Cobalt-Catalyzed Oxidative C–H/N–H Cross-Coupling: Selective and Facile Access to Triarylamines

As a powerful synthetic tool for the formation of aromatic C–N bonds, the reported transition-metal-catalyzed direct C–H amination has been ineffective for the synthesis of triarylamines for a long time. Herein, an elegant strategy for the preparation of triarylamines was disclosed using inexpensive Co(OAc)2·4H2O as the catalyst. It is noteworthy that unactivated arenes and simple anilines were employed as the starting materials with good functional group tolerance. In addition, an organometallic Co(III) species was isolated and identified by X-ray crystallography, thus providing some in-depth insights into the mechanism.