A neat and high yield chemoselective epoxidation of alkene moieties present in tertiary amines is accomplished by treatment of the corresponding amine–boron trifluoride adduct with dimethyldioxirane or methyl(trifluoromethyl)dioxirane.
aromatic amines, anilines and tertiaryamines with dimethyldioxirane (DMD) was examined. Treatment of heterocyclic aromatic amines and anilines with a slight excess of DMD at 0 °C afforded the corresponding N-oxides in quantitative conversion yields. In addition, the oxidation was chemoselective in the presence of carbon-carbon double bonds. On the other hand, most of the tertiaryamines assayed did