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Synthesis 2024; 56(20): 3160-3166
DOI: 10.1055/a-2367-2434
paper

Ni–H-Catalyzed Chemo- and Regioselective Hydroarylation of Vinylsilanes

Daniel Brösamlen 
,
Martin Oestreich  ∗

This research was supported by the Deutsche Forschungsgemeinschaft (Oe 249/25-1). M.O. is indebted to the Einstein Stiftung Berlin for an endowed professorship.
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Abstract

A chemo- and regioselective hydroarylation of vinylsilanes with (hetero)aryl iodides under Ni–H catalysis is reported. This mild and straightforward protocol furnishes the anti-Markovnikov products in good yields as single regioisomers. This study demonstrates excellent control over the chemoselectivity and complements existing methods for the construction of homobenzylic silanes.


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Key words

cross-coupling - hydroarylation - nickel - regioselectivity - silicon

In recent years, transition-metal-catalyzed hydrocarbonation of alkenes has emerged as a superb tool for the construction of C(sp3)–C(sp2) and C(sp3)–C(sp3) bonds.[1] This approach offers an alternative to traditional methods that involve preformed Grignard and organozinc reagents, often facing challenges such as sensitivity to air and moisture and prolonged bench life. Among the many metal complexes that catalyze this reaction, those of nickel have manifested themselves as powerful catalysts.[1`] [c] [d] [e] [f] , [2] Typically, the addition of the generated Ni–H species to a terminal or an internal alkene could lead to two or even more regioisomers. However, nickel’s excellent site selectivity can overcome this issue, including that arising from chain-walking processes. Linear selectivity is usually favored.[3] [4] [5]

Among the attractive olefin building blocks as pronucleophiles, vinylsilanes are particularly interesting due to their chemical stability, ease of preparation, and significance as intermediates in numerous synthetic transformations.[5] [6] [7] [8] While we established methods for the Ni–H-catalyzed regioselective hydroalkylation of this metalloid in both an anti-Markovnikov[5] and a Markovnikov[8] fashion (Scheme [1], top), Shi, Koh, and co-workers reported an enantioselective hydroalkenylation of a vinylsilane with an alkenyl triflate to afford an α-chiral allylic silane (Scheme [1], bottom left).[9] In this regard, enabling a hydroarylation in an anti-Markovnikov fashion would not only access homobenzylic silanes (Scheme [1], bottom right) but also provide an alternative approach to well-established methods such as the hydrosilylation of styrene derivatives[10] and transition-metal-catalyzed hydroarylation of vinylsilanes involving directing-group-assisted C–H activation.[11] [12] These alternative methods can sometimes present challenges such as the utilization of precious metals (even in stoichiometric quantities), the need of a directing group, lack of regiocontrol, and limited functional group tolerance. To complement these existing methods, we present here a straightforward protocol for the hydroarylation of vinylsilanes in a chemo- and regioselective manner.

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Scheme 1 Methods established for the nickel-catalyzed hydrocarbonation of vinylsilanes. Hydroalkylation in an anti-Markovnikov and Markovnikov­ fashion (top) and hydroalkenylation to access α-chiral allylic silanes (bottom left). [Si] = triorganosilyl group. Do = directing group.

The starting point of this study was an examination of the hydroarylation reaction of dimethyl(phenyl)(vinyl)silane (2a) with phenyl iodide (1a) by adapting the optimized conditions from the previously reported protocol for the hydroalkylation of vinylsilanes and -germanes (Table [1]).[5] To our surprise, we were able to isolate the desired product 3aa with excellent regioselectivity when employing 2,2′-bipyridine (L1, bpy) as the ligand (entry 1). An evaluation of other bidentate nitrogen ligands such as dmbpy (L2), BBBPY (L3), phen (L4), BPhen (L5), and quinox (L6) did not further improve the yield and regioselectivity (entries 2–6). This demonstrates that the reaction’s ability to achieve anti-Markovnikov selectivity and its overall success are greatly influenced by the small ligand L1. An optimization of other parameters such as the nickel precatalyst, solvent, and base, as well as the hydride source, was fruitless (not shown).

Table 1 Selected Examples of the Ligand Screeninga

Entry

Ligand

Yield (%) of 3aa b

r.r. (3aa/4aa)c

1

L1

75

99:1

2

L2

65

91:9

3

L3

62

79:21

4

L4

trace

n.d.

