Electrostatically Enhanced 3- and 4-Pyridyl Borate Salt Nucleophiles and Bases
Electrostatically Enhanced 3- and 4-Pyridyl Borate Salt Nucleophiles and Bases
复制标题
静电增强 3- 和 4-吡啶基硼酸盐 亲核试剂和碱
DOI：
10.1021/acs.joc.3c00523
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Kass, Steven R.
中科院分区：
文献类型：
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作者：
Dempsey, Stephen H.;Lovstedt, Alex;Kass, Steven R.
报道了多种静电增强的3-和4-吡啶基硼酸盐催化剂，并且显示出比活化的不带电的中性对照化合物显著的改进。它们在化学计量的SN 2反应中的亲核性和在氨基甲酸酯合成中的催化性能被评价为沿着三种用于快速评价这些物种的碱性的方法。也就是说，在CH 2Cl 2和CHCl 3中进行定性滴定，两个独立的溶液状态的IR研究在CCl 4和CDCl 3的报告，和质子亲合势的盐的阴离子组分进行了计算。的阴离子和它的质子化的两性离子共轭酸之间的电荷差异进行评价沿着与一些令人惊讶的反应性的发现，在两个动力学研究中观察到的关系的阴离子的最高占据的分子轨道。
A variety of electrostatically enhanced 3- and 4-pyridylborate salt catalysts are reported and show significant improvement over an activated noncharged neutral control compound. Their nucleophilicity in a stoichiometric SN2 reaction and catalytic performance in a urethane synthesis are evaluated along with three methods for rapidly evaluating the basicity of these species. That is, qualitative titrations in CH2Cl2and CHCl3were carried out, two separate solution-state IR studies in CCl4and CDCl3are reported, and the proton affinities of the anionic components of the salts were computed. Charge differences between the anion and its protonated zwitterionic conjugate acid are evaluated along with the highest occupied molecular orbitals of the anions in relationship to some of the surprising reactivity findings that were observed in the two kinetic studies.