Asymmetric Catalysis in Main Group Chemistry

描述（申请人提供）：碳-碳双键可以说是所有有机化学中最重要的官能团。除了它在定义 在这种结构中，通过在双键末端引入两个新键来产生两个邻位立体碳原子的能力将其提升到这种稀薄的状态。已经引入了无数的反应来实现双键的区域、非对映体和对映体选择性官能化，具有良好的通用性。然而，直到最近，有机化学家才将注意力转向对映体控制引入主族元素，如硫，氯，溴和碘，与更常见的元素碳，氮和氧结合。虽然有趣，这些最近的报告构成了一个特设的应用已知的催化剂和概念的解决方案，创造新的，催化对映选择性转化。我们的长期目标是为开发普遍适用和高选择性的烯烃官能化反应构建机械/物理有机基础。这项建议的主要目标是：（1）应用这些实验室开发的刘易斯酸的刘易斯碱活化的概念，活化主族中第16和17族中的亲电物质，（2）学习结构/反应性相关性和实现高催化活性的规则（转换频率和转换数），（3）设计手性刘易斯碱，其将赋予高立体选择性和高化学转化率以引入新的碳和杂原子取代的立体中心，和（4）对下述新发明的催化反应进行详细的机理（动力学、光谱学、晶体学、计算）研究。第一个主要的努力将是扩大催化，对映选择性sulfenofunctionalization反应，许多基板类。直接官能化和环官能化的烯烃带有拴系亲核试剂（氧，氮，碳）是一种强大的方法，用于创建立体定向的链，杂环，和碳环。在许多这些转化中，将设计和评价可以影响E-和Z-烯烃的立体选择性磺酰基官能化的新型拓扑结构的刘易斯碱性催化剂。第二个主要的努力，分为两个子目标，是催化，对映体选择性卤官能化反应的发展。这些极其重要的转化的催化剂的发展是由我们的示范，氯铱离子是构型稳定，而溴铱和碘铱离子是不。因此，这些转化的设计标准分为两个子目标：（1）设计为递送溴离子提供对映异构面差异的催化剂，和（2）设计为递送溴（碘）离子提供对映异构面差异并在捕获之前稳定中间体以防止外消旋化的催化剂。

DESCRIPTION (provided by applicant): 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. Countless 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 enantiocontrolled introduction of elements in the main group such as sulfur, chlorine, bromine and iodine, in combination 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, catalytic 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 nucleophile (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 halofunctionalization 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.