- An improved method for the palladium-catalyzed amination of aryl triflates
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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.
- Ahman, Jens,Buchwald, Stephen L.
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- Synthesis, characterization, and catalytic activity of N-heterocyclic carbene (NHC) palladacycle complexes
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(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.
- Viciu, Mihai S.,Kelly III, Roy A.,Stevens, Edwin D.,Naud, Frederic,Studer, Martin,Nolan, Steven P.
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- Influence of biaryl phosphine structure on C-N and C-C bond formation
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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.
- Pratap, Ramendra,Parrish, Damon,Gunda, Padmaja,Venkataraman,Lakshman, Mahesh K.
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- The use of palladium chloride as a precatalyst for the amination of aryl bromides
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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.
- Zhang, Xiao-Xiang,Harris, Michele C.,Sadighi, Joseph P.,Buchwald, Stephen L.
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- 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
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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.
- Hemmati, Saba,Sarachegol, Pegah,Veisi, Hojat
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- Improved schmidt conversion of aldehydes to nitriles using azidotrimethylsilane in 1,1,1,3,3,3-Hexafluoro-2-Propanol
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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.
- Motiwala, Hashim F.,Yin, Qin,Aubé, Jeffrey
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- Green tea extract–modified silica gel decorated with palladium nanoparticles as a heterogeneous and recyclable nanocatalyst for Buchwald-Hartwig C–N cross-coupling reactions
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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.
- Veisi, Hojat,Tamoradi, Taiebeh,Karmakar, Bikash,Hemmati, Saba
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- Ligand-free Buchwald-Hartwig aromatic aminations of aryl halides catalyzed by low-leaching and highly recyclable sulfur-modified gold-supported palladium material
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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
- Al-Amin, Mohammad,Honma, Tetsuo,Hoshiya, Naoyuki,Shuto, Satoshi,Arisawa, Mitsuhiro
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- Copper-catalyzed electrophilic amination of functionalized diarylzinc reagents
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(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
- Berman, Ashley M.,Johnson, Jeffrey S.
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- A group of diphosphine-thiosemicarbazone complexes of palladium: Efficient precursors for catalytic C–C and C–N coupling reactions
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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.
- Thapa, Kiran,Paul, Piyali,Bhattacharya, Samaresh
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- A highly active catalyst for the room-temperature amination and Suzuki coupling of aryl chlorides
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A unique combination of steric and electronic properties appears to determine the effectiveness of phosphanyl-substituted biphenyls as ligands in palladium-catalyzed aminations and Suzuki coupling of aryl chlorides at room temperature [Eq. (1)]. The oxidative addition step is greatly accelerated, and transmetalation (or Pd-N bond formation) and reductive elimination processes are facilitated. Use of these ligands allows for Suzuki coupling at very low catalyst loadings (as little as 10-6 mol % Pd). R'' = cyclohexyl, tert-butyl.
- Wolfe, John P.,Buchwald, Stephen L.
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- Palladium-Catalyzed Amination of Aryl Triflates and Importance of Triflate Addition Rate
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We report that a combination of DPPF (1,1-bis(diphenylphosphino)ferrocene) and Pd(dba)2 leads to the animation of aryl triflates, a reaction that allows for the conversion of phenols to arylamines. A combination of BINAP and Pd(dba)2 also catalyzes the amination of aryl triflates, but P(o-tolyl)3 complexes were not effective catalysts. In some cases, slow addition of the aryl triflate was necessary to prevent cleavage of the triflate and generation of phenol. We found that added halide, necessary in some cross-coupling chemistry of aryl sulfonates, was an unnecessary additive and even inhibited the amination chemistry.
- Louie, Janis,Driver, Michael S.,Hamann, Blake C.,Hartwig, John F.
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- Ligand-free C-C and C-N cross-couplings with Pd/Nf-G nanocomposite
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Abstract The catalytic activity of electrochemical deposited Pd nanoparticles on nafion-graphene support was examined for Buchwald-Hartwig amination reaction and Heck coupling reaction. The developed protocol is very efficient and ecofriendly, providing excellent product yield. The Pd/Nf-G catalyst can be used up to four cycles with slight decrease in catalytic activity.
- Shelkar, Radheshyam S.,Shendage, Suresh S.,Nagarkar, Jayashree M.
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- Synergistic Ligand Effect between N-Heterocyclic Carbene (NHC) and Bicyclic Phosphoramidite (Briphos) Ligands in Pd-Catalyzed Amination
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A synergistic ligand effect between NHC and phosphorus ligands in Pd-catalyzed Buchwald-Hartwig amination reactions was demonstrated with tunable π-acceptor bicyclic bridgehead phosphoramidite (briphos) ligands. The catalytic activity of NHC-Pd-L (L = phosphorus ligand) precatalysts depends on the electronic properties of L. A NHC-Pd-L catalyst with an N-cyclohexyl-substituted briphos ligand was found to be highly efficient. A series of C-N bond coupling reactions between primary or secondary amines and aryl chlorides were performed with high yields under mild reaction conditions.
- Kim, Miji,Shin, Taeil,Lee, Ansoo,Kim, Hyunwoo
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- High pressure organic chemistry; XII. A convenient synthesis of aromatic amines from activated aromatic fluorides
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Aromatic fluorides containing electron-withdrawing substituents are cleanly reacted with amines at 10 kbar pressure to give various aromatic amines.
- Kotsuki,Kobayashi,Matsumoto,Suenaga,Nishizawa
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- Nickel-on-charcoal-catalyzed aromatic aminations and Kumada couplings: Mechanistic and synthetic aspects
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Protocols for aromatic aminations and Kumada couplings catalyzed by 'heterogeneous' nickel-on-charcoal (Ni/C) have been revised, making them simpler and more time efficient. For both types of reactions, reduction of the catalyst precursor Ni(II)/C using n-BuLi prior to addition of a substrate can be avoided. Instead, in amination reactions, the amine in combination with lithium tert-butoxide was found to convert Ni(II)/C to active Ni(0). For Kumada couplings, direct reduction of Ni(II)/C by the Grignard reagent is easily achieved. Reactions run in the presence of triarylphosphine ligands of varying substitution patterns and with differing electronic properties provided insight into the mechanism of these nickel-catalyzed transformations. Ligandless Kumada couplings were facile with aryl Grignards, which may be a consequence of π-complexation of nickel by the aryl group in the reagent. Larger scale reactions of both types of couplings have been successfully performed, suggesting that Ni/C-based processes can be scaled-up as needed.
- Tasler, Stefan,Lipshutz, Bruce H.
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- Efficient palladium catalysts for the amination of aryl chlorides: A comparative study on the use of phosphium salts as precursors to bulky, electron-rich phosphines
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Alkyl-di-(1-adamantyl)phosphonium salts are practical ligand precursors for the palladium-catalyzed amination of aryl chlorides. In the presence of typically 0.5 mol% Pd(OAc)2 and 1 mol% of ligand precursor a variety of activated and deactivated aryl chlorides can be aminated in good to excellent yield (73-99%). Applying optimized conditions catalyst turnover numbers up to 10,000 have been achieved.
- Tewari, Amit,Hein, Martin,Zapf, Alexander,Beller, Matthias
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- Thieme Chemistry Journals Awardees - Where Are They Now? Efficient Cross-Coupling of Secondary Amines/Azoles and Activated (Hetero)Aryl Chlorides Using an Air-Stable DPEPhos/Nickel Pre-Catalyst
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Synthesis and characterization of the new air-stable pre-catalyst (DPEPhos)Ni(2-mesityl)Br (C1) is reported, along with the application of this pre-catalyst in the cross-coupling of secondary amines/azoles with activated (hetero)aryl chlorides to afford t
- Sawatzky, Ryan S.,Ferguson, Michael J.,Stradiotto, Mark
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- An air-stable palladium/N-heterocyclic carbene complex and its reactivity in aryl amination
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(matrix presented) The synthesis and characterization of [Pd(IPr)Cl2]2 (1), an air- and moisture-stable complex, is reported. The utilization of 1 as a catalyst for amination of aryl chlorides and bromides with a variety of amine coupling partners under mild conditions is described. The amination reactions with 1 show a remarkable insensitivity to oxygen and water, and thus the amination reactions could be performed in air on the benchtop with undried reagent grade solvents and substrates with small effects on reaction times and conversions.
- Viciu, Mihai S.,Kissling, Rebecca M.,Stevens, Edwin D.,Nolan, Steven P.
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- Cu(I)-anchored polyvinyl alcohol coated-magnetic nanoparticles as heterogeneous nanocatalyst in Ullmann-type C–N coupling reactions
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In this paper, the preparation of a novel magnetic nanocatalyst (Fe3O4?PVA/CuCl) is described, which involves coating of polyvinyl alcohol (PVA) onto the surface of Fe3O4 nanoparticles and its subsequent coordination with CuCl catalyst. The nanocatalyst was characterized by various analytical methods, including Fourier-transform infrared, X-ray diffraction, inductively coupled plasma spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy, vibrating-sample magnetometry, and EDX elemental mapping. Moreover, the nanocatalyst was efficiently used in the N-arylation of amines via the formation of a carbon–nitrogen bond between the aryl halides and amines by Ullmann-type coupling reactions. The catalyst was sufficiently stable and can be reused for at least seven times in a model Ullmann reaction without remarkable alteration in its catalytic behavior. Heterogeneity of the catalyst was investigated by a hot filtration test.
- Ahany Kamangar, Sheida,Hashemi Salehi, Mirmehdi,Hekmati, Malak,Hemmati, Saba,Yousefi, Mohammad
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- High yields of meta-substituted amination products in the S(N)Ar substitution of benzenes
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Morpholine substitution in fluorobenzenes containing a meta-substituted electron withdrawing group proceeds in DMSO at 100 °C over 60 h to give meta-substitution products (by fluoride ion displacement) in pure isolated yields of 19-98%.
- Brown,Foubister,Ratcliffe
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- Aromatic amination of aryl bromides catalysed by copper/β-diketone catalysts: The effect of concentration
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CuCl ligated with β-diketones were found to be good catalysts for the animation of aryl bromides. Crucial is the concentration of the substrates: at 5 M the rate and selectivity improves substantially. In addition, K 2CO3 can be used as base instead of expensive Cs 2CO3. Primary and secondary amines, heterocycles and anilines could be arylated in good yields. Georg Thieme Verlag Stuttgart.
- De Lange, Ben,Lambers-Verstappen, Marielle H.,Schmieder-Van De Vondervoort, Lizette,Sereinig, Natascha,De Rijk, Ron,De Vries, André H. M.,De Vries, Johannes G.
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- On the nature of the 'heterogeneous' catalyst: Nickel-on-charcoal
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Results from aromatic aminations and Kumada couplings, together with spectroscopic analyses (TEM, EDX, ICP-AES, React-IR), reveal that catalysis using nickel-on-charcoal (Ni/C) is most likely of a homogeneous rather than heterogeneous nature. In the course of a reaction with Ni/C, nickel bleed from the support was calculated to be as high as 78%. However, the existence of an equilibrium for this homogeneous species between nickel located inside vs outside the pore system of charcoal strongly favors the former, thus leaving only traces of metal detectable in solution. This accounts for virtually complete recovery of nickel on the charcoal following filtration of a reaction mixture and allows for recycling of the catalyst. TEM and EDX data were used to explain different reactivity profiles of Ni/C, which depended upon the method of reduction used to convert Ni(II)/C to Ni(0) as well as the level of nickel loading on the support.
- Lipshutz, Bruce H.,Tasler, Stefan,Chrisman, Will,Spliethoff, Bernd,Tesche, Bernd
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- Scope and utility of CsOH·H2O in animation reactions via direct coupling of aryl halides and sec-alcyclic amines
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Direct coupling of aryl halides with sec-alicyclic amines promoted by CsOH·H2O in DMSO to the corresponding aryl substituted amines, with good to excellent yields, is reported herein. A variety of aryl halides and sec-alicyclic amines with a broad range of electronic diversity and functional groups was studied in this transformation, thus offering general applicability in organic synthesis.
- Varala, Ravi,Ramu,Alam, M. Mujahid,Adapa, Srinivas R.
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- Application of a New Bicyclic Triaminophosphine Ligand in Pd-Catalyzed Buchwald-Hartwig Amination Reactions of Aryl Chlorides, Bromides, and Iodides
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The new bicyclic triaminophosphine ligand P(i-BuNCH2) 3CMe (3) has been synthesized in three steps from commercially available materials and its efficacy in palladium-catalyzed reactions of aryl halides with an array of amines has been demonstrated. Electron-poor, electron-neutral, and electron-rich aryl bromides, chlorides, and iodides participated in the process. The reactions encompassed aromatic amines (primary or secondary) and secondary amines (cyclic or acyclic). It has also been shown that the weak base Cs2CO3 can be employed with ligand 3, allowing a variety of functionalized substrates (e.g., those containing esters and nitro groups) to be utilized in our amination protocols. This ligand provides a remarkably general, efficient, and mild palladium catalyst for aryl iodide amination. Although 3 is slightly air and moisture sensitive, easy procedures can be adopted that avoid the need of a glovebox. Comparisons of the efficacy of 3 in these reactions with that of the proazaphosphatrane P(i-BuNCH2CH2)3N (2) reveal that in addition to the opportunity for transannulation in 2 (but not in 3), other significant stereoelectronic contrasts exist between these two ligands which help account for differences in the activities of the Pd/2 and Pd/3 catalytic systems.
- Urgaonkar, Sameer,Xu, Ju-Hua,Verkade, John G.
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- Copper-catalyzed electrophilic amination of organozinc nucleophiles: Documentation of O-benzoyl hydroxylamines as broadly useful R2N(+) and RHN(+) synthons
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This paper details new copper-catalyzed electrophilic amination reactions of diorganozinc reagents using O-benzoyl hydroxylamines as electrophilic nitrogen sources that may be accessed in one step. Simple and functionalized aryl, heteroaryl-, benzyl, n-alkyl, sec-alkyl, and tert-alkyl nucleophiles couple with R2NOC(O)Ph and RHNOC(O)Ph reagents in the presence of catalytic quantities of copper salts to provide tertiary and secondary amines, respectively, in generally good yields. In many cases, the product may be isolated analytically pure after a simple extractive workup. The amination process is shown to tolerate a significant degree of steric demand. The amination of nominally unreactive Caryl-H bonds via a sequential directed ortho metalation/transmetalation/catalytic amination reaction sequence is detailed. The direct Cu-catalyzed amination of Grignard reagents using cocatalysis by ZnCl2 is described.
- Herman, Ashley M.,Johnson, Jeffrey S.
