在高度反选择的Diaza-Cope重组反应中进行预组织
Hae-Jo Kim1, Hyunwoo Kim, Gamil Alhakimi
1Department of Chemistry, University of Toronto, 80 St. George Street, Toronto M5S 3H6, Canada.
Journal of the American Chemical Society
|November 25, 2005
概括
基质二烯酸二烯酸-Cope重新排列发生在高度预先组织的情况下,由键驱动. 这种立体选择性反应以立体化学的反转和优异的酶选择性进行,CD光谱和HPLC证实了这一点.
科学领域:
- 有机化学 有机化学
- 立体化学是一种立体化学.
- 物理化学 物理化学
背景情况:
- 迪亚扎-科普重组是有价值的合成工具.
- 了解反应机制和立体化学结果对于不对称合成至关重要.
研究的目的:
- 为了研究H-键定向的H-Cope重组的机制和立体化学过程.
- 为了确定反应的预组织程度和酶选择性.
主要方法:
- 用X射线晶体学来确定晶体结构.
- 激活分析以评估预组织.
- 循环二极化 (CD) 光谱法用于监测立体化学变化.
- 高性能液体染色学 (HPLC) 用于对酶选择性进行确定.
主要成果:
- 晶体结构和激活的数据显示,在H键定向的Diaza-Cope重组中,存在很高的预组织程度.
- CD光谱和HPLC数据表明立体化学的反转.
- 反应过程具有出色的反选择活性.
结论:
- 键的方向促进了一个高度预先组织的过渡状态,用于奇拉二次数的Diaza-Cope重排.
- 反应机制涉及对立体化学的反转.
- 实现了优异的酶选择性,突出显示了不对称合成的潜力.
相关概念视频
Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.


