ION PAIR CARBON ACIDITY

通常以离子对或聚集体的形式存在的碳离子是很重要的 有机合成多种生物活性天然产物中的中间体 产品、药品、药品等。一种常见的合成过程是 用烷基锂或锂酰胺在金属中金属化衬底 乙醚后与合适的电泳剂反应。我们建议把 这种以定量科学为基础的主要经验性技术 继续测定反应的平衡常数，R M+R‘H=R’M+RH，对于指示性碳氢化合物(例如，荧烯， 芳基甲烷等)在四氢呋喃(THF)中以铯和锂为原料 吉格尼奥斯。这些指标系统将被用来确定均衡 对于具有合成中重要的各种官能团的碳酸： 乙烯基、烯丙基、苯基和芳基化合物、硫衍生物、硅和 含磷化合物、酰胺、醚、杂环化合物、双阴离子和 烯醇化离子。作为温度函数的测定将提供 热力学参数和铯平衡的比较，它们是 已知涉及接触离子对，与相应的锂 平衡，其中各种类型的离子对是可能的，将 促进对更复杂的锂案件的理解。电导性 研究将把离子对与离解离子联系起来。结果将是 借助相关的动态酸度测量进行解释，研究 聚集体系、理论量子化学计算和 电子密度分布的计算机图形分析。

Carbanions, generally involved as ion pairs or aggregates, are important intermediates in the organic synthesis of many biologically active natural products, pharmaceuticals, drugs, etc. A common synthetic procedure is the metallation of a substrate with an alkyl lithium or lithium amide in an ether followed by reaction with a suitable electrophile. We propose to put this largely empirical technique on quantitative scientific basis by continuing our determination of equilibrium constants for the reactions, R M + R'H = R'M + RH, for indicator hydrocarbons (e.g., fluorenes, arylmethanes, etc.) in tetrahydrofuran (THF) with cesium and lithium as gegenions. These indicator systems will be used to determine equilibria for carbon acids with various functional groups important in synthesis: vinyl, allyl, benzyl and aryl compounds, sulfur derivatives, silicon and phosphorus compounds, amides, ethers, heterocyclic compounds dianions and enolate ions. Determinations as a function of temperature will provide thermodynamic quantities and comparison of the cesium equilibria, which are known to involve contact ion pairs, with the corresponding lithium equilibria, in which a variety of types of ion pairs are possible, will facilitate understanding of the more complex lithium cases. Conductivity studies will relate the ion pairs to dissociated ions. The results will be interpreted with the help of related kinetic acidity measurements, studies of aggregated systems, theoretical quantum chemical calculations and computer graphics analysis of electron density distributions.