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Reactive Intermediates in Gold(I) Catalysis

金(I)催化中的反应中间体

基本信息

批准号：
1800273
负责人：
Ross Widenhoefer
金额：
$ 45万
依托单位：
Duke University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2021-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1800273&HistoricalAwards=false
关键词：
Reactive Intermediates Gold Catalysis

项目摘要

In this project funded by the Chemical Structure, Dynamics and Mechanisms B Program of the Chemistry Division, Professor Ross A. Widenhoefer in the Department of Chemistry at Duke University investigates the mechanisms of gold-catalyzed chemical reactions, especially those in which a divalent carbon atom is transferred to a carbon-carbon double bond to form a cyclopropane. This is a synthetic transformation of growing importance. Studies include experiments to determine the scope and mechanisms of gold-catalyzed processes and the structure of gold complexes. This research provides mechanistic insight that will serve the ever growing global community of researchers working toward the development of new and more efficient gold(I) catalyzed transformations. Research activities are fully integrated into the scientific education and training of graduate and undergraduate student researchers, including students from groups traditionally underrepresented in the sciences. Graduate students augment their research experience through participation in educational activities offered through the Duke University Graduate School. Graduate students also participate in community outreach activities in collaboration with Dr. Ben Bobay of the Duke Nuclear Magnetic Resonance (NMR) center which provide local high school students with hands-on exposure to modern high-field NMR spectroscopy and one-on-one instruction in the processing and interpretation of NMR data. This project investigates the structure and reactivity of gold carbenoid complexes and cationic gold carbene complexes, including those relevant to gold-to-alkene carbene transfer (cyclopropanation), gold alpha-oxo carbene and carbenoid complexes, and cationic beta, gamma-unsaturated gold carbene complexes. Despite a growing body of work in this area, limited experimental information is available regarding mechanisms which involve these gold complexes. Research activities fill important gaps in this field and develop an experimentally-grounded understanding of the nature of the complexes generated either through carbene transfer from stabilized diazo compounds or through the oxidation of alkenes in the presence of gold. The research addresses three main areas of inquiry: (1) elucidation of the mechanisms of gold to alkene carbene transfer by modeling the transition state for carbene transfer, independent synthesis of gold metallacyclobutane complexes, and kinetic analysis of gold to alkene carbene transfer under stoichiometric conditions; (2) evaluation of the nature and reactivity of cationic gold alpha-oxo carbene and carbenoid complexes by studying the reactions of gold complexes with stabilized N- and S-ylides and the reactions of pyridine N-oxides and with cationic gold complexes; and (3) interrogation of the structure and reactivity of unsaturated gold carbene complexes through the synthesis and characterization of cationic gold allenylidene and vinyl carbene complexes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系化学结构、动力学和机理B计划资助的这个项目中，Ross A.杜克大学化学系的Wesserhoefer研究了金催化化学反应的机制，特别是那些二价碳原子转移到碳-碳双键形成环丙烷的反应。这是一个重要性日益增加的综合性转变。研究包括确定金催化过程的范围和机制以及金络合物的结构的实验。这项研究提供了机制的见解，将服务于不断增长的全球研究人员社区，致力于开发新的和更有效的金（I）催化转化。研究活动被充分纳入科学教育和研究生和本科生研究人员的培训，包括来自传统上在科学领域代表性不足的群体的学生。研究生通过参加杜克大学研究生院提供的教育活动来增加他们的研究经验。研究生还与杜克核磁共振（NMR）中心的Ben Bobay博士合作参加社区外展活动，为当地高中生提供现代高场NMR光谱学的动手操作和NMR数据处理和解释的一对一指导。本项目研究了金卡宾配合物和阳离子金卡宾配合物的结构和反应性，包括与金到烯烃卡宾转移（环丙烷化）、金α-氧代卡宾和卡宾配合物以及阳离子β，γ-不饱和金卡宾配合物相关的结构和反应性。尽管越来越多的机构在这方面的工作，有限的实验信息是有关机制，涉及这些金络合物。研究活动填补了这一领域的重要空白，并对通过稳定的重氮化合物的卡宾转移或通过在金存在下氧化烯烃产生的络合物的性质进行了有实验依据的理解。本论文的主要研究内容包括三个方面：（1）通过模拟卡宾转移的过渡态来阐明金向烯烃卡宾转移的机理，金金属环丁烷配合物的独立合成，以及在化学计量条件下金向烯烃卡宾转移的动力学分析;（2）通过研究金配合物与稳定的N-和S-的反应，评价阳离子金α-氧代卡宾和类卡宾配合物的性质和反应性。叶立德以及吡啶N-氧化物与阳离子金配合物的反应;以及（3）通过合成和表征阳离子金亚丙二烯基和乙烯基卡宾络合物，探究不饱和金卡宾络合物的结构和反应性。该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响审查标准。