10282-31-2Relevant academic research and scientific papers
An improved method for the palladium-catalyzed amination of aryl triflates
Ahman, Jens,Buchwald, Stephen L.
, p. 6363 - 6366 (1997)
Aryl triflates are coupled with amines using catalytic amounts of Pd(OAc)2 and BINAP and Cs2CO3 as a stoichiometric base. This protocol allows for the efficient amination of electron-poor as well as electron-rich aryl triflates and the reaction conditions are compatible with a wide variety of functional groups.
Synthesis, characterization, and catalytic activity of N-heterocyclic carbene (NHC) palladacycle complexes
Viciu, Mihai S.,Kelly III, Roy A.,Stevens, Edwin D.,Naud, Frederic,Studer, Martin,Nolan, Steven P.
, p. 1479 - 1482 (2003)
(Matrix presented) Palladacycle dimers possessing bridging halides can be easily cleaved by using N-heterocyclic carbenes (NHCs) to generate novel monomeric complexes. The structure of one of these was determined by single-crystal diffraction study and consists of a square-planar coordination around the palladium center where the NHC ligand is trans to the amine of the palladacycle. The complex was found to be equally active in aryl amination and α-arylation of ketones even at very low catalyst loading (0.02 mol %). Primary and secondary alkyl/arylamines are equally active partners in coupling reactions.
Influence of biaryl phosphine structure on C-N and C-C bond formation
Pratap, Ramendra,Parrish, Damon,Gunda, Padmaja,Venkataraman,Lakshman, Mahesh K.
, p. 12240 - 12249 (2009)
In order to understand how electronic and other structural characteristics of biphenyl phosphine ligands affect Pd-catalyzed C-N and C-C bond-forming reactions, a new ligand, 2-(dicyclohexylphosphino)-4′-(N,N-dimethylamino)- 1,1′-biphenyl, was synthesized. This compound is isomeric with the commercially available 2-(dicyclohexylphosphino)-2′-(N,N-dimethylamino)-1, 1′-biphenyl that has been useful in C-N bondforming reactions of nucleosides. The new p-dimethylamino biphenyl ligand bears electronic similarities to the o-dimethylamino isomer, but it also possesses structural similarities to 2-(dicyclohexylphosphino)biphenyl, such as the unsubstituted ortho positions in the non-phosphine ring. Whereas 2-(dicyclohexylphosphino)- biphenyl can support catalysts for C-C bond formation, it was not effective in promoting aryl amination of a nucleoside substrate. However, the new ligand proved to be effective in promoting both aryl amination and C-C bond-forming reactions of nucleoside substrates, with some reactions even occurring at room temperature. Thus, the composite structural elements of this new ligand are thought to be criteria for reactivity of the catalytic system derived from it. We have probed the structures of the isomeric N,N-dimethylamino biphenyl ligands by X-ray crystallographic analysis. Interactions of the two ligands with Pd(OAc)2 have been investigated by 31P NMR, and they show substantial stoichiometry-dependent differences. These results have been compared to the interactions of Pd(OAc)2 with 2- (dicyclohexylphosphino)biphenyl as well as 2-(di-tert-butylphosphino)biphenyl, and they reveal marked differences as well. In this process, three cyclopalladated biaryl derivatives have been isolated and characterized by X-ray analysis.
The use of palladium chloride as a precatalyst for the amination of aryl bromides
Zhang, Xiao-Xiang,Harris, Michele C.,Sadighi, Joseph P.,Buchwald, Stephen L.
, p. 1799 - 1805 (2001)
The use of palladium chloride as a precatalyst for the amination of aryl bromides is reported. To overcome the poor solubility of palladium chloride in commonly used solvents, a procedure was developed in which PdCl2 was preheated with neat amine in the presence of a phosphine ligand before the addition of the other reaction components. This protocol is effective for a broad range of substrate combinations using several types of phosphine ligands.
Palladium(II) anchored on polydopamine coated-magnetic nanoparticles (Fe3O4&at;PDA&at;Pd(II)): A heterogeneous and core–shell nanocatalyst in Buchwald–Hartwig C–N cross coupling reactions
Hemmati, Saba,Sarachegol, Pegah,Veisi, Hojat
, p. 64 - 71 (2018)
An efficient method was proposed to synthesize polydopamine (PDA)-coated Fe3O4 nanoparticles (Fe3O4&at;PDA). For the first time, effective deposition of Pd complex is explained by using Fe3O4&at;PDA as a core–shell magnetic coordinator and stabilizer agent. In this method, palladium ions were adsorbed on Fe3O4&at;PDA surfaces through immersion of the Fe3O4&at;PDA into a palladium plating bath. The structure, morphology and physicochemical features of the prepared particles were studied using various analytical methods including high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP), thermogravimetric analysis (TGA) and FT-IR spectroscopy. Core–shell Fe3O4&at;PDA/Pd(II) nanoparticles showed excellent catalytic performance as a reusable nanocatalyst in Pd-catalyzed Buchwald–Hartwig C–N cross coupling reaction. A variety of aryl amines were prepared through reaction of aryl halides (chloride, bromide and iodide) and amines in high yields. The catalyst can be recycled and reapplied up to six cycles with no considerable change in its catalytic activity.
