Hydrido-Cobalt Catalyst as a Selective Tool for the Dimerisation of Arylacetylenes: Scope and Theoretical Studies
作者:Sandrine Ventre、Etienne Derat、Muriel Amatore、Corinne Aubert、Marc Petit
DOI:10.1002/adsc.201300486
日期:2013.9.16
A simple hydrido‐cobaltcomplex efficiently catalyses the highly regio‐ and stereoselective dimerisation of various terminal arylacetylenes under mild conditions. The corresponding (E)‐1,4‐enynes are obtained as sole isomers with good to excellent yields. DFT calculations revealed that the reaction proceeds via a CH activation/hydrocobaltation pathway.
in toluene at 145 °C for 2 h to give the corresponding head-to-head dimers in good to excellent yields (54 to 99%) with high E-selectivity (67 : 33 to 83 : 17 E/Z). Both strongly electron-donating and electron-withdrawing groups are compatible with this procedure. The bidentate phosphine (dppe) ligand exhibits better catalytic activity than the bidentate amine (DMEDA). The aliphatic acetylene fails to
在DMEDA或dppe的存在下,使用FeCl 3和KO t Bu实现了末端芳基炔烃的区域选择性二聚,以产生共轭烯炔。反应在145°C的甲苯中平稳进行2小时,以高至E的选择性(67:33至83:17 E / Z)以良好至优异的收率(54%至99%)得到相应的头对头二聚体)。强供电子基团和吸电子基团均与该程序相容。双齿膦(dppe)配体显示出比双齿胺(DMEDA)更好的催化活性。脂肪族乙炔无法在该催化体系下反应,这表明叔丁醇钾通过阳离子-π相互作用和pi-pi相互作用激活了芳基乙炔的共轭体系。自由基抑制剂(galvinoxyl或TEMPO)可完全抑制反应。使用FeCl 2代替FeCl 3作为催化剂,仅苯基乙炔以良好的收率提供了相应的头对头二聚体。FeCl 3催化芳基炔烃和FeCl 2的二聚反应的机理途径 已经提出了苯基乙炔的催化二聚作用。
Iron catalyzed highly regioselective dimerization of terminal aryl alkynes
Iron can catalyze head-to-head dimerization of terminal aryl alkynes to give the corresponding (E) selective conjugated enynes in high yields. A variety of substituted aryl acetylenes underwent smooth dimerization using catalytic FeCl3 and DMEDA in the presence of KOtBu.
One-Pot Desilylation/Dimerization of Terminal Alkynes by Ruthenium and Acid-Promoted (RAP) Catalysis
作者:Chiara Pasquini、Mauro Bassetti
DOI:10.1002/adsc.201000347
日期:2010.10.4
promoted by the (p-cymene)ruthenium dichloride dimer/acetic acid system [RuCl2(p-cymene)]2/AcOH} can be performed starting from the trimethylsilylethynyl derivatives (12 substrates), deprotected in situ, to afford 1,4-disubstituted 1-en-3-ynes with high regio- and (E)-stereoselectivity, at room temperature. The extension of this unprecedented two-reaction sequence to a diyne substrate affords a fluorene-based
New platinum(0) complexes of the general formula [(NHC)Pt(dvtms)] (dvtms=1,3‐divinyltetramethyldisiloxane) containing bulkyN‐heterocycliccarbene (NHC) ligands were prepared, characterized, and found to be catalytically active in the fully regio‐ and stereoselective dimerization of terminal acetylenes.