Dimethylphenylsilyl lithium

An ethereal solution of MeMgl (1.1 m, 2 mmol) was added to a solution of dimethylphenylsilyl lithium (0.52m, 2mmol) in THF at 0°C. After stirring for 15min, cis-PtCI2(n-Bu3P)2 (0.01 mmol) was added, and the resulting... 

Dimethylphenylsilyl lithium (1 mmol, above THF solution) was added to copper(i) iodide (0.5 mmol) at — 23 °C, and the mixture was stirred at this temperature for 4h. The enone (0.75-0.5mmol) was then added, and stirring was continued at —23 °C for 0.5 h. The mixture was then poured on to ice(25 g)/HCl(5 ml), and extracted with chloroform (3 x 25 ml). The combined extracts were filtered, washed with HCI (25ml, 3m), water (25 ml), saturated sodium hydrogen carbonate solution (25 ml) and water (25 ml), and dried. Concentration and purification by preparative t.l.c. (eluting solvent 3 7 ether petrol) gave the /J-silylketone (40-99%). 

To (E)-stilbcnc oxide (25 mmol) in THF (35 ml) was added freshly prepared dimethylphenylsilyl lithium (25.35 mmol, 1.3 m in THF) dropwise at ambient temperature. The solution was stirred at ambient temperature for 4h, and then poured into saturated ammonium chloride solution (15ml), diluted with ether, and the separated organic layer was dried and concentrated. The crude product (97 3 (Z) (E), g.I.c.) was purified by chromatography on silica gel to give (Z)-stilbene (18.75 mmol, 75%). 

Fleming has shown (2) that the cuprate reagent (Chapter 8) derived from dimethylphenylsilyl lithium and copper(t) cyanide (molar ratio 2 1) adds regioselectively in an overall syn manner to terminal alkynes, the silyl moiety becoming attached to the terminal carbon atom (variation in reagent... 

To a stirred slurry of copper(i) cyanide (110 mmol) in THF (100 ml), cooled to 0 °C, was added a solution of dimethylphenylsilyl lithium (220 mmol, 1.3 m in THF), and the mixture was stirred at 0°C for a further 30min. After cooling to —78°C, a solution of methyl cinnamate (100mmol) in THF (50 ml) was added, and stirring was continued at —78°Cfor6h. At this time, iodomethane (300 mmol) (CAUTION—CANCER SUSPECT AGENT) was added, and the mixture allowed to warm to ambient temperature with... 

Similarly, a./l-unsaturated bornyl aldehyde undergoes silyl cupration with dimethylphenylsilyl-lithium and copper(I) cyanide to give, after column chromatography, the endo,endo-isomer 7 as the sole product. The silylcuprate attacks the double bond from the endo-face and the addition of the proton from the opposite face leads to the endo,endo-product242. 

Fleming and Roessler have reported that the silyl-copper reagent prepared by mixing two molar equivalents of dimethylphenylsilyl-lithium with one of copper(l) cyanide reacts with terminal acetylenes to give vinyl-copper intermediates with silicon almost exclusively (>99%) at the terminal position [e.g. (30)]. These intermediates react stereospecifically with a wide range of electrophiles, providing access to a variety of 2,2-disubstituted vinylsilanes. ... 

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