Heteroallyl and Alpha-Heterosubstituted Allyllithium Reagents

在有机动力学项目的支持下，杰克曼博士将研究烯醇化锂的溶液结构。本项目将进行以下工作：(i)确定三种烯醇化锂与高氯酸锂和四苯基硼化锂混合聚集体的结构，（ii）混合聚集体中动态过程的核磁共振研究，（iii）一系列取代的苯酚酸锂的溶剂化研究，（iv）综合分析了甲酯在不同溶剂中加入高氯酸锂和四苯基硼化锂后，异丁苯酮和2-异丙基-四酮锂的C-和o -烷基化初始速率；(v)苯酚酸锂的简并质子转移研究；（六）对映选择性有机锂试剂设计。有机锂化合物为合成有机化学家提供了一些最有效的方法来控制涉及新碳-碳键形成过程中的立体化学和区域化学。在过去，由于缺乏对机制的理解，这一领域的进展受到严重阻碍，而这反过来又是由于缺乏对有机锂物种在溶液中采用的精确结构的详细了解。提出的研究解决方案结构的阐明，然后寻求开发基于这些结构的有用的机械概念。研究了溶剂和助溶剂对有机锂溶液结构的特殊影响。此外，将探索基于混合聚合体形成的新型立体选择性试剂。

With support from the Organic Dynamics Program, Dr. Jackman will study solution structures of lithium enolates. The following sutides will be performed in connection with this project: (i) determination of the structures of the mixed aggregates of three lithium enolates with lithium perchlorate and lithium tetraphenylboride, (ii) NMR studies of dynamic processes in mixed aggregates, (iii) studies of the solvation of a series of substituted lithium phenolates, (iv) comprehen-sive analysis of the initial rates of C- and O-alkylation of lithioisobutyrophenone and lithio 2-isopropyl-alpha-tetralone by methyl tosylate in a variety of solvents with added lithium perchlorate and lithium tetraphenylboride, (v) studies of degenerate proton transfer with lithium phenolates, and (vi) design of enantioselective organolithium reagents. %%% Organolithium compounds provide the synthetic organic chemist with some of the most effective methods for controlling stereo- and regiochemistry in processes that involve formation of new carbon-carbon bonds. In the past, progress in this field has been severely hampered by lack of mechanistic understanding, which in turn is a consequence of lack of detailed knowledge of the precise structures that organolithium species adopt in solution. The proposed studies address the elucidation of solution structures and then seek to develop useful mechanistic concepts that are based upon these structures. The special effects of solvents and cosolvents upon the solution structure of organolithium species will be studied. In addition, new stereoselctive reagents that are based upon mixed aggregate formation will be explored.