1,3-环二烯与单一氧的反应. 一个理论研究研究
Journal of the American Chemical Society
|July 18, 2001
概括
单片氧与1,3-环二烯通过一个渐进的二基通路反应,形成环二烯内氧化物. 反应的反应反应的反应
科学领域:
- 计算化学的计算化学
- 有机反应机制 有机反应机制
背景情况:
- 单点氧反应在有机合成和生物过程中至关重要.
- 了解单片氧与二烯的反应途径对于预测产物形成和反应动力学至关重要.
研究的目的:
- 使用高级计算方法阐明单片氧与1,3-环二烯的详细反应机制.
- 将理论预测与反应障碍和产品分布的实验数据进行比较.
主要方法:
- 密度函数理论 (DFT) 计算在B3LYP/6-31G (d) 层面进行几何和零点校正.
- 完成活动空间二级扰动理论 (CASPT2) 计算,在6-31G的 (12e,10o) 活动空间基础上设置 (12e,10o) 活动空间,用于准确的能量评估.
- 分析反应途径,过渡结构,中间体和能量障碍.
主要成果:
- 最初的添加通过一个逐步的二基路径进行,计算的激活屏障为6.5 kcal/mol,与实验结果 (5.5 kcal/mol) 一致.
- 这种反应也可以被视为一个非同步的协调过程,在第二个步骤中存在温度依赖的自由能量障碍.
- 确定了两种 ene 反应,一种是协调的,一种是通过 diradical 中间体进行的. 来自内氧化物的主要途径涉及O-O键裂解,导致1,4-二基和随后形成环氧和二氧化物产物.
结论:
- 反应机制很复杂,涉及阶段性激进和协调的途径,协调性受温度的影响.
- 计算结果准确地预测了关键激活障碍,并提供了对各种产品的形成的见解,包括内氧化物,内引物,环氧基和二氧化物.
- 该研究强调了产品比率对替代剂效应的敏感性,为控制相关系统中的反应结果提供了基础.
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