A study of vinyl cations as intermediates in bond forming reactions

佛蒙特大学化学系的Matthias Brewer教授在化学部化学结构、动力学机制B计划资助的这个项目中，正在研究乙烯基阳离子的反应性。这项研究的目的是更好地了解这些高能中间体的反应性，并开发新的碳-碳键形成反应。这项工作利用了这样一个事实，即乙烯基阳离子可以通过独特的和知之甚少的机制途径，尚未充分利用合成反应。除了提供乙烯基阳离子的固有反应性的更好的理解，这项工作提供了几个有用的复杂性建设成环反应，可以使结构复杂的双环和多环的产品和更基本的分子支架，作为有用的合成中间体的合成。从事该项目的研究生和本科生以及经济困难的高中生（通过ACS Project SEED计划）接受有机化学方面的优秀培训，学习进行机理研究，反应优化和开发研究，并擅长化合物表征和结构解析。此外，PI正在寻找创新的方法来促进本科生的研究机会和出国留学的机会，本科化学和生物化学专业。虽然三取代的阳离子（即碳正离子）是有机化学中研究得最好和最重要的中间体类别之一，但二取代的阳离子（即乙烯基阳离子）尚未受到合成界的同等关注。该提案旨在更好地理解乙烯基阳离子的固有反应性和乙烯基阳离子反应的机制。具体而言，这项工作：1）探索了乙烯基阳离子在内部氧化还原反应中的反应性，该反应导致通过远程C-H官能化形成C-C键; 2）通过机理研究提供了对插入过程的更好理解; 3）定义了乙烯基阳离子的烯烃的1，2-移位中的基团的迁移倾向; 4）研究了乙烯基阳离子与远程π-系统反应形成C-C键。这些研究可以提供新的和独特的方法来制备简单的结构，这将是有价值的合成中间体，以及重要的碳环支架，这将是难以通过传统手段制备。

In this project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Matthias Brewer of the Department of Chemistry at the University of Vermont is studying the reactivity of vinyl cations. The goal of this research is to better understand the reactivity of these high-energy intermediates and to develop new carbon-carbon bond forming reactions. This work takes advantage of the fact that vinyl cations can react through unique and poorly understood mechanistic pathways that have not been fully exploited in synthesis. In addition to providing a better understanding of the inherent reactivity of vinyl cations, this work provides several useful complexity-building ring-forming reactions that could enable the synthesis of structurally complex bicyclic and polycyclic products and more basic molecular scaffolds that serve as useful synthetic intermediates. The graduate and undergraduate students and economically disadvantaged high school students (via the ACS Project SEED program) who work on this project receive excellent training in organic chemistry and learn to conduct mechanistic studies, reaction optimization and development studies, and become adept at compound characterization and structure elucidation. In addition, the PI is looking for innovative ways to promote undergraduate research opportunities and study abroad opportunities for undergraduate Chemistry and Biochemistry majors. While trisubstituted cations (i.e. carbenium ions) are one of the best studied and most important classes of intermediates in organic chemistry, disubstituted cations (i.e. vinyl cations) have not received the same level of attention from the synthetic community. This proposal seeks to better understand the intrinsic reactivity of vinyl cations and the mechanisms through which vinyl cations react. Specifically, this work: 1) Explores the reactivity of vinyl cations in internal redox reactions that result in C-C bond formation by remote C-H functionalization; 2) Provides a better understanding of the insertion process through mechanistic studies; 3) Defines the migratory aptitude of groups in 1,2-shifts across the alkene of vinyl cations; 4) Studies C-C bond formation by reaction of vinyl cations with remote pi-systems. These studies could provide new and unique ways to prepare simple structures that will be valuable synthetic intermediates, as well as important carbocyclic scaffolds that would be difficult to prepare by traditional means.