Domino N₂-Extrusion–Cyclization of Alkynylarylketone Derivatives for the Synthesis of Indoloquinolines and Carbocycle-Fused Quinolines

New synthetic approaches for the synthesis of indoloquinolines and carbocycle-fused quinolines have been developed employing alkynylketone substrates. These synthetic transformations involved the application of N₂-extrusion of azido complexes as a key step to generate carbodiimidium ion and nitrilium ion in situ, which further cyclized intramolecularly with alkyne via a domino process to provide indoloquinolines and carbocycle-fused quinolines, respectively, in moderate to good yields.