Reactions and Stereochemistry of Organometallic Compounds Related to Asymmetric Synthesis and Catalytic Activity

有机化合物经常用作催化剂， 一种有机化合物转化成另一种有机化合物。 不幸的是， 这种转化通常产生异构体的混合物，即， 分子由相同的原子组成，但它们的性质不同。 三维结构。 该项目涉及 高度不对称有机金属化合物的合成 被设计成作为更具体的催化剂来控制 反应产物的三维结构。 三个- 有机分子的空间结构尤其 重要的生物反应，这些有机金属 化合物通常用于实验室合成天然产物。 产品. 将进行研究以开发使用金属的新方法 用于不对称和区域选择性合成的配合物 阐明立体选择性反应的机制， 合成有用。 高氧化的潜在效用 所述用于这些应用有机金属配合物将 探讨了 X射线晶体学已经成为一种常规工具， 固体的结构特征。 但不少 有机金属化合物重新排列或作为以下物质的混合物存在： 溶液中的构象异构体。 这表明， 实验室认为，这些构象的稳定性起着主要作用 在产物立体化学分布中的作用。 反应性 中间体和催化物种通常存在于较低的温度下， 浓度，不能作为固体分离。 一种新方法 将制定详细的结构信息， 溶液 这将涉及配体的设计和合成 含有与有机金属化合物结合的顺磁性金属离子。 产生的各向同性位移和场取向效应 通过这些顺磁性配体将允许详细描绘 （角度和距离）的中间体和催化物种， 溶液

Organometallic compounds are frequently used as catalysts for the conversion of one organic compound into another. Unfortunately, such conversions often result in mixtures of isomers, i.e., molecules comprised of the same atoms, but differing in their three-dimensional structures. This project involves the synthesis of highly unsymmetrical organometallic compounds designed to function as more specific catalysts to control the three-dimensional structures of reaction products. The three- dimensional structures of organic molecules are especially important in biological reactions, and these organometallic compounds are often used in the laboratory synthesis of natural products. Research will be undertaken to develop new methods using metal complexes for asymmetric and regioselective syntheses and to elucidate the mechanisms of stereoselective reactions which are synthetically useful. The potential utility of higher oxidation state organometallic complexes for these applications will be explored. X-ray crystallography has become a routine tool for structural characterization in solids. However, many organometallic compounds rearrange or exist as mixtures of conformational isomers in solution. It has been shown in this laboratory that the stability of these conformers plays a major role in the distribution of product stereochemistry. Reactive intermediates and catalytic species often exist in lower concentrations and cannot be isolated as solids. A new method will be developed to elucidate detailed structural information in solution. This will involve the design and synthesis of ligands containing paramagnetic metal ions which bind to organometallics. The isotropic shifts and the effects of field alignment produced by these paramagnetic ligands will allow detailed delineation (angles and distances) of intermediates and catalytic species in solution.