Electrochemical fluorosulfation of perfluoroallylbenzene

Perfluoroallylbenzene ( I ) can be isomerized under the action of HSO 3 F to form perfluoropropenylbenzene (in the form of a mixture of cis - and trans -isomers) which undergoes anodic oxidation in HSO 3 F 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 ).