Cyclization of cembrane diterpenoids. IV. Stereoselective photochemical cyclization of a norcembrane ketone

The possibility has been shown for the first time of the occurrence of an intramolecular [2+2]-cycloaddition for a derivative of a cembrane diterpenoid. The structure of the product, which was a higher isoprenolog of the bourbonane sesquiterpenoids, was established by the x-ray structural analysis of its epoxide.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 295–299, May–June, 1986.