Elementary Steps Associated with Addition and Elimination Reactions

有机和高分子化学计划支持 海因茨博士和朱迪思·科赫博士的研究旨在 实验研究那些电子因素， 1，2-消除反应。 碱诱导消除a 氢和来自相邻碳的离去基团（X）是 这是一个非常复杂的过程， 和工业化学。 相反的过程，添加 HX穿过双键也是有机化合物中的主要反应。 化学及其各种机制的理解是一个 值得研究的重要课题。 更具体地说，碳和碳原子之间的质子转移反应， 氧气将被研究，并与卤化物的喷射进行比较， 碳负离子中间体是在酒精中产生的 醇盐溶液 饱和卤代烷与 醇盐导致质子从碳转移到氧， 与β-卤化物形成氢键碳负离子。 阴离子 可以通过损失β-卤化物来中和， 烯烃，或质子转移回碳（内部） return）。 后者是一个无反应过程，但它可以 通过研究初级动力学同位素效应， 与消除反应有关的氢。 第三 反应将导致一个新的碳负离子，是免费的接触 稳定化 如果阴离子在卤化物之前被中和 损失，该过程可以通过使用氘代醇来检测 为溶剂 α和β-碳同位素效应 也将测量与消除相关的数据。 氟代卤代烯烃与醇盐的反应生成游离的 碳负离子直接。 如果反应发生在酒精中， 失去卤化物或质子化以中和 阴离子 两种方法产生的负碳离子化学 将被比较。

The Organic and Macromolecular Chemistry Program supports the research of Drs. Heinz and Judith Koch, which aims at an experimental study of those electronic factors that influence 1,2-elimination reactions. The base induced elimination of a hydrogen and a leaving group (x) from an adjacent carbon is a very complicated process that has relevance to both biological and industrial chemistry. The reverse process, the addition of HX across a double bond is also a major reaction in organic chemistry and an understanding of its various mechanisms is an important topic worthy of study. More specifically, proton-transfer reactions between carbon and oxygen will be studied and compared to ejection of halide from carbanion intermediates that are generated in alcoholic alkoxide solutions. Reactions of saturated haloalkanes with alkoxide result in proton transfer from carbon to oxygen to form a hydrogen-bonded carbanion with a beta-halide. The anion can be neutralized by either a loss of the beta-halide to form an alkene, or transfer of the proton back to carbon (internal return). The latter is a no-reaction process, but it can be detected by the study of primary kinetic isotope effects of hydrogen associated with the elimination reaction. A third reaction would lead to a new carbanion that is free of contact stabilization. If that anion is neutralized prior to halide loss, the process can be detected by using a deuterated alcohol as solvent. Both alpha and beta-carbon isotope effects associated with the eliminations will also be measured. Reactions of fluorohaloalkenes with alkoxide generate a free carbanion directly. If reaction occurs in alcohol there is a competition between loss of halide or protonation to neutralize the anion. Chemistry of carbanions generated by both methods will be compared.