Palladium-catalyzed Amination Research Articles

Ditopic Macrocyclic Receptors with a 4,7‐Diamino‐1,10‐phenanthroline Fragment for Multimodal Detection of Toxic Metal Ions

A series of ditopic macrocyclic receptors with variable cavity sizes, containing nitrogen or mixed (nitrogen-oxygen) donor sites and an externally directed 1,10-phenanthroline fragment, were prepared by means of a palladium-catalyzed amination reaction. A ditopic mixed NO-ligand (4 a) was coordinated to [Ru(bpy)2 ]2+ (bpy=2,2'-bipyridine) to prepare a luminescent and chromogenic complex, [Ru(bpy)2 (4 a)][PF]2 , which provided the selective dual-channel detection of CuII ions.

Selective Monoarylation of Primary Amines Using the Pd-PEPPSI-IPent(Cl) Precatalyst.

A single set of reaction conditions for the palladium-catalyzed amination of a wide variety of (hetero)aryl halides using primary alkyl amines has been developed. By combining the exceptionally high reactivity of the Pd-PEPPSI-IPent(Cl) catalyst (PEPPSI=pyridine enhanced precatalyst preparation, stabilization, and initiation) with the soluble and nonaggressive sodium salt of BHT (BHT=2,6-di-tert-butyl-hydroxytoluene), both six- and five-membered (hetero)aryl halides undergo efficient and selective amination.

Selective Monoarylation of Primary Amines Using the Pd-PEPPSI-IPentClPrecatalyst

A single set of reaction conditions for the palladium-catalyzed amination of a wide variety of (hetero)aryl halides using primary alkyl amines has been developed. By combining the exceptionally high reactivity of the Pd-PEPPSI-IPentCl catalyst (PEPPSI=pyridine enhanced precatalyst preparation, stabilization, and initiation) with the soluble and nonaggressive sodium salt of BHT (BHT=2,6-di-tert-butyl-hydroxytoluene), both six- and five-membered (hetero)aryl halides undergo efficient and selective amination.

Palladium-catalyzed amination of 2,3,3-trifluoroallyl esters: synthesis of trifluoromethylenamines via an intramolecular fluorine shift and CF3 group construction.

The palladium-catalyzed reaction of 2,3,3-trifluoroallyl esters with several types of amines afforded trifluoromethylenamines, which were formed by the addition of a nitrogen nucleophile at the C-2 position and the intramolecular construction of the trifluoromethyl group via the fluorine atom shift from the C-2 to the C-3 position.

Redox active dendronized polystyrenes equipped with peripheral triarylamines.

Dendronized polystyrene having peripheral bromo groups was prepared from the dendronization of unfunctionalized polystyrene with dendritic diarylcarbenium ions bearing peripheral bromo groups using the “cation pool” method. The palladium-catalyzed amination of the peripheral bromo groups with diarylamine gave dendronized polystyrene equipped with peripheral triarylamines, which exhibited two sets of reversible redox peaks in the cyclic voltammetry curves.

β-(p-Carboxyaminophenyl)porphyrin derivatives: new dyes for TiO2 dye-sensitized solar cells

New β-(p-carboxyaminophenyl)porphyrin derivatives were efficiently synthesized via palladium-catalysed amination of methyl 4-iodobenzoate with (2-amino-5-10,15,20-tetraphenylporphyrinato)nickel(II), followed by a demetallation/metallation sequence and basic hydrolysis. Optical and electrochemical studies revealed their potentiality for being considered as dyes in DSSCs devices, in which a power conversion efficiency of about 30 % of the more conventional Ru(II)-sensitizer N719 was achieved.

Selective palladium-catalysed amination of 4-chloropyridines with benzylamines using the Josiphos ligand

A synthetic strategy for the synthesis of a library of 4-N-benzylamino-2-N-phenyl-pyridines is herein described. The approach involves a Pd-assisted cross-coupling of a 4-chloro-N-phenylpyridin-2-amine intermediate with a range of benzylamines. A variety of ligands were screened, the most successful being the Josiphos ligand, which gave the desired products in good to moderate yields. The reactions occur quickly, within 30min, with full conversion of the intermediate into the desired product.

