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-<i>a</i>]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 <i>n</i>-alkyl substitution at the 3-position leads to the formation of pyrrolo-acridones <i>via</i> [3 + 2] annulations/ring opening and successive intramolecular cross-aldol condensation