The use of trifluoroperacetic acid with boron trifluoride causes oxidation of alkenes and aromatic rings with concomitant rearrangement of the molecular skeleton.
For alkenes, the reaction gives a ketone product, though the mechanistic process is not simply epoxidation followed by a BF-catalyzed Wagner–Meerwein rearrangement:
For aromatics, an example demonstrated in an Organic Syntheses report is the conversion of hexamethylbenzene to 2,3,4,5,6,6-hexamethyl-2,4-cyclohexadienone: