Combining stereoelectronics, traceless directing groups and dynamic covalent chemistry for the design of alkyne cascades: towards carbon-rich molecules and materials

在这个由化学系化学结构、动力学和机理B以及大分子、超分子和纳米化学项目资助的项目中，佛罗里达州立大学化学和生物化学系的伊戈尔·阿拉布金教授将开发具有预先设计的形状和功能的共轭碳纳米结构的新途径，该方法基于高能炔前体到共轭环状结构的原子经济转化。这种转变将在有机合成和材料科学中有用。特别是，这项工作将为制造富碳共轭分子铺平道路，这些分子可以在光电材料、储能设备、传感器、晶体管、太阳能电池和聚合物复合材料的设计中用作独特的组件。这项研究还将拓宽设计新的有机反应的机理、结构和动力学基础。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、研究生和博士后一级的研究人员提供一个将学习和发现结合起来的机会。这些成果将在同行评议的出版物和外联活动中传播，包括参加本科生和研究生院的座谈会和讲座。在这个项目中，不同大小的邻位聚炔链配备了不同的功能，以模块化的方式使用充分表征和可靠的交叉偶联化学来构建。在关键的一步，这些系统然后通过一系列快速和选择性的激进环化来“拉链”。在多功能底物上的初始自由基攻击的选择性由在一锅法过程中被移除的“无痕迹导向基团”的存在控制。同时，烯烃的自终止反应通过利用烯烃作为炔烃的合成等价物来克服对6-内标环化反应的立体电子限制，并在级联终止步骤中完成最终的“氧化”，作为芳构化C-C键的断裂。

In this project funded by the Chemical Structure, Dynamic & Mechanism B and the Macromolecular, Supramolecular and Nanochemistry Programs of the Chemistry Division, Professor Igor Alabugin of the Department of Chemistry and Biochemistry at Florida State University will develop new routes to conjugated carbon nanostructures with predesigned shape and functionality based on atom-economical transformations of high-energy alkyne precursors into conjugated cyclic structures. Such transformations will be useful in organic synthesis and materials science. In particular, this work will pave the way to carbon-rich conjugated molecules that can serve as unique components in the design of optoelectronic materials, energy storage devices, sensors, transistors, solar cells, and polymer composites. This research will also broaden the mechanistic, structural, and kinetic foundations for design of new 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 peer-reviewed publications and outreach activities, including participation in symposia and lecturing at undergraduate and graduate institutions. In this project, ortho polyyne chains of varying sizes, equipped with different functionalities, are built in a modular fashion using well-characterized and reliable cross-coupling chemistry. In the key step, these systems are then "zipped" up via a cascade of fast and selective radical cyclizations. Selectivity of initial radical attack on the multifunctional substrates is controlled by the presence of "traceless directing groups" that are removed in the course of the one-pot process. In parallel, self-terminating reactions of enynes overcome stereoelectronic restrictions on the 6-endo-dig cyclizations by utilizing alkenes as synthetic equivalents of alkynes with the final "oxidation" accomplished in the cascade termination step as an aromatizing C-C bond scission.