Mechanistic understanding of alkyne haloboration : an Ab initio study
Mechanistic understanding of alkyne haloboration : an Ab initio study
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炔烃卤硼化反应的机理理解：从头算研究
DOI：
10.1002/ejoc.201200975
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Masanobu Uchiyama.
中科院分区：
文献类型：
--
作者：
Chao Wang;Masanobu Uchiyama.
利用二阶Møller-Plesset微扰理论（MP2）进行从头计算，以了解炔卤化的机理。目前的研究揭示了该反应的三个重要方面：(1)反应路线，(2)立体转化途径，(3)物理化学独特性。该- Markovnikov反应路径由一个特征的四中心过渡态控制，反映了炔烃和卤化硼的作用，也反映了产物的稳定性。对于立体转化途径，卤化硼介导的加成-消除过程似乎是最有利的。然而，高激活势垒表明，用过量的卤化硼（通常用于合成）长时间加热有利于顺式/反异构化。最后，通过与其他卤化反应的比较，表明卤化反应在热力学和动力学上具有明显的优势，在许多元素金属化反应中，卤化反应是一种独特的、无需催化剂的反应。
Ab initio calculations have been performed with second‐order Møller–Plesset perturbation theory (MP2) to understand the mechanisms of alkyne haloboration. The present study throws light on three important aspects of this reaction: (1) reaction routes, (2) stereoconversion pathways, and (3) physicochemical uniqueness. Thecis‐Markovnikov reaction route is controlled by a characteristic four‐centered transition state, reflecting the roles of alkynes and boron halides, and also the stability of the product. For the stereoconversion pathways, a boron‐halide‐mediated addition–elimination process appears to be most favorable. Nevertheless, the high activation barrier suggests that prolonged heating with excess boron halide (commonly used in synthesis) would favorcis/transisomerization. Finally, comparison with other halometalations showed clear thermodynamic and kinetic advantages of haloboration as a unique, catalyst‐free protocol among many elemento‐metalation reactions.