AB Initio Calculations on Eliminations and Proton Transfers

AB 从头计算消除和质子转移

• 批准号: 9706242
• 负责人: William Saunders
• 金额: $ 5.1万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 2001-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9706242&HistoricalAwards=false
• 关键词: AB; Initio; Calculations; Eliminations; Proton

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.

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, Jr.教授正在开展消除反应和质子转移反应的量子化学计算。 对氟取代的碳负离子的计算允许评估负离子超共轭的作用，并且氟代烃消除反应的研究解决了 E1cb 和 E2 反应途径之间的界限。 通过考虑电荷分布、同位素效应和离子配对来检查控制协同消除反应的方向和立体化学的因素。 特别注意发展对顺式-反式二分法的理解，其中顺式烯烃是通过反消除产生的，而反式烯烃是通过顺式消除产生的。 表面上最简单的化学反应包括将单个带正电的氢原子（质子）从分子中的一个位置转移到另一个位置的反应。 然而，尽管此类反应看似简单，但实验结果表明相当复杂。 通过应用计算技术并在有机动力学计划的支持下，罗切斯特大学化学系的 William H. Saunders, Jr. 教授正在探索质子转移反应的基本方面。 他的研究还扩展到对质子损失引发的反应的分析，特别关注此类反应的整个反应路径是否涉及同时消除额外的基团，或者这种消除是否发生在初始质子损失之后。 这些问题是极其广泛的化学反应的核心，桑德斯教授的研究正在使人们对控制这些反应的因素有一个基本的了解。