1,1,1,3,3,3-Hexafluoropropan-2-yl 2,3,5,6-tetrafluoro-4-((1,1,1,3,3,3-hexafluoropropan-2-yl)oxy)benzoate

Acyl chloride alcoholysis is a fundamental and typically high-yielding method for ester synthesis. However, competitive side reactions can occur when the acyl chloride possesses multiple electrophilic sites and the alcohol is a strong nucleophile. We report an example of this phenomenon: the reaction of pentafluorobenzoyl chloride with 1,1,1,3,3,3-hexafluoropropan-2-ol yields not only the expected ester but also a significant quantity of the 1,1,1,3,3,3-hexafluoropropan-2-yl 2,3,5,6-tetrafluoro-4-((1,1,1,3,3,3-hexafluoropropan-2-yl)oxy)benzoate. The formation of the latter results from an effective nucleophilic aromatic substitution (SNAr) at the para-fluorine position of the pentafluorophenyl ring by the hexafluoroisopropoxide anion.