Electrochemical recycling of benzoquinone in the Pd/benzoquinone-catalyzed Heck-type reactions from arenes

Palladium(II) acetate-catalyzed Heck-type reactions have been performed from the arene I and alkenes (n-butyl acrylate, styrene) in acetic acid at room temperature, in the presence of a catalytic amount of benzoquinone or hydroquinone. The reactions have been made catalytic in benzoquinone [which is used to continuously oxidize the Pd(0) into to the active Pd(II) species able to activate the Ar-H bond] by the electrochemical oxidation of hydroquinone, formed in the reaction, back to benzoquinone.