107. Substitution electrophile aromatique dans l'anhydride sulfureux liquide. Etude cinetique de la reaction de bromination d'anisoles monosubstitues. Transmission des effets electroniques et caracteristiques de l'etat de transition

Article abstract of DOI:10.1002/hlca.19830660410

Reactivity-structure correlations for anisole and eleven of its substituted derivatives established from bromination rate constants in liquid SO2, unlike observations in water, show the reaction to be highly sensitive to substituent effects, (ρ⁺_H2O = -7.1; ρ⁺_SO2 = -10.51).This result is ascribed to the solvation of the methoxy group which decreases the conjugation of para-substituted (ρ⁺_O = -9.70) compared to that of ortho-substituted derivatives (ρ⁺_p = -8.86).The highly solvated transition state lies far from reactants on the reaction coordinate and the positive charge developed in this state is nearly unity.