Photochemical reactions of 1-methoxymethylbicyclo[4.3.0]non-6-en-8-one and 5-methoxymethylbicyclo[3.3.0]oct-1-en-3-one

Irradiation of the title compounds 5 and 6 with light of wavelengths 350 and 254 nm afforded products in different ratios. Abstractions of hydrogen atoms of the methoxyl groups by both Cα and Cβ are the primary photochemical reactions leading to various products, but the total yield of the products derived from Cβ H-abstraction increased when light of wavelength 350 nm was used. Plausible mechanisms for the formation of the products are proposed.