Asymmetric Trimethylsilylcyanation of Acetophenone Catalyzed by Cinchona Alkaloids

Six cinchona alkaloids were used as catalysts for the study of addition of TMSCN to acetophenone (1) at atmospheric and pressurized conditions. Only the about 10% ee was attained either in hexane or ethyl acetate using quinine or cinchonine. The enantiomeric excesses (ee's) of the cyanohydrin (3) were found to be decreased with pressure in the presence of alkaloids. The rationale of these reactions was discussed.