Murugesan Kathiravan, Bheeter Charles Beromeo, Linnebank Pim R, Spannenberg Anke, Reek Joost N H, Jagadeesh Rajenahally V, Beller Matthias
Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Str. 29a, 18059, Rostock, Germany.
Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
ChemSusChem. 2019 Jul 19;12(14):3363-3369. doi: 10.1002/cssc.201900784. Epub 2019 Jun 18.
A convenient protocol for stereodivergent hydrogenation of alkynes to E- and Z-alkenes by using nickel catalysts was developed. Simple Ni(NO ) ⋅6 H O as a catalyst precursor formed active nanoparticles, which were effective for the semihydrogenation of several alkynes with high selectivity for the Z-alkene (Z/E>99:1). Upon addition of specific multidentate ligands (triphos, tetraphos), the resulting molecular catalysts were highly selective for the E-alkene products (E/Z>99:1). Mechanistic studies revealed that the Z-alkene-selective catalyst was heterogeneous whereas the E-alkene-selective catalyst was homogeneous. In the latter case, the alkyne was first hydrogenated to a Z-alkene, which was subsequently isomerized to the E-alkene. This proposal was supported by density functional theory calculations. This synthetic methodology was shown to be generally applicable in >40 examples and scalable to multigram-scale experiments.
开发了一种使用镍催化剂将炔烃立体选择性氢化为E-烯烃和Z-烯烃的便捷方法。简单的Ni(NO₃)₂·6H₂O作为催化剂前体形成活性纳米颗粒，其对几种炔烃的半氢化有效，对Z-烯烃具有高选择性（Z/E>99:1）。加入特定的多齿配体（三膦、四膦）后，所得分子催化剂对E-烯烃产物具有高选择性（E/Z>99:1）。机理研究表明，Z-烯烃选择性催化剂是多相的，而E-烯烃选择性催化剂是均相的。在后一种情况下，炔烃首先氢化为Z-烯烃，随后异构化为E-烯烃。该提议得到了密度泛函理论计算的支持。这种合成方法在40多个实例中显示出普遍适用性，并且可扩展到多克规模的实验。
