Catalytic Enantioselective Elimination of Cyclobutanols

Brønsted acid-mediated elimination of alcohols is a fundamental transformation in organic chemistry, yet its application in enantioselective catalysis remains largely unexplored. Here, we report a catalytic, enantioselective elimination of cyclobutanols and their trichloroacetimidate derivatives that afford cyclobutenes bearing all-carbon quaternary stereocenters. Mechanistic studies revealed that a chiral Brønsted acid catalyst mediates concerted, enantioselective elimination of cyclobutanols, whereas their trichloroacetimidates undergo stepwise elimination via a catalyst-substrate covalent intermediate. This research lays the foundation for further investigations of enantioselective elimination reactions.