Enantioselective α-chlorination of β-keto esters and amides catalyzed by chiral imidodiphosphoric acids

Abstract Chiral imidodiphosphoric acids were employed as catalysts for the enantioselective α -chlorination of β -keto esters and amides using NCS as the chlorine source, providing a series of optically active products with good to high enantioselectivities (74–95% ee) and excellent yields (92–99%). This represents the first report of the Bronsted acid catalyzed enantioselective α -chlorination of cyclic β -keto derivatives.