Synthesis of macrobicyclic compounds containing diazacrown ether moieties and ortho-aminobenzylic spacers

N,N´-Bis(2-bromobenzyl) diaza-15-crown-5 and -diaza-18-crown-6 ethers were obtained in high yields. Palladium-catalyzed amination of these compounds with equimolar amounts of linear polyamines and oxadiamines afforded a large number of macrobicyclic compounds. It was found that the structure of starting compounds is crucial for the formation of the target cryptands and that their yields can substantially be increased by using larger catalyst loadings.

Palladium-catalyzed amination of aryl chlorides and bromides with ammonium salts.

We report the palladium-catalyzed coupling of aryl halides with ammonia and gaseous amines as their ammonium salts. The coupling of aryl chlorides and ortho-substituted aryl bromides with ammonium sulfate forms anilines with higher selectivity for the primary arylamine over the diarylamine than couplings with ammonia in dioxane. The resting state for the reactions of aryl chlorides is different from the resting state for the reactions of aryl bromides, and this change in resting states is proposed to account for a difference in selectivities for reactions of the two haloarenes.

Asymmetric Palladium-Catalyzed Amination of Allenyl Phosphates

Asymmetric Palladium-Catalyzed Amination of Allenyl Phosphates

Palladium-catalyzed amination of aryl sulfides with anilines.

A combination of a palladium-NHC catalyst and potassium hexamethyldisilazide enables the amination of aryl sulfides with anilines to afford a wide variety of diarylamines. The reaction conditions are versatile enough for the reaction of even bulky ortho-substituted aryl sulfides. This amination can be applied to the modular synthesis of N-aryl carbazoles from the corresponding ortho-bromothioanisoles. As aryl sulfoxides undergo extended Pummerer reactions to afford ortho-substituted aryl sulfides, the Pummerer products are thus useful substrates for the amination to culminate in efficient syntheses of a 2-anilinobenzothiophene and an indole as proof-of-principle of the utility of the extended Pummerer reaction/amination cascade.

Synthesis of triarylamine-containing poly(arylene ether)s by nucleophilic aromatic substitution reaction

We report synthesis of a series of new triarylamine-containing AB-type monomers and their polymers via nucleophilic aromatic substitution (SNAr) reaction. Monomers consisting of a hydroxyl group at the para position of the nitrogen group in one phenyl ring and a fluorine leaving group at the para position in another phenyl ring were synthesized via palladium-catalyzed amination reaction. The fluorine leaving group was activated by trifluoromethyl group at the ortho position and an electron-withdrawing group (EWG) introduced at the para position of the unsubstituted phenyl ring that enabled control over monomer reactivity. SNAr reaction of the monomers successfully produced corresponding poly(arylene ether)s with pendant EWGs that exhibited good solubility and thermal stability. Optical and electrochemical properties of the polymers were also affected by incorporation of EWGs. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2692-2702

Effects of solvent and base on the palladium-catalyzed amination: PdCl2(Ph3P)2/Ph3P-catalyzed selective arylation of primary anilines with aryl bromides

A readily accessible catalytic system, PdCl2(Ph3P)2/Ph3P, was developed for the selective arylation of primary anilines with aryl bromides. The strong influence of solvents and bases on the catalytic activity was observed. In refluxing o-xylene, triphenylphosphine shows high efficiency for Pd-catalyzed intermolecular amination reactions. By changing the bases, mono- and diarylation of primary amines could be selectively achieved in high yields. Moreover, the catalytic system showed good toleration for the steric hindrance of anilines. A series of N,N,N′,N′-tetraaryl-1,1′-biphenyl-4,4′-diamines, important intermediates of OLED hole transport materials, were synthesized facilely via coupling reactions between 4,4′-diaminobiphenyls and aryl bromides.

