Polyfluorocarbanion chemistry. Part I. Reaction of hexafluoropropene with tetrafluoropyrimidine

Abstract

Hexafluoropropene reacts with tetrafluoropyrimidine in a dipolar aprotic solvent in the presence of caesium fluoride to give only one mono-, one bis-, and one tris-perfluoroisopropyl derivative (4-, 4,6-, and 2,4,6-), and perfluoro-(2,4,5,6-tetraisopropylpyrimidine) in amounts determined by reactant ratio and reaction conditions. In the disubstituted derivative both the remaining ring fluorine atoms are easily displaced by cyanide ion; one of the cyano-groups so introduced may be displaced by a heptafluoroisopropyl carbanion. Variable temperature n.m.r. study of the tetrasubstituted derivative shows that at temperatures up to 40° the three adjacent heptafluoroisopropyl groups exist in fixed conformation; pyrolysis of the tetrasubstituted derivative yields compounds formulated as cyclobutapyrimidines.