Base-Promoted [3+3]-Cycloaddition of gamma-Hydroxy-alpha,beta-unsaturated Carbonyls with N,N '-Cyclic Azomethine Imines for Synthesizing Bicyclic Oxadiazines

A novel approach of [3+3]-cycloaddition of N,N '-cyclic azomethine imines with gamma-hydroxy-alpha,beta-unsaturated carbonyls was developed. Bicyclic oxadiazines were readily obtained in moderate to good yields from the reactions of various gamma-hydroxy-alpha,beta-unsaturated ketones, including aromatic and aliphatic ketones, with N,N '-cyclic azomethine imines under mild conditions, demonstrating the broad substrate scope.