Copper-Catalyzed α‑Benzylation of Enones via Radical-Triggered Oxidative Coupling of Two C–H Bonds

A novel copper­(II)-catalyzed, regioselective C–H benzylation of enones with toluenes via radical triggered oxidative coupling has been developed. A series of enones and toluenes with different substituents were successfully incorporated, providing a wide range of α-benzylated enones with TBP as oxidant by cleavage of C­(sp3)–H bond and C­(sp2)–H bond. Preliminary mechanistic study reveals a benzylic carbon radical is generated, and regioselectively reacts with enones to deliver the corresponding products.