RECOVERABLE CHIRAL SULFOXIDES FOR ASYMMETRIC-SYNTHESIS - APPLICATION TO STEREOSELECTIVE CARBONYL REDUCTION AND THE ASYMMETRIC-SYNTHESIS OF ALLYLIC ALCOHOLS

The enantiomerically pure cyclic sulfinamide S-(S)R-(+)-3 reacts with the sodium enolates of ketones to give the corresponding homochiral su lfoxides., Reduction of the carbonyl group ih these products may be ac hieved using a variety of reducing agents the best of which were DIBAL -H or DIBAL-H/ZnBr2, which give complementary products of high diaster eoisomeric excess, Reduction of the hydroxy sulfoxides with Raney nick el proceeds in low yield and causes partial racemisation of the produc ts. However the combined use of a directed reduction followed by a fac ile sulfenic acid elimination provides a synthesis of allylic alcohols in high enantiomeric excess.