139. The Photochemical Behaviour of 5,5-Dimethyl-2(5H)-furanone

Article abstract of DOI:10.1002/hlca.19830660515

The photochemical behaviour of the title compound 2c was investigated in various solvents.In benzene and t-butanol photodimerization afford the cis-anti-cis HH- and HT-dimers (H=head, T=tail).In acetonitrile, cyclohexane and 2-propanol, photoreduction competes with photodimerization.The photoreduction products are hydrodimers, solvent adducts and the saturated lactone (the 2H-reduction product).In acetonitrile and cyclohexane H-abstraction by the β-C-atom of the C=C bond is the predominant reduction process.In 2-propanol, solvent adducts to the α- and β-C-atoms are formed in equal amounts.In xanthone-sensitized irradiations the ratio of HH- to HT-dimer is the same as on direct irradiation and the relative rates of conversion of 2c to products in different solvents are also similar under both conditions.