Asymmetric Sulfa-Michael Addition to α-Substituted Vinyl Ketones Catalyzed by Chiral Primary Amine

The first effective example of asymmetric conjugate addition-protonation reactions of thiols to alpha-substituted vinyl ketones by chiral primary amine catalysis is reported. A simple chiral primary tertiary diamine catalyst derived from L-phenylalanine was found to promote the sulfa-Michael addition-protonation reactions with good to excellent enantioselectivity.