613-33-2Relevant articles and documents
Eisch,Wilcsek
, p. C21 (1974)
N-heterocyclic carbenes: III. N-heterocyclic carbene ligands based on abietane in Suzuki-Miyaura reaction
Glushkov,Valieva,Maiorova,Baigacheva,Gorbunov
, p. 230 - 235 (2011)
By reactions of N-alkyl- and N-arylimidazoles with methyl 12-bromoacetyldehydroabietate a series of unsymmetrically substituted chiral imidazolium bromides with the abietane fragment was synthesized. The salts obtained were suggested as new N-heterocyclic carbene ligands in the Suzuki-Miyaura reaction.
The study and application of three highly porous hyper-crosslinked catalysts possessing similar catalytic centers
Bi, Jiajun,Dong, Yahao,Meng, Di,Zhu, Dajian,Li, Tao
, p. 183 - 190 (2019)
Three new catalysts, in which salen ligands were successfully locked in knitting network polymers, were synthesized through the Friedel-Crafts reaction. As a result, the catalysts possessed high specific surface area as high as 512 m2/g with micro-/mesoporous structures, and showed layered morphologies. Owing to the high surface area, the abundant active centers and pores, the Poly-salen-a-Pd(II) displayed superior performance in the Suzuki-Miyaura coupling reaction of various substrates. In particular, the effect from similar catalytic centers for the catalytic properties and stability was investigated by a series of experiments and analyses such as thermogravimetric analysis (TGA), scanning and transmission electron microscopies (SEM and TEM), X-ray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS). Notably, three catalysts showed high activity in the reaction, and displayed excellent performance in the hot filtration experiments. This strategy is very cost-effective and convenient, which was highly suggestive to diverse professional audiences in a wide range of heterogeneous catalyst design and application.
Uemura et al.
, p. 390 (1971)
Kasahara et al.
, p. 183 (1974)
Catalytic activation of a single C-F bond in trifluoromethyl arenes
Dang, Hester,Whittaker, Aaron M.,Lalic, Gojko
, p. 505 - 509 (2016)
Synthetic methods for the direct transformation of ArCF3 to ArCF2R would enable efficient diversification of trifluoromethyl arenes and would be of great utility in medicinal chemistry. Unfortunately, the development of such methods has been hampered by the fundamental properties of C-F bonds, which are exceptionally strong and become stronger with increased fluorination of the carbon atom. Here, we describe a method for the catalytic reduction of ArCF3 to ArCF2H through a highly selective activation of a single C-F bond. Mechanistic studies reveal separate reaction pathways for the formation of ArCF2H and ArCH3 products and point to the formation of an unexpected intermediate as the source of the unusual selectivity for the mono-reduction.
Iron(II) Corrole Anions
Caulfield, Kenneth P.,Conradie, Jeanet,Arman, Hadi D.,Ghosh, Abhik,Tonzetich, Zachary J.
, (2019)
Reduction of [Fe(TPC)(THF)] (TPC = trianion of 5,10,15-Triphenylcorrole) with KC8 generates the iron(II) corrole anion, K(THF)2[FeII(TPC)] (3a). Compound 3a represents the first example of an isolated and crystallographically characterized corrole complex of divalent iron. The compound adopts an intermediate-spin state (S = 1), displaying square-planar geometry about the iron atom. All-electron density functional theory (OLYP and B3LYP) calculations with STO-TZP basis sets indicate two essentially equienergetic d electron configurations, dxy2dz22dxz1dyz1 (occupation 1) and dxy2dz21dxz1dyz2 (occupation 2), as likely contenders for the ground state of [FeII(TPC)]-, with the optimized geometry of the former in slightly better agreement with the low-Temperature X-ray structure. Solutions of 3a react with carbon monoxide to afford the low-spin (S = 0) complex, [Fe(TPC)(CO)]-, whereas introduction of oxygen at-78 °C leads to a putative O2 adduct, [Fe(TPC)(O2)]-, which decays rapidly even at low temperatures. Treatment of 3a with organic electrophiles results in formal oxidative addition to give both iron(III) and iron(IV) corrole species. With iodomethane, [Fe(TPC)Me] is produced, illustrating the first instance of alkyl ligand coordination in an iron corrole complex.
Palladium-bisimidazol-2-ylidene complexes as catalysts for general and efficient Suzuki cross-coupling reactions of aryl chlorides with arylboronic acids
Zhang, Chunming,Trudell, Mark L.
, p. 595 - 598 (2000)
A series of bisimidazolium salts 1-6 were synthesized and evaluated as precursors to bisimidazol-2-ylidene ligands in palladium-catalyzed Suzuki cross-coupling reactions with aryl chlorides and arylboronic acids. The bisimidazolium salt 6 was found to be superior over imidazolium and other bisimidazolium salts affording high yields of biaryl products employing a wide variety of substrates. (C) 2000 Elsevier Science Ltd.
