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Substitution électrophile aromatique dans l'anhydride sulfureux liquide. Etude cinétique de la réaction de bromation d'anisoles monosubstitués. Transmission des effets électroniques et caractéristiques de l'état de transition
Author(s) -
Castellonèse Paul,
Villa Pierre
Publication year - 1983
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19830660410
Subject(s) - chemistry , substituent , anisole , solvation , reaction rate constant , medicinal chemistry , reactivity (psychology) , halogenation , stereochemistry , organic chemistry , kinetics , molecule , medicine , physics , alternative medicine , pathology , quantum mechanics , catalysis
Reactivity‐structure correlations for anisole and eleven of its substituted derivatives established from bromination rate constants in liquid SO 2 , unlike observations in water, show the reaction to be highly sensitive to substituent effects, (ρ H 2 O += −7.1; ρ SO 2+= −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.