The complex HOF.CH3CN, made directly from fluorine and aqueous acetoni
trile, was used for oxidation of secondary alcohols and for Baeyer Vil
liger oxidation of ketones. By using O-18 labeled reagent it was found
that the ketone oxidation proceeds through the original dioxirane mec
hanism which Baeyer and Villiger suggested a century ago for reactions
with peracids but was later discounted.