Reactions involving fluoride ion. Part 18. Derivatives of perfluorocycloalkenes

Abstract

Unlike perfluorocyclobutene, perfluorocyclo-pentene and -hexene do not form oligomers with pyridine. A range of oligomers is obtained from mixtures of perfluorocycloalkenes in reactions initiated by caesium fluoride. Products are also obtained from perfluorocycloalkenes with perfluoropropene and between perfluorocyclobutene and perfluorobut-2-ene. A variation is observed in the balance between exo- and endo-isomers of perfluorocycloalkene oligomers. It is concluded that conformational interactions dominate the position of equilibrium, except with four-membered rings, where angle strain is also important.