Reactions involving fluoride ion. Part VIII. Syntheses from perfluorocycloalkenes

Abstract

Perfluorocyclo-hexene, -pentene, and to a lesser extent, -butene react with pentafluoropyridine in the presence of caesium fluoride to give perfluorocycloalkylpyridines. Di-and tri-substituted pyridines are obtained only from perfluorocyclohexene, and perfluorocycloalkyl derivatives are isolated only from perfluorocyclohexene on reaction of these cyclic olefins with tetrafluoropyridazine. Fluoride ion induces dimerisation of perfluorocyclo-pentene and -hexene whereas a trimer of perfluorocyclobutene is isolated; the structures of these products are established.