Synthetic and Mechanistic Studies of Organometalloids

有机合成项目将为位于麦迪逊的威斯康星大学化学系的Hans J. Reich博士提供支持。这项工作将通过揭示一些中间体的性质并应用这些知识来发展更大的合成控制，从而开发主要群体的合成潜力。现代农业和医学所使用的复杂分子的合成需要高度复杂的合成方法。本研究主要集中在有机金属和有机金属化学的几个领域。具体来说，实验旨在阐明一些重要的有机锂试剂的复分解反应，金属-卤素交换和有机锡化合物的金属转化反应的机理。由于这些反应在制备有机化学中广泛应用，因此从机理上理解它们是很重要的。所描述的实验将阐明有机配合物在有机锂试剂化学中所起的作用，并将确定配合物本身是否是有用的碳供体。研究了一种测定非立体中心（二价碲）亲核攻击几何结构的新方法。一项探索性研究将确定动态核磁共振技术是否也可以用于研究烯酸盐反应，该技术已经提供了苯锂与碘苯之间简并Li/I交换机理的详细信息。第二部分是手性亲电硒化剂的设计。该试剂被设计为利用高价有机硒物种的几何形状，被认为是中间体在亲电加成的R-Se+物种到烯烃。该工艺如果成功，将为烯烃不对称氧化生成非外消旋烯丙醇或内酯提供一种方法。第三部分涉及继续进行正在进行的研究，以调查使用硅基酮作为羰基酰化物前体的潜力。

The Organic Synthesis Program will provide support to Dr. Hans J. Reich in the Department of Chemistry at the University of Wisconsin in Madison. The work will develop the synthetic potential of the main group by unraveling the nature of some of the intermediates and applying this knowledge to develop greater synthetic control. The synthesis of the complex molecules utilized by modern agriculture and medicine requires highly sophisticated synthetic methodology. This research is in several areas of main group organometalloid and organometallic chemistry. Specifically, experiments aimed at elucidating the mechanism of some important metathesis reactions of organolithium reagents, the metal-halogen exchange and the transmetallation reaction of organotin compounds, are described. Since these reactions are widely used in preparative organic chemistry it is important to understand them mechanistically. The experiments described will clarify the role that ate complexes play in the chemistry of organolithium reagents, and will establish whether the complexes themselves are useful carbanion donors. A new technique for determining geometry of nucleophilic attack at non-stereogenic centers (divalent tellurium) will be examined. An exploratory study will establish whether a dynamic NMR technique which has provided detailed information concerning the mechanism of the degenerate Li/I exchange between phenyllithium and iodobenzene, can also be used to study enolate reactions. The second part concerns the design of a chiral electrophilic selenenylation agent. The reagent is designed to utilize the geometry of hypervalent organoselenium species thought to be intermediates in the electrophilic addition of R-Se+ species to olefins. The process, if successful, would provide a method for asymmetric oxidation of olefins to nonracemic allyl alcohols or lactones. A third part involves the continuation of ongoing research to investigate the potential of using silyl ketones as precursors to carbonyl ylides.