PERFLUOROALKYLATIONS AND PERFLUOROOXAALKYLATIONS .4. CONVERSION OF ARYL PERFLUOROALKANES TO ARYL PERFLUOROALKYL KETONES

The hydrolysis of benzylic fluorines with hydrobromic acid in glacial acetic acid has been utilized to convert some substituted phenyl perfl uoroalkanes to the corresponding ketones. Electron-donating substituen ts such as -OMe, -OH or -NH2 on the benzene ring, ortho or para to the perfluoroalkyl group, were essential for the conversion to occur unde r the experimental conditions used. With an electron-donating substitu ent at the position meta to the perflurooalkyl substituent, only bromi nation of the aromatic ring was observed. In unsubstituted phenyl perf luoroalkanes or those with electron-withdrawing substituents on the ar omatic ring, no hydrolysis of the benzylic fluorines occurred under th e same conditions.