Asymmetric Lewis Base Catalysis in Main Group Chemistry

主族化学中的不对称路易斯碱催化

• 批准号: 8050550
• 负责人: Scott Eric Denmark
• 金额: $ 28.94万
• 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 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8050550
• 关键词: Acids; Alkenes; Bromine; Carbon; Catalysis; Charge; Chemicals; Chemistry; Chlorine; Constitutional; Coupling; Development; Elements; Esters; Foundations; Frequencies; Heating; Intercept; Investigation; Iodine; Ions; Ketones; Kinetics; Learning; Ligands; Methods; Nitrogen; Oxygen; Process; Reaction; Reagent; Research Proposals; Salts; Scheme; Structure; Sulfur; Transition Elements; Variant; azobis(isobutyronitrile); base; chemical reaction; design; electron density; oxidation; programs; public health relevance

DESCRIPTION (provided by applicant): The primary objectives of this proposal are: (1) to demonstrate the concept of Lewis base activation of Lewis acids (Gutmann electron density polarization) as it applies to electrophilic species in Groups 16 and 17 in the Main Group, (2) to develop catalytic variants of classical main group reactions for which catalysis has yet to be realized, (3) to learn the structure/reactivity correlations and the rules for achieving high catalytic activity (turnover frequencies and turnover numbers) for the target reactions, (4) to design chiral Lewis bases that will impart high stereoselectivity and high chemical conversion for the introduction of new carbon and heteroatom substituted stereocenters, and (5) carry out detailed mechanistic (kinetics, spectroscopic, crystallographic, computational) investigations of the newly-invented catalytic reactions described below. The first major effort will be the development of catalytic, enantioselective variants of the most common reactions of electrophilic Group 16 and 17 reagents. Direct functionalization and cyclofunctionalization of alkenes bearing a tethered nucleophile (oxygen, nitrogen, carbon) is a powerful method for creating stereodefined chains, heterocycles and carbocycles. These reactions are efficiently initiated by electrophilic sulfur(II), chlorine(I), bromine(I), and iodine(I) reagents The design of Lewis bases to catalyze and control the constitutional and enantiofacial selectivity will constitute a major component of this program. The synthetic manipulation of the enantiomerically enriched, sulfur-containing products constitutes the second major activity. In addition to well-known functional manipulations, new, stereocontrolled, constructive replacements of the C-S bond that employ transition metal catalyzed coupling and direct ligand coupling reactions will be developed. A third major effort will be the invention, development, and exploration of a new subclass of Lewis base catalyzed reactions that employs higher oxidation state iodine(III) reagents for carbon-carbon bond formation. Catalysis of the ligand coupling reaction of iodonium salts is unprecedented and will be investigated for the construction of enantiomerically enriched ?-aryl, ?-alkenyl, ?-alkynyl, and also potentially ?-aryl substituted ketones and esters. PUBLIC HEALTH RELEVANCE: This research proposal aims to develop a fundamentally new class of catalytic reactions of the main group elements, sulfur, chlorine, bromine, and iodine in various oxidation states. The conceptual foundation for the ability of Lewis bases to activate the electrophilic character of these elements has almost unlimited potential. Already, catalysis is involved in the processing of nearly a trillion dollars worth of goods produced annually in the US, and our contribution is for chemical reactions for which there is currently no catalytic process.

DESCRIPTION (provided by applicant): The primary objectives of this proposal are: (1) to demonstrate the concept of Lewis base activation of Lewis acids (Gutmann electron density polarization) as it applies to electrophilic species in Groups 16 and 17 in the Main Group, (2) to develop catalytic variants of classical main group reactions for which catalysis has yet to be realized, (3) to learn the structure/reactivity correlations and the rules for achieving high catalytic activity (turnover frequencies and turnover numbers) for the target reactions, (4) to design chiral Lewis bases that will impart high stereoselectivity and high chemical conversion for the introduction of new carbon and heteroatom substituted stereocenters, and (5) carry out detailed mechanistic (kinetics, spectroscopic, crystallographic, computational) investigations of the newly-invented catalytic下面描述的反应。第一个主要努力是开发16和17种试剂的最常见反应的催化，对映选择性变体。带有束缚亲核试剂（氧，氮，碳）的烷烃的直接功能化和循环化是一种强大的方法，可用于产生刻板的链，杂环和碳动物。这些反应是通过亲电硫（II），氯（I），溴（i）和碘（I）试剂有效引发的。刘易斯碱基的设计以催化和控制该计划的主要组成部分。对映体富集的含硫产物的合成操作构成了第二个主要活动。除了众所周知的功能操纵外，还将开发出使用过渡金属催化的耦合和直接配体偶联反应的新的，立体控制的，建设性的替换。第三个重大努力是对刘易斯基碱基的新子类的发明，开发和探索，该反应采用了较高的氧化态碘（III）试剂来形成碳 - 碳键形成。碘盐配体偶联反应的催化是前所未有的，将研究以对映体富集？-ARYL，？ - 烷烯基，？ - 碱基，以及可能的？Aryl取代的酮和酯。 公共卫生相关性：该研究建议旨在开发主要组元素（硫，氯，溴和碘）在各种氧化状态下的基本新的催化反应。刘易斯基地激活这些元素的亲电特征能力的概念基础几乎具有无限的潜力。催化已经参与了美国每年生产的近一百万美元的商品的处理，我们的贡献是对于目前没有催化过程的化学反应。