5

L5

59

86:14

6

L6

57

93:7

a Reactions were performed on a 0.10-mmol scale with 1.5 equivalents of 1a and 1.0 equivalent of 2a.

b Yields were determined by GLC analysis with biphenyl as an internal standard.

c Ratio of the regioisomers was determined by NMR spectroscopic analysis. r.r. = regioisomeric ratio. n.d. = not determined.

With the optimal conditions established, we first investigated the silicon substitution pattern of various vinylsilanes using 1a as the representative pronucleophile (Scheme [2]). Substituents of different sizes were all tolerated, including Et3Si- in 2b, t-BuMe2Si- in 2c, Me2PhSi- in 2a, and Ph3Si- in 2g. The products were obtained in good yields and with excellent regioselectivities. Modifying the aryl group in the model substrate 2a with an electron-donating group at the ortho position resulted for 2d → 3ad (-OMe) in an improved yield for the linear regioisomer. In turn, that regioselectivity dropped for 2e → 3ae (-SMe), suggesting a potential interaction between the weakly coordinating sulfur atom and the nickel catalyst, thereby directing the nickel center towards the branched position. Finally, having a heteroaryl unit such as a thienyl group attached to the silicon atom was also tolerated, enabling product formation in 55% yield (2f → 3af). In contrast to the reported hydroalkylation protocol for anti-Markovnikov[5] and Markovnikov selectivity,[8] we did not observe any transformation with vinylgermanes (not shown).

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Scheme 2 Scope I: Ni–H-catalyzed regioselective hydroarylation of vinylsilanes­ 2a–2g with aryl iodide 1a. Unless otherwise noted, all reactions were performed on a 0.10-mmol scale according to the general procedure. Yields are isolated yields after flash column chromatography on silica gel. a r.r. = 86:14.

Next, we investigated the chemoselectivity of this transformation (Scheme [3]). We installed an allyl and a vinyl group on the silicon atom as in 2h and subjected this pronucleophile to the general procedure. This resulted in the exclusive formation of the allyl-substituted product 3ah. This result displays the superior reactivity of the vinyl over the allyl moiety in the hydroarylation reaction. This chemo- selectivity aligns with the results previously observed in the hydroalkylation protocol.[5] Notably, an allylsilane alone did not result in any product formation (not shown). Furthermore, a substrate decorated with an isopropenyl group in the presence of the vinyl moiety as in 2i confirmed once more the chemoselectivity of this protocol. Product 3ai was formed in 58% yield with the isopropenyl group untouched. Nevertheless, in the absence of the more reactive vinyl unit, the reaction still proceeded, yielding the hydroarylated product in 45% yield (2j → 3aj), indicating that steric hindrance of the alkene moiety does not necessarily impede the transformation.

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Scheme 3 Scope II: Ni–H-catalyzed chemoselective transformation of vinylsilanes 2h–2j with aryl iodide 1a. Unless otherwise noted, all reactions were performed on a 0.10-mmol scale according to the general procedure. Yields are isolated yields after flash column chromatography on silica gel. a 1.0 equivalent of 1a was used.

We then turned our attention to the scope of the (hetero)aryl iodide 1, employing vinylsilane 2a as the standard substrate (Scheme [4]). An electron-donating group such as a methoxy group at the para or meta position gave satisfactory yields and excellent regioselectivities. However, no product formation was achieved with that group at the ortho position. Other aryl iodides with different electron-withdrawing groups at the para position were compatible with this method, including a trifluoromethoxy (3ea), a trifluoromethyl (3fa), a nitrile (3ga), and an ester group (3ha). Moderate to good yields and excellent regioselectivities were obtained throughout. Notably, an aldehyde as in 4-iodobenzaldehyde (1i) was also tolerated to afford product 3ia in good yield. Lastly, extending the scope by a heteroaryl iodide furnished the product in 61% yield as a single regioisomer (1j → 3ja).

Zoom Image
Scheme 4 Scope III: Ni–H-catalyzed regioselective hydroarylation of vinylsilane 2a with (hetero)aryl iodides 1b–1j. Unless otherwise noted, all reactions were performed on a 0.10-mmol scale according to the general procedure. Yields are isolated yields after flash column chromatography on silica gel. n.r. = no reaction. a r.r. = 96:4.

In summary, we disclosed here a Ni–H-catalyzed chemo- and regioselective hydroarylation of vinylsilanes with (hetero)aryl iodides to achieve the formation of a C(sp3)–C(sp2) bond. This mild protocol features 18 examples and complements existing methods.

