相关实验视频

Updated: Jun 13, 2025

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Published on: July 30, 2017

在温和条件下的单基化合物中催化C ((sp³) -H激活:一项综合实验和理论机制研究

Tatiana E Kokina¹, Nikita A Shekhovtsov¹, Alexey V Tkachev²

¹Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.

|September 13, 2024

概括

在温和条件下,Palladium催化sp3 C-H激活单烯联体发生迅速. 这项研究揭示了一种新的机制,涉及连接体去和HCl喷射,提供了一种更有效的合成途径.

科学领域:

有机金属化学有机金属化学
催化剂是一种催化剂.
有机合成有机合成

背景情况:

催化C-H激活在有机合成中至关重要.
激活sp3 C-H 键,特别是在像单烯这样的复杂分子中,仍然具有挑战性.
现有的方法往往需要严苛的条件,限制了它们的适用性.

研究的目的:

报告一种基于单烯的化合物中罕见的催化 sp3 C-H 键激活实例.
研究一种新的,快速和温和的C-H激活反应途径.
用理论计算来阐明这种转换的机制.

主要方法:

PdCl2与一种 (+) - 3 - 烯基联结体 (HL) 的反应.
由此产生的[PdLCl]复合体的特征.
密度函数理论 (DFT) 计算用于研究联体脱质和反应机制.

主要成果:

通过催化sp3 C-H激活成功合成了[PdLCl]复合体.
在温和的条件下,反应迅速进行,与典型的C-H激活反应不同.
DFT计算提供了对机制的洞察,涉及同时协调,结合和HCl喷射.

结论:

已经实现了一种新且高效的催化sp3 C-H激活单烯配体.
反应机制是由驱动的,通过喷射HCl.
这一发现为复杂有机分子中C-H功能化提供了一个新的,更温和的合成策略.

关键词:

计算化学是一种计算化学.在 C−H 激活过程中.金属循环的使用方法帕拉是什么意思?帕拉是什么意思?类物质是指类物质.

更多相关视频

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Published on: March 20, 2014

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis

Published on: February 16, 2020

相关概念视频

Cycloaddition Reactions: MO Requirements for Thermal Activation

Cycloaddition Reactions: MO Requirements for Thermal Activation

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.

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.

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...

Photochemical Electrocyclic Reactions: Stereochemistry

Photochemical Electrocyclic Reactions: Stereochemistry

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

Reduction of Alkenes: Catalytic Hydrogenation

Reduction of Alkenes: Catalytic Hydrogenation

Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...