58. Synthesis of Tricyclo [6.2.1.0^1,5]undecadiones via Intramolecular Photoaddition of 5-(1-Cyclopentenylmethyl)-3-alkoxy-2-cyclopentenones
    Oppolzer, W.; Burford, S. C.
    Helv. Chim. Acta 1980, 63, 788-792

Irradiation of the dienone methyl ether 3a furnished the unstable regioisomeric photoadducts 4a and 5a which on Lewis acid-catalyzed fragmentation afforded the tricyclic diketones 6,7 and 8. The same mixture was obtained from the isobutyl ether 3b (Scheme 2).

DOI : 10.1002/hlca.19800630406