Cr(III)(salen)Cl Catalyzed Enantioselective Intramolecular Addition of Tertiary Enamides to Ketones: A General Access to Enantioenriched 1H-Pyrrol-2(3H)-one Derivatives Bearing a Hydroxylated Quaternary Carbon Atom

Catalyzed by a chiral Cr(III)(salen)Cl complex 3e, tertiary enamides 1 underwent an efficient and enantioselective intramolecular addition reaction to an activated carbonyl moiety to produce in excellent yield highly enantioenriched 1H-pyrrol-2(3H)-one derivatives 2 that bear a hydroxylated quaternary carbon atom. The synthetic application of resulting compounds has been demonstrated in the synthesis of (3S,5S)-3,5-diphenyl-3-pyrrolidinol.