Functionalisation of secondary and tertiary hydrofluorocarbons by electrooxidation in fluorosulphuric acid: novel route to perfluoroketones and tertiary alcohols

Abstract

Aliphatic and alicyclic secondary and tertiary hydrofluorocarbons are indirectly electro-oxidised in fluorosulphuric acid. Thus, 2H-heptafluoropropane and undecafluorocyclohexane are transformed into the corresponding perfluorosulphates. Pyrolysis of these latter compounds over caesium fluoride afforded the corresponding ketones. This method constitutes a novel route to perfluoro ketones particularly hexafluoroacetone. Tertiary hydroperfluoroalkanes are less reactive than secondary compounds vis-à-vis electro-oxidation. Nevertheless, the reaction of 1H-undecafluoronorbornane with the peroxide (FSO₃)₂, followed by hydrolysis of the ester so obtained, yielded perfluoronorbornan-1-ol.