Triphosgene and Triphenylphosphine Oxide-Mediated Cascade Heterocyclization of N-Acylated Anilines: One-Pot Synthesis of 2,4-Dichloroquinolines

A one-pot cascade chlorination/heterocyclization strategy has been developed for the synthesis of 2,4-dichloro-substituted quinolines from acylated anilines using triphosgene and triphenylphosphine oxide. Obviating the conventional harsh conditions of chlorination, synthetic useful quinolines with moderate to good yields were obtained through this reaction. The mechanism study exhibited that the formation of a β-enamine intermediate plays a vital role in the generation of the final product.