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. (C) 2002 Elsevier Science Ltd. All rights reserved.