Direct Synthesis of N‑H Carbazoles via Iridium(III)-Catalyzed Intramolecular C–H Amination

The iridium-catalyzed dehydrogenative cyclization of 2-aminobiphenyls proceeds smoothly in the presence of a copper cocatalyst under air as a terminal oxidant through intramolecular direct C–H amination to produce N-H carbazoles. A similar iridium/copper system can also catalyze the unprecedented dimerization reaction of 2-aminobiphenyl involving 2-fold C–H/N–H couplings.