All reactions were performed in oven-dried glassware using conventional Schlenk techniques under a static pressure of nitrogen gas unless otherwise stated. Liquids and solutions were transferred via syringes. Standard solvents and reagents were obtained from commercial suppliers and were dried and purified following standard procedures. Technical grade solvents for extraction or chromatography (CH2Cl2, tert-butyl methyl ether, n-pentane) were distilled prior to use. Et2O and THF were dried over sodium/benzophenone and freshly distilled prior to use. Unless otherwise noted, all commercially available reagents were used as received, including NiBr2·DME (ABCR) and dimethylacetamide (DMA; 99.5%, extra dry over molecular sieves, AcroSeal, Acros Organics). CDCl3 was obtained from commercial suppliers and used as received. (Hetero)aryl iodides 1a–1j and vinylsilanes 2a–2c and 2g were obtained from commercial suppliers and used as received. Vinylsilanes 2d,[5] 2e,[5] 2f,[13] 2h,[14] and 2j [15] are known compounds and prepared accordingly. The synthesis of the new vinylsilane 2i and its characterization data are provided (vide infra). Flash column chromatography was performed on Grace silica gel 60 (40–63 μm, 230–400 mesh, ASTM) using the indicated solvents. IR spectra were recorded on an Agilent Technologies Cary 630 FT-IR spectrometer equipped with a diamond ATR unit. Selected signals are reported in wavenumbers (cm–1). 1H, 13C, 19F, and 29Si NMR spectra were recorded in CDCl3 at 298 K on Bruker AV500 instruments. Chemical shifts are reported in parts per million (ppm) and are referenced to the residual solvent resonance as the internal standard (CHCl3: δ = 7.26 ppm for 1H NMR, CDCl3: δ = 77.16 ppm for 13C NMR). All other nuclei (19F and 29Si) were referenced in compliance with the unified scale for NMR chemical shifts as recommended by IUPAC, stating the chemical shift relative to BF3·OEt2, CCl3F, and Me4Si.[16] Data are reported as follows: chemical shift, multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet), coupling constant(s) (Hz), and integration. High-resolution mass spectra (HRMS) were obtained from the Center of Mass Spectrometry at the Institut für Chemie, Technische Universität Berlin. Analytical GLC was performed on an Agilent Technologies 7820A gas chromatograph equipped with an Agilent Technologies J&W HP-5 capillary column (30 m × 0.32 mm, 0.25 μm film thickness) by using the following conditions: N2 carrier gas, injection temperature 250 °C, detector temperature 300 °C, flow rate 1.7 mL/min, temperature program: start temperature 40 °C, heating rate 10 °C/min, end temperature 280 °C for 10–30 min. Melting points were determined on a Leica Galen III hot-stage microscope and are uncorrected.


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Diphenyl(prop-1-en-2-yl)(vinyl)silane (2i)

Following a modified literature procedure,[15] a flame-dried round-bottom flask equipped with a magnetic stir bar was charged chlorodiphenyl(vinyl)silane (1.2 g, 5.0 mmol, 1.0 equiv) and sealed with a septum cap. After placing the flask under high vacuum and backfilling with N2 (3 times), the solution was diluted in anhydrous THF (10 mL) and the mixture was cooled to 0 °C. After adding prop-1-en-2-ylmagnesium bromide (6.0 mmol, 1.2 equiv) dropwise, the reaction mixture was warmed to room temperature and stirred for 15 h. The mixture was quenched with 1 N HCl (1 mL) and Et2O (3 × 10 mL) was used for extraction. The combined organic layers were dried with anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash column chromatography on silica gel (pentane) to afford vinylsilane 2i (1.0 g, 4.1 mmol, 82% yield) as a colorless oil; Rf = 0.62 (pentane).

IR (ATR): 3048, 2942, 1427, 1107, 1005, 930, 696 cm–1.

1H NMR (500 MHz, CDCl3): δ = 7.55–7.54 (m, 4 H), 7.43–7.36 (m, 6 H), 6.56 (dd, J = 14.7, 20.1 Hz, 1 H), 6.28 (dd, J = 3.7, 14.7 Hz, 1 H), 5.90 (dd, J = 1.6, 2.5 Hz, 1 H), 5.79 (dd, J = 3.7, 20.2 Hz, 1 H), 5.40 (dd, J = 1.4, 1.8 Hz, 1 H), 1.93 (d, J = 1.1 Hz, 3 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 142.7, 136.5, 135.9, 134.0, 133.6, 130.9, 129.6, 128.0, 23.4.

