Ketone-Directed Cobalt(III)-Catalyzed Regioselective C2 Amidation of Indoles.

An efficient cobalt(III)-catalyzed method for the direct C-H amidation of unprotected indoles for 2-amino indole scaffold construction has been developed. With dioxazolone as the amidating reagent, a variety of 2-amino indole derivatives were achieved in moderate to excellent yields using an organic acid as the additive and a ketone as the directing group.