Preparation, fluorination and synthetic utility of a CFC-olefin adduct

Abstract

1,1,1 -Trichlorotrifluoroethane was added to ethylene using the catalyst system Fe/triethylphosphite, which eliminated the need for a solvent and avoided the corrosion problems inherent in CuCl-catalyzed reactions. The adduct, CF 3CCl 2CH 2CH 2Cl, was fluorinated with HF over a chromium(III) oxide catalyst. A series of alternating dehydrochlorinations and HF additions to internal C=C double bonds was proposed and supported by thermodynamic calculations to explain the formation of CF 3CF 2CH=CH 2 as the principal fluorination product. An intermediate, CF 3CCl=CHCH 2Cl, formed cleanly by dehydrochlorination of the adduct in the absence of HF, was converted into 4,4,4- trifluorobutanol and other compounds of the type CF 3CCl=CHCH 2X (X = OAc, OH, Br, I, H).