Palladium-Catalyzed [5 + 2] Cycloaddition of Vinyloxiranes with Sulfamate-Derived Cyclic Imines To Construct 1,3-Oxazepine Heterocycles

Palladium-catalyzed [5 + 2] cycloaddition of 2-aryl-2-vinyloxiranes with sulfamate-derived cyclic imines is described. The zwitterionic allylpalladium intermediates act as five-membered synthon to react with sulfamate-derived cyclic imines to furnish [5 + 2] cycloaddition, giving 1,3-oxazepine derivatives in moderate to excellent yields with excellent regioselectivities.