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.