AB Initio Calculations on Eliminations and Proton Transfers

在有机动力学项目的支持下，罗切斯特大学化学系的William H. Saunders教授正在进行消去反应和质子转移反应的量子化学计算。对氟取代碳离子的计算可以评估负离子超偶联的作用，对氟烃消除反应的研究解决了E1cb和E2反应途径之间的边界问题。通过考虑电荷分布、同位素效应和离子配对，研究了控制协同消除反应取向和立体化学的因素。特别注意的是发展对正反二分法的理解，其中顺式烯烃是通过反消除产生的，而反式烯烃是通过syn消除产生的。表面上最简单的化学反应是将一个带正电的氢原子（质子）从分子的一个地方转移到另一个地方。然而，尽管这些反应表面上很简单，实验结果却表明相当复杂。罗彻斯特大学化学系的William H. Saunders教授，在有机动力学项目的支持下，通过应用计算技术，正在探索质子转移反应的基本方面。他的研究还扩展到分析由质子损失引发的反应，特别关注这些反应的整个反应路径是否涉及同时消除额外的基团，或者这种消除是否在初始质子损失之后发生。这些问题是非常广泛的化学反应的核心，桑德斯教授的研究使人们对控制化学反应的因素有了基本的了解。

With the support of the Organic Dynamics Program, Professor William H. Saunders, Jr., of the Department of Chemistry at the University of Rochester, is carrying out quantum chemical calculations on elimination and proton transfer reactions. Calculations on fluorine-substituted carbanions permit the assessment of the role of negative ion hyperconjugation, and studies of elimination reactions of fluorohydrocarbons address the borderline between E1cb and E2 reaction pathways. Factors governing the orientation and stereochemistry of concerted elimination reactions are examined through consideration of charge distributions, isotope effects, and ion pairing. Particular attention is placed on developing an understanding of the syn-anti dichotomy, wherein cis olefins are produced by anti elimination but trans olefins are produced by syn elimination. Among the superficially simplest chemical reactions are those involving the transfer of a single positively-charged hydrogen atom (a proton) from one place in a molecule to another. Despite the apparent simplicity of such reactions, however, experimental results indicate appreciable complexity. Through the application of calculational techniques and with the support of the Organic Dynamics Program, Professor William H. Saunders, Jr., of the Department of Chemistry at the University of Rochester, is exploring the fundamental aspects of proton transfer reactions. His studies also extend to the analysis of reactions initiated by the loss of a proton, focusing in particular on whether the overall reaction path for such reactions involves simultaneous elimination of an additional group or if such elimination occurs subsequently to the initial proton loss. These issues are central to an extraordinarily wide variety of chemical reactions, and Professor Saunders' studies are leading to a fundamental understanding of the factors controlling them.