Copper(II)-Catalyzed Synthesis of Benzo[f]pyrido[1,2-a]indole-6,11-dione Derivatives via Naphthoquinone Difunctionalization Reaction

Benzo[f]pyrido[1,2-a]indole-6,11-diones have been synthesized in high yields by copper(II)-catalyzed three-component reactions of acyl bromide, 1,4-naphthoquinone, and pyridine (or isoquinoline) via sp2–C–H difunctionalization of naphthoquinone followed by intramolecular cyclization and oxidative aromatization. In an attempt to expand the reaction scope and to help clarify the reaction mechanism, 1,3-dicarbonyl compounds are used in place of acyl bromides to take part in this reaction, and the benzo[f]pyrido[1,2-a]indole-6,11-diones derivatives are also obtained in excellent yields.