在PIII/PV合成循环中循环氧化添加,连接物转化和减少消除
Soohyun Lim1, Alexander T Radosevich1
1Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
Journal of the American Chemical Society
|September 10, 2020
概括
这项研究引入了使用新型三胺的合成循环来替代C-F键. 该循环涉及氧化添加,配体转化和还原性消除,表明主要组位点的关键机械步骤.
科学领域:
- 有机金属化学
- 主要组化学
- 合成有机化学
背景情况:
- 在合成化学中,Aryl C-F键的激活仍然是一个重大挑战.
- 开发用于C-F键功能化的催化循环对于获得新型化化合物至关重要.
- 了解C-X键替代所涉及的基本步骤是反应机制研究的基础.
研究的目的:
- 报告一个合成循环的C-F替代.
- 在中心研究氧化添加,配体转化和还原性消除的机制性途径.
- 提供完整的C-X替代步骤三元组的特征示例.
主要方法:
- 一种Cs-对称三胺的合成和表征 (1).
- 三胺 (1) 与素 (ArF-F) 的反应以获得C-F的氧化添加.
- 使用DIBAL-H的连接物转化,以替换P-替代物为化物.
- 酸的热分解 (1·[H][ArF) 来再生催化剂并研究C-H的减少消除.
- 实验和计算研究以阐明反应机制.
主要成果:
- 使用三胺 (1) 建立了C-F替代的合成循环.
- 氧化添加C-F发生在与 perfluoroarenes反应时,产生酸 (1·[F][ArF).
- 与DIBAL-H生成的酸 (1·[H][ArF) 的连接物转化.
- 酸的加热导致 (1) 通过 ArF-H 的降解消除.
- 实验和计算数据证实了C-H减少的协同但高度异步的机制.
结论:
- 这项研究成功地证明了在主要基部位进行基替代的完整合成循环.
- 良好的介质和产品提供了对基C-X替代的基本步骤的宝贵见解.
- 这些发现有助于对C-F键激活和功能化反应的机制理解.
相关概念视频
Cycloaddition Reactions: Overview
3.2K
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.
3.2K
Olefin Metathesis Polymerization: Overview
2.4K
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...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
2.4K
Cycloaddition Reactions: MO Requirements for Thermal Activation
4.0K
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.
4.0K
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
2.9K
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...
2.9K
Pericyclic Reactions: Introduction
9.5K
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...
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic...
9.5K
Aldehydes and Ketones to Alkenes: Wittig Reaction Mechanism
4.6K
The Wittig reaction, which converts aldehydes or ketones to alkenes using phosphorus ylides, proceeds through a nucleophilic addition‒elimination process.
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
4.6K

![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)
