High Regio‐ and Chemoselectivity [2 + 4] Tandem Annulations Catalyzed by CsF to the Synthesis of 4‐Quinolones under Continuous‐Flow Reactor

A high regio‐ and chemoselectivity route to the synthesis of 4‐quinolone derivatives involving a CsF‐catalyzed [2 + 4] tandem annulations under continuous‐flow reactor has been developed. This practical and concise protocol between aryne precursors and β‐enamino diesters provided a range of structurally diverse 4‐quinolones (28 examples) in good to excellent yields. The characteristics of this continuous‐flow are safe operation, high regio‐ and chemoselectivity in a short time. This approach can enrich and develop aryne chemistry, and might provide new opportunities for the discovery of 4‐quinolone drugs.