Organocatalytic Asymmetric Synthesis of Chiral Pyrrolizines by Cascade Conjugate Addition−Aldol Reactions

Abstract

As the first N-centered heteroaromatic nucleophile for organocatalytic cascade reactions, pyrroles underwent the enantio- and diastereoselective organocatalytic cascade conjugate addition-aldol reactions of α,β-unsaturated aldehydes that afford the highly functionalized chiral pyrrolizines bearing three consecutive stereocenters in good yields, high enantioselectivities (90-98% ee), and excellent diastereoselectivities (>20:1 dr in all cases).