Exploring and Understanding the Effect of Cation-Pi Interactions in Asymmetric Catalysis

在这个由化学系化学结构、动力学和机制-B计划资助的项目中，南卡罗来纳大学化学和生物化学系的Sheryl Wiskur教授试图了解分子间相互作用如何控制化学反应，以便合理设计催化剂。光学活性中间体在制药和农化工业中的重要性日益增加。获得这些具有重要商业价值的化合物的新方法正在不断开发中。重要的是要了解有助于实现选择性产物形成的相互作用，以便合理地设计催化剂。这项研究调查了分子间相互作用，称为阳离子-pi相互作用，是如何参与控制选择性的。这项研究可以帮助开发更有效的不对称催化剂，这是药物开发和许多其他化学品制造所需的。该项目还考虑到研究生在进行实验以了解这种超分子相互作用时所接受的宝贵培训。更广泛的影响包括指导女性科学家帮助留住女性从事科学工作。离域阳离子经常被提出通过底物和催化剂之间的阳离子-pi相互作用来帮助控制不对称反应，但离域阳离子还没有得到广泛的研究。这个项目通过两种方式探索这种超分子相互作用。我们将研究四种常见的有机催化剂核心结构的结合热力学。该团队还将调查结合趋势如何与模型反应的速度和选择性相关，因为圆周率体系上的电子发生了变化。通过计算探讨了结合的静电学，以了解结合的取向和电荷的局域化。研究了阳离子(即被取代的催化剂)中的电子变化，以了解这些变化如何在热力学、动力学和选择性方面影响同一模型反应。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。

In this project, funded by the Chemical Structure, Dynamics and Mechanisms-B Program of the Chemistry Division, Professor Sheryl Wiskur of the Department of Chemistry and Biochemistry at the University of South Carolina is attempting to understand how intermolecular interactions control chemical reactions in order to rationally design catalysts. Optically active intermediates are of increasing in importance in the pharmaceutical and agrochemical industries. New approaches to obtaining these commercially important compounds are constantly being developed. It is important to understand the interactions that aid in achieving selective product formation in order to rationally design catalysts. This research investigates how the intermolecular interactions, termed a cation-pi interactions, are involved in controlling selectivity. The research could aid the development of more efficient asymmetric catalysts, which are needed in drug development and the manufacture of many other chemicals. The project also takes into account the valuable training graduate students receive while carrying out the experiments to understand this supramolecular interaction. Broader impacts include the mentoring of women scientists to aid in retaining women in science.Delocalized cations are often proposed to aid in controlling asymmetric reactions through cation-pi interactions between the substrate and catalyst, yet delocalized cations have not been as widely studied. This project explores this supramolecular interaction in two ways. The thermodynamics of binding of four common organocatalyst core structures will be studied. The team will also investigate how the binding trends relate to the rate and selectivity of a model reaction as electronics on the pi system are altered. The electrostatics of binding are explored computationally to understand binding orientations and localization of charge. The electronic changes in the cation (i.e., substituted catalysts) are examined to understand how those changes affect the same model reaction in terms of thermodynamics, kinetics, and selectivity.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.