N-heterocyclic carbene-catalyzed intramolecular aza-Michael addition of alkyl amines to α,β-unsaturated carboxylic acid: Synthesis of pyrrolidines and piperidines

Abstract N-heterocyclic carbene-catalyzed intramolecular aza-Michael addition of alkyl amines to α,β-unsaturated carboxylic acid has been realized. The corresponding pyrrolidine and piperidine derivatives can be obtained in good to excellent yields. Reaction using chiral NHC catalyst showed promising enantioselectivities up to 55% ee. Further chemical transformations of the products provided carboxylic acids, alcohols, and unprotected amines.