Diastereoselectivity-switchable and regiospecific hetero Diels–Alder reaction of N-sulfinylper(poly)fluoroalkanesulfinamides with dienes

N-Sulfinylper(poly)fluoroalkanesulfinamides reacted readily with dienes in methylene chloride at −78 °C to give the corresponding cycloadducts with complete regioselectivities and good diastereoselectivities. The diastereoselectivity of the reaction was switchable to the opposite under the catalysis of Lewis acids such as TiCl4 and SnCl4.