DEUTERIUM OXIDE SOLVENT ISOTOPE EFFECTS IN NUCLEOPHILIC REACTIONS OF PHENYL ESTERS
DEUTERIUM OXIDE SOLVENT ISOTOPE EFFECTS IN NUCLEOPHILIC REACTIONS OF PHENYL ESTERS
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DOI：
10.1021/ja00863a019
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发表时间：
1962-01-01
影响因子：
15
通讯作者：
POLLOCK, EJ
中科院分区：
文献类型：
--
作者：
BENDER, ML;NEVEU, M;POLLOCK, EJ
测定了两种分子内和三种分子间亲核试剂催化的苯酯水解反应中氘氧溶剂的同位素效应。利用羧酸根离子作为亲核试剂的反应得到1.8的kU 1。/kD的比率，而利用叔胺作为亲核试剂的反应得到0.9至1.0的比率。在考虑次级氘同位素效应12的基础上计算的羧酸根离子反应中的同位素效应值为1.5至1.6，与实验值合理一致。比较了一般碱和亲核试剂催化水解反应中的动力学同位素效应，分别反映了一级和二级氘同位素效应。虽然区分这些同位素效应存在模糊性，但在某些限制情况下，它们可以用作区分一般碱催化和亲核试剂催化水解的经验标准。
Deuterium oxide solvent isotopeeffects in two intramolecular and three intermolecular nucleophile-catalyzed hydrolyses of phenyl esters have been determined. Reactions utilizing carboxylate ion as a nucleophile resulted in ratios of kUl0/kD> of 1.8 while reactions utilizing a tertiary amine as a nucleophile gave ratios of 0.9 to 1.0. Values of the isotope effect in the carboxylate ion reactions calculated on the basis of the consideration of the secondary deuterium isotope effects12 were 1.5 to 1.6 in reasonable agreement with the experimental values. A comparisonis made ofkinetic isotopeeffects in general base-and nucleophile-catalyzed hydrolyses, reflecting primary and secondary deuterium isotope effects, respectively. While there is ambiguity in distinguishing between these isotope effects, they may be used in certain restricted situations as an empirical criterion in distinguishing between general base-and nucleophile-catalyzed hydrolyses.