N-Heterocyclization of Naphthylamines with 1,2-and 1,3-Diols Catalyzed by an Iridium Chloride/BINAP System

Benzoquinoline derivatives were successfully synthesized by iridium-catalyzed N-heterocyclization of naphthylamines with diols. For instance, the reaction of 1-naphthylamine with 1,3-propanediol catalyzed by IrCl3 combined with BINAP as a ligand produced 7,8-benzoquinoline in quantitative yield. The N-heterocyclization reaction was found to be markedly influenced by the ligands employed. Benzoindoles were also synthesized by the same strategy from napthylamines with 1,2-diols. A reaction mechanism for the N-heterocyclization of naphthylamines with 1,3-diols by IrCl3 was proposed.