Short synthesis of 4-chloro-4′-(chlorodifluoromethoxy)benzophenone

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.