The 1, 4-Diesters of 2-Butene by Phase-Transfer Catalyzed Nucleophilic Displacement and Isomerization of Dichlorobutene Mixtures

1, 4-Dichloro-2-butene (1) reacts quantitatively with salts of carboxylic acids under phase-transfer catalytic (PTC) conditions to form 1, 4-diesters of 2-butene. 3, 4-Dichloro-l-butene (2) does not react with carboxylate nucleophiles. 2 is isomerized to 1 by quaternary ammonium halide catalysts, but no reaction is observed with quaternary ammonium carboxylases. By proper adjustment of the reaction conditions, isomer mixtures of dichlorobutene can be directly converted to pure 1, 4-derivates of 2-butene.