Intra-/Intermolecular 1,2-Diamination of Alkenyl Oximes with O-Benzoylhydroxylamines Enabled by Copper Catalysis.

We here describe a versatile, convenient, and efficient approach to synthesize cyclic nitrone compounds by diamination of alkene, which was catalyzed by simple copper salts under basic conditions with good chemoselectivity. The method utilized γ,δ-unsaturated ketoximes with O-benzoylhydroxylamines as an electrophilic nitrogen source to realize intra-/intermolecular 5-exo-trig cyclization of internal alkenes of unsaturated ketoximes without external oxidants required, and a series of substitution patterns, both donor and withdrawing substituted moieties, are well-tolerated, leading to target products in moderate to good yields.