Mechanistic Studies Directed Toward Universal Ligands and Catalytic Reactions of Samarium Diiodide

化学结构，动力学和机制B计划支持教授罗伯特A。弗劳尔斯的利哈伊大学进行机械研究的化学二碘化钐（钐2）。 SmI2是有机合成中的一种重要试剂，因为它在介导有机合成中的许多基本重要的反应中具有多功能性，包括还原，还原偶联和级联反应。 SmI2的重要特征之一是，添加助溶剂或添加剂可用于控制反应的化学选择性和非对映选择性。 这项工作有两个科学目标。 第一个目标是进行机制研究，定义的影响的亲和力的溶剂，质子供体，并协调或螯合添加剂的Sm（II）试剂。这些变量和Sm（II）的反应性之间的关系将被应用到开发的替代方法减少官能团的SmI2使用容易获得的，廉价的，无毒的添加剂。 本工作的第二个目标将集中于机理研究，旨在检查已知的SmI2基催化体系，并利用从这些研究中收集的信息来帮助开发使用SmI2和其他Sm（II）基还原剂的催化反应。许多通过电子转移进行的有机反应的高度复杂性是基于我们对阴离子，阳离子，自由基，和相关的自由基离子。化学家通过使用基于金属的氧化剂和还原剂来相互转化这些中间体的能力已经导致了在成键事件中利用一种或多种反应性中间体来合成具有巨大社会重要性的复杂分子的反应的发展。 最广泛使用的单电子还原剂是SmI2，但添加剂在这些反应中的作用还不清楚。 在该项目框架内进行的实验旨在提供对Sm（II）基化学的机械理解以及添加剂的作用，这些添加剂可以外推并应用于一系列重要和有用的过程，包括催化反应的发展。 利用这种以机制为中心的方法进行的研究可能会为科学界提供比单一合成应用的演示更长期的好处。

The Chemical Structure, Dynamics and Mechanisms B Program supports Professor Robert A. Flowers of Lehigh University to carry out mechanistic studies on the chemistry of samarium diiodide (SmI2). SmI2 is an important reagent in organic synthesis due to its versatility in mediating numerous, fundamentally important reactions in organic synthesis including reductions, reductive couplings, and cascade reactions. One of the important features of SmI2 is that the addition of cosolvents or additives can be used to control the chemo- and diastereoselectivity of reactions. There are two scientific objectives of this work. The first objective is to carry out mechanistic studies that define the impact of the affinity of solvents, proton donors, and coordinating or chelating additives for Sm(II) reagents. The relationship between these variables and the reactivity of Sm(II) will be applied to the development of alternative approaches for the reduction of functional groups by SmI2 using readily available, inexpensive, and non-toxic additives. The second objective of this work will focus on mechanistic studies designed to examine known SmI2-based catalytic systems and employ the information gleaned from these studies to aid in the development of catalytic reactions employing SmI2 and other Sm(II)-based reductants.The high degree of sophistication of many organic reactions that proceed through the transfer of electrons is based on our mechanistic understanding of anions, cations, radicals, and related radical ions. The ability of chemists to interconvert these intermediates through the use of metal-based oxidants and reductants has led to the development of reactions that utilize one or more reactive intermediates in bond-forming events to synthesize complex molecules of great societal importance. The most widely used single electron reductant is SmI2, but the roles of additives in these reactions are not well understood. The experiments carried out within the framework of this project are designed to provide a mechanistic understanding of Sm(II)-based chemistry and the role of additives that can be extrapolated and applied to a range of important and useful processes including the development of catalytic reactions. Studies utilizing this mechanism-centered approach are likely to provide longer-term benefits to the scientific community than the demonstration of a single synthetic application.