Nickel-Catalyzed Lactamization Reaction of 2-Arylanilines with CO₂

Transition-metal-catalyzed lactamization and lactonization of C–H bonds with CO2 assisted by the chelation of amino or hydroxyl groups have been developed but limited to the use of precious metal catalysts such as palladium and rhodium. In this work, we report the nonprecious metal nickel-catalyzed lactamization reaction of 2-arylanilines with CO2 under redox-neutral conditions via C–H bond activation. The reaction displayed excellent functional group tolerance, providing various phenanthridinones with moderate to high yields.