HRMS (APCI): m/z [M – C6H5]+ calcd for [C11H13Si]+: 173.0781; found: 173.0781.


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Hydroarylation of Vinylsilanes with (Hetero)aryl Iodides under Nickel Catalysis; General Procedure 1 (GP1)

To an oven-dried Schlenk tube equipped with a magnetic stir bar was added (hetero)aryl iodide 1a–1j (0.15 mmol, 1.5 equiv), NiBr2·DME (3.1 mg, 0.010 mmol, 10 mol%), 2,2′-bipyridine (L1; 2.3 mg, 0.015 mmol, 15 mol%), KF (14 mg, 0.25 mmol, 2.5 equiv), and vinylsilane 2a–2j (0.10 mmol, 1.0 equiv). After placing the tube under high vacuum and backfilling with N2 (3 times), the solution was diluted in anhydrous DMA (1.0 mL). After stirring the reaction mixture at room temperature for 5 min, diethoxymethylsilane (40 μL, 0.25 mmol, 2.5 equiv) was added. After 24 h, the reaction was stopped by the addition of NH4Cl (0.1 mL), followed by dilution with pentane (0.5 mL). The aqueous phase was extracted with pentane (4 × 1 mL) and the combined organic layers were dried with anhydrous Na2SO4, filtered, and concentrated under reduced pressure. Purification of the residue by flash column chromatography on silica gel with the indicated solvent as eluent afforded the coupling product.


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Dimethyl(phenethyl)(phenyl)silane (3aa)

Prepared from iodobenzene (1a) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3aa (14.2 mg, 0.0590 mmol, 59%) as a colorless oil; Rf = 0.25 (pentane).

1H NMR (500 MHz, CDCl3): δ = 7.53–7.51 (m, 2 H), 7.36–7.35 (m, 3 H), 7.24–7.23 (m, 2 H), 7.17–7.12 (m, 3 H), 2.64–2.61 (m, 2 H), 1.14–1.10 (m, 2 H), 0.28 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 145.1, 139.2, 133.7, 129.1, 128.4, 127.9, 127.9, 125.7, 30.1, 17.8, –3.0.

The spectroscopic data are in accordance with those reported in the literature.[17]


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Triethyl(phenethyl)silane (3ab)

Prepared from iodobenzene (1a) with triethyl(vinyl)silane (2b) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3ab (17.8 mg, 0.0810 mmol, 81%) as a colorless oil; Rf = 0.88 (pentane).

1H NMR (500 MHz, CDCl3): δ = 7.27–7.24 (m, 2 H), 7.19 (d, J = 7.4 Hz, 2 H), 7.14 (t, J = 7.2 Hz, 1 H), 2.61–2.58 (m, 2 H), 0.94 (t, J = 7.9 Hz, 9 H), 0.89–0.86 (m, 2 H), 0.54 (q, J = 8.0 Hz, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 145.8, 128.4, 127.8, 125.6, 30.2, 13.8, 7.6, 3.4.

The spectroscopic data are in accordance with those reported in the literature.[17]


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tert-Butyldimethyl(phenethyl)silane (3ac)

Prepared from iodobenzene (1a) with tert-butyldimethyl(vinyl)silane (2c) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3ac (15.6 mg, 0.0720 mmol, 72%) as a colorless oil; Rf = 0.83 (pentane).

1H NMR (500 MHz, CDCl3): δ = 7.28–7.13 (m, 5 H), 2.62–2.58 (m, 2 H), 0.88 (s, 9 H), 0.86–0.85 (m, 2 H), –0.04 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 145.7, 128.5, 127.9, 125.6, 30.6, 26.7, 16.7, 14.9, –6.2.

The spectroscopic data are in accordance with those reported in the literature.[18]


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(2-Methoxyphenyl)dimethyl(phenethyl)silane (3ad)

Prepared from iodobenzene (1a) with (2-methoxyphenyl)dimethyl(vinyl)silane[5] (2d) according to GP1. Purification by flash column chromatography (silica gel; pentane/MTBE, 80:1) afforded 3ad (21.3 mg, 0.0790 mmol, 79%) as a colorless oil; Rf = 0.44 (pentane/MTBE, 60:1).

