Solvent effects on the photocycloaddition and photoenolisation reactions of isophorone

The influence of solvent on two photochemical reactions of isophorone has been investigated. The photocycloaddition of isopropenyl acetate to isophorone (3,5,5-trimethylcyclohex-2-en-1-one) (1) is best achieved using methanol as solvent. Photodeconjugation of isophorone (1) to the exocyclic methylene isomer 2 proceeds most efficiently in ethyl acetate.