The tetrahydroquinolines obtained through the Povarov multicomponent reaction have been oxidized to the corresponding quinoline, giving access to a single product through a two-step sequence. Several oxidizing agents were studied and manganese dioxide proved to be the reagent of choice, affording higher yields, cleaner reactions and practical protocols.
Keywords: Povarov; manganese dioxide; multicomponent reactions; oxidation; quinolines; tetrahydroquinolines.