IR (ATR): 3024, 2951, 1428, 1235, 1025, 835, 755 cm–1.

1H NMR (500 MHz, CDCl3): δ = 7.40–7.35 (m, 2 H), 7.27–7.24 (m, 2 H), 7.19–7.14 (m, 3 H), 6.97 (t, J = 7.3 Hz, 1 H), 6.84 (d, J = 8.2 Hz, 1 H), 3.81 (s, 3 H), 2.64–2.61 (m, 2 H), 1.20–1.16 (m, 2 H), 0.29 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 164.5, 145.7, 135.4, 131.0, 128.3, 127.9, 126.8, 125.5, 120.6, 109.6, 55.1, 30.3, 17.7, –2.6.

HRMS (APCI): m/z [M – H]+ calcd for [C17H21OSi]+: 269.1356; found: 269.1358.


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Dimethyl(2-(methylthio)phenyl)(phenethyl)silane (3ae)

Prepared from iodobenzene (1a) with dimethyl(2-(methylthio)phenyl)(vinyl)silane[5] (2e) according to GP1. Purification by flash column chromatography (silica gel; pentane/MTBE, 80:1) afforded 3ae (15.2 mg, 0.0530 mmol, 53%) as a colorless oil; Rf = 0.45 (pentane/MTBE, 60:1).

IR (ATR): 3023, 2919, 1420, 1248, 809, 742 cm–1.

1H NMR (500 MHz, CDCl3): δ = 7.37 (d, J = 7.2 Hz, 1 H), 7.29–7.24 (m, 2 H), 7.20–7.17 (m, 3 H), 7.12–7.06 (m, 3 H), 2.57–2.54 (m, 2 H), 2.42 (s, 3 H), 1.26–1.23 (m, 2 H), 0.32 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 144.4, 144.2, 137.8, 134.2, 129.0, 127.4, 127.0, 126.5, 124.6, 124.0, 29.3, 17.0, 17.0, –2.7.

HRMS (APCI): m/z [M + H + O]+ calcd for [C17H23OSSi]+: 303.1233; found: 303.1235.


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Dimethyl(phenethyl)(thiophen-2-yl)silane (3af)

Prepared from iodobenzene (1a) with dimethyl(thiophen-2-yl)(vinyl)silane[13] (2f) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3af (13.5 mg, 0.0550 mmol, 55%) as a colorless oil; Rf = 0.44 (pentane).

IR (ATR): 3060, 2954, 1249, 1212, 989, 771, 695 cm–1.

1H NMR (500 MHz, CDCl3): δ = 7.62 (d, J = 4.6 Hz, 1 H), 7.29–7.15 (m, 7 H), 2.70–2.66 (m, 2 H), 1.17–1.14 (m, 2 H), 0.34 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 144.9, 144.4, 134.5, 130.8, 128.5, 128.3, 127.9, 125.7, 30.0, 18.8, –1.8.

HRMS (APCI): m/z [M – CH3]+ calcd for [C13H15SSi]+: 231.0658; found: 231.0659.


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Phenethyltriphenylsilane (3ag)

Prepared from iodobenzene (1a) with triphenyl(vinyl)silane (2g) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3ag (14.9 mg, 0.0410 mmol, 41%) as a white solid; Rf = 0.19 (pentane).

1H NMR (500 MHz, CDCl3): δ = 7.57–7.56 (m, 6 H), 7.44–7.36 (m, 9 H), 7.28–7.25 (m, 2 H), 7.20–7.15 (m, 3 H), 2.80–2.76 (m, 2 H), 1.76–1.73 (m, 2 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 145.1, 135.8, 135.0, 129.7, 128.5, 128.1, 127.9, 125.8, 30.2, 15.6.

The spectroscopic data are in accordance with those reported in the literature.[19]


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Allyldimethyl(phenethyl)silane (3ah)

Prepared from iodobenzene (1a) with allyldimethyl(vinyl)silane[14] (2h) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3ah (13.7 mg, 0.0670 mmol, 67%) as a colorless oil; Rf = 0.65 (pentane).

IR (ATR): 3025, 2953, 1249, 1153, 892, 833 cm–1.

