Development of Stable Carbocations for Lewis Acid-Assisted Transformations

在化学系化学合成项目的支持下，亚利桑那大学的托马斯吉亚内蒂和他的研究小组正在开发制造稳定的碳阳离子的方法-碳原子上带有正电荷的有机分子-连接到富电子基团，可以作为催化剂或过渡金属中心的配体，具有双重功能。正在研究这些化合物，以确定它们是否比使用缺电子硼中心而不是碳阳离子的更传统的系统提供更大的可调性和耐受性。此外，Gianetti博士和他的研究团队正在测试这些两亲性碳阳离子作为过渡金属络合物的配体，与金属中心协同作用，以激活小分子形成新的键。这些研究还将为有机化学家提供制造增值化合物的新方法，并有望为这些新的碳阳离子化合物如何用于进入新的化学空间以支持合成化学提供基本见解。Gianetti博士还致力于改善科学家和政策制定者之间的沟通，并正在与法学院开发一门联合课程，以建立一个能够跨越学科障碍讨论环境政策的本科生群体。虽然碳阳离子的物理有机性质已经被仔细研究，关于这些化合物在合成化学中作为催化剂和过渡金属催化剂的配体的用途知之甚少。托马斯吉亚内蒂和他的研究小组正在开发碳阳离子挫折刘易斯对和测试他们的反应性亲核加成多聚甲醛和烯烃。此外，这些催化剂的螺旋手性类似物将被制备和研究催化不对称转化。将这些两亲性碳阳离子并入配体支架中有待进一步探索，以支持小分子如烯丙醇和NO2的协同活化。这些活动将协同为亚利桑那大学的研究生和本科生提供合成化学和有机金属概念的重要培训。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 Program in the Division of Chemistry, Thomas Gianetti of the University of Arizona and his research group are developing ways to make stable carbocations – organic molecules that have a positive charge on a carbon atom – that are attached to electron-rich groups and can serve as catalysts, or ligands for transition metal centers, with dual functionalities. These compounds are being studied to determine if they provide greater tunability and tolerance than more traditional systems that use electron-deficient boron centers instead of carbocations. In addition, Dr. Gianetti and his research team are testing these ambiphilic carbocations as ligands for transition metal complexes to work synergistically with the metal center to activate small molecules toward new modalities for bond formation. These studies will also provide new ways for organic chemists to make value-added compounds and are expected to provide fundamental insight into how these new carbocationic compounds can be used to access new chemical space to support of synthetic chemistry. Dr. Gianetti is also committed to improving communication between scientists and policymakers and is developing a joint course with the College of Law to build a cohort of undergraduate students that can discuss environmental policy across disciplinary barriers.While the physical organic properties of carbocations have been carefully studied, little is known about the use of these compounds as catalysts and ligands for transition metal catalysts in synthetic chemistry. Thomas Gianetti and his research team are developing carbocationic frustrated Lewis pairs and testing their reactivity for nucleophilic additions to paraformaldehyde and alkenes. In addition, helically chiral analogues of these catalysts will be prepared and investigated for catalytic asymmetric transformations. Incorporation of these ambiphilic carbocations into ligand scaffolds is to be further explored to support the cooperative activation of small molecules such as allylic alcohols and NO2. These activities will synergistically provide important training in synthetic chemistry and organometallic concepts for a diverse group of graduate and undergraduate students at the University of Arizona.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.