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• 95-78-3 2,5-Dimethylaniline 
• 123-75-1 pyrrolidine 
• 1122-42-5 2-iodo-p-xylene 
• 95-72-7 2-chloro-1,4-dimethyl-benzene 
• 553-94-6 4-bromo-m-xylene 

Relevant academic research and scientific papers

Synergistic Ligand Effect between N-Heterocyclic Carbene (NHC) and Bicyclic Phosphoramidite (Briphos) Ligands in Pd-Catalyzed Amination

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.

Controlling first-row catalysts: Amination of aryl and heteroaryl chlorides and bromides with primary aliphatic amines catalyzed by a BINAP-ligated single-component Ni(0) complex

First-row metal complexes often undergo undesirable one-electron redox processes during two-electron steps of catalytic cycles. We report the amination of aryl chlorides and bromides with primary aliphatic amines catalyzed by a well-defined, single-component nickel precursor (BINAP)Ni(η2-NC- Ph) (BINAP = 2,2′-bis(biphenylphosphino)-1,1′-binaphthalene) that minimizes the formation of Ni(I) species and (BINAP)2Ni. The scope of the reaction encompasses electronically varied aryl chlorides and nitrogen-containing heteroaryl chlorides, including pyridine, quinoline, and isoquinoline derivatives. Mechanistic studies support the catalytic cycle involving a Ni(0)/Ni(II) couple for this nickel-catalyzed amination and are inconsistent with a Ni(I) halide intermediate. Monitoring the reaction mixture by 31P NMR spectroscopy identified (BINAP)Ni(η2-NC-Ph) as the resting state of the catalyst in the amination of both aryl chlorides and bromides. Kinetic studies showed that the amination of aryl chlorides and bromides is first order in both catalyst and aryl halide and zero order in base and amine. The reaction of a representative aryl chloride is inverse first order in PhCN, but the reaction of a representative aryl bromide is zero order in PhCN. This difference in the order of the reaction in PhCN indicates that the aryl chloride reacts with (BINAP)Ni(0), formed by dissociation PhCN from (BINAP)Ni(η2-NC-Ph), but the aryl bromide directly reacts with (BINAP)Ni(η2-NC-Ph). The overall kinetic behavior is consistent with turnover-limiting oxidative addition of the aryl halide to Ni(0). Several pathways for catalyst decomposition were identified, such as the formation of the catalytically inactive bis(amine)-ligated arylnickel(II) chloride, (BINAP)2Ni(0), and the Ni(I) species [(BINAP)Ni(μ-Cl)] 2. By using a well-defined nickel complex as catalyst, the formation of (BINAP)2Ni(0) is avoided and the formation of the Ni(I) species [(BINAP)Ni(μ-Cl)]2 is minimized.

Ortho, ortho′-Substituted KITPHOS monophosphines: Highly efficient ligands for palladium-catalyzed C-C and C-N bond formation

ortho, ortho′-Substitution of the phosphinoalkyne-derived aryl ring in KITPHOS (11-dicyclohexylphosphino-12-phenyl-9,10-ethenoanthracene) monophosphines enhances the performance of this class of ligand in palladium-catalyzed Suzuki-Miyaura cross-couplings and BuchwaldHartwig aminations, compared with their unsubstituted and mono-substituted counterparts. An alternative complementary synthesis of KITPHOS monophosphines has been developed and two new members of this family, 2,6-Me2-KITPHOS [11-dicyclohexylphosphino-12-(2,6-dimethylphenyl)-9,10-ethenoanthracene] and 2,6-(MeO)2-KITPHOS [11-dicyclohexylphosphino-12-(2,6-dimethoxyphenyl)-9,10-ethenoanthracene], have been prepared; palladium complexes of both are highly efficient catalysts for C - C and C - N bond formation with a range of electron-rich and electron-poor aromatic chlorides as well as heteroaryl chlorides.

Simple, efficient catalyst system for the palladium-catalyzed amination of aryl chlorides, bromides, and triflates

Palladium complexes supported by (o-biphenyl)P(t-Bu)2 (3) or (o- biphenyl)PCy2 (4) are efficient catalysts for the catalytic amination of a wide variety of aryl halides and triflates. Use of ligand 3 allows for the room-temperature catalytic amination of many aryl chloride, bromide, and triflate substrates, while ligand 4 is effective for the amination of functionalized substrates or reactions of acyclic secondary amines. The catalysts perform well for a large number of different substrate combinations at 80-110 °C, including chloropyridines and functionalized aryl halides and triflates using 0.5-1.0 mol % Pd; some reactions proceed efficiently at low catalyst levels (0.05 mol % Pd). These ligands are effective for almost all substrate combinations that have been previously reported with various other ligands, and they represent the most generally effective catalyst system reported to date. Ligands 3 and 4 are air-stable, crystalline solids that are commercially available. Their effectiveness is believed to be due to a combination of steric and electronic properties that promote oxidative addition, Pd-N bond formation, and reductive elimination.

Scope and Limitations of the Pd/BINAP-Catalyzed Amination of Aryl Bromides

Mixtures of Pd2(dba)3 or Pd(OAc)2 and BINAP catalyze the cross-coupling of amines with a variety of aryl bromides. Primary amines are arylated in high yield, and certain classes of secondary amines are also effectively transformed. The process tolerates the presence of several functional groups including methyl and ethyl esters, enolizable ketones, and nitro groups provided that cesium carbonate is employed as the base. Most reactions proceed to completion with 0.5-1.0 mol % of the palladium catalyst; in some cases, catalyst levels as low as 0.05 mol % Pd may be employed. Reactions are considerably faster if Pd(OAc)2 is employed as the precatalyst, and the order in which reagents are added to the reaction has a substantial effect on reaction rate. It is likely that the catalytic process proceeds via bis(phosphine)palladium complexes as intermediates. These complexes are less prone to undergo undesirable side reactions which lead to diminished yields or catalyst deactivation than complexes of the corresponding monodentate triarylphosphines.

A highly active catalyst for the room-temperature amination and Suzuki coupling of aryl chlorides

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.

Nickel-catalyzed amination of aryl chlorides

Aryl chlorides are converted to aniline derivatives using catalytic amounts of Ni(COD)2 (COD = 1,5-cyclooctadiene) and DPPF (DPPF = 1,1'- bis(diphenylphosphino)ferrocene) or 1,10-phenanthroline in the presence of sodium tert-butoxide. This procedure has a broad substrate scope: electron- rich or electron-poor aryl chlorides, as well as chloropyridine derivatives, can be combined with primary and secondary amines to give the desired aryl amine products in moderate to excellent yields. Additionally, a procedure which utilizes the air-stable precatalysts (DPPF)NiCl2 or (1,10- phenanthroline)NiCl2 is also described.

SYNTHESIS OF STERICALLY HINDERED 1-ARYLPYRROLIDINES AND 1-ARYLPIPERIDINES BY CONDENSATION OF PRIMARY AROMATIC AMINES WITH CYCLIC ETHERS OR DIOLS

A variety of 1-(o-alkylphenyl)- and 1-(o-o'-dialkylphenyl)-pyrrolidines and -piperidines were prepared by the gas phase alumina mediated condensation of tetrahydrofuran (THF), tetrahydropyran (THP) or the corresponding diols with primary aromatic amines in fair to high yield.This methodology can also be used for the synthesis of 1-phenylhexahydroazepine from aniline.A mechanistic interpretation of the catalytic action of alumina is presented.