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 reaction, and an emerging approach using phosphenium ions can also cleave sp2 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.