CAREER: Iridium Catalysts for the Activation and Functionalization of Ethereal Substrates

乙醚分子在为现代社会提供动力的化学中无处不在。简单的醚可用作溶剂、汽车燃料添加剂以及塑料和环氧树脂等聚合材料的前体。复合醚被用来合成现代生化应用所需的碳水化合物。醚类化合物的一个重要特征是反应活性低。然而，这种有用的性质限制了它们进一步化学修饰的选择，从而限制了它们的有用性。在国家科学基金化学催化计划的支持下，该研究项目正在开发新的催化方法来实现乙醚反应。范德比尔特大学的Schley教授和他的团队正在探索乙醚活化的新方法，旨在解决使用简单和复杂乙醚所面临的独特挑战。范德比尔特与大纳什维尔地区的当地社区大学之间的密切联系丰富了该团队。施利教授正在组织一个外展项目，旨在为社区学院的学生提供本科生的研究机会。社区学院的应届毕业生或应届毕业生在范德比尔特大学进行暑期研究的实习机会也在增加。乙醚官能团对氧化剂、强碱和亲核剂的攻击具有稳定性，在许多方面是一个有价值的性质，但限制了直接乙醚衍生化的途径。因此，尽管简单烷基醚的可获得性、可负担性和低毒性，它们主要局限于低价值的应用。同样，用于乙醚C-O裂解的苛刻化学计量方法限制了与含聚醚的复杂分子(包括碳水化合物衍生物)的兼容性。通过这一项目，Schley研究小组正在探索两种以Ir离子为载体的亲电性乙醚活化方式，包括乙醚脱氢生成亲电性烷氧基卡宾和乙醚硅基化反应生成硅氧烷离子。这些中间体被激活为完整碳-氧键的亲核裂解反应，并代表了选择性催化乙醚裂解反应的不同机械路线。这项研究是与纳什维尔地区的当地社区大学的外展活动一起进行的。作为一名前社区大学学生，Schley教授正在试行一项外展计划，旨在为田纳西州的社区大学学生传播有关本科生研究机会的信息。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。

Ether molecules are ubiquitous in the chemistry that powers modern society. Simple ethers find applications as solvents, motor fuel additives, and as precursors to polymeric materials such as plastics and epoxies. Complex ethers are used to synthesize carbohydrates required for modern biochemical applications. A defining characteristic of ethers is their low reactivity. However, this useful property limits options for their further chemical modification and thus, usefulness. With support from the Chemical Catalysis program of the National Science Foundation, this research project is developing new catalytic methods to enable ether reactivity. Professor Schley and his group at Vanderbilt University are exploring new methods for ether activation designed to address challenges unique to the utilization of both simple and complex ethers. The team is enriched by strong connections between Vanderbilt and local community colleges in the greater Nashville area. Professor Schley is organizing an outreach program designed to promote undergraduate research opportunities for community college students. Internship opportunities for current or recent community college graduates to conduct summer research at Vanderbilt University are also being created.The stability of the ether functional group with respect to attack by oxidants, strong bases, and nucleophiles is a valuable property in many respects, but limits avenues for direct ether derivatization. As a result, despite the availability, affordability, and low toxicity of simple alkyl ethers, they have been primarily limited to low-value applications. Similarly, the harsh stoichiometric methods used for ether C-O cleavage limits compatibility with complex polyether-containing molecules including carbohydrate derivatives. Through this project the Schley research group is exploring two modes for iridium-mediated electrophilic ether activation involving ether dehydrogenation to electrophilic alkoxycarbenes and ether silylation to give silyloxonium ions. These intermediates are activated towards nucleophilic cleavage reactions of the integral carbon-oxygen bond and represent mechanistically distinct routes to selective, catalytic ether cleavage reactions. This research is being pursued in tandem with outreach to local community colleges in the Nashville area. As a former community college student himself, Professor Schley is piloting an outreach program aimed at disseminating information about undergraduate research opportunities for community college students in Tennessee.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.