Nucleophile-reactive sulfonated compounds used as precursors to (radio)labelled (bio)molecules are produced by pre-introduction of a nucleophilic compound R* through an unusual nucleophile-induced ring-opening reaction of the sultone moiety of the precursor. The precursors and compounds conform to respective formulae (Ip) and (I): Also disclosed are methods for producing these precursors and compounds, as well as for conjugation of these compounds with (bio)molecules, and to the drugs obtained by this method.