One-Step Catalytic Synthesis of Alkyl-Substituted Quinolines

Difficult-to-access alkyl-substituted quinolines are formed directly from commercially available anilines, aldehydes, and alkynes bearing a variety of substituents. Copper(II) triflate catalyzes this three-component coupling without ligand, cocatalyst, solvent, or inert atmosphere. In addition, a two-component Povarov reaction forms 2,3-dialkyl quinolines under the same green conditions that enable the selective three-component synthesis of 2-alkyl quinolines as well as more common aryl quinolines.