; 121: 9554
- 20 Ghostin J, Bordereau C, Braekman JC. Nat. Prod. Res. 2011; 25: 560