A short, efficient synthesis of the lignan (+)-lyoniresinol dimethyl ether is described. The synthesisis achieved by asymmetric photocyclization of an achiral dibenzylidenesuccinate to a chiralaryldihydronaphthalene. (−)-Ephedrine is used as a chiral auxiliary to bias the atropisomericequilibrium in the dibenzylidenesuccinate prior to the photochemical reaction. The synthesis ofthe title compound was accomplished in five steps, and the final product was recrystallized toconstant melting point and rotation.