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.