Yb(OTf)3: an efficient catalyst for the synthesis of 3-arylbenzo [f]quinoline-1,2-dicarboxylate derivatives via imino-Diels–Alder reaction

A mild and facile method for the synthesis of 3-arylbenzo[f]quinoline-1,2-dicarboxylate derivatives is reported by an imino-Diels–Alder reaction in high yields (76–92%). This procedure includes a novel three-component reaction of aromatic aldehyde, naphthalen-2-amine, and but-2-ynedioate catalyzed by Yb(OTf)3 in toluene. The results are obviously different from those of the simple substituted aniline-involved reactions catalyzed by ZnCl2 or KOH in the literature.