51. Intramolecular de Mayo Reactions of 3-Acetoxy-2-alkenyl-2-cyclohexenones. Preliminary communication
    Oppolzer, W.; Bird, T. G. C.
    Helv. Chim. Acta 1979, 62, 1199-1202

The photoaddition, hydrolysis, retro-aldol sequences 1 → 2 → 3 and 4 → 5 + 6 → 7 proceeded in high yield and in a regiospecific manner. However, the enol acetate 8 on irradiation furnished the tricyclic ketoacetate 9 as the major product, presumably by a hydrogen shift in the intermediate diradical 11. Hydrolysis of the minor photoadduct 10 gave the dione 13.

DOI : 10.1002/hlca.19790620429