Visible-Light Induced and Oxygen-Promoted Oxidative Cyclization of Aromatic Enamines for the Synthesis of Quinolines Derivatives

The dual transition metal-visible light photoredox catalysis for the synthesis of quinoline derivatives by using dioxygen as an oxygen source is developed. By using visible light, the direct oxidative cyclization of aromatic enamines with alkynes or alkenes can be achieved at mild conditions with an aid of copper or palladium catalysts, and a variety of multisubstituted quinoline derivatives could be obtained in good to moderate yields under mild reaction conditions.