Cu(I)-Catalyzed Oxygen and Nitrogen Nucleophiles Triggered Regioselective Synthesis of Furo/Pyrrolo-Annulated Quinolines

Abstract

Cu(I)-catalyzed intramolecular annulation of <i>o</i>-ethynylquinoline-3-carbaldehydes leads to the synthesis of alkoxy/imidazole-substituted 1,3-dihydrofuro[3,4-<i>b</i>]quinolines via C-O and C-N bond formation. The scope of the reaction was further extended to <i>o</i>-ethynylquinoline-3-carbonitriles for the synthesis of alkoxy-substituted 3<i>H</i>-pyrrolo[3,4-<i>b</i>]quinolines using alcohols as nucleophiles. These reactions are regioselectively favoring the 5-<i>exo-dig</i> cyclizations in all the annulation processes.