N‐Heterocyclic Carbenes: Useful Ligands for the Palladium‐Catalysed Direct C5 Arylation of Heteroaromatics with Aryl Bromides or Electron‐Deficient Aryl Chlorides
Pd-N-heterocyclic carbene complexes have been prepared and employed for palladium-catalysed directarylation of heteroaromatic derivatives by using aryl halides. These catalyst precursors promote the coupling of challenging aryl halides such as deactivated or congested arylbromides and also activated aryl chlorides. This procedure employs only 1 mol-% of an air-stable palladium complex. This is a
Synthesis, characterization and catalytic behaviour of a palladium complex bearing a hydroxy-functionalized N-heterocyclic carbene ligand
作者:Annaluisa Mariconda、Fabia Grisi、Chiara Costabile、Salvatore Falcone、Valerio Bertolasi、Pasquale Longo
DOI:10.1039/c3nj01281f
日期:——
The synthesis of a new stable palladium(II) complex (3) featuring an unsymmetrical substituted N-heterocyclic carbene (NHC) ligand with a pendant hydroxy-functionalized group was successfully accomplished via transmetalation of the corresponding bis-NHC silver(I) complex (2). Solid-state structures of both 2 and 3 were determined by single-crystal X-ray diffraction. The catalytic behaviour of 3 in
Palladium(<scp>ii</scp>)/N-heterocyclic carbene (NHC) catalyzed direct C–H arylation of heteroarenes with different aryl bromides and chlorides
作者:Donia Bensalah、Lamjed Mansour、Mathieu Sauthier、Nevin Gürbüz、Ismail Özdemir、Waleed S. Koko、Rafik Gatri、Naceur Hamdi
DOI:10.1039/d3nj04209j
日期:——
The growing interest of industry in the field of bi(hetero)arene compounds motivated us to synthesize these compounds via a homogeneous catalytic route using Pd PEPPSI-type complexes through direct arylation. In this study, new Pd PEPPSI-type complexes bearing NHC spectator ligands were synthesized and characterized using spectroscopic techniques, such as 1HNMR, 13C NMR, MS spectrometry, FTIR spectroscopy
工业界对双(杂)芳烃化合物领域日益增长的兴趣促使我们使用 Pd PEPPSI 型配合物通过直接芳基化通过均相催化路线合成这些化合物。在本研究中,使用光谱技术合成并表征了带有 NHC 观察配体的新型 Pd PEPPSI 型配合物,例如1 HNMR、13 C NMR、MS 光谱、FTIR 光谱和元素分析(PEPPSI = 吡啶增强预催化剂制备稳定和引发) 。所有合成的 Pd( II ) 配合物都是稳定的。这些配合物的催化性能在呋喃、2-乙酰基噻吩和N-甲基吡咯-2-甲醛衍生物与多种(杂)芳基卤化物的直接C 5单芳基化中进行了评估。人们发现这种对环境有吸引力的方法能够耐受芳基卤化物上的多种官能团,并且在 1 mol% 催化剂负载量存在下在 150 °C 下持续 2 小时获得了良好的产率。此外,含有吸电子基团的底物的转化率高于含有给电子基团的取代基的转化率。
Plausible PEPPSI catalysts for direct C–H functionalization of five-membered heterocyclic bioactive motifs: synthesis, spectral, X-ray crystallographic characterizations and catalytic activity
salts were synthesized as asymmetric N-heterocyclic carbene (NHC) precursors. Nine novel palladium complexes with the general formula [PdX2(NHC)(pyridine)] were synthesized using benzimidazolium salts in the PEPPSI (Pyridine Enhanced Precatalyst Preparation, Stabilization and Initiation) theme. All synthesized Pd(ii) complexes are stable. The synthesized compounds were thoroughly characterized by respective
bi(hetero)arenes in ongoing medicinal and industrial research fields promotes their efficient synthesis by Pd-PEPPSI-bearing NHC spectator ligands encapsulated as site-selective direct C-H functionalization agents. Eight new asymmetric N-heterocyclic carbenes ligands and their plausible pyridine-assisted Pd (II) complexes are reported in this work. The synthesized compounds were thoroughly characterized