Palladium-Catalyzed Regioselective [3 + 2] Annulation of Internal Alkynes and Iodo-pyranoquinolines with Concomitant Ring Opening

A regioselective tandem synthesis of highly functionalized pyrrolo[1,2-a]quinolines has been developed through a novel strategy by palladium-catalyzed [3 + 2] annulation of iodo-pyranoquinolines and internal alkynes with subsequent ring opening. Pyranoquinoline with n-alkyl substitution at the 3-position leads to the formation of pyrrolo-acridones via [3 + 2] annulations/ring opening and successive intramolecular cross-aldol condensation.