An economically useful process for producing CF2ClCFClCFR<AF>CF2OCF(CF3)COF (R<AF> is a fluorine atom etc.) is provided. CH2=CHCHR<A>CH2OCH(CH3)CH2OH (1) is reacted with a compound (2) such as FCOCF(CF3)OCF2CF2CF3 to obtain a compound (3) such as CH2=CHCHR<A>CH2OCH(CH3)CH2OCOCF(CF3)OCF2CF2CF3, which is reacted with a chlorinating agent to obtain a compound (4) such as CH2ClCHClCHR<A>CH2OCH(CH3)CH2OCOCF(CF3)OCF2CF2CF3, which is reacted with fluorine by liquid phase fluoriration.
