A one-pot, highly selective synthesis of 4-chloro-4′-(chlorodifluoromethoxy) benzophenone suitable for an industrial scale-up was developed. Fluorination of 4-(trichloromethoxy) benzoyl chloride at–20° C with HF to 4-(chlorodifluoromethoxy) benzoyl fluoride followed by an in situ Friedel–Crafts reaction with chlorobenzene in the presence of BF3 at–5° C yielded the title compound in excellent yield.