ChemInform Abstract: Use of a Readily Removable Auxiliary Group for the Synthesis of Pyrrolidones by the Palladium‐Catalyzed Intramolecular Amination of Unactivated γ C(sp3)—H Bonds.

Easy on, easy off: Directing groups found to promote the palladium-catalyzed amination of γ C(sp(3) )H and C(sp(2) )H bonds of secondary amides included 5-methoxy-8-aminoquinoline, which can be removed under mild conditions (see scheme; CAN=ceric ammonium nitrate). In conjunction with a β-CH methylation or γ-CH arylation step, the γ-C(sp(3) )H amination provided access to complex pyrrolidones from readily available precursors.

Palladium-Catalyzed Amination of Unprotected Five-Membered Heterocyclic Bromides

An efficient method for the palladium-catalyzed amination of unprotected bromoimidazoles and bromopyrazoles is presented. The transformation is facilitated by the use of our newly developed Pd precatalyst based on the bulky biarylphosphine ligand tBuBrettPhos (L4). The mild reaction conditions employed allow for the preparation of a broad scope of aminoimidazoles and aminopyrazoles in moderate to excellent yields.

Palladium-catalyzed amination of meso-(bromophenyl)porphyrins with diamines and azamacrocycles

Novel diamino and azamacrocycle functionalized porphyrins were efficiently synthesized by palladium-catalyzed amination of mono- and bis(meso-(bromophenyl))porphyrins. The optimization of reaction conditions allowed us to achieve high yields of products with substrates of different types. Supramolecular utility of the thus obtained aminoporphyrins was shown by investigations of processes of coordination self-assembly in solution by NMR and UV-Vis spectroscopy. The crystalline 1D-coordination polymer formed via self-assembly of N,N-dimethylethylenediamine substituted zinc porphyrin was characterized by X-ray diffraction.

Palladium-catalyzed amination of allylic carbonates with ammonia: access to primary amines

Allylic amination of allylic carbonates with ammonia gas or aqueous ammonia was successfully carried out using (SIPr)Pd(allyl)Cl as the catalyst and Ph3P, which is essential for the reaction.

Synthesis of Macrobicycles Comprising 2,7-Diaminonaphthalene Moiety via Palladium-Catalyzed Amination Reaction

Synthesis of Macrobicycles Comprising 2,7-Diaminonaphthalene Moiety via Palladium-Catalyzed Amination Reaction

Cover Picture: Amination of meso‐Bromoporphyrins and 9‐Haloanthracenes with Diarylamines Catalyzed by a Palladium–PEPPSI Complex (Asian J. Org. Chem. 12/2013)

A large number of triarylamine-based functional devices have been reported. However, efficient routes to bulky triarylamines are still underdeveloped. In their Full Paper on page 1066 ff., Hideki Yorimitsu, Atsuhiro Osuka and co-workers report a very efficient palladium-catalyzed amination of bulky aryl halides. The reactions are applicable to meso-bromoporphyrins and 9-haloanthracenes with a wide variety of diarylamines. Commercially available and air-stable Pd-PEPPSI complexes that have N-heterocyclic carbenes as ligands are the most catalytically active in this reaction.

Effect of Electronic Enrichment of NHCs on the Catalytic Activity of [Pd(NHC)(acac)Cl] in Buchwald–Hartwig Coupling

A series of [Pd(NHC)(acac)Cl] (NHC = N-heterocyclic carbene) complexes have been synthesized and characterized to investigate the electronic and steric effects of NHC ligands in catalysis. Their reactivity in Buchwald–Hartwig coupling has been explored and compared with that of their nonmethoxylated congeners. Combining the optimal steric and electronic properties, [Pd(IHeptOMe)(acac)Cl] performed excellently in the palladium-catalyzed amination of deactivated aryl chlorides with various anilines.