Iridium-Catalyzed Direct Ortho -C-H Amidation of α-Ketoesters with Sulfonyl Azides Using a Transient Directing Group Strategy.

Direct C-H amidation of α-ketoesters was accomplished using various organic azides as the amino source through the combination of transient directing group strategy and iridium catalysis. Excellent functional group tolerance and wide substrate scope were explored under simple and mild conditions. Importantly, it was found that the steric hindrance of the ester moiety played a pivotal role for the reaction efficacy. In addition, the reaction could be enlarged to gram scale, and several useful heterocycles were readily constructed via one-step late-stage derivatization.