Steric shielding of the α-oxide 2-C-atom, as well as increase in the volume of the attacking nucleophilic agent, is shown to hinder the usual opening of polyfluorinated α-oxides at the 2- C-atom and to direct the nucleophilic attack to an other reaction centre. A mechanism of isomerisation of polyfluorinated α-oxides under the action of nucleophilic agents is suggested.
