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The ortho ‐Substituent Effect on the Ag‐Catalysed Decarboxylation of Benzoic Acids
Author(s) -
Grainger Rachel,
Cornella Josep,
Blakemore David C.,
Larrosa Igor,
Campanera Josep M.
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402931
Subject(s) - decarboxylation , substituent , steric effects , chemistry , benzoic acid , stereochemistry , medicinal chemistry , photochemistry , organic chemistry , catalysis
Abstract A combined experimental and computational investigation on the Ag‐catalysed decarboxylation of benzoic acids is reported herein. The present study demonstrates that a substituent at the ortho position exerts dual effects in the decarboxylation event. On one hand, ortho ‐substituted benzoic acids are inherently destabilised starting materials compared to their meta ‐ and para ‐substituted counterparts. On the other hand, the presence of an ortho ‐electron‐withdrawing group results in an additional stabilisation of the transition state. The combination of both effects results in an overall reduction of the activation energy barrier associated with the decarboxylation event. Furthermore, the Fujita–Nishioka linear free energy relationship model indicates that steric bulk of the substituent can also exert a negative effect by destabilising the transition state of decarboxylation.