6-Endo-dig与5-exo-dig:利用高层次量子化学方法与第一,第二和第三排链接器探索激进循环化偏好
Abdulkader Baroudi1, Khaled Jaradat1, Amir Karton2
1College of Engineering and Technology, American University of the Middle East, Kuwait.
概括
这项研究使用先进的计算方法探索了hex-5-yn-1-yl基的循环反应. 结果显示,特定的链接器有利于6个末位数循环,为设计循环化合物提供了洞察力.
科学领域:
- 计算化学的计算化学
- 有机合成 有机合成
背景情况:
- 德温规则预测有机反应中的循环化路径.
- 了解影响激素循环的因素对于合成化学至关重要.
研究的目的:
- 研究具有多种链接器的hex-5-yn-1-yl基系的循环化偏好.
- 为循环化合物的合理设计提供基本见解.
- 开发一种用于预测循环化偏好的预测工具.
主要方法:
- 使用结合集群单,双和三倍 (CCSD(T)) 方法的高级计算建模.
- 使用SMD () -G4 (MP2) 热化学协议.
- 对立体电子效应,循环化障碍和内在障碍的分析.
主要成果:
- 具有B,Si,P,S,Ge,As和Se链接器的系统倾向于6个末位数循环,而不是C,O和N链接器.
- 循环化偏好主要受到5位元位数反应障碍物变化的影响.
- 在激进攻击轨迹角度和反应屏障高度之间发现了强烈的相关性,预测了循环化偏好.
结论:
- 计算建模揭示了基于链接类型的不同的循环化偏好.
- 基于激进的结构参数,开发了一种用于预测循环化偏好的新工具.
- 立体电子效应显著影响循环化通路,特别是在高价系统中.
相关概念视频
Radical Reactivity: Intramolecular vs Intermolecular
1.8K
Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an electrophilic alkene or vice versa. In such reactions, the radical and generally the alkene, which is also called the radical trap, are two different molecules. Additionally, for such intermolecular reactions to occur, the radical trap must be active, present in an excess concentration, and the radical starting material must have a weak...
1.8K
Radical Reactivity: Overview
2.1K
Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired...
2.1K
Radical Reactivity: Nucleophilic Radicals
2.1K
Radicals adjacent to electron-donating groups are called nucleophilic radicals. These radicals readily react with electrophilic alkenes. The SOMO–LUMO interactions are the driving force for the reaction, where the high-energy SOMO of the electron-rich, nucleophilic radicals interacts with the low-energy LUMO of the electron-deficient, electrophilic alkenes. Such SOMO–LUMO interactions are the basis of reactive radical traps, affecting the selectivity in radical reactions. For...
2.1K
Radical Chain-Growth Polymerization: Overview
2.5K
Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the reaction proceeds via a free-radical intermediate. The free radical is formed from radical initiators, which spontaneously generate free radicals by homolytic fission. Organic peroxides (such as dibenzoyl peroxide, as shown in Figure 1) or azo compounds are popular radical initiators. A low concentration ratio of radical initiator to monomer is...
2.5K
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
4.7K
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.
4.7K
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
10.3K
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.
10.3K


![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)