Oxazepine synthesis by copper-catalyzed intermolecular cascade reactions between O-propargylic oximes and dipolarophiles.

Three-step cascade: Oxazepine derivatives were efficiently prepared from O-propargylic oximes and dipolarophiles through copper-catalyzed cascade reactions which proceed through a 2,3-rearrangement, [3+2] cycloaddition, and subsequent 1,3-oxygen rearrangement. The process involves the cleavage of C- and N-O bonds.