Efficient Intermolecular [2 + 2 + 2] Alkyne Cyclotrimerization in Aqueous Medium Using a Ruthenium(IV) Precatalyst
作者:Victorio Cadierno、Sergio E. García-Garrido、José Gimeno
DOI:10.1021/ja066552k
日期:2006.11.1
bis(allyl)-ruthenium(IV) complex [Ru(eta3:eta3-C10H16)(mu-Cl)Cl}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) was found to catalyze efficiently the [2 + 2 + 2] cyclization of terminal and internal alkynes in aqueous medium.
Evaluating the Effect of Catalyst Nuclearity in Ni-Catalyzed Alkyne Cyclotrimerizations
作者:Sudipta Pal、Christopher Uyeda
DOI:10.1021/jacs.5b04990
日期:2015.7.1
reactions of the dinickel catalyst with hindered silyl acetylenes enable characterization of the alkyne complex and the metallacycle that are implicated as catalytic intermediates. Based on these experiments and supporting DFT calculations, the role of the dinuclear active site in promoting regioselective alkyne coupling is discussed. Together, these results demonstrate the utility of exploring nuclearity
介绍了对 Ni 催化的炔低聚反应中催化剂核效应的评估。一种双核配合物,具有由萘啶二亚胺 (NDI) 配体支持的 Ni-Ni 键,可促进快速和选择性的环三聚反应,形成 1,2,4-取代的芳烃产物。带有相关 N 供体螯合物(2-亚氨基吡啶、2,2'-联吡啶或 1,4,-二氮杂二烯)的单镍同类物活性明显较低,并产生复杂的产物混合物。二镍催化剂与受阻甲硅烷基乙炔的化学计量反应能够表征作为催化中间体的炔络合物和金属环。基于这些实验和支持 DFT 计算,讨论了双核活性位点在促进区域选择性炔烃偶联中的作用。一起,
Concerted Catalysis by Adjacent Palladium and Gold in Alloy Nanoparticles for the Versatile and Practical [2+2+2] Cycloaddition of Alkynes
A Pd‐Au alloy efficiently catalyzed the [2+2+2] cycloaddition of substituted alkynes. Whereas monometallic Pd and Au catalysts were totally ineffective, Pd‐Au alloy nanoparticle catalysts with a low Pd/Au molar ratio showed high activity to give the corresponding polysubstituted arenes in high yields. A variety of substituted alkynes participated in various modes of cycloaddition under Pd‐Au alloy
N,N,N′-Trimethylallylthiourea promotes the intermolecularPauson–Khandreaction with alkynes in the presence of Co2(CO)8 and moderate pressure of CO followed by thiourea elimination allowing the formation of methylenecyclopentenone derivatives.
Exploiting Carbonyl Groups to Control Intermolecular Rhodium-Catalyzed Alkene and Alkyne Hydroacylation
作者:Thomas J. Coxon、Maitane Fernández、James Barwick-Silk、Alasdair I. McKay、Louisa E. Britton、Andrew S. Weller、Michael C. Willis
DOI:10.1021/jacs.7b05713
日期:2017.7.26
Rh-catalyzed intermolecular alkene and alkynehydroacylation reactions. By using cationic rhodium catalysts incorporating bisphosphine ligands, efficient and selective reactions are achieved for β-amido, β-ester, and β-keto aldehyde substrates, providing a range of synthetically useful 1,3-dicarbonyl products in excellent yields. A correspondingly broad selection of alkenes and alkynes can be employed