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相关概念视频

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
Electrodeposition01:08

Electrodeposition

788
Electrodeposition is a technique used to separate an analyte from interferents by electrochemical processes. Here, the analyte is a metal ion that can be deposited on an electrode immersed in the sample solution. The electrochemical setup consists of an anode and a cathode. When an electric current is applied to the setup, oxidation occurs at the anode. At the cathode, which consists of a large metal surface, metal ions undergo reduction and deposit onto the surface.
Electrodeposition can...
788
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

2.2K
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.
2.2K
Controlled-Potential Coulometry: Electrolytic Methods01:17

Controlled-Potential Coulometry: Electrolytic Methods

343
Controlled-potential coulometry, also known as potentiostatic coulometry, employs a three-electrode system in which the working electrode's potential is precisely regulated using a potentiostat. Platinum working electrodes are utilized for positive potentials, while mercury pool electrodes are favored for extremely negative potentials. The platinum counter electrode is separated from the analyte using a membrane or salt bridge to avoid interference in the analysis.
The chosen potential...
343
Sharpless Epoxidation02:57

Sharpless Epoxidation

4.4K
The conversion of allylic alcohols into epoxides using the chiral catalyst was discovered by K. Barry Sharpless and is known as Sharpless epoxidation. The use of a chiral catalyst enables the formation of one enantiomer of the product in excess. This chiral catalyst is mainly a chiral complex of titanium tetraisopropoxide and tartrate ester (specific stereoisomer). The stereoisomer used in the chiral catalyst dictates the formation of the enantiomer of the product. In other words, the use of...
4.4K
Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

2.0K
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
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相关实验视频

Updated: Oct 18, 2025

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction
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Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

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使用快速交替极性进行化学选择性电合成

Yu Kawamata1, Kyohei Hayashi1, Ethan Carlson1

  • 1Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.

Journal of the American Chemical Society
|October 1, 2021
PubMed
概括
此摘要是机器生成的。

通过快速交替极性 (rAP) 电解来实现碳化合物的化学选择性减少. 这种新的电化学方法提供了精确的控制,在复杂的有机合成中优于传统的直流电解和化学试剂.

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Simultaneous Multi-surface Anodizations and Stair-like Reverse Biases Detachment of Anodic Aluminum Oxides in Sulfuric and Oxalic Acid Electrolyte
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Reductive Electropolymerization of a Vinyl-containing Poly-pyridyl Complex on Glassy Carbon and Fluorine-doped Tin Oxide Electrodes
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Reductive Electropolymerization of a Vinyl-containing Poly-pyridyl Complex on Glassy Carbon and Fluorine-doped Tin Oxide Electrodes

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科学领域:

  • 有机化学
  • 电化学
  • 合成方法

背景情况:

  • 有机合成中的化学选择性传统上依赖于可调试试剂或保护组.
  • 电化学方法提供氧化还原控制,但与多个氧化还原活性位点作斗争.
  • 直流 (DC) 电解是标准的,而交流 (AC) 效应在准备合成中未得到充分研究.

研究的目的:

  • 开发一种新的电化学方法,用于精确的碳化合物的化学选择性降解.
  • 在复杂的有机合成中展示交流电的战略利用.
  • 展示快速交替极性的实用性,以克服合成挑战.

主要方法:

  • 使用方形波形传递快速交替极性 (rAP) 的电流.
  • 研究碳化合物的化学选择性降解.
  • 将rAP电解与直流电解和化学试剂进行比较.

主要成果:

  • 快速交替极性 (rAP) 电解可以控制碳化合物的化学选择性降解.
  • 使用直流电解或常规化学试剂无法复制观察到的rAP反应性.
  • 在合辅助去除和PROTAC合成中已被证明具有合成效用.

结论:

  • 快速交替极性 (rAP) 电解是一种强大的新工具,用于实现有机合成中的化学选择性.
  • 这种方法提供了独特的反应性和控制,扩大了电合成的范围.
  • 在古典合成问题和现代药物化学应用中,rAP电解具有显著的优势.