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Umpolung Methods with Electron Rich Aromatic Systems: Aza-ortho-Xylylenes, and N,N-Dialkylaniline N-Oxides in Synthesis

富电子芳族体系的 Umpolung 方法：合成中的氮杂邻二甲苯和 N,N-二烷基苯胺 N-氧化物

基本信息

批准号：
1955159
负责人：
William Chain
金额：
$ 45万
依托单位：
University of Delaware
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2024-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1955159&HistoricalAwards=false
关键词：
Umpolung Methods Electron Rich Aromatic

项目摘要

With this award, the Chemical Synthesis Program of the Division of Chemistry is supporting the research of Dr. William J. Chain of the Department of Chemistry and Biochemistry at the University of Delaware. Dr. Chain and his team of students are developing new reactions of aromatic compounds that reverse the normal behavior of these molecules. The Chain group is manipulating normally electron-rich aromatic compounds chemically such that they behave as species with low electron density. This strategy temporarily changes the reactivity of these pi-systems and triggers the formation of new carbon-carbon, carbon-oxygen, carbon-nitrogen, and carbon-sulfur bonds that are found in compounds used in industrial, medicinal, and material applications. These studies are serving to train a diverse group of graduate, undergraduate, and high school students in synthetic chemistry. The Chain group is also actively engaged in outreach activities in local elementary, middle, and high schools to promote science education and excitement towards STEM (science, technology, engineering, and mathematics) disciplines. While Friedel-Crafts reactions are well-established processes for aromatic substitution, there are still significant limitations in electron-rich settings. Professor Chain and his research group are addressing this gap in aromatic functionalization technology by developing ways to temporarily invert the reactivity of electron-rich anilines. In one approach, ortho-toluidines are being converted to aza-ortho-xylylenes (AOXs) via an electrochemical oxidation event and used as electron-acceptors for carbon-carbon bond formation. In a second approach, anilines are being oxidized to the corresponding N-oxides, which facilitates a wide array of bond formations and cyclizations that take advantage of the excision of the weak N–O bond. By virtue of the extremely mild reaction conditions associated with these new processes, the scope and application of umpolung reactions with electron rich aromatic rings is expanded thereby opening up new opportunities for organic synthesis. A better understanding of the fundamental reactivity behind these processes is also being established through collaborative computational studies. The educational plan is targeting outreach to local elementary, middle, and high schools with integration of high school students into the research program in the form of research internships.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.

通过这一奖项，化学系的化学合成计划支持特拉华大学化学和生物化学系的William J.Chain博士的研究。链博士和他的学生团队正在开发芳香化合物的新反应，这些反应可以逆转这些分子的正常行为。链基对通常富含电子的芳香族化合物进行化学操作，使其表现为具有低电子密度的物种。这一策略暂时改变了这些pi体系的反应性，并触发了新的碳-碳、碳-氧、碳-氮和碳-硫键的形成，这些键存在于工业、医药和材料应用中的化合物中。这些研究正在服务于培养一批不同的合成化学研究生、本科生和高中生。链家集团还积极参与当地小学、初中和高中的外展活动，以促进科学教育和对STEM(科学、技术、工程和数学)学科的兴奋。虽然Friedel-Craft反应是芳香族取代的成熟过程，但在电子丰富的环境中仍有很大的局限性。Chain教授和他的研究小组正在通过开发暂时逆转富含电子的苯胺的反应性的方法来解决芳香族官能化技术中的这一差距。在一种方法中，邻甲基苯胺通过电化学氧化事件转化为氮杂邻二甲苯(AOXs)，并用作碳-碳键形成的电子受体。在第二种方法中，苯胺被氧化成相应的N-氧化物，这促进了一系列广泛的键形成和环化反应，这些反应利用了弱N-O键的切除。由于这些新工艺的反应条件极其温和，扩展了富含电子芳环的Upolung反应的范围和应用，从而为有机合成开辟了新的机会。通过合作计算研究，还可以更好地理解这些过程背后的基本反应性。该教育计划旨在扩大到当地小学、初中和高中，以研究实习的形式将高中生纳入研究计划。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。