Determination of Transition Structure Geometries for Reactions at Nonstereogenic Atoms

在有机动力学项目的支持下， 利用“内环限制试验”来研究 允许在缺乏的原子上发生反应的几何形状 立体化学特征在这种方法中， 非立体异构杂原子的取代在其中 成键基团和离去基团通过链连接。 分子内环所需的大小 转移限制了可用的反应几何形状。附图理解 与其他机械工具相结合， 方法应提供重要的详细信息 关于过渡态的几何形状， 原子转移反应 在氧、氮、卤素， 硫和氢将被研究。机制涉及 协调的、联合的和/或分离的步骤将被 评估每一个案例。其他机械探针，例如， 交叉实验、动力学研究和测定 分子内和分子间同位素效应，将用于 通过应用内环的补充结果 限制性试验

With support from the Organic Dynamics Program, Dr. Beak will utilize the "endocyclic restriction test" to investigate allowed geometries for reactions that occur at atoms which lack stereochemical features. In this approach, transfer of non-stereogenic heteroatoms is performed in systems wherein the bond forming group and the leaving group are joined by a chain. The size of the endocyclic ring required for intramolecular transfer limits the available reaction geometry. When taken in combination with other mechanistic tools, application of this approach should provide important, detailed information regarding the geometry of the transition states in atom-transfer reactions. The geometries of reactions at oxygen, nitrogen, halogen, sulfur, and hydrogen will be investigated. Mechanisms involving concerted, associative and/or dissociative steps are to be evaluated for each case. Other mechanistic probes, e.g., crossover experiments, kinetic studies, and determinations of intra- and intermolecular isotope effects, will be used to supplement results obtained via application of the endocyclic restriction test.