Reactions of metal cyanides with polyfluorobenzenes

Abstract

Hexafluorobenzene and chloropentafluorobenzene react with alkali-metal cyanides in methanol to give products in which fluorine has been replaced by both cyano- and methoxy-groups. The formation of these products is rationalised in terms of initial attack by cyanide ion, followed by attack on the resulting nitrile by methoxide ion. Pentafluorobenzonitrile is substituted in the 4-position by methoxide ion (sodium cyanide in methanol) or by dimethylamine (derived from dimethylformamide).