On the hydroxylation of bicyclo[2.1.0]pentane using dioxiranes

The oxidn. of bicyclo[2.1.0]pentane by isolated dimethyldioxirane and by the more powerful methyl(trifluoromethyl)dioxirane, affords selectively, the corresponding endo-2 alc. along with the 2,3-diol in high yield, and no rearrangement products; this suggests that a concerted O-insertion mechanism should be preferred over radical pathways.