Enantioselective Intramolecular Formal [2 + 4] Annulation of Acrylates and α,β-Unsaturated Imines Catalyzed by Amino Acid Derived Phosphines

Abstract

The first chiral phosphine-catalyzed activation of acrylates for intramolecular formal [2 + 4] reactions with unsaturated imines is described. The catalytic reactions afford N-heterocycles with exceptionally high diastereo- and enantioselectivities. The [2 + 4] products are amenable for further transformations to useful molecules such as chiral piperidines and multicyclic structures.