Photochemistry of Substituted 4,4-Dimethoxy-2,5-Cyclohexadienones

Article abstract of DOI:10.1002/jccs.199800001

4,4-Dimethoxy-2,5-cyclohexadienones 9-14 were prepared from the corresponding hydroquinone monomethyl ethers by oxidation with thallium trinitrate in methanol. Irradiation of solutions of 9-13 in methanol with a broad band of UV light centered at 350 nm in a Rayonet reactor afforded 2-cyclopentenone derivatives 15-19 in moderate to excellent yields, whereas irradiation of 14 in methanol gave phenol 8 along with other unidentified products. Irradiation of 11-14 in benzene yielded substituted phenols. The plausible reaction pathways for the product formation are discussed.