Reactions involving fluoride ion. Part 19. Observable perfluorocycloalkylanions

Abstract

Carbanions are generated by reaction of fluoride ion with perfluorocycloalkene derivatives, e.g. perfluorobicyclobutylidene (3), and this anion is relatively unchanged over a range of temperature or on prolonged standing, as indicated by the ¹⁹F n.m.r. spectrum. Internal return by fluoride ion to the same carbon atom is suggested to account for the ¹⁹F n.m.r. spectra of the ions. Trapping experiments with bromine and chlorine provide further evidence for the structures of the ions.