Improved schmidt conversion of aldehydes to nitriles using azidotrimethylsilane in 1,1,1,3,3,3-Hexafluoro-2-Propanol
Motiwala, Hashim F.,Yin, Qin,Aubé, Jeffrey
, (2016)
The Schmidt reaction of aromatic aldehydes using a substoichiometric amount (40 mol %) of triflic acid is described. Low catalyst loading was enabled by a strong hydrogen-bond-donating solvent hexafluoro-2-propanol (HFIP). This improved protocol tolerates a broad scope of aldehydes with diverse functional groups and the corresponding nitriles were obtained in good to high yields without the need for aqueous work up.
Green tea extract–modified silica gel decorated with palladium nanoparticles as a heterogeneous and recyclable nanocatalyst for Buchwald-Hartwig C–N cross-coupling reactions
Veisi, Hojat,Tamoradi, Taiebeh,Karmakar, Bikash,Hemmati, Saba
, (2020)
A novel green tea extract–encapsulated silica gel decorated with in situ–generated Pd nanoparticles is reported as an efficient, green heterogeneous catalyst in the Buchwald-Hartwig C–N cross-coupling reaction. It was characterized by several analytical techniques. Thereafter, a wide range of aryl amines were synthesized in good to excellent yields by reaction of different substituted aryl halides and secondary amines over the catalyst. The material is sufficiently stable and could be used at least six times in a model Buchwald-Hartwig reaction without noticeable change in its catalytic activity. Heterogeneity of the catalyst was examined by a hot filtration test.
Ligand-free Buchwald-Hartwig aromatic aminations of aryl halides catalyzed by low-leaching and highly recyclable sulfur-modified gold-supported palladium material
Al-Amin, Mohammad,Honma, Tetsuo,Hoshiya, Naoyuki,Shuto, Satoshi,Arisawa, Mitsuhiro
, p. 1061 - 1068 (2012)
A stable heterogeneous catalyst precursor, sulfur-modified gold-supported palladium material (SAPd), has proved to be an excellent source of leached, ligand-free, Pd for the amination of aryl bromides and chlorides. The reaction-enabling catalyst is provided in situ as leached Pd in low catalyst loading (0.21±0.02mol%). This allows the precatalyst (SAPd) to be filtered off and used for a minimum of ten reaction cycles without loss of catalytic activity. SAPd released only trace amounts, less than 0.6ppm, of highly active Pd during the reaction without any aggregation. Copyright
Copper-catalyzed electrophilic amination of functionalized diarylzinc reagents
Berman, Ashley M.,Johnson, Jeffrey S.
, p. 364 - 366 (2005)
(Chemical Equation Presented). The copper-catalyzed electrophilic amination of functionalized diarylzinc reagents with O-acyl hydroxylamines allows for the preparation of functionalized tertiary arylamines in high yields, and is noteworthy for the mild re
A group of diphosphine-thiosemicarbazone complexes of palladium: Efficient precursors for catalytic C–C and C–N coupling reactions
Thapa, Kiran,Paul, Piyali,Bhattacharya, Samaresh
, p. 232 - 239 (2019)
Reaction of 4-R-benzaldehyde thiosemicarbazone (denoted in general as HL-R; where H stands for the dissociable acidic proton and R (R = OCH3, CH3, H, Cl and NO2) for the substituent) with [Pd(dppe)(EtOH)2]2+, generated in situ via interaction of [Pd(dppe)Cl2] (dppe = 1,2-bis(diphenylphosphino)ethane) with AgNO3 in hot ethanol, in the presence of triethylamine affords a group of orange complexes of the type [Pd(dppe)(L-R)]NO3. Structures of [Pd(dppe)Cl2] and [Pd(dppe)(L-OCH3)]NO3 have been determined by X-ray crystallography. In the [Pd(dppe)(L-R)]NO3 complexes, the thiosemicarbazone ligands are coordinated to the metal center as monoanionic bidentate N,S-donors forming five-membered chelate rings. The [Pd(dppe)(L-R)]NO3 complexes show intense absorptions in the visible and ultraviolet regions, which have been analyzed by TDDFT calculations. All the [Pd(dppe)(L-R)]NO3 complexes are found to efficiently catalyze Suzuki-type C–C and Buchwald-type C–N coupling reactions.
