Highly regioselective synthesis of fused seven-membered rings through copper-catalyzed cross-coupling.

A highly efficient protocol of copper catalysis for the one-pot synthesis of fused dibenzo[b,f][1,4]oxazepines is reported. The transformation involves a Smiles rearrangement, leading to the completely different regioselectivity from the classical cross-coupling. The easy reaction of aryl chlorides as substrates enhances the practical application of the methodology.