Aerobic Copper-Catalyzed Halocyclization of Methyl N-Heteroaromatics with Aliphatic Amines: Access to Functionalized Imidazo-Fused N-Heterocycles.

A new aerobic copper-catalyzed halocyclization reaction of methyl N-heteroaromatics and aliphatic amines has been developed, which enables straightforward access to functionalized imidazo-fused N-heterocycles with the merits of good functional tolerance, use of easily available copper salts as the catalysts, lithium halides as the halogen sources, and O2 as a sole oxidant. Due to the reaction features' selective introduction of halogen functionalities to the newly formed imidazo ring, further extensions of the developed chemistry toward synthetic diversity, including effective access to functional materials, are easily envisioned.