Towards Catalytic C-H Activation Using Main Group Elements

Catalytic C-H activation reactions are now established as a means to directly transform organic molecules and are commonly associated with metals such as palladium, rhodium, ruthenium and iridium. This Account will describe a short number of reports demonstrating that structures containing main group elements can facilitate C-H activation processes. In particular, boron-based catalysts can promote catalytic arene C-H borylation reactions, and an emerging approach using phosphenium ions can also cleave sp(2) C-H bonds. These processes use a Lewis acidic main group atom combined with a pendant base to cleave C-H bonds, which compares with metal-catalyzed reactions that proceed via concerted metalation deprotonation mechanisms.