Exploring Mechanism of Additions to Alkenes; Extending a New Technique by Four Reactions

提案有两个目标。第一个是扩展开发的技术，这已经开发的PI，相关的可测量的特性，在加成反应的烯烃，以获得有用的信息，机械和合成。PI已经将该技术应用于足够的系统以确定其可行性，但其范围尚未确定。该技术使（1）一个程序，以确定相对大小的空间和电子效应的速率决定步骤，（2）一个相对简单的方法来预测取代基的影响，反应速率的合成目的，和（3）的方法，选择替代提出的反应机制在某些情况下。要扩展的简单技术是相关（绘图）的日志的相对速率（log krel）的烯烃加成反应的研究与可测量的特性的烯烃，如电离势（IP），其最高占据分子轨道能量（HOMO），在某些情况下，其最低未占分子轨道能量（LUMO）。以前的机制研究使用IP与log krel比较、表格和图;该技术的不同之处在于它集中于空间效应与电子效应的分离，为了使数据点分布更广，便于可视化，需要更多的数据点和烯烃中具有各种电子效应的取代基，许多已研究和待研究的反应都是基础反应反应，这出现在本科有机化学教科书。令人惊讶的是，许多这些的相对反应性没有被研究，在所有，在某些情况下，错误的结论已经得出了使用太少的数据点或烯烃轴承取代基没有足够宽的范围内的电子效应。该项目将促进对这些基本反应的理解，并使化学家在合成中使用加成反应受益，因为当分子中存在一个以上双键时，相对反应性数据将能够预测位点选择性，但希望只在一个双键上进行反应。第二个目标是增加本地代表性不足的少数民族（URM）在化学中的参与。赠款的直接影响将是有限的，由于其短（一年）的时间，但随后的资金可以继续努力实现目标。

There are two proposal objectives. The first is to extend development of a technique, which has been developed by the PI, for correlating measurable characteristics in addition reactions of alkenes in order to gain information useful mechanistically and synthetically. The PI has applied the technique to enough systems to establish its viability, but its range is not determined. The technique enables (1) a procedure to determine relative magnitudes of steric and electronic effects in the rate-determining step, (2) a relatively simple way to predict the effects of substituents on reaction rates for synthetic purposes, and (3) a method to choose between alternative proposed reaction mechanisms in some cases. The simple technique to be extended is correlating (plotting) the logs of the relative rates (log krel) of the alkene addition reactions studied versus measurable characteristics of the alkenes, such as ionization potentials (IPs), their highest occupied molecular orbital energies (HOMOs), and in some cases their lowest unoccupied molecular orbital energies (LUMOs). There have been previous mechanistic studies making use of IP vs log krel comparisons, tables, and plots; this technique differs in that it focuses on the separation of steric versus electronic effects, and it requires more data points and substituents with a variety of electronic effects in the alkenes in order to spread out the data points and to facilitate visualization.Many of the reactions studied and to be studied are fundamental reactions, which appear in undergraduate organic chemistry texts. Surprisingly, the relative reactivities of many of these have not been studied at all, and in some cases, erroneous conclusions have been drawn by using too few data points or alkenes bearing substituents without a wide enough range of electronic effects. This project will advance the understanding of these fundamental reactions and benefit chemists using addition reactions in synthesis, because relative reactivity data will enable prediction of site selectivity when more than one double bond is present in the molecule, but it is desired to effect reaction at only one.The second objective is to increase the participation of native under-represented minorities (URMs) in chemistry. The direct influence of the grant will be limited due to its short (one year) duration, but subsequent funding can continue efforts toward the goals.