Diastereodifferentiating the [2+2] Photocycloaddition of Ethylene to Arylmenthyl Cyclohexenonecarboxylates: Stacking-Driven Enhancement of the Product Diastereoselectivity That Is Correlated with the Reactant Ellipticity
Upon diastereodifferentiating the [2+2] photocycloaddition of ethylene to a series of p‐substituted (−)‐8‐phenylmenthyl cyclohexenonecarboxylates, the diastereoselectivity was critically controlled by the nature of the substituent introduced to the chiral auxiliary, and the p‐nitro‐substituted substrate afforded the cycloadducts in 90 % diastereomeric excess (de) and with 97 % isolated yield. Detailed