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

Base-Catalyzed Ring-Opening of Epoxides02:26

Base-Catalyzed Ring-Opening of Epoxides

8.4K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
8.4K
Acid-Catalyzed Ring-Opening of Epoxides02:24

Acid-Catalyzed Ring-Opening of Epoxides

7.3K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
7.3K
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration02:34

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

8.4K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
8.4K
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)01:16

Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)

2.6K
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
2.6K
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH301:11

ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3

6.0K
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
6.0K
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

2.0K
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.
2.0K

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

Highly Selective and Modular Assembly of Densely Substituted Tetrahydrofurans.

Journal of the American Chemical Society·2026
Same author

Restoration of Spirulina growth in recycled medium via a combined strategy of nutrient supplementation and flocculation treatment.

Bioresource technology·2026
Same author

Reactions of Strained Cycloalkanes with Radicals and Diradicaloids: The Roles of Diradical Character and Strain Release.

Journal of the American Chemical Society·2026
Same author

Linoleic acid accelerates osteoarthritis progression in male rats by targeting iron-sulfur clusters to drive ferroptosis in chondrocytes.

Nature communications·2026
Same author

Aloin suppresses cancer cell growth via autophagy-promoted NEDD8 de-NEDDylation to target GPX4 for ferroptosis induction.

Bioorganic chemistry·2026
Same author

Sex-specific associations between prenatal PM<sub>2.5</sub> exposure and reproductive hormone levels in offspring aged 1-2 years: A prospective birth cohort study.

Environmental research·2026

相关实验视频

Updated: Jun 27, 2025

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
12:19

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

8.5K

碳酸辅助的环开放

Zengrui Cheng1, Haoran Xu2, Zhibin Hu1

  • 1State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191 Beijing, China.

Journal of the American Chemical Society
|May 1, 2024
PubMed
概括

研究人员开发了一种新型的碳辅助策略,用于环开放,将酸转化为多联酶. 这一突破简化了合成并扩大了碳素化学应用.

更多相关视频

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions
04:38

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Published on: July 28, 2022

3.0K
Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
06:46

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Published on: June 21, 2017

7.4K

相关实验视频

Last Updated: Jun 27, 2025

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
12:19

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

8.5K
Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions
04:38

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Published on: July 28, 2022

3.0K
Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
06:46

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Published on: June 21, 2017

7.4K

科学领域:

  • 有机化学
  • 合成化学
  • 催化剂

背景情况:

  • 甲脱氧化和C-H功能化已经进步,但甲环开放仍然具有挑战性.
  • 芳香化合物的高结合解离和共振能阻碍了环开放反应.

研究的目的:

  • 引入一种新的碳酸辅助策略,以有效地打开环.
  • 从散装的化学物质中合成具有附加价值的多连接链分子.
  • 提供从酸中获得多联酶的简化途径.

主要方法:

  • 开发一种碳辅助反应,用于环开放.
  • 密度函数理论 (DFT) 计算以阐明反应机制.
  • 该方法应用于复杂分子和化环系统的后期修改.

主要成果:

  • 展示了一种新的碳酸辅助环开放策略.
  • 成功地将各种酸衍生物转化为有价值的多联酶.
  • 在简单的条件下实现合成,避免多步前体和交叉合反应.
  • 通过DFT计算验证了该机制,强调其广泛应用的潜力.

结论:

  • 碳化合物辅助策略为环开放提供了新的途径.
  • 这种方法简化了多联合酶的合成,克服了传统方法的局限性.
  • 这些发现预计将刺激在合成复杂的合分子中使用.