Pursuing <i>E</i>-Selective Olefin Metathesis: Tuning Steric and Electronic Properties of S,N-Chelated Ruthenium Alkylidenes
作者:Immanuel Reim、Giovanni Occhipinti、Karl W. Törnroos、Vidar R. Jensen
DOI:10.1021/acs.organomet.3c00522
日期:2024.4.8
investigated N-heterocyclic carbene (NHC) ligands that are less bulky than Me2IMes. We also hypothesized that a S,N ligand with a less nucleophilic nitrogen atom than that of indole might improve catalyst stability. However, catalyst Ru7, bearing 2-sulfidophenyltrifluoromethylsulfonylamide L2 instead of L1, was not significantly more productive or E-selective than Ru5. Whereas Ru nanoparticles formed on
在第一个Z-选择性复分解催化剂被报道十多年后,直接从1-烯烃选择性形成E-烯烃仍然是一个未解决的问题。硫代吲哚内酯基复合物Ru5 (Ru( L1 )( Me 2 IMes )(py)(=CHR); Me 2 IMes = 1,3-二甲基-4,5-二甲基咪唑-2-亚基; py =吡啶;R = 2-噻吩基;L1 = 7-硫代吲哚-1-化物)最初通过密度泛函理论(DFT)计算预测为E选择性。然而,Ru5被证明具有较低的催化活性,并且由于异常受阻的产物解离而具有中等的Z选择性 [Reim 等人,2017]。顶部。加塔尔。 2022, 65, 448]。为了降低解离势垒,我们在这里研究了比Me 2 IMes体积更小的 N-杂环卡宾 (NHC) 配体。我们还假设具有比吲哚更少亲核氮原子的 S,N 配体可能会提高催化剂稳定性。然而,带有2-硫基苯基三氟甲基磺酰胺L2而不是L1的催化剂Ru7并不比Ru5显着更高的产率或E选择性。虽然