Biotransformations of organosilicon compounds: enantioselective reduction of acyl silanes by means of baker's yeast

The enantioselective reduction of acyl silanes has been performed employing baker's yeast (BY) in fermenting conditions: a series of substrates of different structure was investigated, showing that the reactivity as well as the level of enentioselectivity depends on the steric bulk of the substituents on the acyl silane. The products α-hydroxy silanes were obtained with chemical and optical yields over 90% in the most favourable cases.