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- Palladium-catalyzed amination of aryl bromides using temperature-controlled microwave heating
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Fast Palladium-catalyzed aminations of aryl bromides have been conducted in a non-inert reaction medium with temperature-controlled microwave heating. With a reaction time of 4 minutes at 130°C or 180°C, both electron-rich and electron-deficient aryl bromides reacted with various amines to provide fair to good yields of the corresponding secondary and tertiary anilines. As an example the amination of 4-bromobenzonitrile with imidazole is presented.
- Wan, Yiqian,Alterman, Mathias,Hallberg, Anders
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- Structural diversity of phenoxy functionalized triazol-5-ylidene palladium(II) complexes and their application in C-N bond formation
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The preparation and isolation of a variety of mono-, bis-, and heteroleptic mesoionic triazol-5-ylidene palladium(II) complexes is reported. Treatment of phenoxy functionalized triazolium salts [Bn-MIC(H)]+I- (1) and [Mes-MIC(H)]+I- (2) with half equivalent of palladium acetate, produced complexes 3 and 4 with a general structure of [(MIC)2Pd(I)2] as isomeric cis/trans mixtures. When the reaction of palladium acetate and the cationic precursors was carried out with equimolar amounts in presence of sodium iodide, the μ2-I2 bridged complexes 5 and 6 of the type [(MIC)PdI2]2 were obtained as unique products. Additionally, the preparation of the heteroleptic PEPPSI-type complexes ([Py(PdI2)MIC]) 7 and 8 was readily achieved by the thermal treatment of the triazolium precursors with PdCl2, K2CO3, and sodium iodide in pyridine. All complexes have been fully characterized by 1H and 13C NMR, FT-IR, elemental analysis, and in the case of 2, 3trans, 6, and 7 single crystal X-ray diffraction. Preliminary catalytic results with the palladium series established the enhanced performance of PEPPSI complexes 7 and 8 in the Buchwald-Hartwing catalyzed formation of C-N bonds between aryl halides and primary/secondary amines under mild reaction conditions.
- Mendoza-Espinosa, Daniel,González-Olvera, Rodrigo,Osornio, Cecilia,Negrón-Silva, Guillermo E.,álvarez-Hernández, Alejandro,Bautista-Hernández, Claudia I.,Suárez-Castillo, Oscar R.
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- Palladium-Catalyzed Amination of Aryl Triflates
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The conversion of aryl triflates to the corresponding aniline derivatives was accomplished in moderate to good yield using a catalyst consisting of the combination of palladium acetate (2 mol %) and either BINAP or Tol-BINAP. In contrast to the corresponding palladium-catalyzed amination of aryl bromides and iodides, electronically neutral aryl triflates gave higher yields of arylamines than did electron deficient aryl triflates, presumably due to the increased rate of base-promoted triflate cleavage in electron deficient substrates.
- Wolfe, John P.,Buchwald, Stephen L.
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- HFIP-Promoted Substitution in the Ferrocene Series: Smooth Approach towards Original Catalysts**
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Pseudo-benzylic substitution is an important reaction in the ferrocene series, especially to obtain ligands for catalysis. Herein, we described new reactions conditions, using fluorinated alcohols as both solvent and promoter, able to deliver iodoferrocen
- Erb, William,Carré, Victor,Roisnel, Thierry
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- Rapid and convenient synthesis of N-arylmorpholines under microwave irradiation
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A series of N-arylmorpholines 1a-1n was obtained by cyclocondensation of arylamines and diethylene glycol dimesylate under microwave irradiation in an aqueous potassium carbonate medium. The reaction is rapid and convenient, and a variety of functional groups are tolerated in the process.
- Li, Hong Bo,Liang, Wu,Ma, Chang Peng,Kai, Yong Mao,Li, Lei,Zhang, Yong Gang
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- New ligands for a general palladium-catalyzed amination of aryl and heteroaryl chlorides
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The synthesis and application of monodentate N-substituted heteroarylphosphines is described. In general, the ligands are conveniently prepared by selective metallation at the 2-position of the respective N-substituted heterocycle (pyrrole, indole) by using n-butyllithium/ tetramethylethylenediamine (TMEDA) followed by quenching with dialkyl- or diarylchlorophosphines. Of the different ligands prepared, the new dialkyl-2-(N-arylindolyl)phosphines (cataCXium P) perform excellently in the palladium-catalyzed amination of aryl and heteroaryl chlorides. Coupling of both activated and deactivated chloroarenes proceeds under mild conditions (room temperature to 60°C). By using optimized conditions remarkable catalyst productivity (total turnover number, TON, up to 8000) and activity (turnover frequency, TOF = 14000 h-1 at 75% conversion) are observed.
- Rataboul, Franck,Zapf, Alexander,Jackstell, Ralf,Harkal, Surendra,Riermeier, Thomas,Monsees, Axel,Dingerdissen, Uwe,Beller, Matthias
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- Nickel-Catalyzed Decarbonylative Amination of Carboxylic Acid Esters
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The reaction of carboxylic acid derivatives with amines to form amide bonds has been the most widely used transformation in organic synthesis over the past century. Its utility is driven by the broad availability of the starting materials as well as the kinetic and thermodynamic driving force for amide bond formation. As such, the invention of new reactions between carboxylic acid derivatives and amines that strategically deviate from amide bond formation remains both a challenge and an opportunity for synthetic chemists. This report describes the development of a nickel-catalyzed decarbonylative reaction that couples (hetero)aromatic esters with a broad scope of amines to form (hetero)aryl amine products. The successful realization of this transformation was predicated on strategic design of the cross-coupling partners (phenol esters and silyl amines) to preclude conventional reactivity that forms inert amide byproducts.
- Malapit, Christian A.,Borrell, Margarida,Milbauer, Michael W.,Brigham, Conor E.,Sanford, Melanie S.
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- Development of second generation gold-supported palladium material with low-leaching and recyclable characteristics in aromatic amination
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An improved process for the preparation of sulfur-modified gold-supported palladium material [SAPd, second generation] is presented. The developed preparation method is safer and generates less heat (aqueous Na 2S2O8 and H2SO4) for sulfur fixation on a gold surface, and it is superior to the previous method of preparing SAPd (first generation), which requires the use of the more heat-generating and dangerous piranha solution (concentrated H 2SO4 and 35% H2O2) in the sulfur fixation step. This safer and improved preparation method is particularly important for the mass production of SAPd (second generation) for which the catalytic activity was examined in ligand-free Buchwald-Hartwig cross-coupling reactions. The catalytic activities were the same between the first and second generation SAPds in aromatic aminations, but the lower palladium leaching properties and safer preparative method of second generation SAPd are a significant improvement over the first generation SAPd.
- Al-Amin, Mohammad,Arai, Satoshi,Hoshiya, Naoyoki,Honma, Tetsuo,Tamenori, Yusuke,Sato, Takatoshi,Yokoyama, Mami,Ishii, Akira,Takeuchi, Masashi,Maruko, Tomohiro,Shuto, Satoshi,Arisawa, Mitsuhiro
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- Synthesis and Study of a Dialkylbiaryl Phosphine Ligand; Lessons for Rational Ligand Design
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The rational design and synthesis of a novel dialkylbiarylphosphine ligand, 2′-(dimethylphosphine)-2,6-dimethoxy-1,1′-biphenyl (MeSPhos), for palladium-catalyzed C-N cross-coupling reactions is described. Based on previous results, it was hypothesized that a ligand with electronic properties similar to (2-biphenyl)dimethylphosphine (MeJPhos) but with greater steric bulk would allow the cross-coupling of previously inaccessible deactivated aryl chlorides. As predicted, MeSPhos exhibited similar electronic properties to MeJPhos. However, MeSPhos surprisingly showed a significantly smaller steric profile than MeJPhos. In comparison to the widely used CySPhos (2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl), MeSPhos promoted the oxidative addition of highly deactived aryl chlorides for which CySPhos was ineffective, but significantly decreased the rate of reductive elimination. The kinetics of cross-coupling reactions showed that the altered steric and electronic parameters of MeSPhos had a significant impact on the rate of cross-coupling, and the decreased steric bulk had a profound deleterious impact on the catalyst stability. With regard to this latter point, only the most activated aryl chlorides reacted at a sufficient rate to overcome the rate of catalyst decomposition. These results indicate that the relationship between the electron-donating ability of the phosphine ligand and the rate of oxidative addition is complex, and they also illustrate that increasing substitution on the biphenyl structure does not necessarily increase the steric bulk of the ligand.
