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氧化盐作为疏水性环氧化试剂:在烯酸环氧化过程中显著的疏水性导向选择性
Mark R Biscoe1, Ronald Breslow
1Department of Chemistry, Columbia University, New York, NY 10027, USA. rb33@columbia.edu
Journal of the American Chemical Society
|August 4, 2005
概括
通过选择性环氧化检测到过渡状态中的疏水性结合. 氧化盐在水中具有很高的选择性,表明化学反应中的疏水性相互作用.
科学领域:
- 有机化学 有机化学
- 物理化学 物理化学
背景情况:
- 研究过渡状态中的疏水相互作用对于理解反应机制至关重要.
- 选择性环氧化反应提供了一种探测这些相互作用的方法.
研究的目的:
- 在水溶液中的环氧化反应期间检测 cinnamates 在过渡状态中的疏水性结合.
- 为了比较不同氧化剂对这种疏水性结合的作用.
主要方法:
- 在水中使用疏水氧化剂选择性氧化 cinnamates 与crotonate.
- peracids 和 oxaziridinium 盐作为氧化剂的比较.
- 使用2-propanol抑制选择性.使用2-propanol抑制选择性.
- 通过使用oxone从iminium盐生成oxaziridinium离子.
主要成果:
- 检测到与氧化盐的疏水性结合,由水中的肉酸盐的高选择性证明.
- 这种选择性被2-propanol抑制,证实了相互作用的疏水性.
- 甲酸盐没有表现出这种选择性,这与计算的几何形状一致,防止基质-氧化剂堆叠.
- 观察到的疏水性诱导的选择性变化是显著的,超过了以前的原子转移反应中的变化.
结论:
- 氧化盐在水中环氧化过程中有效地显示过渡状态的疏水相互作用.
- 这些发现强调了疏水效应在化学反应和反应设计中的重要性.
- 预计观察到的基质选择性将扩展到聚反应中的位置选择性.
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