1H NMR (500 MHz, CDCl3): δ = 7.29–7.26 (m, 2 H), 7.21–7.15 (m, 3 H), 5.84–5.75 (m, 1 H), 4.88–4.83 (m, 2 H), 2.66–2.62 (m, 2 H), 1.55 (dd, J = 2.9, 8.1 Hz, 2 H), 0.93–0.89 (m, 2 H), 0.02 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 145.3, 135.2, 128.5, 127.9, 125.7, 113.0, 30.0, 23.3, 17.0, –3.7.

HRMS (APCI): m/z [M – C2H3]+ calcd for [C11H17Si]+: 177.1094; found: 177.1093.


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Phenethyldiphenyl(prop-1-en-2-yl)silane (3ai)

Prepared from iodobenzene (1a) with diphenyl(prop-1-en-2-yl)(vinyl)silane (2i) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3ai (19.0 mg, 0.0580 mmol, 58%) as a colorless oil; Rf = 0.30 (pentane).

IR (ATR): 3022, 2935, 1426, 1106, 930, 695 cm–1.

1H NMR (500 MHz, CDCl3): δ = 7.55–7.53 (m, 4 H), 7.41–7.34 (m, 6 H), 7.24–7.22 (m, 2 H), 7.18–7.13 (m, 3 H), 5.87 (q, J = 1.5 Hz, 1 H), 5.44 (q, J = 1.8 Hz, 1 H), 2.72–2.69 (m, 2 H), 1.89 (s, 3 H), 1.55–1.50 (m, 2 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 145.2, 143.1, 135.6, 134.6, 130.1, 129.5, 128.5, 128.0, 127.9, 125.8, 30.2, 23.5, 14.9.

HRMS (APCI): m/z [M – H]+ calcd for [C23H23Si]+: 327.1564; found: 327.1563.


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Dimethyl(phenyl)(1-phenylpropan-2-yl)silane (3aj)

Prepared from iodobenzene (1a) with dimethyl(phenyl)(prop-1-en-2-yl)silane[15] (2j) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3aj (11.4 mg, 0.0450 mmol, 45%) as a colorless oil; Rf = 0.26 (pentane).

IR (ATR): 3064, 2951, 1248, 1111, 809, 768, 697 cm–1.

1H NMR (500 MHz, CDCl3): δ = 7.55–7.53 (m, 2 H), 7.38–7.37 (m, 3 H), 7.24 (d, J = 7.5 Hz, 2 H), 7.15 (t, J = 7.2 Hz, 1 H), 7.10 (d, J = 7.4 Hz, 2 H), 2.87 (dd, J = 3.5, 13.7 Hz, 1 H), 2.21 (dd, J = 13.5, 14.2 Hz, 1 H), 1.24–1.17 (m, 1 H), 0.84 (s, 3 H), 0.30 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 142.6, 138.4, 134.1, 129.0, 128.9, 128.2, 127.9, 125.7, 38.0, 21.8, 13.8, –4.8, –4.9.

HRMS (APCI): m/z [M – CH3]+ calcd for [C16H19Si]+: 239.1251; found: 239.1247.


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(4-Methoxyphenethyl)dimethyl(phenyl)silane (3ba)

Prepared from 1-iodo-4-methoxybenzene (1b) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3ba (18.4 mg, 0.0680 mmol, 68%) as a colorless oil; Rf = 0.21 (pentane).

1H NMR (500 MHz, CDCl3): δ = 7.54–7.52 (m, 2 H), 7.37–7.36 (m, 3 H), 7.09 (d, J = 8.6 Hz, 2 H), 6.81 (d, J = 8.6 Hz, 2 H), 3.78 (s, 3 H), 2.61–2.57 (m, 2 H), 1.12–1.09 (m, 2 H), 0.29 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 157.8, 139.3, 137.3, 133.7, 129.0, 128.8, 127.9, 113.9, 55.4, 29.2, 18.1, –2.9.

The spectroscopic data are in accordance with those reported in the literature.[20]


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(3-Methoxyphenethyl)dimethyl(phenyl)silane (3ca)

Prepared from 1-iodo-3-methoxybenzene (1c) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3ca (11.3 mg, 0.0420 mmol, 42%) as a colorless oil; Rf = 0.21 (pentane).

