Proline potassium salt: a superior catalyst to synthesize 4-trifluoromethyl quinoline derivatives via Friedlander annulation

Proline potassium salt was successfully firstly used to catalyze the Friedlander annulation toward the synthesis of 4-trifluoromethyl-substituted quinolines from the substituted 2-trifluoroacetyl anilines and variety carbonyl compounds under mild conditions in good to excellent yields. This catalyst provides several advantages, such as shorter reaction time, high regioselectivity, functional group tolerance, and broad substrate scope.