Highly enantioselective reduction of achiral ketones with NaBH4/Me3SiCl catalyzed by (S)-α,α-diphenylpyrrolidinemethanol

The reducing agent prepared from sodium borohydride, trimethylsilyl chloride and a catalytic amount of (S)-α,α-diphenylpyrrolidinemethanol has been successfully applied to the enantioselective reduction of ketones. The optically active secondary alcohols were obtained in excellent enantiomeric excess and almost quantitative chemical yield.