Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

Cycloaddition Reactions: MO Requirements for Photochemical Activation01:12

Cycloaddition Reactions: MO Requirements for Photochemical Activation

2.2K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.2K
Cycloaddition Reactions: Overview01:16

Cycloaddition Reactions: Overview

2.9K
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.
2.9K
Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

1.9K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
1.9K
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

2.5K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.5K
Cycloaddition Reactions: MO Requirements for Thermal Activation01:16

Cycloaddition Reactions: MO Requirements for Thermal Activation

3.8K
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
3.8K
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

2.1K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.1K

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

Chain Length Dependence of Chemically Controlled Reactions in Polymerization.

Journal of the American Chemical Society·2026
Same author

Dithioketal Polymers Via Radical Polymerization of γ-Dithiobutyrolactone.

Angewandte Chemie (International ed. in English)·2026
Same author

Spontaneous trisulfide metathesis in polar aprotic solvents.

Nature chemistry·2026
Same author

Thermal imaging using sulfur polymer optics.

Nature communications·2026
Same author

Efficient Removal of Short-Chain Perfluoroalkyl Substances by Cavity-Directed Aggregation in a Molecular Cage Host.

Angewandte Chemie (International ed. in English)·2026
Same author

Efficient and stable catalytic hydrolysis of perfluorocarbon enabled by SO<sub>2</sub>-mediated proton supply.

Nature communications·2026

相关实验视频

Updated: Oct 7, 2025

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
07:12

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

Published on: July 17, 2020

6.4K

使用理论和光谱学调节光化驱动的循环添加

Jiao Yu J Wang1, Mitchell T Blyth1, Michael S Sherburn1

  • 1Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia.

Journal of the American Chemical Society
|January 7, 2022
PubMed
概括

本研究使用计算和实验方法探索光化/迪尔斯-阿尔德 (PEDA) 反应序列. PEDA序列与碳烯具有广泛的适用性,而硫烯和胺则具有独特的反应性挑战和机遇.

科学领域:

  • 有机光化学
  • 计算化学
  • 反应机制研究

背景情况:

  • 光化/迪尔斯-阿尔德反应是一种强大的合成工具.
  • 了解PEDA序列的范围和局限性对于其应用至关重要.
  • 之前的研究没有全面研究影响PEDA反应性的因素.

研究的目的:

  • 进行PEDA序列的广泛调查.
  • 检查各种替代剂和反应伙伴对PEDA反应的影响.
  • 探索相应反应途径的潜力,如光化/单体添加 (PECA).

主要方法:

  • 使用SMD溶解的M06-2X/6-31+G{d,p) 计算.
  • 通过实验性紫外线光谱来支持计算结果.
  • 研究了一组具有不同电子和结构性质的20个prodienes和20个dienophiles的测试组.

主要成果:

  • PEDA序列对碳基prodienes中的大多数替代模式具有耐受性.
  • 由于系统间的交叉和相互竞争的原子转移途径,硫衍生物的反应速度较慢.
  • 在激发状态下,基胺表现出更高的障碍物,但如果克服,可以轻易地经历PEDA.
  • 迪尔斯-阿尔德反应的范围比之前报告的更广泛,可能涉及乙烯和富电子的基.

更多相关视频

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
11:44

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Published on: October 18, 2018

26.9K
Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
10:35

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

Published on: May 29, 2018

8.9K

相关实验视频

Last Updated: Oct 7, 2025

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
07:12

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

Published on: July 17, 2020

6.4K
Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
11:44

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Published on: October 18, 2018

26.9K
Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
10:35

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

Published on: May 29, 2018

8.9K
  • 预计一氧化碳 (CO) 将经历一个简单的 (4+1) 基质添加 (PECA),而不是一个 [4+2] 基质添加.

    • 结论:

    • PEDA序列是一种多功能反应,具有广泛的适用性,特别是对于碳烯.
    • 硫和胺衍生物具有独特的反应性,可以在特定条件下加以利用.
    • 新的光化/切莱特罗普添加 (PECA) 序列提供了一个无金属的路径,用于化环.