Highly Enantioselective Diels–Alder Reaction of a Photochemically Generated o‐Quinodimethane with Olefins

Four stereogenic centers in one step are established with almost perfect control of the absolute and relative configuration in a photochemically induced Diels–Alder reaction of substrate 1 and dimethyl fumarate. The carrier of the chiral information, lactam 2, fixes the substrate by hydrogen bonds in a chiral environment and in this way controls the configuration of the stereogenic centers of product 3.