Synthesis of N‐Substituted 4‐Quinolones via Palladium‐Catalyzed Enantioselective C−N Coupling and Base‐Promoted Reactions

Abstract A highly efficient palladium‐catalyzed asymmetric synthesis of N ‐substituted 4‐quinolones was developed via C−N coupling reaction. Various chiral quinolones were readily obtained with desirable enantioselectivity (up to 95% ee) and excellent yield (up to 99%), enabled by a simple system of palladium acetate and chiral ferrocene bisphosphine as auxiliary ligand. The corresponding racemic derivatives can also be synthesized by a transition metal‐free strategy of potassium hydroxide in DMSO. The influence of temperature on the configurational stability of these C−N axially chiral compounds was also investigated. The efficient functionalization at 3‐position further expands the application range of this synthetic technique. magnified image