Trimethyl vinyl silane

The mechanism of the cross-coupling reaction should follow the well-accepted catalytic cycle [1]. Namely, (1) Pd(0)L2 catalyst, generated by an unclear pathway, undergoes 

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This test was successfully applied for the hydrosilylat-ion of trimethyl(vinyl)silane by triethoxysilane catalysed by Rh or Pt colloids. The addition of mercury to catalytic mixture led to catalytic activity loss, consistent with a heterogeneous catalyst [12,14]. 

The carbomagnesiation of vinyisiianes is a powerful method for the generation of synthetically useful a-silyl carbanions. However, simple vinyisiianes such as trimethyl(vinyl) silane do not undergo carbometalation with Grignard reagents (Scheme 59) °. In early days, only limited success had been achieved by using perfluorovinylsilanes °°. 

Trimethyl vinyl silane [754-05-2] M 100.2, 54.4 /744mm, 55.5°/767mm, d 0.6865, n 1.3880. If the H NMR spectrum shows impurities then dissolve in Et20, wash with aq NH4CI soln, dry over CaCl2, filter, evaporate and distil at atmospheric pressure in an inert atmosphere. It is used as a copolymer and may polymerise in the presence of a free radical donor. It is soluble in CH2CI2. [JOC 17 1379 7952]. 

Aryl vinyl sulfides and sulfoxidesArylsulfenyl chlorides add to trimethyl vinyl-silane in CH2CI2 at -78 - 20° to form 2-chloro-l-(trimethylsilyl)ethyl aryl sulfides in 90-95% yield. These adducts are converted into aryl vinyl sulfides in high yield by KF-2H20 DMSO at 70 100°. The sulfides, as expected, can be oxidized to the corresponding sulfoxides by m-chlo roper benzoic acid in CH2C12 at 20". 

In the presence of an excess of trimethyl(vinyl)silane, the olefmic Rh complex 191 slowly undergoes rearrangement to the complex 66, containing an 7] -coordinated silole ligand <1999JA4385>. 

There are scattering examples that neutral organosilanes R-SiMe3 undergo a desilylative coupling reaction with aryl halides in the presence of a palladium catalyst. Hallberg and his co-workers disclosed that trimethyl(vinyl)silane reacts with an arylpalladium(II) complex to afford coupled products accompanied by aryl-substituted alkenylsilanes formed through the Heck type reaction... 

Although trimethyl(vinyl)silane undergoes the coupling reaction with aryl halides in the presence of TASF and a palladium catalyst as described in Section 1 (Eq. 3), those having an aliphatic substituent on vinyl fail to couple with aryl iodides under similar conditions, probably because they are not capable of affording pentacoordinate silicates efficiently owing to the electron-donating nature of the substituent. To assist the formation of the pentacoordinated intermediates, the methyl on silicon was replaced by fluorine [13]. The cou-... 

A THF solution of TASF (1.0 M solution, 0.40 ml, 0.40 mmol) was added to trimethyl(vinyl)silane (40 mg, 0.40 mmol) and (f -C3H5PdCl)2 (2.7 mg, 0.0075 mmol) dissolved in HMPA (0.3 ml) at 0 °C under an argon atmosphere. 1-Iodonaphthalene (76 mg, 0.30 mmol) was injected to the resulting solution, and the mixture was stirred at 50 °C for 2 h. After completion of the reaction, the bulk of the solvent was removed by passing through a silica gel column with pentane as the eluent. Evaporation of pentane under reduced pressure gave pure 1-vinylnaphthalene (42 mg, 98% yield). 

To trimethyl(vinyl)silane (26.0 g, 259 mmol) and tert-butyl peroxybenzoate (1.02 g, 5 mmol) in MeOH (100 mL) was slowly added NaHSOs (52.6 g, 505 mmol) in HjO (100mL) at rt. The mixture was refluxed for 48 h, carefully concentrated (CAUTION peroxides ) and H2O was removed by azeotropic distillation with MeOH (3 x) by rotary evaporation. The residue was extracted with MeOH (3 x with a total of 250 mL), and the resulting soln was taken to dryness and dried at 150 °C under reduced pressure giving sodium 2-(trimethylsilyl)ethanesulfonate yield 37.0 g (70%). 

The same reaction conditions were applied to the coupling reaction of Trimethyl(vinyl)silane [Eq.(3)] with limited success [3], Thus, the mechanism of these silicon-based reactions appears to be different from those of the cross-coupling reactions using the main-group metal reagents. 

Also, in studies with optically active vinyl ethers it was observed [104] that trimethyl vinyl silane, which is bulky and non-chiral forms highly syndiotactic polymers. Equally bulky, but chiral (—)-menthyl vinyl ether, however, produces isotactic polymers in polar solvents. This suggests that isotactic propagation is preferred in a polar medium because of helical conformation of the polymer... 

Trimethyl(vinyl)silane (124 pL) was added to a soln of [W(=CHt-Bu)(=NC6H3-2,6-iPr2) OC-Me(CF3)2 2] (212 mg) in pentane (15 mL). The solvent was removed in vacuo after 2h to give a light yellow product that was recrystaUized from pentane to give light yellow crystals. The jdeld of the crude product was essentially quantitative. 

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