Enantioselective Aza-Henry Reaction of Seven-Membered Cyclic Imines, Dibenzo[b,f][1,4]oxazepines, by Bifunctional Organocatalysis

In this study, we have successfully developed the first organocatalytic asymmetric aza-Henry reaction of dibenzo[b,f][1,4]oxazepines as a representative class of unactivated seven-membered cyclic imines with nitroalkanes. In the presence of a Cinchona alkaloid-based thiourea catalyst, a range of structurally diverse nitrogen-containing heterocycles were produced in good to excellent yields and enantioselectivities. Furthermore, the ready transformation of the aza-Henry products into enantioenriched 1,2-diamine derivatives bode well for the potential applications of this route.