The activation of SNAr reactions by the superstrong electron-withdrawing substituent CF3S(O)=NSO2CF3

Abstract The chlorine lability of the 2-nitrochlorobenzene derivative which contains the superstrong electron-withdrawing substituent CF 3 S(O)=NSO 2 CF 3 in position 4 has been compared with the analogous 4-trifluoromethylsulphonylderivative and picryl chloride in nucleophilic substitution. During interaction with hard nucleophilic agents, the effect of one superstrong substituent approximately corresponds to the influence of two nitro groups in positions 2 and 4. With soft reagents, picryl chloride is more active than the compound containing the CF 3 S(O)=NSO 2 CF 3 group, polarizable only with difficulty.