Chiral Phosphoric Acid-Catalyzed Enantioselective Three- Component Aza-Diels-Alder Reactions of Aminopyrroles and Aminopyrazoles

A highly stereoselective three-component Povarov reaction, catalyzed by (R)- and (S)-BINOL hydrogen phosphate, was achieved for the first time with aminopyrroles and aminopyrazoles as 2-azadiene precursors. A variety of aldehydes, enecarbamates, amino-substituted azines participated in the reaction to afford the tetrahydropyrrolopyridines and tetrahydropyrazolopyridines in good yields with excellent diatereo- and enantioselectivities. A stereochemical model is proposed to account for the observed absolute stereochemistry.