Asymmetric Aza-Henry Reaction of Ketoimines

Significance

Shibasaki and Jørgensen were the first to develop enantioselective aza-Henry reactions of aldimines under heterometallic and copper catalysis, respectively. Later, organocatalysts including thioureas, ammonium salts, phase transfer catalysts, and others have been applied to this reaction with great success. However, utilization of ketoimines has been a longstanding problem due to low reactivity and difficulty in enantiofacial discrimination. The authors describe the first examples of an aza-Henry reaction of ­ketoimines catalyzed by a copper-N,N′-dioxide complex to provide products in modest yields and high enantioselectivities.