LiTMP Trans-Metal-Trapping of Fluorinated Aromatic Molecules: A Comparative Study of Aluminum and Gallium Carbanion Traps
LiTMP Trans-Metal-Trapping of Fluorinated Aromatic Molecules: A Comparative Study of Aluminum and Gallium Carbanion Traps
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LiTMP 跨金属捕获氟化芳香族分子：铝和镓碳负离子陷阱的比较研究
DOI：
10.1002/ange.201706064
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发表时间：
2017
影响因子：
--
通讯作者：
McLellan R
中科院分区：
文献类型：
--
作者：
McLellan R
由于锂离子中间体的稳定性较低，含氟芳香族化合物支架对锂离子的催化性能提出了挑战。在这里，我们将跨金属捕集(TMT)应用于一系列关键的含氟芳香族化合物。在TMT中，LiTMP执行金属化，而有机金属陷阱拦截出现的碳离子。本研究对比了Bu2AlTMP和Ga(CH2SiMe3)3的捕获能力，对它们的TMT反应进行了结构映射，并用核磁共振研究了金属化芳烃中间体的相对稳定性。结果表明，Al-−-C(芳基)键比Ga-−-C(芳基)更容易被苯生成和Li-F释放分解。因此，后者在与苯甲酰氯的交叉偶联反应中生成酮的反应中表现出更好的向前反应活性。
Fluoroaromatic scaffolds pose a challenge to lithiation due to low stability of lithiated intermediates. Here we apply trans‐metal‐trapping (TMT) to a series of key fluorinated aromatics. In TMT, LiTMP performs the metalation, while an organometallic trap intercepts the emergent carbanion. This study contrasts the trapping abilities ofiBu2AlTMP and Ga(CH2SiMe3)3, structurally mapping their TMT reactions and probing relative stabilities of metalated fluoroaromatic intermediates by NMR studies. Results show the installed Al−C(aryl) bonds are more prone to decomposition by benzyne formation and Li‐F liberation, than the Ga−C(aryl) species. The latter are thus better for onward reactivity as demonstrated in cross‐coupling reactions with benzoyl chloride that produce ketones.