Electrochemical fluorosulfation of perfluoroallylbenzene

Perfluoroallylbenzene (I) can be isomerized under the action of HSO3F to form perfluoropropenylbenzene (in the form of a mixture of cis- and trans-isomers) which undergoes anodic oxidation in HSO3F to give α,β-bis(fluorosulfonyloxy)perfluoropropylbenzene (III). Reaction of III with CsF in tetraglyme gives perfluoro-2-methylbenzoxolene (XII), whereas III is converted to perfluoromethylphenyl-α-dione (IX) by reacting with AcONa/AcOH. Cyclization of (IX) catalyzed by CsF occurs to form perfluoro-2-methyl-3-oxobenzoxolene (XIII).