1,2,3-triazines的反向电子需求迪尔斯-阿尔德反应:明显的替代剂对反应性和循环添加范围的影响
Erin D Anderson1, Dale L Boger
1Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Journal of the American Chemical Society
|July 9, 2011
概括
这项研究表明,C5替代剂显著增强了1,2,3-triazines的反向电子需求Diels-Alder反应. 这种可预测的调制扩大了它们作为异环亚的合成效用和范围.
科学领域:
- 有机化学 有机化学
- 异环化学 异环化学
- 反应机制 反应机制
背景情况:
- 反向电子需求的迪尔斯-阿尔德反应在有机合成中至关重要.
- 1,2,3-triazines是已知的,但较少探索的异环亚二烯.
- 了解替代剂效应是优化反应性的关键.
研究的目的:
- 系统地研究C5替代剂对1,2,3-triazine逆电子需求反应的影响. 迪尔斯-阿尔德反应.
- 评估这些替代剂如何影响循环添加反应性和区域选择性.
- 为了确定1,2,3-triazines作为合成应用的多功能异环亚.
主要方法:
- 系统合成和表征1,2,3-triazines与不同的C5替代剂.
- 对反向电子需求的实验调查 迪尔斯-阿尔德反应与多种不同的二氧化物.
- 分析反应动力学和区域选择性,以确定替代剂效应.
主要成果:
- C5替代剂极大地影响了1,2,3-triazines的循环添加反应性.
- 观察到的反应顺序是:CO(2) Me > Ph > H.
- 替代物增强或维持区域选择性,同时显著扩大反应范围.
- 1,2,3-氨酸被证明是强大的异环亚氨酸.
结论:
- C5替代的1,2,3-triazines在反向电子需求的迪尔斯-阿尔德反应中非常有效.
- 这种方法提供了对现有的异环亚 (1,2,4-和1,3,5-酸) 的补充方法.
- 可预测的反应性调制扩大了合成的可能性和对各种异环系统的访问.
相关概念视频
[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 Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.
Diels–Alder Reaction: Characteristics of Dienes
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
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.
Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
Diels–Alder Reaction: Characteristics of Dienophiles
In a Diels–Alder reaction, the diene is usually an electron-rich system and acts as a nucleophile, whereas the dienophile is electron-deficient and functions as an electrophile. Much like the diene, the nature of the dienophile significantly impacts the outcome of the reaction.
Characteristics of Dienophiles
Generally, the best dienophiles are alkenes containing electron-withdrawing substituents such as carbonyl, nitrile, and nitro groups. The feasibility of a Diels–Alder reaction depends on...
Characteristics of Dienophiles
Generally, the best dienophiles are alkenes containing electron-withdrawing substituents such as carbonyl, nitrile, and nitro groups. The feasibility of a Diels–Alder reaction depends on...


