Asymmetric Catalysis in Main Group Chemistry

主族化学中的不对称催化

• 批准号: 8635171
• 负责人: Scott Eric Denmark
• 金额: $ 28.89万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-22 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8635171
• 关键词: Acids; Alkenes; Attention; Bromine; Carbon; Catalysis; Charge; Chemicals; Chemistry; Chlorine; Complex; Development; Dissociation; Elements; Face; Foundations; Frequencies; Goals; Indium; Investigation; Iodine; Ions; Kinetics; Laboratories; Learning; Methods; Nitrogen; Organic Chemistry; Organic Synthesis; Oxygen; Positioning Attribute; Process; Reaction; Reporting; Research Proposals; Scheme; Solutions; Structure; Sulfur; base; catalyst; chemical reaction; design; functional group; novel; pi bond; programs; public health relevance; racemization

PROJECT SUMMARY/ABSTRACT The carbon-carbon double bond is arguably the most important functional group in all of organic chemistry. Aside from its central position in defining structure, the ability to create two vicinal stereogenic carbon atoms by the introduction of two new bonds at the termini of a double bond has elevated it to this rarefied status. Count- less reactions have been introduced to effect regio, diastereo and enantioselective functionalization of double bonds with good generality. However, only recently have organic chemists turned their attention to the enantio- controlled introduction of elements in the main group such as sulfur, chlorine, bromine and iodine, in combina- tion with the much more common elements carbon, nitrogen and oxygen. Although intriguing, these recent reports constitute an ad hoc application of known catalysts and concepts to the solution of creating new, cata- lytic enantioselective transformations. Our long-term goal is to construct the mechanistic/physical organic foundation for the development of generally applicable and highly selective alkene functionalization reactions. The primary objectives of this proposal are to: (1) apply the concept of Lewis base activation of Lewis acids developed in these laboratories, activate electrophilic species in Groups 16 and 17 in the Main Group, (2) learn the structure/reactivity correlations and the rules for achieving high catalytic activity (turnover frequencies and turnover numbers) for the target reactions, (3) design chiral Lewis bases that will impart high stereoselectivity and high chemical conversion for the introduction of new carbon and heteroatom substituted stereocenters, and (4) carry out detailed mechanistic (kinetic, spectroscopic, crystallographic, computational) investigations of the newly invented catalytic reactions described below. The first major effort will be the expansion of catalytic, enantioselective sulfenofunctionalization reactions to many substrate classes. Direct functionalization and cyclofunctionalization of alkenes bearing a tethered nu- cleophile (oxygen, nitrogen, carbon) is a powerful method for creating stereodefined chains, heterocycles, and carbocycles. Lewis basic catalysts of novel topology that can effect the stereoselective sulfenofunctionalization of E- and Z-alkenes will be designed and evaluated in many of these transformations. The second major effort, divided into two sub goals, is the development of catalytic, enantioselective halo- functionalization reactions. The development of catalysts for these extremely important transformations is guided by our demonstration that chloriranium ions are configurationally stable whereas bromiranium and iodiranium ions are not. Thus, the design criteria for these transformations diverge into two sub goals: (1) the design of catalysts that provide enantiotopic face differentiation for the delivery of a chlorenium ion, and (2) the design of catalysts that provide enantiotopic face differentiation for the delivery of a bromenium (iodenium) ion AND stabilize the intermediate against racemization prior to capture.

项目摘要/摘要 碳碳双键可以说是所有有机化学中最重要的功能群。 除了定义结构的中心位置外，还可以通过 在双债券的末端引入了两个新债券，已将其提升到了这种稀有状态。数数- 引入了较少的反应以实现double的良性，映射和对映选择性功能化 具有良好的纽带。但是，直到最近才有有机化学家将注意力转移到对映体上 在组合中受控引入主要组的元素，例如硫，氯，溴和碘 具有更常见的元素，氮和氧气。尽管很有趣，但这些最近 报告构成了已知催化剂和概念的临时应用，以创建新的，cata- 裂解对映选择性转换。我们的长期目标是构建机械/物理有机 开发通常适用且高度选择性的烯烃功能化反应的基础。 该提案的主要目标是：（1）应用路易斯酸的刘易斯基础激活的概念 在这些实验室中开发的，在主要组中激活第16和17组的亲电种，（2）学习 结构/反应性相关性以及实现高催化活性的规则（营业频率和 目标反应的营业额数），（3）设计手性刘易斯基地，它将赋予高立体选择性 以及用于引入新碳和杂原子取代的立体中心的高化学转化率， （4）进行详细的机械（动力学，光谱，晶体学，计算）研究 下面描述的新发明的催化反应。 第一个重大努力是扩大催化性，对映选择性磺性功能的反应 许多底物类。烷烃的直接功能化和循环功能化，带有束缚的nu- 克氏菌（氧气，氮，碳）是一种创建立体构造链，异环和杂环和的强大方法 碳循环。刘易斯的基本催化剂的新拓扑基本催化剂可以影响立体选择性磺化功能 E-和Z-Alkenes将在许多这些转换中进行设计和评估。 第二个主要努力分为两个子目标，是发展催化，对映选择性光环的发展 功能化反应。这些极为重要的转变的催化剂的发展是 在我们的演示指导下，氯兰氏离子在构型稳定上是稳定的 碘餐离子不是。因此，这些转换的设计标准分为两个子目标：（1） 催化剂的设计可为供映射的面部分化以递送氯离子，以及（2） 催化剂的设计，可为溴化（iodenium）离子提供映射面部分化 并在捕获之前稳定反对种族化的中间体。