Phosphonate functionalized N-heterocyclic carbene Pd(II) complexes as efficient catalysts for Suzuki-Miyaura cross coupling reaction
Bhattacharyya, Bagmita,Gogoi, Nayanmoni,Guha, Ankur Kanti,Kalita, Amlan Jyoti
, (2021)
A N-heterocyclic carbene (NHC) ligand, L1 bearing a pendant phosphonate ester group is used to prepare two new NHC-Pd(II) complexes, [Pd(L1)2I2] (1) and [Pd(L1)(py)I2] (2) (py = pyridine). Hydrolysis of phosphonate ester group in 2 results another Pd(II)-NHC complex, [Pd(L2)(py)I2] (3) where a phosphonic acid group is attached to the NHC ligand L2. All the three complexes are characterized by analytical and spectroscopic studies while the molecular structures of 1-2 are also determined by single crystal X-ray diffraction measurement. The catalytic efficacies of 1-3 in Suzuki-Miyaura cross coupling reactions of aryl halides and aryl boronic acid are investigated. DFT calculations were performed to decipher the role phosphonate ester or phosphonic acid substituents on the catalytic efficacy.
A Kumada Coupling Catalyst, [Ni{(Ph2P)2N(CH2)3Si(OCH3)3-P,P′}Cl2], Bearing a Ligand for Direct Immobilization onto Siliceous Mesoporous Molecular Sieves
Stamatopoulos, Ioannis,Giannitsios, Dimitrios,Psycharis, Vassilis,Raptopoulou, Catherine P.,Balcar, Hynek,Zukal, Arno?t,Svoboda, Jan,Kyritsis, Panayotis,Vohlídal, Ji?í
, p. 3038 - 3044 (2015)
The ligand-exchange reaction between [Ni(PPh3)2Cl2] and (Ph2P)2N(CH2)3Si(OCH3)3 afforded the novel NiII complex [Ni{(Ph2P)2N(CH2)3Si(OCH3)3-P,P′}Cl2] (1) in which the square-planar NiP2Cl2 coordination sphere contains a four-membered Ni-P-N-P ring. Comparison of the structure of 1 and related NiII square-planar or Ni0 tetrahedral complexes containing similar P-N-P ligands shows that the magnitude of the P-Ni-P angle is controlled by the presence of the Ni-P-N-P ring, irrespective of the geometry of the nickel coordination sphere. Direct anchoring of 1 onto SBA-15 molecular sieves through the trimethoxysilyl end-group of the ligand afforded heterogeneous catalyst 1/SBA-15. Both 1 and 1/SBA-15 catalyze Kumada cross-coupling reactions, exhibiting similar activity and a slightly higher product selectivity than the [Ni{Ph2P(CH2)3PPh2-P,P′}Cl2] and [Ni{(Ph2P)2N-(S)-CHMePh-P,P′}X2] (X = Cl, Br) complexes described in the literature. The Grignard reagent employed is likely to induce leaching of the catalyst, which retains its activity in solution.
Face-Directed Tetrahedral Organic Cage Anchored Palladium Nanoparticles for Selective Homocoupling Reactions
Bhandari, Pallab,Mondal, Bijnaneswar,Howlader, Prodip,Mukherjee, Partha Sarathi
, (2022/02/02)
Numerous metalla-supramolecular architectures have been designed using coordination-driven self-assembly, while the number of analogous organic architectures is still very limited. In this regard, mainly di-, tri- and a few tetra-aldehydes have been exploited as precursors in combination with appropriate di-/tri-amines to obtain the desired structures with limited complexities. We report here facile synthesis of two face-directed tetrahedral organic cages (TC-R and TC-S) that were formed by [4+12] imine condensation of a new hexa-aldehyde precursor with two enantiomers of 1,2-diaminocyclohexane separately (CA-R and CA-S). The covalent imine cages are very large with an intrinsic porous cavity of ～1250 ?3 and the faces of the cages consist of aromatic aldehyde units whereas each corner is occupied by three semi-flexible diamine moieties. Palladium (PdNPs) nanoparticles (3.5±0.3 nm) were synthesized employing the cage TC-R as a solid support via double-solvent approach. Furthermore, the cage hosted PdNPs [Pd(0)@TC-R-A] exhibited efficient catalytic activity for selective homocoupling of aryl- and hetero-aryl halides with high thermal stability and reusability.
Palladium-catalyzed aryl group transfer from triarylphosphines to arylboronic acids
Enright, Dale R.,Gogate, Akash R.,Smoliakova, Irina P.,Vasireddy, Purna C. R.
, (2021/11/11)
A study of Pd-catalyzed arylation of arylboronic acids with triarylphosphines is presented. Various parameters of this transformation, such as the oxygen presence, choice of solvent, temperature, palladium source, bases and oxidants, were tested and the optimal conditions of the aryl transfer were determined. The effect of electron-withdrawing and electron-donating substituents on the aryl groups of both reactants was also investigated. The unusual transfer of the acetate group from Pd(OAc)2 to p-nitrophenylboronic acid in the presence of PAr3 is reported. A plausible mechanism of the Pd-catalyzed aryl group transfer from PAr3 to the arylboronic acid is proposed.
