Pentafluorosulfanyldifluoroacetic acid: rebirth of a promising building block.

Three novel, easily scalable routes for the synthesis of pentafluorosulfanyldifluoroacetic acid, SF5CF2C(O)OH, are described. Reactions of its acid chloride with amines and alcohols led to a small library of 15 amides and five esters, respectively. The reaction of the acid chloride with phenylmagnesium bromide gave the corresponding acetophenone.