Solubilized zirconocene dihydride as a promotor of alkene coupling reactions
摘要:
The THF-soluble bis(methoxyethyl)zirconocene dihydride 3 displayed novel reactivity patterns and was used to reductively couple alkenes, dienes, and enynes. A plausible mechanism involves the formation of a 14-electron zirconium(II) and zirconacyclopentane species. (C) 2000 Published by Elsevier Science Ltd.
Carbonylation of ethylenically unsaturated compounds
申请人:Eastham Graham Ronald
公开号:US09334227B2
公开(公告)日:2016-05-10
A process for the carbonylation of ethylenically unsaturated compounds including vinyl esters and a process for the production of 3-hydroxy propanoate esters or acids. The process comprises reacting said compound with carbon monoxide in the presence of a source of hydroxyl groups and of a catalyst system. The catalyst system is obtainable by combining: (a) a metal of Group 8, 9 or 10 or a compound thereof: and (b) a bidentate ligand of general formula (I): X1(X2)-Q2-A-R—B-Q1-X3(X4).
PROBLEM TO BE SOLVED: To provide a process for the carbonylation of ethylenically unsaturated compounds including vinyl esters and a process for the production of 3-hydroxypropanoate esters or 3-hydroxypropanoic acids.SOLUTION: The process comprises reacting the compound with carbon monoxide in the presence of a source of hydroxyl groups and of a catalyst system. The catalyst system is obtainable by combining: (a) a metal of Group 8, 9 or 10 or a compound thereof: and (b) a bidentate ligand of general formula (I): X(X)-Q-A-R-B-Q-X(X).
Development of Effective Bidentate Diphosphine Ligands of Ruthenium Catalysts toward Practical Hydrogenation of Carboxylic Acids
作者:Shota Yoshioka、Ke Wen、Susumu Saito
DOI:10.1246/bcsj.20210023
日期:2021.5.15
represents one of the most ideal reduction methods for utilizing abundant CAs as alternative carbon and energy sources. However, systematic studies on the effects of metal-to-ligand relationships on the catalytic activity of metal complex catalysts are scarce. We previously demonstrated a rational methodology for CA hydrogenation, in which CA-derived cationic metal carboxylate [(PP)M(OCOR)]+ (M = Ru and Re;
将羧酸(CA)加氢成醇代表了最理想的还原方法之一,该方法可利用丰富的CA作为替代碳和能源。但是,关于金属与配体之间的关系对金属络合物催化剂催化活性的影响的系统研究很少。我们之前展示了一种合理的CA加氢方法,其中CA衍生的阳离子金属羧酸盐[(PP)M(OCOR)] +(M = Ru和Re; P =一个P配位)用作CA自诱导的CA氢化的催化剂原型。本文中,我们报告了有关如何通过修饰分子Ru催化剂的双齿二膦(PP)配体结构来实现更高催化活性的系统试验研究。连接两个P原子以及PP配体的P原子上取代的Ar基的碳链发生剧烈变化,并且从预催化剂Ru(acac)3诱导了活性Ru催化剂被广泛调查。结果,(PP)Ru催化剂的活性和耐用性与其他分子式Ru催化剂体系(包括我们的原始Ru催化剂)相比大大提高了。结果证实了我们改进催化剂性能的方法,这将有利于CA自诱导CA加氢的进一步发展。
Phosphine Ligands in the Palladium-Catalysed Methoxycarbonylation of Ethene: Insights into the Catalytic Cycle through an HP NMR Spectroscopic Study
作者:Verónica de la Fuente、Mark Waugh、Graham R. Eastham、Jonathan A. Iggo、Sergio Castillón、Carmen Claver
DOI:10.1002/chem.200903158
日期:——
backbone, ligands 7 and 9, containing four‐ and six‐membered ring backbones giving more active systems. The acid used as co‐catalyst has a strong influence on the activity, with excess trifluoroacetic acid affording the highest conversion, whereas excess methyl sulfonic acid inhibits the catalytic system. An in operando NMR spectroscopic mechanistic study has established the catalytic cycle and resting
Various five-membered cyclic ketones were prepared from 1,4-dihaloalkanes and potassium tetracarbonylferrate(2—) in moderate to high yields. However, the yields of six- or seven-membered cyclic ketones from the corresponding dihalides were rather low.