A highly efficient synthesis of 1,2,3,4-tetrahydroquinolines by molecular iodine-catalyzed domino reaction of anilines with cyclic enol ethers

A highly efficient method for the synthesis of 1,2,3,4-tetrahydroquinoline derivatives via a molecular iodine catalyzed domino reaction of anilines with cyclic enol ethers, such as 2,3-dihydrofuran and 3,4-dihydro-2H-pyran, is described. The reaction may proceed through an aza-Diels–Alder process between an in situ generated 2-azadiene and another equivalent of cyclic enol.