5748-38-9Relevant academic research and scientific papers
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.
Agglomeration of Pd0 nanoparticles causing different catalytic activities of Suzuki carbonylative cross-coupling reactions catalyzed by PdII and Pd0 immobilized on dopamine-functionalized magnetite nanoparticles
Long, Yu,Liang, Kun,Niu, Jianrui,Tong, Xin,Yuan, Bing,Ma, Jiantai
, p. 2988 - 2996 (2015/04/14)
Solvent-dispersible magnetite nanoparticles (Fe3O4) end-functionalized with amino groups were successfully prepared by a facile one-pot template-free method to immobilize PdII and Pd0 using a metal adsorption and reduction procedure. They were characterized by TEM, XRD, XPS, FT-IR and VSM. Interestingly, the PdII catalyst exhibited better catalytic activity for carbonylative cross-coupling reactions than the Pd0 catalyst. According to the catalytic activities of a variety of arylboronic acids and aryl iodides catalyzed by two kinds of Pd catalysts, the proposed reaction mechanism of Suzuki carbonylative cross-coupling reactions using the Pd catalyst was also inferred. More importantly, agglomeration of Pd0 nanoparticles was obviously observed in the TEM images of the catalysts after reactions. Therefore, agglomeration of Pd0 nanoparticles should be considered as a significant reason for different catalytic activities of the reactions catalyzed by immobilized PdII and Pd0 catalysts. Furthermore, the PdII catalyst revealed high efficiency and stability during recycling stages.
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.
Stabilizing PdII on hollow magnetic mesoporous spheres: A highly active and recyclable catalyst for carbonylative cross-coupling and Suzuki coupling reactions
Niu, Jianrui,Liu, Mengmeng,Wang, Peng,Long, Yu,Xie, Miao,Li, Rong,Ma, Jiantai
, p. 1471 - 1476 (2014/05/06)
A hollow magnetic mesoporous silica sphere (HMMS) catalyst has been synthesized using polystyrene microspheres as a chemical template. The catalyst was characterized by TEM, XRD, XPS and vibrating sample magnetometry (VSM). The catalyst shows high activity for the carbonylative cross-coupling reaction of aryl iodides with arylboronic acids and Suzuki coupling reactions. The newly developed catalyst is easy to recover by magnetic separation from the liquid phase of the reaction and can be recycled. Importantly, the catalyst revealed high efficiency and high stability under the reaction conditions and during recycling stages.
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.
Palladium-catalyzed reactions of arylindium reagents prepared directly from aryl iodides and indium metal
Papoian, Vardan,Minehan, Thomas
supporting information; experimental part, p. 7376 - 7379 (2009/05/07)
(Chemical Equation Presented) Treatment of aryl iodides with indium metal in the presence of lithium chloride leads to the formation of an organoindium reagent capable of participating in cross-coupling reactions under transition-metal catalysis. Combination with aryl halides in the presence of 5 mol % Cl2Pd(dppf) furnishes biaryl compounds in good yields; similarly, reaction with acyl halides or allylic acetates/carbonates in the presence of 5-10 mol % palladium catalyst leads to arylketones and allylic substitution products, respectively, in moderate yields. The reactions are tolerant of the presence of protic solvents, and ~85% of the indium metal employed can be recovered by reduction of the residual indium salts with zinc(0).
A new palladium catalyzed protocol for atom-efficient cross-coupling reactions of?triarylbismuths with aryl halides and triflates
Rao, Maddali L.N.,Jadhav, Deepak N.,Banerjee, Debasis
, p. 5762 - 5772 (2008/09/21)
A new palladium catalyzed protocol for an atom-efficient cross-coupling reaction of triarylbismuths with aryl halides and triflates has been described. The palladium catalytic system with Cs2CO3 base was found to be very efficient in DMA solvent to furnish excellent yields of cross-coupled functionalized biaryls in short reaction times.
Palladium-Catalyzed Stille Couplings with Fluorous Tin Reactants
Hoshino, Masahide,Degenkolb, Peter,Curran, Dennis P.
, p. 8341 - 8349 (2007/10/03)
A new class of "fluorous" aryl tin reactants was investigated for use in the Stille coupling. Fluorous compounds partition into a fluorocarbon (fluorous) phase in a fluorous/organic extraction. The coupling of tris[(perfluorohexyl)ethyl]phenyl tin [(C6F13CH2CH2)3SnPh] with bromobenzene occurs smoothly in DMF/THF (1/1) at 80 °C in the presence of a catalytic amount of PdCl2(PPh3)2 and 3 equiv of LiCl. Partitioning between CH2Cl2 and FC-72 (a mixture of perfluorohexanes) provided biphenyl in 90% yield from the organic phase and tris[(perfluorohexyl)ethyl]tin chloride in > 90% yield from the fluorous phase. The tin chloride was reacted with phenylmagnesium bromide to regenerate the starting tin reactant. A study to optimize reaction conditions is described, and the scope of the method is illustrated with 20 coupling reactions. The beneficial effect of lithium choride is an unusual feature of the reaction, but it also promotes the formation of some fluoroalkyl-coupled products. These can be suppressed by adding CuI. The paper describes a prototypical example of how to render a tin reactant fluorous. This process should be advantageous in small- and large-scale synthesis, as well as in automated synthesis.
