Photoinduced functionalization of the C-20 methyl group of the nor-diterpene atractyligenin

Irradiation of the nor-diterpene atractyligenin at λ=254 nm in methanol gave, on one hand, the decarboxylation product, and provided, on the other hand, the transformation of the C-20 angular methyl into a methylene-carbomethoxy group. A photochemical pathway involving formation of C-19/C-20 bond is suggested.