1H NMR (500 MHz, CDCl3): δ = 7.54–7.53 (m, 2 H), 7.37–7.36 (m, 3 H), 7.18 (t, J = 7.8 Hz, 1 H), 6.77 (d, J = 7.6 Hz, 1 H), 6.72–6.70 (m, 2 H), 3.79 (s, 3 H), 2.63–2.60 (m, 2 H), 1.14–1.11 (m, 2 H), 0.30 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 159.8, 146.8, 139.2, 133.7, 129.4, 129.1, 127.9, 120.3, 113.6, 111.0, 55.3, 30.1, 17.7, –3.0.

The spectroscopic data are in accordance with those reported in the literature.[21]


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Dimethyl(phenyl)(4-(trifluoromethoxy)phenethyl)silane (3ea)

Prepared from 1-iodo-4-(trifluoromethoxy)benzene (1e) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel; pentane/MTBE, 80:1) afforded 3ea (24.0 mg, 0.0740 mmol, 74%) as a colorless oil; Rf = 0.27 (pentane/MTBE, 60:1).

IR (ATR): 2955, 2862, 1506, 1252, 1159, 813, 699 cm–1.

1H NMR (500 MHz, CDCl3): δ = 7.53–7.51 (m, 2 H), 7.37–7.36 (m, 3 H), 7.17–7.16 (m, 2 H), 7.10–7.08 (m, 2 H), 2.65–2.61 (m, 2 H), 1.13–1.09 (m, 2 H), 0.30 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 147.3, 143.8, 138.9, 134.2, 133.7, 129.2, 129.1, 128.3, 128.0, 127.8, 121.0, 29.5, 17.9, –3.0.

HRMS (APCI): m/z [M + H]+ calcd for [C17H20F3OSi]+: 325.1230; found: 325.1241.


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Dimethyl(phenyl)(4-(trifluoromethyl)phenethyl)silane (3fa)

Prepared from 1-iodo-4-(trifluoromethyl)benzene (1f) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel, pentane) afforded 3fa (20.0 mg, 0.0650 mmol, 65%) as a colorless oil; Rf = 0.35 (pentane).

1H NMR (500 MHz, CDCl3): δ = 7.53–7.49 (m, 4 H), 7.38–7.35 (m, 3 H), 7.27–7.25 (m, 2 H), 2.70–2.66 (m, 2 H), 1.14–1.11 (m, 2 H), 0.31 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 149.2, 138.7, 133.7, 129.2, 128.2, 128.0, 127.8, 125.3, 125.3, 30.1, 17.7, –3.0.

19F NMR (470 MHz, CDCl3): δ = –62.3 (s).

The spectroscopic data are in accordance with those reported in the literature.[21]


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4-(2-(Dimethyl(phenyl)silyl)ethyl)benzonitrile (3ga)

Prepared from 4-iodobenzonitrile (1g) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel; pentane/MTBE, 80:1) afforded 3ga (12.9 mg, 0.0490 mmol, 49%) as a colorless oil; Rf = 0.27 (pentane/MTBE, 60:1).

1H NMR (500 MHz, CDCl3): δ = 7.54–7.50 (m, 4 H), 7.38–7.36 (m, 3 H), 7.25 (d, J = 8.1 Hz, 2 H), 2.68–2.65 (m, 2 H), 1.12–1.08 (m, 2 H), 0.31 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 150.7, 138.5, 133.7, 132.3, 129.3, 128.7, 128.0, 119.3, 109.5, 30.4, 17.6, –3.1.

The spectroscopic data are in accordance with those reported in the literature.[17]


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Methyl 4-(2-(Dimethyl(phenyl)silyl)ethyl)benzoate (3ha)

Prepared from methyl 4-iodobenzoate (1h) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel; pentane/MTBE, 80:1) afforded 3ha (21.2 mg, 0.0710 mmol, 71%) as a colorless oil; Rf = 0.28 (pentane/MTBE, 60:1).

1H NMR (500 MHz, CDCl3): δ = 7.93 (d, J = 8.4 Hz, 2 H), 7.54–7.52 (m, 2 H), 7.38–7.36 (m, 3 H), 7.23 (d, J = 8.5 Hz, 2 H), 3.90 (s, 3 H), 2.69–2.66 (m, 2 H), 1.14–1.11 (m, 2 H), 0.30 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 167.3, 150.7, 138.8, 133.7, 129.8, 129.2, 128.0, 128.0, 127.7, 52.1, 30.3, 17.6, –3.0.

