Nucleophilic displacement in polyhalogenoaromatic compounds. Part 7. Kinetics of methoxydefluorination of polyfluoronitrobenzenes

Abstract

Rates and orientations of methoxydefluorination (NaOMe–MeOH) of twelve polyfluoronitrobenzenes have been measured at 298.2 K. The fluorine substituent effects are less well defined in the presence of the nitro-group, and are dependent not only upon the orientation of the fluorine substituent with respect to the reaction site, but also with respect to the nitro-group. The resulting attenuation seems to be electronic rather than steric in origin, and may be described as a mutually weakening interaction of the mesomeric effects of halogen and nitro-group. Two fluorine atoms ortho to the nitro-group cause a further diminution of effect consistent with this explanation.