Heterocyclic compounds pentafluoropyridine

Table 9.7 Nucleophilic attack on pentafluoropyridine and related heterocyclic compounds, and some...

Although controlled substitution with molecular fluorine is difficult to attain, noteworthy is the recent success in perfluorinating both saturated and unsaturated heterocycles by electrolysis in anhydrous hydrogen fluoride. Cf. T. C. Simmons and F. W. Hoffmann, J. Am. Chem. Soc. 79, 3429 (1957), for the preparation of undecafluoropiperidine (from piperidine). The latter compound can be converted into pentafluoropyridine by passing it over an iron contact at 600° [R. E. Banks, A. E. Ginsberg, and R. N. Haszeldine, J. Chem. Soc. p. 1740 (1961)]. 

Banks RE, Burgess JE, Cheng WM et al (1965) Heterocyclic polyfluoro-compounds. Part IV. -Nucleophilic substitution in pentafluoropyridine the preparation and properties of some 4-substituted 2,3,5,6-tetrafluoro-pyridines. J Chem Soc (resumed) 1965 575-581... 

---