Heteroallyl and alpha-Heterosubstituted Allyllithium Reagents

杂烯丙基和 α-杂取代烯丙基锂试剂

• 批准号: 8801884
• 负责人: Lloyd Jackman
• 金额: $ 33.69万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-06-01 至 1991-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8801884&HistoricalAwards=false
• 关键词: Heteroallyl; alpha; Heterosubstituted; Allyllithium; Reagents

This grant in Organic and Macromolecular Chemistry provides support for Dr. Lloyd Jackman, Pennsylvania Stata University. The work focuses on the chemistry and mechanisms of various organic salts, particularly those involving lithium. These species are among the most important reagents used in synthetic chemistry and an understanding of their fundamental aspects has important practical significance. The most important single group of synthetically useful organic reactions is that based on ambident anions of the type C=C-X(-). The number of representatives of this group is rapidly increasing. A proper mechanistic understanding of the reactions of these anions with electrophiles does not exist, in part because the structures of the ambident anion salts in solution are usually unknown. With methodologies for solving such structural problems in the case of lithium salts, this study will extend our knowledge by effecting a comparison between the 13C, 6Li, and 7Li nmr spectral characteristics in solution with those in the solid state for known crystal structures. All the above techniques will be applied to lithium enolates, ester enolates and enamides and to heterosubstituted allyllithium reagents. It is becoming clear that mixed aggregates (dimers, tetramers) between lithium carbanion salts and lithium salts which are strong electrolytes are important entities in weakly polar solvents in that they control rates and regiochemistry. The thermodynamics of mixed aggregate formation will be studied in order to determine the factors controlling their stabilities. The structural information will be used in conjunction with reaction kinetics to establish the reaction mechanisms of the transesterification of lithium phenolates, the aldol reaction, and the alkylation of phenolates, enolates, and enamides. Particular emphasis will be placed on defining the primary reactant species and understanding the role of mixed aggregates as intermediate species. The involvement of coordination induced proximity effects arising when the electrophilic reagents possess basic centers which can interact with lithium in aggregates will also be probed. The reactions to be studied include some that are widely used in synthetic organic chemistry. The results of these studies should allow synthetic chemists to perform them more efficiently and to design new ones for achieving high regio- and stereo-selectivities.

有机和高分子化学的这项资助提供了 支持劳埃德杰克曼博士，宾夕法尼亚州斯塔塔大学。 这项工作的重点是化学和机制的各种 有机盐，特别是涉及锂的那些。这些 物种是合成中使用的最重要的试剂之一 化学及其基本方面的理解， 重要的现实意义。 最重要的一组合成有用的有机物 反应是基于以下类型的两亲阴离子 C=C-X（-）。该小组的代表人数为 迅速增加。 正确的机械理解 这些阴离子与亲电试剂的反应不存在， 部分原因是由于两齿阴离子盐的结构， 解决办法通常是未知。 用方法来解决 在锂盐的情况下， 研究将通过进行比较来扩展我们的知识 13 C、6Li和7 Li的NMR谱特征之间的关系， 已知晶体的固态溶液 结构. 所有上述技术将应用于 烯醇化锂、烯醇化酯和烯酰胺， 杂取代的烯丙基锂试剂。 越来越清楚的 锂离子之间的混合聚集体（二聚体，四聚体） 作为强电解质的碳负离子盐和锂盐 是弱极性溶剂中的重要实体，因为它们 控制速率和区域化学。 混合气体的热力学 将研究聚集体的形成，以确定 控制其稳定性的因素。 结构性 信息将与反应动力学结合使用 建立酯交换反应机理 苯酚锂的合成、羟醛缩合反应和烷基化反应 酚盐、烯醇盐和烯酰胺。 特别强调 将被放置在定义主要反应物种类上， 理解混合骨料作为中间体的作用 物种 协调的参与导致了接近 当亲电试剂具有碱性时产生的效应 能与聚集体中的锂相互作用的中心也将 被探测。 要研究的反应包括一些， 广泛应用于有机合成化学。 的结果 这些研究应该允许合成化学家进行 更有效地，并设计新的，以实现高 区域和立体选择性。