NONCOVALENT INTERACTIONS AND HYPERCONJUGATION IN CONTROL OF RADICAL REACTIVITY: APPLICATION TO 5-ENDO-DIG CYCLIZATIONS

这一建议将炔反应性的研究拓展到一个新的方向。它将集中在控制炔的自由基环化的基本因素，并利用这些知识来设计综合有用的转换。由于烯烃和炔的自由基环化反应的立体电子模式是显著不同的，理解这些基本差异对于炔化学的发展是必不可少的。在这个项目中，Alabugin小组将利用立体电子和热力学因素来寻找表面上有利但实际上尚未探索的自由基过程：5-内-二氢自由基环化反应，并将此反应及相关反应应用于新的碳环和杂环体系的合成。拟议的实验将测试早期的计算预测不同的环化模式的相对效率，发现新的环化拓扑结构和测试效率的合作hyperconjugative相互作用控制的自由基反应。与此同时，该小组将结合联合收割机有效的自由基环化与自由基易位功能化多环系统的快速建设。这些反应通过在C-C键形成步骤中利用炔部分的两个π键来利用存在于炔中而不存在于烯烃中的合成潜力。这项研究的智力价值在于通过实验和理论研究相结合，揭示了控制自由基过程效率和选择性的电子和结构因素的贡献。对电子效应的关注将增加这些发现的普遍重要性，拓宽对这些基本因素的理解，并导致自由基反应性新范式的发展。 更广泛的影响将是奠定了机械，结构和动力学基础的成功应用的自由基反应的炔在合成和材料科学。拟议的研究将提高对炔部分以及自由基物种的反应性的理解。计算和动力学研究的结合将用于验证有机反应研究的理论方法。 这项工作的理论和实验部分将允许培训每个领域的专家，并将为本科生，研究生和博士后水平的研究人员提供整合学习和发现的机会。研究结果将在PI的出版物和外联活动中传播，包括参加研讨会和在本科生和研究生机构讲课。PI和他的学生还将为全球科学工程和技术教育推广（GEOSET）录制他们的研究报告，这是一项通过新技术提供优秀科学，工程和技术（SET）教材的新举措。记录的研究报告将发布在GEOSET网站上，并链接到PI和部门网站。这种接触也将有助于参与学生进一步的职业机会的发展，因为这些录音甚至可以取代工作面试，从而减少碳足迹和未来雇主的旅行成本。

This proposal extends studies of unusual aspects of alkyne reactivity into a new direction. It will concentrate on fundamental factors controlling radical cyclizations of alkynes and utilize this knowledge for the design of synthetically useful transformations. Because stereoelectronic patterns are significantly different for radical cyclizations of alkenes and alkynes, understanding these fundamental differences is essential for the development of alkyne chemistry.In this project, the Alabugin group will utilize stereoelectronic and thermodynamic factors in search of the apparently favorable but virtually unexplored radical process: 5-endo-dig radical cyclization and apply this and related reactions to the synthesis of new carbo- and heterocyclic systems. Proposed experiments will test earlier computational predictions regarding the relative efficiency of different cyclization patterns, discover new cyclization topologies and test the efficiency of cooperative hyperconjugative interactions in control of radical reactivity. In parallel, the group will combine efficient radical cyclizations with radical translocations for the rapid construction of functionalized polycyclic systems. These reactions take advantage of synthetic potential which is present in alkynes but not in alkenes by utilizing both pi-bonds of the alkyne moiety in the C-C bond forming steps. The intellectual merit of this research is in unraveling the contribution of electronic and structural factors controlling the efficiency and selectivity of radical processes through a combination of experimental and theoretical studies. The underlying focus on electronic effects will increase the general importance of these findings, broaden understanding of these fundamental factors and lead to the development of new paradigms of radical reactivity. The broader impact will be the laying of mechanistic, structural, and kinetic foundations for successful applications of radical reactions of alkynes in synthesis and materials science. The proposed research will enhance understanding of the reactivity of the alkyne moiety as well as radical species. The combination of computations and kinetic studies will be used to validate theoretical approaches for studies of organic reactions. The theoretical and experimental components of this work will allow training of specialists in each area and will provide researchers at the undergraduate, graduate and postdoctoral levels with an opportunity to integrate learning and discovery. The results will be disseminated in the PI's publications and outreach activities, including participation in symposia and lecturing at undergraduate and graduate institutions. The PI and his students will also record their research presentations for the Global Educational Outreach for Science Engineering and Technology (GEOSET), a new initiative to provide outstanding Science, Engineering and Technology (SET) teaching material through the new technology. The recorded research presentations will be posted on the GEOSET website and linked to the the PI's and Departmental websites. This exposure will also help in the development of further career opportunities for participating students since these recordings may even take the place of job interviews, thus reducing carbon footprints and travel costs to prospective employers.