Phase-Transfer Catalytic One-Pot Approach to Alkaloid Core Structures

Significance

The authors present an elegant and highly enantioselective synthesis of pyrrolidine, hexahydropyrrolizine, and octahydroindoli­zine core structures. Key step is the asymmetric conjugate addition of N-(diphenylmethylene)-­glycine ester to α,β-enones catalyzed by chiral phase-transfer catalyst 1. Intramolecular reduc-tive amination and subsequent in situ acetal ­hydrolysis-reductive amination using Hantzsch ester 2 and trifluoroacetic acid gives access to alkaloid core structures in a simple one-pot procedure.