- Bryant, Dillon J.,Zakharov, Lev N.,Tyler, David R.
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- Nickel-catalyzed electrophilic amination of organozinc halides
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The nickel-catalyzed electrophilic amination of organozinc halides with O-benzoyl N,N-dialkyl hydroxylamines allows for the preparation of a variety of aryl and alkyl tertiary amines in good yield. The reaction is noteworthy for the mild reaction conditions employed (room temperature) and the ease of product purification (acid/base extractive work up). Georg Thieme Verlag Stuttgart.
- Berman, Ashley M.,Johnson, Jeffrey S.
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Read Online
- Immobilized Pd nanoparticles on silica-starch substrate (PNP-SSS): Efficient heterogeneous catalyst in Buchwald–Hartwig C–N cross coupling reaction
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An immobilized Pd nanoparticle on silica-starch substrate (PNP-SSS) is introduced as an efficient heterogeneous catalyst in Pd-catalyzed Buchwald–Hartwig C–N cross coupling reaction. A range of aryl amines were synthesized using reaction of aryl halides (chloride, bromide and iodide) and amines using PNP-SSS catalyst in good to excellent yields. The PNP-SSS catalyst shows high catalytic activity in C-N bond formation reaction and it is reusable in this reaction at least for five times without significant decreasing in its catalytic activity.
- Panahi, Farhad,Daneshgar, Fatemeh,Haghighi, Fatemeh,Khalafi-Nezhad, Ali
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Read Online
- A “universal” catalyst for aerobic oxidations to synthesize (hetero)aromatic aldehydes, ketones, esters, acids, nitriles, and amides
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Functionalized (hetero)aromatic compounds are indispensable chemicals widely used in basic and applied sciences. Among these, especially aromatic aldehydes, ketones, carboxylic acids, esters, nitriles, and amides represent valuable fine and bulk chemicals, which are used in chemical, pharmaceutical, agrochemical, and material industries. For their synthesis, catalytic aerobic oxidation of alcohols constitutes a green, sustainable, and cost-effective process, which should ideally make use of active and selective 3D metals. Here, we report the preparation of graphitic layers encapsulated in Co-nanoparticles by pyrolysis of cobalt-piperazine-tartaric acid complex on carbon as a most general oxidation catalyst. This unique material allows for the synthesis of simple, functionalized, and structurally diverse (hetero)aromatic aldehydes, ketones, carboxylic acids, esters, nitriles, and amides from alcohols in excellent yields in the presence of air.
- Bartling, Stephan,Beller, Matthias,Chandrashekhar, Vishwas G.,Jagadeesh, Rajenahally V.,Rabeah, Jabor,Rockstroh, Nils,Senthamarai, Thirusangumurugan
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supporting information
p. 508 - 531
(2022/02/11)
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- Electrochemical Cross-Dehydrogenative Aromatization Protocol for the Synthesis of Aromatic Amines
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The introduction of amines onto aromatics without metal catalysts and chemical oxidants is synthetically challenging. Herein, we report the first example of an electrochemical cross-dehydrogenative aromatization (ECDA) reaction of saturated cyclohexanones and amines to construct anilines without additional metal catalysts and chemical oxidants. This reaction exhibits a broad scope of cyclohexanones including heterocyclic ketones, affording a variety of aromatic amines with various functionalities, and shows great potential in the synthesis of biologically active compounds.
- Tao, Shao-Kun,Chen, Shan-Yong,Feng, Mei-Lin,Xu, Jia-Qi,Yuan, Mao-Lin,Fu, Hai-Yan,Li, Rui-Xiang,Chen, Hua,Zheng, Xue-Li,Yu, Xiao-Qi
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supporting information
p. 1011 - 1016
(2022/02/05)
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- Nickel-Catalyzed Reversible Functional Group Metathesis between Aryl Nitriles and Aryl Thioethers
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We describe a new functional group metathesis between aryl nitriles and aryl thioethers. The catalytic system nickel/dcype is essential to achieve this fully reversible transformation in good to excellent yields. Furthermore, the cyanide- and thiol-free reaction shows high functional group tolerance and great efficiency for the late-stage derivatization of commercial molecules. Finally, synthetic applications demonstrate its versatility and utility in multistep synthesis.
- Delcaillau, Tristan,Boehm, Philip,Morandi, Bill
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supporting information
p. 3723 - 3728
(2021/04/07)
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- Ligand compound for copper catalyzed aryl halide coupling reaction, catalytic system and coupling reaction
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The invention provides a ligand compound capable of being used for copper catalyzed aryl halide coupling reaction, the ligand compound is a three-class compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group, and the invention also provides a catalytic system for the aryl halide coupling reaction. Thecatalytic system comprises a copper catalyst, a compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group adopted as a ligand, alkali and a solvent, and meanwhile, the invention also provides a system for the aryl halide coupling reaction adopting the catalyst system. The compound containing the 2-(substituted or non-substituted) aminopyridine nitrogen oxygen group can be used as the ligand for the copper catalyzed aryl chloride coupling reaction, and the ligand is stable under a strong alkaline condition and can well maintain catalytic activity when being used for the copper-catalyzed aryl chloride coupling reaction. In addition, the copper catalyst adopting the compound as the ligand can particularly effectively promote coupling of copper catalyzed aryl chloride and various nucleophilic reagents which are difficult to generate under conventional conditions, C-N, C-O and C-S bonds are generated, and numerous useful small molecule compounds are synthesized. Therefore, the aryl halide coupling reaction has a very good large-scale application prospect by adopting the copper catalysis system of the ligand.
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Paragraph 0086-0091; 0099
(2021/05/29)
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- Synthesis method of linezolid intermediate
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The invention provides a synthesis method of a linezolid intermediate 3-fluoro-4-(4-morpholinyl)aniline. The linezolid intermediate 3-fluoro-4-(4-morpholinyl)aniline is preferably obtained by taking acompound 3, 4-difluorobenzoic acid or 3, 4-difluorobenzonitrile as a raw material, performing morpholine substitution, converting into corresponding amide and performing Hofmann degradation. Comparedwith the prior art, the method has the advantages that the raw material and reagents used in the invention are cheap and easily available, most synthesis steps can be carried out under mild conditions, the environmental pollution is small, intermediate products and end products are easy to purify, the total yield is high, the nitration reaction is effectively avoided, the requirement on equipmentis not high, and the method is more suitable for industrial production.
