5748-38-9Relevant articles and documents
Mechanism insight and scope of PEPPSI-catalyzed cross-coupling reaction between triarylbismuth and arylbromide
Cassirame, Bénédicte,Condon, Sylvie,Pichon, Christophe
, p. 94 - 102 (2016/10/04)
In this paper we report the first cross-coupling reaction of Ar3Bi with Ar'X mediated by Pd-NHC complexes by keeping the ability of Ar3Bi to transfer the three aryl moieties. Investigations were carried out in order to minimize the quantity of the side product Ar-Ar coming from the conversion of Ar3Bi. The results showed that PEPPSI IPr was a good catalyst precursor. Efforts were focussed on the rule of each additive such as PPh3 and the base. It was notably found that the presence of PPh3 (ratio PEPPSI IPr/PPh3: 1/1) was essential to keep the process efficient. Therefore NHC-Pd-PPh3 has been assumed as being the catalytic species. Under the optimized reaction conditions the concomitant formation of the undesired biaryl side product was restricted to its inherent formation consecutive to the reduction of the catalyst precursor to Pd(0). In a last study, the scope and the limitation of the new catalytic methodology were examined and a large range of unsymmetrical biaryl compounds Ar-Ar’ bearing various substituents from strongly electron-donating to electron-withdrawing ones have been prepared and fully characterized.
Palladium(II) complexes of 1,2,4-triazole-based N-heterocyclic carbenes: Synthesis, structure, and catalytic activity
Turek, Jan,Panov, Illia,Semler, Miloslav,Stepnicka, Petr,De Proft, Frank,Padelkova, Zdenka,Ruzicka, Ales
supporting information, p. 3108 - 3118 (2014/07/08)
Six palladium(II) complexes bearing three different triazole-based N-heterocyclic carbene (NHC) ligands, [1-tert-butyl-4-{2-[(N,N-dimethylamino) methyl]phenyl}-3-phenyl-1H-1,2,4-triazol-4-ium-5-ide, 1-tert-butyl-4-(2- methoxyphenyl)-3-phenyl-1H-1,2,4-triazol-4-ium-5-ide, and 1-tert-butyl-4-(4- methylphenyl)-3-phenyl-1H-1,2,4-triazol-4-ium-5-ide], were synthesized and fully characterized. NMR spectroscopy and X-ray diffraction analysis revealed that the amino-group-substituted NHC ligand is coordinated in bidentate fashion, forming a monocarbene chelate complex with an additional intramolecular Pd ← N bond with the nitrogen donor atom. The 4-methylphenyl- and 2-methoxyphenyl-substituted NHC ligands coordinate as C-monodentate donors, forming simple biscarbene Pd(II) complexes. The evaluation of the catalytic performance in the Suzuki-Miyaura cross-coupling reaction revealed very promising performance of the intramolecularly coordinated monocarbene complexes under relatively mild conditions even in direct comparison with the commercially available PEPPSI catalyst. In contrast, the biscarbene complexes proved inactive in this catalytic process. According to theoretical calculations (EDA and NOCV analysis), functionalization of the 1,2,4-triazole-based NHC with the 2-[(N,N-dimethylamino)methyl]phenyl group has a significant effect on the stability of the NHC-metal bond.
Preparation of recoverable Fe3O4/PPy-PdII catalysts for carbonylative cross-coupling reactions
Niu, Jianrui,Xie, Miao,Zhu, Xiaohang,Long, Yu,Wang, Peng,Li, Rong,Ma, Jiantai
, p. 247 - 252 (2014/07/07)
The hierarchical porous Fe3O4/PPy-PdII catalyst has been synthesized using Fe3O4 microspheres both as chemical template and oxidant source under sonication. The catalyst characterized by TEM, XRD, FT-IR, XPS and vibrating sample magnetometry (VSM). The catalyst showed high reactivity for the carbonylative cross-coupling reaction of aryl iodides with arylboronic acids. This newly developed catalyst could be easily recovered and revealed high efficiency and high stability under the reaction conditions and during recycling stages.
