Photochemically Catalyzed Diels-Alder Reaction of N-Arylimines with 2,3-Dihydrofuran and 3,4-Dihydro-2H-dihydropyran

Imino Diels-Alder reactions between N-arylimines and electron-rich dienophiles provide an easy entry into the tetrahydroquinoline derivatives. 1] This imino Diels-Alder reaction has been reported to be catalyzed by BF3· Et2O,FeCl3, InCl3 and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) etc.