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Titolo:
Concurrent S(N)1 and S(N)2 reactions in the benzylation of pyridines
Autore:
Yoh, SD; Cheong, DY; Lee, CH; Kim, SH; Park, JH; Fujio, M; Tsuno, Y;
Indirizzi:
Kyushu Univ, Inst Fundamental Res Organ Chem, Fukuoka, Japan Kyushu Univ Fukuoka Japan st Fundamental Res Organ Chem, Fukuoka, Japan Kyungpook Natl Univ, Dept Chem Educ, Taegu 702701, South Korea Kyungpook Natl Univ Taegu South Korea 702701 , Taegu 702701, South Korea
Titolo Testata:
JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
fascicolo: 3, volume: 14, anno: 2001,
pagine: 123 - 130
SICI:
0894-3230(200103)14:3<123:CSASRI>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
CORRELATION INTERACTION COEFFICIENTS; NUCLEOPHILIC-SUBSTITUTION REACTIONS; STRUCTURE-REACTIVITY RELATIONSHIPS; SN2-SN1 SPECTRUM; MENSCHUTKIN REACTION; SOLVENT ASSISTANCE; LEAVING GROUPS; ION-PAIRS; MECHANISMS; CARBON;
Keywords:
Menschutkin reaction; benzyl bromides; duality of S(N)1-S(N)2 mechanisms;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Fujio, M Kyushu Univ, Inst Fundamental Res Organ Chem, Fukuoka, Japan Kyushu Univ Fukuoka Japan ental Res Organ Chem, Fukuoka, Japan
Citazione:
S.D. Yoh et al., "Concurrent S(N)1 and S(N)2 reactions in the benzylation of pyridines", J PHYS ORG, 14(3), 2001, pp. 123-130

Abstract

The Menschutkin reactions of 3,4-methylenedioxybenzyl and 3,4-dimethoxybenzyl bromides and also p-methoxybenzyl bromide with Y-substituted pyridines were kinetically studied for a range of amine concentration in acetonitrile. The strongly activated benzyl bromides showed a significant positive intercept in the plot of the pseudo-first-order rate constants against the concentrations of nucleophiles, while less activated benzyl bromides did not give such significant intercepts. The rate data for respective substrates were fitted to the equation k(obs) = k(1) + k(2)[Nu]. The first-order rate constant, k(1), is unaffected by the nature of the nucleophile, whereas the second-order rate constant, k(2), increased with increasing nucleophilicity. This was ascribed to the simultaneous occurrence of S(N)1 and S(N)2 reactions without an intermediate mechanism. These results an taken as evidence for the duality of S(N)1 and S(N)2 mechanisms in the Menschutkin reaction in the non-solvolyzing solvent acetonitrile. Copyright (C) 2001 John Wiley & Sons, Ltd.

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Documento generato il 10/04/20 alle ore 15:56:07