相关实验视频

Updated: May 10, 2025

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

使用双酸的酸催化乙烯甲基碳化:联体的立体化学如何影响催化剂的活动

Robert Franke¹, Jiali Liu², Helfried Neumann³

¹Evonik Oxeno GmbH & Co. KG, Evonik Oxeno GmbH & Co. KG, Paul-Baumann-Str. 1, 45772, Marl, GERMANY.

Chemistry (Weinheim an der Bergstrasse, Germany)

|April 23, 2025

概括

基拉尔双酸P-连接体,特别是py^tbpx (B),增强了催化乙烯甲基氧碳化. 种族性py^tbpx (B) 由于连接体稳定性和内置基因效应,显示出最高的活动.

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.
一致性催化剂的同质性

背景情况:

双酸P连接体在同质催化中起着至关重要的作用,影响反应结果.
乙烯甲基基化是生产甲基酸盐的重要工业过程.

研究的目的:

为了研究乙烯 methoxycarbonylation 中的双酸 P- 连接体的二聚体控制.
为了比较复合体与LIKATphos (py) 和Lucite (d) 连接体的催化活性.

主要方法:

系统的实验和计算调查.
用racemic, meso和epimerized py^tbpx (B) 和 d^tbpx (A) 连接体对 Pd-复合物的催化活性评估.

主要成果:

种族性py^tbpx (B) 呈现出最高的催化活性;d^tbpx (A) 显示出最低的催化活性;meso py^tbpx (B) 显示出中等活性.
活动顺序与CO协调能与B的化相关,甲醇化作为A的速度限制步骤.
与p^tbpx (B) 相比,与化物复合物的稳定性和CO复合物的可变性相关的性py^tbpx (B) 的增强活性.

结论:

P-配方体的二聚体形式显著影响乙烯 methoxycarbonylation 中的催化活性.
py^tbpx (B) 联体的内置基因效应有助于比d^tbpx (A) 联体具有更高的活性.

关键词:

密度函数理论密度函数理论催化剂周期的催化剂周期双立体体 ( diastereomers) 是一种多立体体.一致的催化剂.methoxycarbonylation 的含量是什么意思

更多相关视频

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

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Published on: June 24, 2022

相关概念视频

Regioselectivity and Stereochemistry of Hydroboration

Regioselectivity and Stereochemistry of Hydroboration

A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...

Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry

Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry

Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.

Regioselectivity of Electrophilic Additions-Peroxide Effect

Regioselectivity of Electrophilic Additions-Peroxide Effect

In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. The free radical reaction mechanism involves three stages: initiation, propagation, and termination.

Diels–Alder Reaction Forming Cyclic Products: Stereochemistry

Diels–Alder Reaction Forming Cyclic Products: Stereochemistry

The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.

Directing and Steric Effects in Disubstituted Benzene Derivatives

Directing and Steric Effects in Disubstituted Benzene Derivatives

When disubstituted benzenes undergo electrophilic substitution, the product distribution depends on the directing effect of both substituents. When the directing effects of both substituents reinforce each other, a single product is obtained. For example, bromination of p-nitrotoluene occurs ortho to the methyl group and meta to the nitro group, which is the same position, resulting in a single product. However, if the directing effects of the two groups oppose each other, the...