A Lewis Base Nucleofugality Parameter, <i>N</i><sup><i>F</i></sup><sub>B</sub>, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
作者:Nicholas P. Taylor、Jorge A. Gonzalez、Gary S. Nichol、Andrés García-Domínguez、Andrew G. Leach、Guy C. Lloyd-Jones
DOI:10.1021/acs.joc.1c02729
日期:2022.1.7
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3–nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation
已经测量了从广泛的路易斯碱硼烷加合物中置换 BH 3的奎宁环动力学。这些速率的参数化使得能够开发出离核量表 (NF B ),以量化和预测一系列其他路易斯碱基的离去基团能力。在多个系列 R' 3– n R n X (X = P, N; R' = 芳基, 烷基) 中观察到的可加性允许制定相关的取代基参数 ( n f PB , n f AB ),提供了一种方法计算N F B一系列路易斯碱基的值远远超出了实验得出的值。通过取代基参数n f PB与一系列烷基和芳基 MIDA 硼酸盐在中性条件下的水解速率的相关性,探索了核离性参数的效用。这允许鉴定具有接近反应中心的杂原子的 MIDA 硼酸盐,显示出不寻常的动力学不稳定性或水解稳定性。