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Paragraph 0050-0053
(2021/01/11)
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- Product selective reaction controlled by the combination of palladium nanoparticles, continuous microwave irradiation, and a co-existing solid; ligand-free Buchwald-Hartwig aminationvs.aryne amination
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We have developed a continuous microwave irradiation-assisted Buchwald-Hartwig amination using our original Pd nanoparticle catalyst with a copper plate as a co-existing metal solid. In this methodology, a microwave-controlled product selectivity was achieved between Buchwald-Hartwig amination and aryne amination performed under strongly basic conditions and at a high reaction temperature, because a polar chemical species such as Ar-Pd-halogen might be activated selectively by microwave radiation. Moreover, our catalyst could be used repeatedly over 10 times, and the amount of Pd leaching could be suppressed to a low level.
- Akiyama, Toshiki,Arai, Masayoshi,Arisawa, Mitsuhiro,Haneoka, Hitoshi,Harada, Kazuo,Murai, Kenichi,Murakami, Yosuke,Ohki, Yuuta,Ohta, Ryousuke,Sako, Makoto,Sirimangkalakitti, Natchanun,Suzuki, Takeyuki,Takahashi, Naoyuki,Takehara, Tsunayoshi,Yamada, Makito
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supporting information
p. 8131 - 8137
(2021/10/29)
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- Coupling of Alternating Current to Transition-Metal Catalysis: Examples of Nickel-Catalyzed Cross-Coupling
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The coupling of transition-metal to photoredox catalytic cycles through single-electron transfer steps has become a powerful tool in the development of catalytic processes. In this work, we demonstrated that transition-metal catalysis can be coupled to al
- Bortnikov, Evgeniy O.,Semenov, Sergey N.
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supporting information
p. 782 - 793
(2020/12/01)
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- Integrating CuO?Fe2O3 Nanocomposites and Supramolecular Assemblies of Phenazine for Visible-Light Photoredox Catalysis
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A photoredox catalytic ensemble consisting of CuO-Fe2O3 nanocomposites and oligomeric derivative of phenazine has been developed. The prepared system acts as an efficient photoredox catalyst for C?N bond formation reaction via SET mechanism under ‘green’ conditions (aerial environment, mixed aqueous media, recyclable), requiring less equivalents of base and amine substrate. The present study demonstrates the significant role of supramolecular assemblies as photooxidants and reductants upon irradiation and their important contribution towards the activation of the metallic centre through energy transfer and electron transfer pathways. The potential of oligomer 4: CuO-Fe2O3 has also been explored for C?C bond formation reactions via the Sonogashira protocol.
- Kaur, Lovjot,Deol, Harnimarta,Kumar, Manoj,Bhalla, Vandana
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supporting information
p. 892 - 898
(2020/03/04)
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- Catalyst-free photodecarbonylation ofortho-amino benzaldehyde
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It is almost a consensus that decarbonylation of the aldehyde group (-CHO) needs to not only be mediated by transition metal catalysts, but also requires severe reaction conditions (high temperature and long reaction time). In this work, inspired by the “conformational-selectivity-based” design strategy, we broke this consensus and discovered a catalyst-free photodecarbonylation of the aldehyde group. It revealed that decarbonylation can be easily achieved with visible light irradiation by introducing a tertiary amine into theortho-position of the aldehyde group. A diverse array of tertiary amines is tolerated by our photodecarbonylation under mild conditions. Furthermore, the (QM) computations of the mechanism and the experiments on well-designed special substrates revealed that our photodecarbonylation depends on the conformational specificity of the aldehyde group and tertiary amine, and occurs through an unusual [1,4]-H shift and a subsequent [1,3]-H shift.
- Li, Lamei,Wang, Songping,Wei, Wentao,Yan, Ming,Zhou, Jingwei
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supporting information
p. 3421 - 3426
(2020/06/25)
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- A convenient reagent for the conversion of aldoximes into nitriles and isonitriles
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For the dehydroxylation of aldoximes with 4-nitro-1-((trifluoromethyl)sulfonyl)-imidazole (NTSI), slight modifications of reaction conditions resulted in significantly different reaction paths to provide either nitriles or isonitriles. The challenging conversion of aldoximes into isonitriles was achieved under mild conditions.
- Zhang, Wei,Lin, Jin-Hong,Zhang, Pengfei,Xiao, Ji-Chang
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supporting information
p. 6221 - 6224
(2020/06/29)
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- Palladium-Catalyzed Cyanation of Aryl Halides Using Formamide and Cyanuric Chloride as a New “CN” Source
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A new source of “CN” employing formamide and cyanuric chloride is introduced for the cyanation reactions. The treatment of formamide and 2,4,6-trichloro-1,3,5-triazine (TCT; cyanuric chloride) afforded an efficient cyanating agent which it can be used as a nontoxic, readily available, and non-expensive reagent in the cyanation transformations. In this study, palladium-catalyzed cyanation of aryl halides was successfully accomplished using this new “CN” source in high yields.
- Niknam, Esmaeil,Panahi, Farhad,Khalafi-Nezhad, Ali
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p. 2699 - 2707
(2020/04/08)
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- Photo-induced dealdehyding method
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The invention provides a photo-induced dealdehyding method, and belongs to the technical field of organic synthesis. The photo-induced dealdehyding method comprises the following steps that a mixtureof a compound shown in the formula I and a solvent are reacted under an inert gas atmosphere and visible light irradiation, a dealdehyding product is obtained, and no photocatalyst is used in the whole process; wherein the structural formula of the formula I shown in the specification, R is a functional group and is selected from hydrogen, methyl, methoxyl, cyano, chlorine, bromine or fluorine. According to the photo-induced dealdehyding method, in the inert gas atmosphere, the compound shown in the formula (I) can be excited to generate carbon-oxygen bond homogeneous cracking through visiblelight irradiation, then free radical migration and double bond displacement are conducted, finally carbon monoxide is removed, aldehyde group removal is completed, no photocatalyst is needed in the whole process, operation is easy and convenient, and conditions are mild.
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Paragraph 0048-0053; 0084-0089
(2020/06/16)
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- Phenazine-Based Donor Acceptor Systems as Organic Photocatalysts for "metal-free" C-N/C-C Cross-Coupling
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With an aim to achieve a balance between ground-state and excited-state reduction potential of donor acceptor systems for efficient C-N/C-C cross-coupling, a series of donor acceptor systems DA1-DA4 have been synthesized by varying the donor strength and connecting positions. With an increase in donor strength, systematic elevation in the ground-state reduction potential and decrease in the HOMO-LUMO gap was observed. Interestingly, all the derivatives DA1-DA4 could catalyze the C-N bond formation reaction between activated aryl halides and amines at low catalytic loading under metal-free conditions without the need of any external base upon irradiation with white LED. A balance was realized in the case of derivative DA2, which exhibits high efficiency in C-N couplings. Different control experiments support the validity of the energy as well as electron transfer pathways in the visible light-mediated C-N bond formation. This study further reveals the potential of derivative DA1 in "metal-free"Sonogashira coupling involving activated aryl halides which is attributed to its high excited-state reduction potential.
- Deol, Harnimarta,Singh, Gurpreet,Kumar, Manoj,Bhalla, Vandana
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p. 11080 - 11093
(2020/10/12)
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- Ni(COD)(DQ): An Air-Stable 18-Electron Nickel(0)–Olefin Precatalyst
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We report that Ni(COD)(DQ) (COD=1,5-cyclooctadiene, DQ=duroquinone), an air-stable 18-electron complex originally described by Schrauzer in 1962, is a competent precatalyst for a variety of nickel-catalyzed synthetic methods from the literature. Due to its apparent stability, use of Ni(COD)(DQ) as a precatalyst allows reactions to be conveniently performed without use of an inert-atmosphere glovebox, as demonstrated across several case studies.
