Estimated rate constants for hydrogen abstraction from N-heterocyclic carbene-borane complexes by an alkyl radical.
Estimated rate constants for hydrogen abstraction from N-heterocyclic carbene-borane complexes by an alkyl radical.
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DOI：
10.1021/ol101014q
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发表时间：
2010-06
期刊：
影响因子：
5.2
通讯作者：
A. Solovyev;S. Ueng;Julien Monot;L. Fensterbank;M. Malacria;Emmanuel Lacôte;D. Curran
中科院分区：
文献类型：
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作者：
A. Solovyev;S. Ueng;Julien Monot;L. Fensterbank;M. Malacria;Emmanuel Lacôte;D. Curran
用吡啶-2-硫代羰基（PTOC）竞争动力学方法测定了20种N-杂环卡宾-硼烷（NHC-硼烷）配合物在单浓度点壬基自由基夺氢的速率常数。速率常数范围为<1 × 10（4）~ 8 × 10（4）M（-1）s（-1）。它们对卡宾核的电子性质几乎没有依赖性，但随着卡宾N-取代基尺寸的减小，速率常数有增加的趋势。已鉴定出两种具有小N-取代基（R = Me）的有前途的新试剂。
Rate constants for hydrogen abstraction by a nonyl radical from 20 complexes of N-heterocyclic carbenes and boranes (NHC-boranes) have been determined by the pyridine-2-thioneoxycarbonyl (PTOC) competition kinetic method at a single concentration point. The rate constants range from <1 x 10(4) to 8 x 10(4) M(-1) s(-1). They show little dependence on the electronic properties of the carbene core, but there is a trend for increasing rate constants with decreasing size of the carbene N-substituents. Two promising new reagents with small N-substituents (R = Me) have been identified.