The photo-induced reaction of cyclic α, β-unsaturated ketones with protic media is described. The irradiation of 2-cycloheptenone or 2-cyclooctenone in various protic solvents (alcohols, acetic acid, water, and diethylamine) results in the formation of Michael-type solvent adducts. The chemically-reactive species have been demonstrated to be the highly strained trans isomers in a ground state. The irradiation of cis-2-cyclononenone affords ...
