Reactions involving fluoride ion. Part 44. Synthesis and chemistry of aromatics with bulky perfluoroalkyl substituents

The observable perfluoroalkyl carbanion 1a, generated by addition of fluori de ion to perfluoroalkene 1, reacts efficiently with benzyl bromide and a r ange-of related derivatives 3a-g and this provides methodology for the prep aration of aromatic rings with large perfluoroalkyl substituents. Purificat ion of the perfluoroalkylated products 4a-g was accomplished by selective e xtraction from the reaction medium by a perfluorocarbon fluid. Products obt ained upon nitration and bromination of 4a demonstrate that the orientation of electrophilic substitution in 4a is controlled predominantly by the ste ric rather than electronic effects of the polyfluoroalkyl group. The method ology was applied to the preparation of azo-dyes 15a-c that are completely soluble in perfluorocarbon quids.