Direct Oxidative Coupling of Arenes with Olefins by Rh-Catalyzed C-H Activation in Air: Observation of a Strong Cooperation of the Acid

A [{RhCl(cod)}2]/CCl3COOH system was developed for the oxidative coupling of non-chelate-assisted arenes with olefins in the presence of catalytic amounts of Cu(OAc)2 center dot H2O as a co-oxidant and oxygen as the terminal oxidant. The acid was an indispensable component in this system and played a very important role in the coupling reaction. This catalytic system was applied to the direct oxidative coupling of a series of arenes and olefins and the corresponding products were afforded in high yields with special chemo- and regioselectivity. This reaction provides an atom-efficient route to vinylarenes, which are widely used in various fine chemicals.