Acyl–oxygen fission in reactions of organosilicon carboxylates with sodium methoxide in methanol
Abstract
The compounds (Me3Si)3CSiMe2O2CR [R = Me, CH2Cl, CF3, Ph, C6H4NO2-p, C6H3(NO2)2-3,5] and But3SiO2CCF3, in which there is serious steric hindrance to nucleophilic attack at silicon, react with 0.20M-NaOMe in MeOH to give the corresponding silanols, (Me3Si)3CSiMe3OH and But2SiOH; i.e., exclusive acyl–oxygen fission occurs rather than the normal silicon–oxygen fission. With both trifluoroacetates the reaction is complete within ca. 1 min at room temperature. For the (Me3Si)3CSiMe2O2CR species the reactivity sequence is R = CF3 > C6H3(NO2)2-3,5 > CH2Cl > C6H4NO2-p > Me > Ph.