The aim of the invention is to provide a method for preparing carboxylic acid derivatives by aromatic nucleophilic substitution, in which a carboxylic acid derivative having a single carboxyl functional group, or one of the salts thereof, said carboxylic acid derivative having, in the ortho position of the carboxyl functional group, a leaving group, which is preferably an atom of fluorine or of chlorine or an alkoxy group, chiral or not, preferably a methoxy group, said carboxylic acid derivative not being substituted by an electroattractive group other than the leaving group if any; is reacted with a reactant MNu, where M is a metal and Nu is a nucleophile, chiral or not, said aromatic nucleophilic substitution reaction being carried out without a catalyst and without a step of protecting/deprotecting the acid functional group of the starting compound.