A-silyl nitriles

Many other catalysts based on cobalt, ruthenium, rhodium, and platinum are now known to catalyze the hydrosilylation of alkenes, and the types of products can be controlled by the choice of catalyst and silane. Rhodium complexes, such as Wilkinson s catalyst, have been used frequently. A comprehensive treatment of selectivities is beyond the scope of this chapter, but several reviews provide information on the products formed from different catalysts and silanes.As one example, crotononitrile undergoes hydrosilylation in the presence of Wilkinson s catalyst to form the a-silyl nitrile product (Equation 16.23), and this regioselectivity contrasts with that for the reaction of the related acrylic acid ester in Equation 16.19 conducted with Speier s catalyst. 

Peterson reactions of a-silyl nitriles provide facile access to a,yS-unsaturated nitriles. The a-silyl carbanion derived from a-(trimethylsilyl)acetonitrile is treated with carbonyl compounds to give the corresponding a,yS-unsaturated nitriles in good to moderate yields (Scheme 2.78) [220-222]. a-Alkyl-a-(trimethylsilyl)acetonitriles are also effective for this type of reaction [223, 224]. 

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