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Structure-reactivity correlations in nucleophilic substitution reactions of Y-substituted phenyl X-substituted benzoates with anionic and neutral nucleophiles

Title
Structure-reactivity correlations in nucleophilic substitution reactions of Y-substituted phenyl X-substituted benzoates with anionic and neutral nucleophiles
Authors
Um I.-H.Lee J.-Y.Fujio M.Tsuno Y.
Ewha Authors
엄익환
SCOPUS Author ID
엄익환scopusscopus
Issue Date
2006
Journal Title
Organic and Biomolecular Chemistry
ISSN
1477-0520JCR Link
Citation
vol. 4, no. 15, pp. 2979 - 2985
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
A kinetic study is reported for the reactions of 4-nitrophenyl X-substituted benzoates (1a-l) and Y-substituted phenyl benzoates (2a-l) with two anionic nucleophiles (OH- and CN-) and three amines (piperidine, hydrazine, and glycylglycine) in 80 mol% H2O-20 mol% dimethyl sulfoxide (DMSO) at 25.0 ± 0.1 °C. Each Hammett plot exhibits two intersecting straight lines for the reactions of 1a-l with the anionic nucleophiles and piperidine, while the Yukawa-Tsuno plots for the same reactions are linear. The Hammett plots for the reactions of 2a-l with hydrazine and glycylglycine demonstrate much better linear correlations with σ- constants than with σ° or σ constants, indicating that the leaving group departure occurs at the rate determining step (RDS). On the contrary, σ- constants result in poorer Hammett correlation than σ° constants for the corresponding reactions with OH- and CN-, indicating that the leaving group departure occurs after the RDS for the reactions with the anionic nucleophiles. The large ρX value (1.7 ± 0.1) obtained for the reactions of 1a-l with the anionic nucleophiles supports the proposal that the reactions proceed through an addition intermediate with its formation being the RDS. © The Royal Society of Chemistry 2006.
DOI
10.1039/b607194e
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자연과학대학 > 화학·나노과학전공 > Journal papers
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