Cu-Mediated Stereoselective [4+2] Annulation between N-Hydroxybenzimidoyl Cyanide and Norbornene

A Cu-mediated stereoselective [4+2] annulation between N-hydroxybenzimidoyl cyanides and norbornene (NBE) has been developed for the synthesis of 4H-1,2-oxazin-4-ones. The reaction proceeds through sequentially forming C–O/C–C bonds. The advantage of this reaction includes high stereoselectivity, excellent yields, as well as simple and mild reaction conditions. A total of 26 examples are presented along with some control experiments.