The Origins of Stereoselection in Asymmetric Reductions and Hydrogenations

化学系的化学结构、动力学和机制计划支持加州大学默塞德分校的马修·迈耶教授研究不对称还原和氢化反应中立体选择的起源。动力学同位素效应将被用来定量地探索在Corey-Bakshi-Shibata还原和Ru(II)催化的氢化反应中支配立体选择的物理相互作用。Kie将被用于开发实验证实的高度立体选择性氢化的过渡结构模型。一种新的方法，即立体选择的同位素微扰，将被用来研究系列TunePhos配体对Ru(II)催化剂环境的系统变化。所研究的反应的跃迁结构将通过计算进行研究，以询问支配立体选择的相互作用。催化不对称反应在精细化工和医药工业中具有重要意义。这些行业目前的重点是减少原料和支持环境友好技术，因此迫切需要新的催化不对称方法。令人惊讶的是，大多数开发中的方法学对手性转移的详细机制知之甚少。这个项目将在两大类反应中完善对立体选择的机械理解。年轻的科学家在成长为专业人士的过程中必须受到管理。该项目将为不同的学生群体提供培训，其中许多学生来自代表性不足的群体。一个重要的组成部分将包括让本科生接触计算化学以及有机化学的实验方面。PI还将参与与默塞德县4-H的外联活动，其中包括国家科学日4-H实验。

The Chemical Structure, Dynamics and Mechanisms Program of the Chemistry Division supports Professor Matthew Meyer at the University of California, Merced for studies into the origins of stereoselection in asymmetric reductions and hydrogenations. Kinetic isotope effects will be used (KIEs) to quantitatively probe physical interactions that govern stereoselection in Corey-Bakshi-Shibata reductions and in Ru(II) catalyzed hydrogenations. The KIEs will be used to develop experimentally-corroborated transition structure models of highly stereoselective hydrogenations. A new method, isotopic perturbation of stereoselection, will be used to study systematic changes in Ru(II) catalyst environment using the series of TunePhos ligands. The transition structures for the reactions studied will be investigated computationally in order to interrogate the interactions that govern stereoselection. Catalytic asymmetric reactions are of great importance to the fine chemicals and pharmaceutical industry. These industries, with their current focus on reducing feedstocks and enabling environmentally friendly technologies, have a critical need for new catalytic asymmetric methodologies. Surprisingly, the detailed mechanisms by which chirality is transferred are poorly understood in most developing methodologies. This project will refine the mechanistic understanding of stereoselection in two broad classes of reactions. Young scientists must be stewarded as they develop into professionals. The project will provide training to a diverse group of students, many from under-represented groups. An important component will involve exposing undergraduates to computational chemistry as well as the experimental aspects of organic chemistry. The PI will also be involved in outreach activities with Merced County 4-H that include the National Science Day 4-H experiment.