Chemo- and Diastereoselectivities in the Oxidation of Cyclopentenols with Dimethyldioxirane and Methyl(trifluoromethyl)dioxirane

A comparison of the diastereoselectivity and the chemoselectivity (epoxidation versus allylic oxidation) attained in the oxidation of cyclopentenols using dimethyldioxirane and methyl(trifluoromethyl)dioxirane is reported. The results indicate that with both dioxiranes diastereoselective epoxidation of allylic cyclopentenols is accompanied by competitive allylic oxidation to the corresponding enone; for the latter, a likely rationale is proposed.