The spectroscopic data are in accordance with those reported in the literature.[22]


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4-(2-(Dimethyl(phenyl)silyl)ethyl)benzaldehyde (3ia)

Prepared from 4-iodobenzaldehyde (1i) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel; pentane/MTBE, 60:1) afforded 3ia (11.3 mg, 0.0420 mmol, 42%) as a white solid; mp 105–106 °C (pentane); Rf = 0.22 (pentane/MTBE, 60:1).

IR (ATR): 2955, 2884, 1673, 1604, 1246, 1111, 770 cm–1.

1H NMR (500 MHz, CDCl3): δ = 9.96 (s, 1 H), 7.77 (d, J = 8.3 Hz, 2 H), 7.54–7.52 (m, 2 H), 7.38–7.37 (m, 3 H), 7.32 (d, J = 8.0 Hz, 2 H), 2.72–2.68 (m, 2 H), 1.15–1.11 (m, 2 H), 0.31 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 192.1, 152.7, 134.5, 133.7, 130.1, 129.2, 128.6, 128.0, 30.5, 17.7, –3.0.

HRMS (APCI): m/z [M – H]+ calcd for [C17H19OSi]+: 267.1200; found: 267.1200.


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2-(2-(Dimethyl(phenyl)silyl)ethyl)pyridine (3ja)

Prepared from 2-iodopyridine (1j) with dimethyl(phenyl)(vinyl)silane (2a) according to GP1. Purification by flash column chromatography (silica gel; pentane/MTBE, 40:1) afforded 3ja (14.7 mg, 0.0610 mmol, 61%) as a pale-yellow oil; Rf = 0.13 (pentane).

1H NMR (500 MHz, CDCl3): δ = 8.51 (d, J = 4.2 Hz, 1 H), 7.62 (t, J = 7.4 Hz, 1 H), 7.55–7.53 (m, 2 H), 7.36–7.35 (m, 3 H), 7.16 (d, J = 7.9 Hz, 1 H), 7.13 (t, J = 6.2 Hz, 1 H), 2.87–2.83 (m, 2 H), 1.25–1.22 (m, 2 H), 0.32 (s, 6 H).

13C{1H} NMR (125 MHz, CDCl3): δ = 163.8, 148.4, 138.9, 137.6, 133.9, 133.6, 129.2, 129.0, 128.1, 127.8, 122.7, 122.5, 121.4, 121.2, 32.2, 16.2, –3.0, –3.1.

The spectroscopic data are in accordance with those reported in the literature.[21]


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Conflict of Interest

The authors declare no conflict of interest.

Acknowledgment

The authors thank Sarah Marie Zoe Perry (TU Berlin) for her experimental contributions to this project.

Supporting Information

    Supporting information for this article is available online at https://doi-org.accesdistant.sorbonne-universite.fr/10.1055/a-2367-2434.
  • Supporting Information

Corresponding Author

Martin Oestreich
Institut für Chemie, Technische Universität Berlin
Straße des 17. Juni 115, 10623 Berlin
Germany   

Publication History

Received: 21 June 2024

Accepted after revision: 16 July 2024

Accepted Manuscript online:
16 July 2024

Article published online:
06 August 2024

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Zoom Image
Scheme 1 Methods established for the nickel-catalyzed hydrocarbonation of vinylsilanes. Hydroalkylation in an anti-Markovnikov and Markovnikov­ fashion (top) and hydroalkenylation to access α-chiral allylic silanes (bottom left). [Si] = triorganosilyl group. Do = directing group.
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Scheme 2 Scope I: Ni–H-catalyzed regioselective hydroarylation of vinylsilanes­ 2a–2g with aryl iodide 1a. Unless otherwise noted, all reactions were performed on a 0.10-mmol scale according to the general procedure. Yields are isolated yields after flash column chromatography on silica gel. a r.r. = 86:14.
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Scheme 3 Scope II: Ni–H-catalyzed chemoselective transformation of vinylsilanes 2h–2j with aryl iodide 1a. Unless otherwise noted, all reactions were performed on a 0.10-mmol scale according to the general procedure. Yields are isolated yields after flash column chromatography on silica gel. a 1.0 equivalent of 1a was used.
Zoom Image
Scheme 4 Scope III: Ni–H-catalyzed regioselective hydroarylation of vinylsilane 2a with (hetero)aryl iodides 1b–1j. Unless otherwise noted, all reactions were performed on a 0.10-mmol scale according to the general procedure. Yields are isolated yields after flash column chromatography on silica gel. n.r. = no reaction. a r.r. = 96:4.