Rhodium(III)-Catalyzed Directed C-H Amidation of N-Nitrosoanilines and Subsequent Formation of 1,2-Disubstituted Benzimidazoles.

An efficient rhodium-catalyzed direct C-H amidation of N-nitrosoanilines with 1,4,2-dioxazol-5-ones as amidating agents has been developed. This method featured mild reaction conditions, a wide substrate scope and satisfactory yields. Besides, the amidated products could be readily converted to pharmaceutically valuable 1,2-disubstituted benzimidazoles via an HCl-mediated deprotection/cyclization process in one pot.