A simple synthetic strategy to dihalophenylacetic acids and specifical
ly 3,5-difluorophenylacetic acid an important pharmaceutical intermedi
ate was developed. The aromatic nucleophilic substitution of dihaloflu
orobenzenes using the anion of ethyl cyanoacetate yielded ethyl dihalo
phenylcyanoacetates. The basic decarboxylation of the ethyl dihalophen
ylcyanoacetates produced targeted dihalophenylacetic acids.