Reactions involving fluoride ion. Part 44.1 Synthesis and chemistry of aromatics with bulky perfluoroalkyl substituents

Abstract

The observable perfluoroalkyl carbanion 1a, generated by addition of fluoride ion to perfluoroalkene 1, reacts efficiently with benzyl bromide and a range of related derivatives 3a–g and this provides methodology for the preparation of aromatic rings with large perfluoroalkyl substituents. Purification of the perfluoroalkylated products 4a–g was accomplished by selective extraction from the reaction medium by a perfluorocarbon fluid. Products obtained upon nitration and bromination of 4a demonstrate that the orientation of electrophilic substitution in 4a is controlled predominantly by the steric rather than electronic effects of the polyfluoroalkyl group. The methodology was applied to the preparation of azo-dyes 15a–c that are completely soluble in perfluorocarbon fluids.