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.