- Apolinar, Omar,Derosa, Joseph,Eastgate, Martin D.,Engle, Keary M.,Joannou, Matthew V.,Li, Zi-Qi,Tran, Van T.,Wisniewski, Steven R.
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supporting information
p. 7409 - 7413
(2020/04/10)
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- CuI/2-Aminopyridine 1-Oxide Catalyzed Amination of Aryl Chlorides with Aliphatic Amines
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A class of 2-aminopyridine 1-oxides are discovered to be effective ligands for the Cu-catalyzed amination of less reactive (hetero)aryl chlorides. A wide range of functionalized (hetero)aryl chlorides reacted with various aliphatic amines to afford the desired products in good to excellent yields under the catalyst of CuI/2-aminopyridine 1-oxides. Furthermore, the catalyst system worked well for the coupling of cyclic secondary amines and N-methyl benzylamine with (hetero)aryl chlorides.
- Chen, Xiahong,He, Yongqiang,Liang, Yun,Liu, Wenjie,Wang, Deping,Xia, Xiaohong,Xu, Jiamin,Xu, Zhifeng,Zhang, Fuxing,Zhang, Xin
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supporting information
p. 7486 - 7490
(2020/10/12)
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- Aryl-Diadamantyl Phosphine Ligands in Palladium-Catalyzed Cross-Coupling Reactions: Synthesis, Structural Analysis, and Application
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Synthesis, temperature-dependent NMR structure investigation and utilization of a new, stable and easily accessible aryl-diadamantylphosphine ligand family is reported. The bulky and electron-rich phosphorus center of the ligand enhances the catalytic activity of palladium in cross-coupling reactions of sterically demanding ortho-substituted aryl halides. In our study, we demonstrated the synthetic applicability of the new phosphine ligands in Buchwald-Hartwig and tosyl hydrazone coupling reactions.
- Sinai, ádám,Simkó, Dániel Cs.,Szabó, Fruzsina,Paczal, Attila,Gáti, Tamás,Bényei, Attila,Novák, Zoltán,Kotschy, András
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supporting information
p. 1122 - 1128
(2020/03/03)
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- Nickel-catalyzed cyanation of aryl halides and triflates using acetonitrile: Via C-CN bond cleavage assisted by 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine
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We developed a non-toxic cyanation reaction of various aryl halides and triflates in acetonitrile using a catalyst system of [Ni(MeCN)6](BF4)2, 1,10-phenanthroline, and 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine (Si-Me4-DHP). Si-Me4-DHP was found to function as a reductant for generating nickel(0) species and a silylation reagent to achieve the catalytic cyanation via C-CN bond cleavage.
- Ueda, Yohei,Tsujimoto, Nagataka,Yurino, Taiga,Tsurugi, Hayato,Mashima, Kazushi
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p. 994 - 999
(2019/02/03)
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- METHODS FOR FORMING ARYL CARBON-NITROGEN BONDS USING LIGHT AND PHOTOREACTORS USEFUL FOR CONDUCTING SUCH REACTIONS
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The disclosure relates to a method for forming aryl carbon-nitrogen bonds and to photoreactors useful in these and other light-driven reactions. The method comprises contacting an aryl halide with an amine in the presence of a Ni salt catalyst solution and an optional base, thereby forming a reaction mixture; exposing the reaction mixture to light under reaction condition sufficient to produce the aryl carbon-nitrogen bonds. In certain embodiments, the amine may be present in a molar excess to the aryl halide. In certain embodiments, the Ni salt catalyst solution includes a Ni(II) salt and a polar solvent, wherein the Ni(II) salt is dissolved in the polar solvent. In certain embodiments, the reactions conditions include holding the reaction mixture at between about room temperature and about 80° C. for between about 1 hour and about 20 hours such that at least about 50% yield is obtained.
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Paragraph 0097-0098; 0172-0173
(2019/11/22)
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- Organic semiconductor photocatalyst can bifunctionalize arenes and heteroarenes
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Photoexcited electron-hole pairs on a semiconductor surface can engage in redox reactions with two different substrates. Similar to conventional electrosynthesis, the primary redox intermediates afford only separate oxidized and reduced products or, more rarely, combine to one addition product. Here, we report that a stable organic semiconductor material, mesoporous graphitic carbon nitride (mpg-CN), can act as a visible-light photoredox catalyst to orchestrate oxidative and reductive interfacial electron transfers to two different substrates in a two- or three-component system for direct twofold carbon–hydrogen functionalization of arenes and heteroarenes. The mpg-CN catalyst tolerates reactive radicals and strong nucleophiles, is straightforwardly recoverable by simple centrifugation of reaction mixtures, and is reusable for at least four catalytic transformations with conserved activity.
- Ghosh, Indrajit,Khamrai, Jagadish,Savateev, Aleksandr,Shlapakov, Nikita,Antonietti, Markus,K?nig, Burkhard
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p. 360 - 366
(2019/08/15)
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- Robust Buchwald-Hartwig amination enabled by ball-milling
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An operationally simple mechanochemical method for the Pd catalysed Buchwald-Hartwig amination of arylhalides with secondary amines has been developed using a Pd PEPPSI catalyst system. The system is demonstrated on 30 substrates and applied in the context of a target synthesis. Furthermore, the performance of the reaction under aerobic conditions has been probed under traditional solution and mechanochemical conditions, the observations are discussed herein.
- Cao, Qun,Nicholson, William I.,Jones, Andrew C.,Browne, Duncan L.
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supporting information
p. 1722 - 1726
(2019/02/20)
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- Dihalogen-bridged NHC-palladium(i) dimers: Synthesis, characterisation and applications in cross-coupling reactions
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A di-iodo-bridged PdI dimer bearing an N-heterocyclic carbene ligand was made accessible via the reduction of [(IPr)PdI2]2 in basic methanol solution. The structural features of [(IPr)PdI]2 were explored by single-crystal X-ray analysis. It was found to be a convenient one-component precatalyst with high activity in Suzuki-Miyaura, Buchwald-Hartwig, and Sonogashira reactions.
- Pirkl, Nico,Del Grosso, Alessandro,Mallick, Bert,Doppiu, Angelino,Goo?en, Lukas J.
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supporting information
p. 5275 - 5278
(2019/05/08)
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- Bulky 1,1′-Ferrocenyl Ligands Featuring Diazaphospholene or Dioxaphosphepine Donor Fragments: Catalytic Screening in Nickel-Catalyzed C-N Cross-Coupling
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1,1′-Ferrocenyl ligands featuring either bulky dioxaphosphepine (L1) or diazaphospholene (L2) donor moieties have been prepared, crystallographically characterized, and tested in representative nickel-catalyzed C–N cross-coupling reactions. Ligand L1 prov
- McGuire, Ryan. T.,Clark, Jillian S. K.,Gatien, Alexandre V.,Shen, M. Yue,Ferguson, Michael J.,Stradiotto, Mark
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p. 4112 - 4116
(2019/11/02)
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- Identification of N-Benzyl 3,5-Dinitrobenzamides Derived from PBTZ169 as Antitubercular Agents
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A series of benzamide scaffolds were designed and synthesized by the thiazinone ring opening of PBTZ169, and N-benzyl 3,5-dinitrobenzamides were finally identified as anti-TB agents in this work. 3,5-Dinitrobenzamides D5, 6, 7, and 12 exhibit excellent in vitro activity against the drug susceptive Mycobacterium tuberculosis H37Rv strain (MIC: 0.0625 μg/mL) and two clinically isolated multidrug-resistant strains (MIC 0.016-0.125 μg/mL). Compound D6 displays acceptable safety and better pharmacokinetic profiles than PBTZ169, suggesting its promising potential to be a lead compound for future antitubercular drug discovery.
