Intramolecular Cobalt/Visible Light Cocatalyzed Reductive Coupling of Unactivated Arenes with Unactivated Alkenes

A protocol for the intramolecular reductive coupling of unactivated arenes with unactivated alkenes has been developed with the aid of a cooperative visible light/cobalt catalytic system. This coupling is achieved via radical cascade cyclization using amines as terminal reducing reagents and water as the main hydrogen source. In their form, readily available N-allyl benzamides are converted to the corresponding spiro cyclohexadiene-lactam or β-phenethylamine analogues in moderate to excellent yields.