PHENYLIODINE(III) BIS(TRIFLUOROACETATE) AS A RADICAL-CATION GENERATING REAGENT

The use of phenyliodine(III) bis(trifluoroacetate) (PIFA) as a one-electron oxidant For aromatic compounds has been explored. In trifluoroacetic acid or 1,1,1,3,3,3-hexafluoro-2-propanol, a number of radical cations were generated in the temperature range -10 to 20 degrees C and structurally assigned by EPR spectroscopy. The oxidative power of PIFA was found to be similar to that of thallium(III) trifluoroacetate under the conditions employed. Thus PIFA oxidation is a useful, less toxic complement to existing methods of radical cation generation. 1,1,1,3,3,3-Hexafluoro-2-propanol was found to be an excellent solvent for radical cations. The use of PIFA in 'inverted spin trapping' with alpha-phenyl-N-tert-butylnitrone (PEN) was investigated briefly, and it was found that it sustains this reaction with nucleophiles such as fluoride, chloride and acetate ion, tetramethylsuccinimide anion and benzotriazolate anion.