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: 8213452
• 负责人: Scott Eric Denmark
• 金额: $ 28.95万
• 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/8213452
• 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.

描述（申请人提供）：本提案的主要目标是：（1）论证刘易斯酸的刘易斯碱活化概念（Gutmann电子密度极化），因为它适用于主族中第16和17族中的亲电物质，（2）开发尚未实现催化的经典主族反应的催化变体，（3）了解结构/反应性相关性和获得高催化活性的规则（转换频率和转换数），（4）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（5）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开发最常见的亲电基团16和17试剂反应的催化，对映选择性变体。直接官能化和环官能化的烯烃带有一个系留的亲核试剂（氧，氮，碳）是一个强大的方法，用于创建立体定向链，杂环和碳环。这些反应是有效地引发的亲电硫（II），氯（I），溴（I），碘（I）试剂的刘易斯碱的催化和控制的宪法和对映选择性的设计将构成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第二主要活性。除了众所周知的功能操作，新的，立体控制的，建设性的C-S键，采用过渡金属催化偶联和直接配体偶联反应的替代品将被开发。第三个主要的努力将是发明、开发和探索一种新的刘易斯碱催化反应的子类，该反应采用较高氧化态的碘（III）试剂来形成碳-碳键。碘鎓盐的配体偶联反应的催化是前所未有的，并将被研究用于构建对映体富集的？芳基，？-烯基，？-炔基，也可能是？芳基取代的酮和酯。 公共卫生关系：该研究计划旨在开发一种全新的主族元素硫、氯、溴和碘在各种氧化态下的催化反应。刘易斯碱激活这些元素亲电特性的能力的概念基础几乎具有无限的潜力。在美国，每年生产的价值近1万亿美元的商品的加工过程中已经涉及到催化，而我们的贡献是用于目前没有催化过程的化学反应。