The electrochemical oxidation of trifluoroacetate anion in the presence of activated dienes, ROOCCH=CH(CH2)nCH=CHCOOR, gave bis(trifluoromethyl) alicyclic products. The ring size of the products was determined by comparing the fluorine nuclear magnetic resonance spectra of the protonated with the corresponding α,α′-dideuterated compounds. The results can be explained by an intramolecular radical addition and by an intramolecular coupling of a biradical intermediate.