- Li, Linhu,Lv, Kai,Yang, Yupeng,Sun, Jingquan,Tao, Zeyu,Wang, Apeng,Wang, Bin,Wang, Hongjian,Geng, Yunhe,Liu, Mingliang,Guo, Huiyuan,Lu, Yu
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supporting information
p. 741 - 745
(2018/07/05)
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- Ultrafine hybrid Cu2O-Fe2O3 nanoparticles stabilized by hexaphenylbenzene-based supramolecular assemblies: A photocatalytic system for the Ullmann-Goldberg coupling reaction
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Ultrafine hybrid Cu2O-Fe2O3 NPs have been prepared using the supramolecular assemblies of hexaphenylbenzene (HPB) derivative 3 as nanoreactors and stabilizers. The as-prepared hybrid Cu2O-Fe2O3 NPs serve as an efficient and recyclable photocatalytic system for carrying out C-N coupling between aryl halides and various amines (aliphatic, aromatic and N-heterocyclic) at room temperature in mixed aqueous media under visible light irradiation. Amazingly, Cu2O-Fe2O3 NPs also exhibited high efficiency in the reactions involving the synthesis of biologically important N-substituted carbazole derivatives. The work being presented in this article demonstrates the preparation of a 'dip strip' coated with the as-prepared catalytic system and utilization of this paper strip as a recyclable and portable heterocatalytic system for carrying out the Ullmann-Goldberg coupling.
- Singh, Gurpreet,Kumar, Manoj,Bhalla, Vandana
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p. 5346 - 5357
(2018/12/05)
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- Cobalt-Catalyzed Electrophilic Amination of Aryl- and Heteroarylzinc Pivalates with N-Hydroxylamine Benzoates
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Aryl- and heteroarylzinc pivalates can be aminated with O-benzoylhydroxylamines at 25 °C within 2–4 h in the presence of 2.5–5.0 % CoCl2?2 LiCl to furnish the corresponding tertiary arylated or heteroarylated amines in good yields. This electrophilic amination also provides access to diarylamines and aryl(heteroaryl)amines. A new tuberculosis drug candidate (Q203) was prepared in six steps and 56 % overall yield by using this cobalt-catalyzed amination as the key step.
- Chen, Yi-Hung,Gra?l, Simon,Knochel, Paul
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p. 1108 - 1111
(2018/01/01)
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- Buchwald-Hartwig amination reaction of aryl halides using heterogeneous catalyst based on Pd nanoparticles decorated on chitosan functionalized graphene oxide
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In this work, graphene oxide was functionalized with chitosan (GO-Chit) followed by a simple approach for immobilization of palladium nanoparticles onto a chitosan grafted graphene oxide surface. The Pd-nanocomposite (GO-Chit-Pd) was characterized using Transmission Electron Microscopy (TEM), Fourier transforms infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) measurements. The catalytic activity of the prepared heterogeneous graphene oxide functionalized chitosan-palladium (GO-Chit-Pd) was investigated in term of C-N coupling reaction (Buchwald-Hartwig amination reaction of aryl halides) yielding products of N-arylamines. The easy purification, convenient operation, and environmental friendliness, combined with a high yield, render this method viable for use in both laboratory research and larger industrial scales. Studying the reusability of the catalyst in this work showed that it could be reused for five times without obvious loss in catalytic activity.
- Sarvestani, Mosayeb,Azadi, Roya
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- C-N Cross-Coupling via Photoexcitation of Nickel-Amine Complexes
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C-N cross-coupling is an important class of reactions with far-reaching impacts across chemistry, materials science, biology, and medicine. Transition metal complexes can elegantly orchestrate diverse aminations but typically require demanding reaction conditions, precious metal catalysts, or oxygen-sensitive procedures. Here, we introduce a mild nickel-catalyzed C-N cross-coupling methodology that operates at room temperature using an inexpensive nickel source (NiBr2·3H2O), is oxygen tolerant, and proceeds through direct irradiation of the nickel-amine complex. This operationally robust process was employed for the synthesis of diverse C-N-coupled products (40 examples) by irradiating a solution containing an amine, an aryl halide, and a catalytic amount of NiBr2·3H2O with a commercially available 365 nm LED at room temperature without added photoredox catalyst and the amine substrate serving additional roles as the ligands and base. Density functional theory calculations and kinetic isotope effect experiments were performed to elucidate the observed C-N cross-coupling reactivity.
- Lim, Chern-Hooi,Kudisch, Max,Liu, Bin,Miyake, Garret M.
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supporting information
p. 7667 - 7673
(2018/05/31)
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- Making Copper(0) Nanoparticles in Glycerol: A Straightforward Synthesis for a Multipurpose Catalyst
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Small zero-valent copper nanoparticles (CuNPs) have been straightforwardly prepared from Cu(I) and Cu(II) precursors in glycerol and in the presence of polyvinylpyrrolidone as stabilizer. Thanks to the negligible vapor pressure of the solvent, these original nano-systems could be directly characterized in glycerol as well as in the solid state, exhibiting relevantly homogeneous colloidal dispersions, also even after catalysis. CuNPs coming from the well-defined coordination complex di-μ-hydroxobis[(N,N,N′,N′-tetramethylethylenediamine)copper(II)] chloride {[Cu(κ2-N,N-TMEDA)(μ-OH)]2Cl2} have been highly efficient in C–C and C–heteroatom bond formation processes. This new catalytic system has proved its performance in C–N couplings and in the synthesis of differently substituted propargylic amines through cross-dehydrogenative couplings, multi-component reactions such as A3 (aldehyde-alkyne-amine) and KA2 (ketone-alkyne-amine) couplings, as well as in the formation of heterocycles such as benzofurans, indolizines, and quinolines under smooth conditions. No significant copper amount was detected in the extracted organic compounds from the catalytic phase by inductively coupled plasma-atomic emission spectroscopic (ICP-AES) analyses, proving a highly efficient immobilization of copper nanoparticles in glycerol. From a mechanistic point of view, spectroscopic data (infrared and ultraviolet-visible spectra) agree with a surface-like catalytic reactivity. (Figure presented.).
- Dang-Bao, Trung,Pradel, Christian,Favier, Isabelle,Gómez, Montserrat
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p. 2832 - 2846
(2017/08/23)
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- Nickel-Catalyzed Cyanation of Aryl Chlorides and Triflates Using Butyronitrile: Merging Retro-hydrocyanation with Cross-Coupling
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We describe a nickel-catalyzed cyanation reaction of aryl (pseudo)halides that employs butyronitrile as a cyanating reagent instead of highly toxic cyanide salts. A dual catalytic cycle merging retro-hydrocyanation and cross-coupling enables the conversion of a broad array of aryl chlorides and aryl/vinyl triflates into their corresponding nitriles. This new reaction provides a strategically distinct approach to the safe preparation of aryl cyanides, which are essential compounds in agrochemistry and medicinal chemistry.
- Yu, Peng,Morandi, Bill
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supporting information
p. 15693 - 15697
(2017/12/02)
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- Nickel-Catalyzed Amination of Aryl 2-Pyridyl Ethers via Cleavage of the Carbon-Oxygen Bond
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Reaction of aryl 2-pyridyl ethers with amines was carried out via Ni-catalyzed C-OPy bond cleavage, giving aniline derivatives in reasonable to excellent yields. Both electron-rich and electron-poor aryl 2-pyridyl ethers and a wide range of amines can be used in the transformation. The method provides a conversion way for the 2-pyridyloxy directing group in the C-H bond functionalization reactions.
