Enantioselective Protonation by Aza‐Michael Reaction between Pyrazoles and α‐Substituted Vinyl Ketones

Abstract

Abstract An enantioselective protonation by means of chiral scandium complex‐catalyzed aza‐Michael reaction was realized. A series of α‐aryl‐substituted vinyl ketones reacted with pyrazoles smoothly, affording the corresponding enantiomerically enriched pyrazole derivatives with excellent results (up to 99% yield, 94% ee ). Water and hydrogen chloride were found to accelerate the protonation process. magnified image