Stereoselective Alkyne Hydrogenation by using a Simple Iron Catalyst
作者:Bernhard J. Gregori、Felix Schwarzhuber、Simon Pöllath、Josef Zweck、Lorena Fritsch、Roland Schoch、Matthias Bauer、Axel Jacobi von Wangelin
DOI:10.1002/cssc.201900926
日期:2019.8.22
stereoselective hydrogenation of alkynes constitutes one of the key approaches for the construction of stereodefined alkenes. The majority of conventional methods utilize noble and toxic metal catalysts. This study concerns a simple catalyst comprised of the commercial chemicals iron(II) acetylacetonate and diisobutylaluminum hydride, which enables the Z-selective semihydrogenation of alkynes under near ambient
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。
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
unsymmetrically 1,2-disubstituted alkynes with alkylzirconocene complexes, which are generated by hydrozirconation of alkenes. High regioselectivity is achieved when the two substituents of the alkynes are sterically different enough, giving rise to the regio- and stereodefinedtrisubstitutedalkenes.
Asymmetric Synthesis of Axially Chiral 2-Aminobiaryls by Rhodium-Catalyzed Benzannulation of 1-Arylalkynes with 2-(Cyanomethyl)phenylboronates
作者:Fei Xue、Tamio Hayashi
DOI:10.1002/anie.201806324
日期:2018.8.6
Asymmetric benzannulation of 1‐arylalkynes, where the aryl group is an ortho‐substituted aromatic group, with 2‐(cyanomethyl)phenylboronate was catalyzed by a rhodium complex coordinated with a chiral diene ligand to give high yields of axially chiral 2‐aminobiaryls with greater than 90 % ee.
Efficient Synthesis of 2-Substituted Indoles Based on Palladium(II) Acetate/Tri-tert-butylphosphine-Catalyzed Alkynylation/Amination of 1,2-Dihalobenzenes
作者:Zhen-Yu Tang、Qiao-Sheng Hu
DOI:10.1002/adsc.200606022
日期:2006.5
A simple, efficientpalladium(II) acetate/tri-tert-butylphosphine-catalyzedindolesynthesis from o-alkynylhalobenzenes, readily available from 1,2-dihalobenzenes, has been achieved in good to excellent yields. A one-pot, Pd(OAc)2/t-Bu3P-catalyzed sequential reaction from 1-chloro-2-iodobenzene, phenylacetylene and amines has also been achieved in good yields.
由邻-炔基卤代苯简单,有效的乙酸钯(II)/三叔丁基膦催化的吲哚合成,可以容易地从1,2-二卤代苯获得,收率良好至极佳。还已经以良好的产率实现了由1-氯-2-碘苯,苯乙炔和胺进行的一锅法Pd(OAc)2 / t - Bu 3 P催化的顺序反应。