Ligand-accelerated non-directed C–H functionalization of arenes
作者:Peng Wang、Pritha Verma、Guoqin Xia、Jun Shi、Jennifer X. Qiao、Shiwei Tao、Peter T. W. Cheng、Michael A. Poss、Marcus E. Farmer、Kap-Sun Yeung、Jin-Quan Yu
DOI:10.1038/nature24632
日期:2017.11
challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C–H functionalization with arene as the limiting reagent. This protocol is compatible with
Two Pd(II)–NHC complexes bearing benzimidazole and pyridine groups have been successfully prepared and fully characterized by NMR and X‐ray diffraction analysis. The structure of palladium complexes are a typical square‐planar with palladium surrounded by two pairs of trans‐arranged benzimidazole and carbene ligands. The Pd–NHC complexes have been proved to be a highly efficient catalyst for the Mizoroki–Heck
Palladium on Polydopamine: Its True Potential in Catalytic Transfer Hydrogenations and Heck Coupling Reactions
作者:Attila Kunfi、Vivien Szabó、Ágnes Mastalir、Imre Bucsi、Miklós Mohai、Péter Németh、Imre Bertóti、Gábor London
DOI:10.1002/cctc.201700609
日期:2017.8.23
which may be owing to their reaction with the catalyst support leading to catalyst deactivation. By using magnetic Fe3O4@Pd–polydopamine system, facilitated catalyst recovery and reuse for five consecutive cycles without considerable loss of activity in nitro‐group reduction. The efficiency of the catalyst in Heck reactions was comparable to that in transferhydrogenation, however, no catalytic activity
报道了Pd-聚多巴胺和磁性Fe 3 O 4 @ Pd-聚多巴胺催化剂在催化转移加氢反应和Heck芳基化反应中的应用。尽管发现羰基化合物的还原不太普遍,但可以有效地将带有给电子和吸电子取代基的多种芳香族硝基化合物还原成相应的苯胺。在后一种情况下,仅芳族酮可被还原为相应的醇,而醛底物不受影响,这可能是由于它们与催化剂载体反应导致催化剂失活。通过使用磁性Fe 3 O 4@ Pd-聚多巴胺系统可促进催化剂的回收和连续使用五个周期,而不会导致硝基还原活性的显着降低。Heck反应中催化剂的效率与转移氢化中的效率相当,但是,在这种情况下再利用时未观察到催化活性,这很可能是金属浸出的结果。我们还探索了串联Heck反应/催化转移加氢序列,但是,这两个反应在应用条件下均显示出有限的相容性。
Synthesis of new Pro-PYE ligands as co-catalysts toward Pd-catalyzed Heck–Mizoroki cross coupling reactions
[H2L1][OTf]2–[H2L5][I]2 from two new precursors, [P3Et][I] and [P2Me][CF3SO3]. The structure elucidations of the compounds were confirmed by multinuclear NMR (1H, 13C), FT-IR and by single crystal XRD techniques. Theoretical DFT studies were carried out to get better insight into the electronic levels and structural features of all the molecules. These synthesized new Pro-PYE ligands [H2L1][OTf]2–[H2L5][I]2 were
目前的研究工作描述了从两种新前体 [P 3 Et ][I] 和[H 2 L 1 ][OTf] 2 –[H 2 L 5 ][I] 2合成五种含有吡啶胺的新配体[P 2 Me ][CF 3 SO 3 ]。化合物的结构通过多核NMR ( 1 H, 13 C)、FT-IR 和单晶XRD 技术得到证实。进行理论 DFT 研究是为了更好地了解所有分子的电子能级和结构特征。这些合成的新 Pro-PYE 配体 [H 2 L 1 ][OTf] 2 –[H 2 L 5 ][I] 2被发现作为 Pd(CH 3 CO 2 ) 2向 Heck–的助催化剂具有显着活性。宽底物范围的 Mizoroki 偶联反应顺序为 [H 2 L 1 ][OTf] 2 ≫ [H 2 L 2 ][OTf] 2 > [H 2 L 3 ][OTf] 2 > [H 2 L 4 ] [OTf] 2 > [H 2 L 5 ][I] 2。