氨基基化试剂 - - 结构和动态
H J Reich1, W S Goldenberg, B O Gudmundsson
1Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
Journal of the American Chemical Society
|August 17, 2001
概括
五环氨基基合甲基试剂表现出强烈的合,并在以太溶剂中形成稳定的二元体. 与模型系统相比,这些二极体显示出独特的化异构体和增强的热力学和运动稳定性.
科学领域:
- 有机金属化学 有机金属化学
- 解决状态结构分析
- 化学的化学性质
背景情况:
- 阿里利试剂在有机合成中至关重要.
- 了解它们的聚合和溶解是控制反应性的关键.
- 氨基团的化显著影响试剂的行为.
研究的目的:
- 为了阐明五分环氨基基化酸试剂的溶液结构.
- 研究各种乙烯溶剂和辅溶剂 (TMEDA,PMDTA,HMPA) 对这些结构的影响.
- 为了比较稳定性和聚合性行为与模型酸系统.
主要方法:
- 采用了多核核核磁共振光谱 (同位素丰富6Li和15N) 的方法.
- 动态NMR研究被用来确定相互转换率和激活能量.
- 射线晶体学提供了固态结构确认.
主要成果:
- 所有研究的试剂都具有强烈的合物,并在富含THF的溶剂中形成稳定的二次体.
- 确定和表征了三种不同的二极体的化异构体 (A,B,C).
- 这些二极体比模型酸化合物具有更大的热力学和运动稳定性.
- 该o-methoxy模拟物 (4) 显示由于硬质阻碍而减少二聚化,但可以与HMPA形成三重离子.
结论:
- 氨基化强烈稳定了二度的阿里利物种.
- 涉及氨基脱协调和环旋转的动态过程控制着同位素相互转换.
- 合甲基二元体合甲基二元体代表强大而稳定的有机金属结构.
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