2,2'-DIHALO-BIS(PERFLUOROCYCLOALKENES) .1. SYNTHESIS

An improved synthesis of 1-chloro-2-iodo-perfluorocycloalkenes and their copper coupled products, 2,2′-dichloro-bis(perfluorocycloalkenes) is reported. Mixtures of equal molar quantities of different chloroiodoperfluorocycloalkenes react with copper to give predominately the mixed coupled product. For example, 1-chloro-2-iodoperfluorocyclobutene and 1-chloro-2-iodoperfluorocyclopentene react with copper to give 2-chloro-1-[1′-2′-chlorohexafluorocyclopentenyl)]-tetrafluorocyclobutene in 70% yield. The 2,2′-dichloro-bis(perfluorocycloalkenes) react with potassium iodide in DMF to substitute one or both vinylic chlorine atoms by iodine. Copper coupling of 2,2′-diiodo-bis(perfluorocyclopentene) gives the cyclic tetramer perfluorotetracyclopentenocyclo-octatetraene, whereas 2-chloro-2′-iodo-bis(perfluorocyclopentene) and copper gives the linear tetramer 2,2‴-dichlorotetrakis(perfluorocyclopentene). © 1979.