Camphorsulfonic Acid Catalyzed One-Pot Three-Component Reaction for the Synthesis of Fused Quinoline and Benzoquinoline Derivatives

A simple and an efficient
one-pot three-component reaction of arylamines,
aromatic aldehydes, and cyclic ketones was described for the synthesis
of various fused quinoline, benzoquinoline, and naphthoquinoline derivatives
by using camphorsulfonic acid as a catalyst. The exploitation of pregnenolone
steroid for benzoquinolines and terephthalaldehyde for bis-benzoquinolines
synthesis was achieved with 68–75% yields. The reactivity of
arylamines and the mechanistic study for the formation of benzoquinoline
was described precisely. The present protocol offers a great potential
for atom-economy under mild conditions.