InCl3-Catalyzed hetero-Diels–Alder reaction: an expeditious synthesis of pyranoquinolines

Indium trichloride catalyzes efficiently the cycloaddition reactions of aryl amines with 3,4-dihydro-2H-pyran (DHP) under mild reaction conditions to afford the corresponding pyrano[3,2-c]quinolines in high yields with high diastereoselectivity.