炔烃的立体选择性加氢构成构造立体烯烃的关键方法之一。大多数常规方法利用贵金属和有毒金属催化剂。这项研究涉及一种由工业化学品乙酰丙酮铁(II)和氢化二异丁基铝组成的简单催化剂,该催化剂能够在接近环境条件(1-3 bar H2、30°C,5 mol%[Fe] )。既不需要复杂的催化剂制备也不需要添加配体。机理研究(动力学中毒,X射线吸收光谱法,TEM)强烈表明了小铁簇和颗粒催化剂的运行。
Copper-NHC-Mediated Semihydrogenation and Hydroboration of Alkynes: Enhanced Catalytic Activity Using Ring-Expanded Carbenes
作者:Jonathan W. Hall、Darcy M. L. Unson、Paul Brunel、Lee R. Collins、Mateusz K. Cybulski、Mary F. Mahon、Michael K. Whittlesey
DOI:10.1021/acs.organomet.8b00467
日期:2018.9.24
tert-butoxide complexes bearing five-, six-, and seven-membered ring N-heterocycliccarbenes, prepared by protonolysis of (NHC)CuMes with tBuOH, have been used as catalytic precursors in the semihydrogenation of alkynes with silanes/tBuOH and the hydroboration of alkynes with HBPin. Both processes proceed with high regioselectivity and show enhancements with six- and seven-membered ring carbenes.
由(NHC)CuMes与t BuOH质子分解制得的一系列带有五元,六元和七元环N-杂环卡宾的二配位叔丁醇铜配合物已被用作苯甲酸半加氢反应的催化前体。炔烃与硅烷/ t BuOH的混合,以及炔烃与HBPin的硼氢化。两种方法都具有较高的区域选择性,并显示六元和七元环卡宾具有增强作用。
Stereoselective Chromium‐Catalyzed Semi‐Hydrogenation of Alkynes
作者:Bernhard J. Gregori、Michal Nowakowski、Anke Schoch、Simon Pöllath、Josef Zweck、Matthias Bauer、Axel Jacobi von Wangelin
DOI:10.1002/cctc.202000994
日期:2020.11.5
very little applications as hydrogenation catalysts. Here, we report a Cr‐catalyzed semi‐hydrogenation of internal alkynes to the corresponding Z‐alkenes with good stereocontrol (up to 99/1 for dialkyl alkynes). The catalyst comprises the commercial reagents chromium(III) acetylacetonate, Cr(acac)3, and diisobutylaluminium hydride, DIBAL−H, in THF. The semi‐hydrogenation operates at mild conditions
Metal‐Catalyzed Remote Functionalization of ω‐Ene Unsaturated Ethers: Towards Functionalized Vinyl Species
作者:Guo‐Ming Ho、Lina Judkele、Jeffrey Bruffaerts、Ilan Marek
DOI:10.1002/anie.201802434
日期:2018.7.2
The combined ruthenium‐catalyzed chain walking with the nickel‐catalyzed cross‐coupling reaction of ω‐alkenyl ethers provide a unique entry to functionalized vinyl species. This transformation illustrates the power and flexibility of remote functionalization by demonstrating the compatibility of two independent reactions involving unrelated sites.
Catalyst Deactivation by β‐Hydride Elimination: Olefin and Alkyne Insertion into Arenido–Nickel(II) Bonds
作者:Monika M. Lindner、Udo Beckmann、Eva Eichberger、Guido J. Reiß、Wolfgang Kläui
DOI:10.1002/ejic.200901179
日期:2010.6
been elucidated by investigating the reactions of such complexes with aliphatic unsaturated compounds like olefins and alkynes. We have shown that the double or triple bond, respectively, inserts into the nickel–carbon bond followed by β-hydride elimination resulting in aryl-substituted olefins and allenes, which have been identified by means of GC/MS. The remaining nickel forms a bis(N,O-chelate ligand)nickel
包含 N,O-螯合配体的方形平面芳烃-(三苯基膦)镍 (II) 配合物 (3) 是一氧化碳/乙烯共聚反应的催化剂。通过研究此类配合物与脂肪族不饱和化合物(如烯烃和炔烃)的反应,阐明了催化剂失活的途径。我们已经表明,双键或三键分别插入镍-碳键,然后β-氢化物消除,产生芳基取代的烯烃和丙二烯,这些已通过 GC/MS 进行鉴定。剩余的镍形成双(N,O-螯合配体)镍络合物,其晶体结构已确定。镍原子由两个配体以方形平面方式配位。