Base Metal Catalysts for Photochemical C–H Borylation That Utilize Metal–Metal Cooperativity

Heterobimetallic Cu–Fe and Zn–Fe complexes catalyze C–H borylation, a transformation that previously required noble metal catalysts. The optimal catalyst, (IPr)­Cu-FeCp­(CO)2, exhibits efficient activity at 5 mol% loading under photochemical conditions, shows only minimal decrease in activity upon reuse, and is able to catalyze borylation of a variety of arene substrates. Stoichiometric reactivity studies are consistent with a proposed mechanism that exploits metal–metal cooperativity and showcases bimetallic versions of the classical organometallic processes, oxidative addition and reductive elimination.