Versatile Enantioselective [3+2] Cyclization between Imines and Allenoates Catalyzed by Dipeptide-Based Phosphines

A fast one: The title reaction proceeds in the presence of 5 mol % of the catalyst 1, and is complete within an hour. The 2‐alkyl‐ and 2‐aryl‐substituted 3‐pyrroline products are obtained in good yield and with high enantioselectivity. The application of the method to the concise formal synthesis of (+)‐trachelanthamidine is also demonstrated. Boc=tert‐butoxycarbonyl, M.S.=molecular sieves, TBDPS=tert‐butyldiphenylsilyl.