A Rapid Injection NMR Study of the Reaction of Organolithium Reagents with Esters, Amides, and Ketones
作者:Kristin N. Plessel、Amanda C. Jones、Daniel J. Wherritt、Rebecca M. Maksymowicz、EricT. Poweleit、Hans J. Reich
DOI:10.1021/acs.orglett.5b00650
日期:2015.5.15
Unexpectedly high rates of reaction between alkyllithium reagents and amides, compared to esters and ketones, were observed by Rapid Inject NMR and competition experiments. Spectroscopic investigations with 4-fluorophenyllithium (ArLi, mixture of monomer and dimer in THF) and a benzoate ester identified two reactive intermediates, a homodimer of the tetrahedral intermediate, stable below −100 °C, and
通过Rapid Inject NMR和竞争实验观察到,与酯和酮相比,烷基锂试剂和酰胺之间的反应速率异常高。用4-氟苯基锂(ArLi,单体和二聚体在THF中的混合物)和苯甲酸酯进行的光谱研究确定了两个反应性中间体,即四面体中间体的均二聚体(在100°C以下稳定),以及与ArLi混合的二聚体。直接形成二聚体表明ArLi二聚体可能是反应性聚集体,而不是通常更具反应性的单体。相反,用酮进行的RINMR实验表明ArLi单体是反应性物质。