γ‐di‐aryl propanones. The salient feature of this strategy involves the sequential hydride transfer, regiospecific condensation, regiospecific dearylation, and aromatization under metal‐free reaction conditions. The synthesis of unsymmetricallysubstituted triphenylenes by oxidative coupling of the synthesized 1,2,4‐triaryl benzenes has also been demonstrated.
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.
Iron-Catalyzed Cyclotrimerization of Terminal Alkynes by Dual Catalyst Activation in the Absence of Reductants
作者:Davide Brenna、Matteo Villa、Tim N. Gieshoff、Fabian Fischer、Marko Hapke、Axel Jacobi von Wangelin
DOI:10.1002/anie.201705087
日期:2017.7.10
metals under mild conditions is at the heart of sustainable synthesis. The cyclotrimerization of alkynes is a valuable atom‐efficient reaction in organic synthesis that is enabled by several metal catalysts, including iron. This study reports an effective iron‐catalyzed cyclotrimerization for the regioselective synthesis of 1,2,4‐substituted arenes (1 mol % catalyst, toluene, 20 °C, 5 min). A dual activation
Can the Ti(OiPr)<sub>4</sub>/<i>n</i>BuLi combination of reagents function as a catalyst for [2+2+2] alkyne cyclotrimerisation reactions?
作者:Gabriela Siemiaszko、Yvan Six
DOI:10.1039/c8nj04931a
日期:——
Catalysis of the cyclotrimerisation of alkynes with the Ti(OiPr)4/nBuLi system was studied, leading to the development of a particularly convenient and reliable protocol. This method allows the [2+2+2] cycloadditionreaction to proceed within a few minutes under microwave conditions, with generally good selectivity from a variety of aromatic and aliphatic alkynes.
研究了用Ti(OiPr)4 / n BuLi体系催化炔烃的环三聚反应,从而开发了一种特别方便和可靠的方案。该方法允许[2 + 2 + 2]环加成反应在微波条件下在几分钟之内进行,对各种芳族和脂族炔烃的选择性通常都很好。
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,