Development of transition-metal-catalyzed C–H functionalization reactions via electrolytic/chemical oxidation of metal intermediates

Abstract

The development of transition-metal-catalyzed C–H functionalization under mild conditions via high-valent metal intermediates, which are highly reactive compared to low-valent metal intermediates has been intensively investigated recently. In particular, iridium and rhodium can activate C–H bonds under the mild conditions and generate high-valent metal intermediates by both built-in oxidant and external oxidant. Due to these advantages, they have high potential to be employed as catalysts in diverse C–H functionalization reactions. In this regard, herein we describe the development of C–H functionalization reactions through the strategy of electrolytic/chemical oxidation of unreactive iridium and rhodium metal complexes to form highly reactive high-valent metal intermediates. (i) Amidation of benzylic C–H bonds by high-valent Ir–nitrenoid intermediate. (ii) Electrolytic C–H oxygenation via oxidatively induced reductive elimination of high-valent Rh–carboxylate intermediate. (iii) Access to high-valent Ir–nitrenoid intermediates by metallic oxidation of Ir–amido complexes.