Organosilanes inductive effects

Alkylation and arylation of organosilanes occur readily with alkyl and arji alkah metal compounds. Yields from these reactions are good but are influenced by steric requirements on both silane and metal compounds. There is httle inductive effect by the oiganic groups attached to sihcon, as measured by the yield of products (126,127). These reactions proceed more readily in tetrahydrofiiran and ethji ether than inhgroin or petroleum ether, where R and R are alkyl or aryl and M is Li, Na, or K. 

Reduction of cyclohexanones. Doyle and West have conducted extensive investigations on the reduction of cyclohexanones by organosilanes in acidic media. Steric factors play a dominant role in the stereochemical outcome. However, inductive effects of alkyl substituents in the silane are pronounced. The geometry of transition states in this hydride transfer has been discussed. 

Mechanistically the rate-determining step is nucleophilic attack involving the hydroxide ion and the more positive siUcon atom in the Si—H bond. This attack has been related to the Lewis acid strength of the corresponding silane, ie, to the abiUty to act as an acceptor for a given attacking base. Similar inductive and steric effects apply for acid hydrolysis of organosilanes (106). 

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