Hexadehydro-Diels-Alder (HDDA) Reaction-Enabled Synthesis of Structurally Elaborate, Polycyclic Aromatic Compounds

在化学系化学合成（SYN）项目的支持下，明尼苏达大学的托马斯·霍耶教授正在研究一种多功能的化学合成新方法，即六氢-狄尔斯-桤木（HDDA）反应。HDDA反应仅需要简单加热适当设计的前体（称为三炔的反应物）即可产生称为苯炔的高反应性物质。反过来，这种中间体可以参与无数类型的“捕获剂”，往往导致前所未有的化学转化类型。资助的研究重点是使用HDDA反应作为工具，以发现构建多环芳烃分子的新方法。这类化合物通常表现出对现代光电子器件的操作至关重要的光化学和光物理性质，所述现代光电子器件对社会具有巨大价值;例如，有机发光二极管（OLED），其用于节能显示器和照明单元，以及光伏电池，其用于将太阳能转化为电能。除了促进多环芳烃的制备外，该项目的目标预计将促进对各种新型化学转化的基本理解，并为获得以前难以理解的化学结构类型提供手段和灵感。计划对更广泛的利益相关者群体（包括学生，教师和更广泛的科学界）产生一些重大的更广泛的影响。特别值得注意的是（1）一个被称为“物理有机化学中的小插曲”的活动，其中霍耶教授和他的同事将准备（并在策划的网站上提供）在机械有机化学领域历史上重要发展的有教学价值的文件，以及（2）开发和传播对NMR光谱学用户具有实用价值的教程提示和技巧，HDDA反应是分析有机反应和结构的最有价值和最强大的工具。该奖项使Hoye研究小组能够继续利用HDDA反应的能力，以促进高度共轭多环芳烃的简洁和有效的阐述。合成此类化合物的新方法和策略是该项目预期产生的最重要成果，但也可能出现根本性的重要机械知识。要探讨的具体课题包括萘和蒽为模板的HDDA反应，环内HDDA反应，“传播HDDA反应”的共轭聚合物的合成，并使用迭代指数增长策略，以产生离散的聚炔基板设计进行长序列的“多米诺HDDA反应”，导致低聚线性聚并苯。霍耶教授持有主要的教学奖项，以表彰他在本科和研究生阶段对学生教育的长期承诺。该项目支持的更广泛的活动将使化学研究生在多个层面受益。这些科学进步有可能为材料科学家开辟新的途径，他们在发光二极管、光化学和太阳能电池的设置中使用有机电子和光子化合物，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Synthesis (SYN) Program in the Division of Chemistry, Professor Thomas Hoye of the University of Minnesota is studying the use of a versatile new method for chemical synthesis known as the hexadehydro-Diels-Alder (HDDA) reaction. The HDDA reaction requires merely the simple heating of an appropriately designed precursor (a reactant known as a triyne) to produce a highly reactive species known as a benzyne. In turn, this intermediate can engage myriad types of “trapping agents,” often resulting in unprecedented types of chemical transformation. The funded research focuses on using the HDDA reaction as a tool to discover new ways to build molecules known as polycyclic aromatics. Compounds of this class often exhibit photochemical and photophysical properties critical for the operation of modern optoelectronic devices that are of great value to society; for example, organic light emitting diodes (OLEDs), which are used in energy efficient displays and lighting units, and photovoltaic cells, which are used for the conversion of solar energy into electricity. In addition to facilitating the preparation of polycyclic aromatics, pursuit of the project aims is anticipated to advance both fundamental understanding of various new types of chemical transformations as well as providing the means and inspiration to access previously elusive types of chemical structures. A number of significant broader impacts of benefit to a wider group of stakeholders – including students, instructors, and the broader scientific community – are planned. Of particular note are (1) an activity dubbed “Vignettes in Physical Organic Chemistry” in which Professor Hoye and his coworkers will prepare (and make available on a curated website) pedagogically valuable documents of historically important developments in the field of mechanistic organic chemistry, and (2) the development and dissemination of tutorial tips and tricks of practical value to the users of NMR spectroscopy, the single most valuable and powerful tool for analyzing organic reactions and structures.This award is enabling the Hoye research group to continue to capitalize on the capacity of the HDDA reaction to facilitate concise and efficient elaborations of highly conjugated polycyclic aromatics. The new methods and strategies for the syntheses of such compounds are the most important outcomes that are anticipated to result from this project but fundamentally important mechanistic knowledge will likely also emerge. Specific topics to be explored include naphthalene- and anthracene-templated HDDA reactions, intra-annular HDDA reactions, “propagating HDDA reactions” for the synthesis of conjugated polymers, and the use of an iterative exponential growth strategy to produce discreet polyyne substrates designed to undergo long sequences of “domino HDDA reactions” leading to oligomeric linear polyacenes. Professor Hoye holds major teaching awards that recognize his career-long commitment to the education of students at both the undergraduate and graduate levels. Broader activities supported by this project will benefit chemistry research students at multiple levels. The scientific advances have the possibility of opening new avenues for pursuit by materials scientists who use organic electronic and photonic compounds in the settings of light-emitting diodes, photovoltaics, and solar cells, applications that have a large potential for societal impact.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.