- Li, Jing,Wang, Zhong-Xia
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supporting information
p. 3723 - 3726
(2017/07/26)
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- Decarbonylative Cyanation of Amides by Palladium Catalysis
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Transition-metal-catalyzed cyanation of aryl halides is a process of significant importance in the preparation pharmaceuticals, organic materials and agrochemicals. Here, we demonstrate a palladium-catalyzed decarbonylative cyanation of amides by highly selective carbon-nitrogen bond cleavage for the synthesis of a wide range of aryl nitriles. The utility of this technology is demonstrated by the synthesis of isotopically labeled aryl nitriles and orthogonal cross-coupling reactions of bench-stable amides to establish cross-coupling synthons with opposite polarity.
- Shi, Shicheng,Szostak, Michal
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p. 3095 - 3098
(2017/06/23)
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- Evaluating 1,1′-Bis(phosphino)ferrocene Ancillary Ligand Variants in the Nickel-Catalyzed C-N Cross-Coupling of (Hetero)aryl Chlorides
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Previous reports in the literature have established the utility of 1,1′-bis(diphenylphosphino)ferrocene (DPPF, LPh) in the nickel-catalyzed cross-coupling of (hetero)aryl electrophiles with primary or secondary amines. In an effort to evaluate
- Clark, Jillian S. K.,Voth, Christopher N.,Ferguson, Michael J.,Stradiotto, Mark
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supporting information
p. 679 - 686
(2017/04/21)
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- Bisphosphine-Ligated Nickel Pre-catalysts in C(sp2)–N Cross-Couplings of Aryl Chlorides: A Comparison of Nickel(I) and Nickel(II)
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The influence of ancillary ligand and nickel oxidation state in the nickel-catalyzed C(sp2)–N cross-coupling of aryl chlorides is examined by use of experimental and DFT methods for the first time, focusing on (L)NiCl and (L)Ni(o-tolyl)Cl pre-catalysts (PAd-DalPhos, L1; dppf, L2). Whereas Ni(II) pre-catalysts generally out-performed Ni(I) species in our study, the viability and in some cases superiority of Ni(I) pre-catalysts in challenging aminations is established. Computational analyses support the viability of Ni(0)/Ni(II) cycles featuring rate-limiting C–N reductive elimination, as well as parallel Ni(I)/Ni(III) mechanisms involving rate-limiting C–Cl oxidative addition. (Figure presented.).
- Lavoie, Christopher M.,McDonald, Robert,Johnson, Erin R.,Stradiotto, Mark
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supporting information
p. 2972 - 2980
(2017/09/06)
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- Compounds and methods for inhibiting phosphate transport
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Compounds having activity as phosphate transport inhibitors, more specifically, inhibitors of intestinal apical membrane Na/phosphate co-transport, are disclosed. The compounds have the following structure (I): including stereoisomers, pharmaceutically acceptable salts and prodrugs thereof, wherein X, Y, A, R1 and R2 are as defined herein. Methods associated with preparation and use of such compounds, as well as pharmaceutical compositions comprising such compounds, are also disclosed.
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Page/Page column 228
(2016/05/02)
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- Preparation method of novel bidentate phosphite ligand and application thereof in Buchwald-Hartwig reaction
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The invention discloses a preparation method of novel bidentate phosphite ligands and application thereof in Buchwald-Hartwig reaction and belongs to the field of organic synthetic chemistry. A series of novel bidentate phosphite ligands are synthesized by using 3,3',5,5'-tetra-tert-butyl-2,2'-dihydroxyl diphenyl and glycols with different structures as raw materials through a two-step one-pot method, are compounds very wide in application range and have the following structures. The novel preparation method has the advantages of being stable in structure, simple and convenient to synthesize, high in yield and easy to prepare in a large-scale mode. The ligands have higher reaction activity and substrate universality in the Pd catalyzed Buchwald-Hartwig reaction.
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Paragraph 0050; 0051; 0052; 0053; 0054; 0057; 0058; 0060-65
(2016/10/09)
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- Immobilized Pd(0) nanoparticles on phosphine-functionalized graphene as a highly active catalyst for Heck, Suzuki and N-arylation reactions
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In this study, a phosphine group was chemically grafted to the surface of graphene in order to prepare a reusable ligand with high surface area, incorporating a phosphine moiety. The treatment of graphene oxide (GO) with hydroxide followed by an aqueous work-up yields an OH-functionalized graphene material (GOH) via ring-opening of the epoxide groups. Reaction of GOH with chlorodiphenylphosphine (ClPPh2) gives a new material, GOPPh2 (PFG), which can be used for stabilization of metal nanoparticles or complexation of transition metals in order to prepare a reusable metal catalyst. Stabilization of palladium nanoparticles on the surface of GOPPh2 resulted in the production of an efficient heterogeneous Pd catalyst (PFG-Pd) for application in C-C and C-N bond formation reactions. The PFG-Pd catalyst was characterized using some different microscopic and spectroscopic techniques such as FT-IR, XRD, TEM, SEM, EDX, and ICP analysis. The applicability of the PFG-Pd catalyst was evaluated in Heck, Suzuki and N-arylation reactions. The catalyst system showed high catalyst activity in these processes and the target products were obtained in high isolated yields. The PFG-Pd catalyst was reusable in these reactions for at least 5 times with no significant decrease in its catalytic activity.
- Fareghi-Alamdari, Reza,Haqiqi, Mohsen G.,Zekri, Negar
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p. 1287 - 1296
(2016/02/19)
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- A comparative reactivity survey of some prominent bisphosphine nickel(II) precatalysts in C-N cross-coupling
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The synthesis and characterization of the new air-stable precatalyst (L1)Ni(o-tol)Cl (C1; where L1 = JosiPhos CyPF-Cy) is reported, along with the results of a comparative reactivity survey involving C1 and analogous PAd-DalPhos- and DPPF-containing precatalysts (C2 and C3, respectively) in representative nickel-catalyzed C(sp2)-N cross-coupling reactions. Precatalyst C1 was found to be competitive with, and in some cases complementary to, C2 in the monoarylation of ammonia and primary alkylamines with (hetero)aryl chlorides, including in otherwise challenging room temperature transformations. (Pseudo)halide comparison studies involving the cross-coupling of furfurylamine at room temperature revealed that in contrast to C2 precatalyst C1 performs less effectively with aryl bromides. Whereas C3 was found to be ineffective for such transformations, this DPPF-derived precatalyst proved superior to C1 and C2 in reactions involving the secondary dialkylamine test substrate morpholine.
- Clark, Jillian S. K.,Lavoie, Christopher M.,MacQueen, Preston M.,Ferguson, Michael J.,Stradiotto, Mark
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supporting information
p. 3248 - 3254
(2016/10/09)
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- Accelerating Effect of Triazolyl and Related Heteroaryl Substituents on SNAr Reactions: Evidence of Hydrogen-Bond Stabilized Transition States
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The remarkable accelerating effect of 1,2,3-triazolyl substituents on SNAr reactions has been investigated through systematic experiments and density functional theory calculations. The lone pair electrons of an ortho-triazolo substituent play
- Qian, Wenyuan,Wang, Hao,Bartberger, Michael D.
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p. 12261 - 12268
(2015/10/12)
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