Highly efficient organocatalytic asymmetric Michael addition of homoserine lactone derived cyclic imino esters to nitroolefins

An efficient stereoselective Michael addition reaction of homoserine lactone derived cyclic imino esters to nitroolefins promoted by a bis(cinchona alkaloid) (DHQD)2AQN was achieved. This catalytic system features a wide substrate scope, furnishing the corresponding products with excellent diastereoselectivity (>95:5 dr) and good enantioselectivity (up to 87% ee) under mild conditions, and the Michael adducts could be easily transformed into highly functionalized spirocyclic γ-butyrolactone-pyrrolidines through a sequential nitro-Mannich reaction.