Dysprosium(III) catalyzed formation of hexahydrofuro[3,2-c]quinolines via 2:1 coupling of dihydrofuran with substituted anilines

A novel dysprosium(III) catalyzed 2:1 coupling reaction between substituted anilines and 2 equiv. of dihydrofuran that yields substituted hexahydrofuro[3,2-c]quinolines is described. The reaction proceeds via a formal Diels–Alder process between an in situ generated 2-azadiene with another equivalent of dihydrofuran and may proceed either through a stepwise or an asynchronous concerted mechanism.