相关实验视频

Updated: May 2, 2026

Utilization of Stop-flow Micro-tubing Reactors for the Development of Organic Transformations

Utilization of Stop-flow Micro-tubing Reactors for the Development of Organic Transformations

Published on: January 4, 2018

循环[4]乙烯的逐步化学降解:立体转化和选择性金属复合

Zheng Zhou¹, Yong Yang², Jianwei Liang¹

¹School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.

Precision chemistry

|January 31, 2025

概括

研究人员合成了一种应变的宏循环, [4]cyclo[4]helicenylene ([4]CH),并用金属减少它. 这揭示了电子吸收时的可逆立体化学转变,提供了改变环烯配置的新方法.

科学领域:

有机化学有机化学
超分子化学超分子化学
立体化学是一种立体化学.

背景情况:

高压力宏循环很难合成和表征.
烯及其宏环衍生物具有独特的结构和电子特性.
在复杂的分子架构中控制立体化学是研究的一个关键领域.

研究的目的:

为了合成和描述一种新的紧张宏循环, [4]cyclo[4]helicenylene ([4]CH).
为了研究 [4]CH 和其产生的离子物种的化学还原.
探索 [4]CH 在减少时发生的立体化学转化,并了解底层机制.

主要方法:

单宏环化用于合成 [4]CH.CH.
使用性金属 (Na和K) 的化学还原.
阳离子物种的分离和晶体学特征 (X射线衍射).
理论计算以了解立体化学转换.

主要成果:

成功合成了张力宏循环 [4]cyclo[4]helicenylene ([4]CH) 的成功合成.
证明了 [4]CH 的四电子还原过程,产生稳定的二,三和四.
在两个电子吸收时观察 (S,R,S,R) 和 (S,S,R,R) 配置之间的可逆立体化学转换.
结构变形和金属复杂化在减少状态.

结论:

该研究介绍了一种新型应变宏循环, [4]CH,及其还原化学.
发现了一种由电子吸收驱动的可逆立体化学转变,受电荷和金属复合的影响.
这项工作提出了一个新的策略,用于改变超越热方法的环烯配置.

更多相关视频

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Published on: November 9, 2019

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Published on: December 16, 2022

相关概念视频

Thermal and Photochemical Electrocyclic Reactions: Overview

Thermal and Photochemical Electrocyclic Reactions: Overview

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.

Thermal Electrocyclic Reactions: Stereochemistry

Thermal Electrocyclic Reactions: Stereochemistry

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.

Olefin Metathesis Polymerization: Overview

Olefin Metathesis Polymerization: Overview

Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...

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

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

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...

Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)

Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)

Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...

Pericyclic Reactions: Introduction

Pericyclic Reactions: Introduction

Pericyclic reactions are organic reactions that occur via a concerted mechanism without generating any intermediates. The reactions proceed through the movement of electrons in a closed loop to form a cyclic transition state, where rearrangement of the σ and π bonds yields specific products.
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic...