Cyclic oligomers containing hexafluoroiso-propylidene(HFIP) units were prep
ared in excellent yields by a nucleophilic aromatic substitution reaction o
f 4,4(7)- (hexafluoroisopropylidene) diphenol with difluoro-monomers in the
presence of anhydrous potassium carbonate under pseudo high dilution condi
tions. A combination of GPC, MALDI-TOF MS and NMR analysis confirmed the st
ructure of the cyclic oligomers. All macrocyclic oligomers are crystalline
and undergo facile melt polymerization to give high molecular weight fluori
nated polyethers.