<i>p</i>-Toluenesulfonic Acid Promoted Annulation of 2-Alkynylanilines with Activated Ketones: Efficient Synthesis of 4-Alkyl-2,3-Disubstituted Quinolines
Reactions between readily available 2-alkynylanilines and activatedketones such as β-keto esters promoted by p-toluenesulfonicacid afford 4-alkyl-2,3-disubstitutedquinolines in good to excellent yields. The generality of substituents at the other end of the triple bond of 2-alkynylanilines makes the method a valuable approach to diversified 4-alkylquin-olines, which are difficult to obtain by classical