Direct Synthesis of 4-Quinolones via Copper-Catalyzed Intermolecular Cyclization of Anilines and Alkynes.

A unique and direct approach for constructing 4-quinolones from simple and readily available anilines and alkynes is described. Under the optimal conditions, both N-alkyl- and N-aryl-substituted anilines can be successfully transformed into the corresponding 4-quinolones. This reaction is characterized by mild reaction conditions, high functional-group tolerance, and amenability to gram-scale synthesis.