Reaction Of Bromobenzene Research Articles

Microwave assisted P–C coupling reactions without directly added P-ligands

Our group introduced a green protocol for the Pd(OAc)2- or NiCl2-catalyzed P–C coupling reaction of aryl halides and various > P(O)H-compounds under MW conditions without directly added P-ligands. The reactivity of a few aryl derivatives in the Pd(OAc)2-catalyzed Hirao reaction was also studied. An induction period was observed in the reaction of bromobenzene and diphenylphosphine oxide. Finally, the less known copper(I)-promoted P–C coupling reactions were investigated experimentally. The mechanism was explored by quantum chemical calculations.

Palladium supported on structurally stable phenanthroline-based polymer nanotubes as a high-performance catalyst for the aqueous Suzuki–Miyaura coupling reaction

One-dimensional Pd-supported catalyst exhibits excellent catalytic activity since its TOF value is 3077 h−1for the Suzuki–Miyaura coupling reaction of bromobenzene and phenylboronic acid under ambient conditions.

Suzuki‐Miyaura Cross‐Coupling Using Plasmonic Pd‐Decorated Au Nanorods as Catalyst: A Study on the Contribution of Laser Illumination

AbstractThe interaction between plasmonic metal catalysts and visible light can be exploited to increase their catalytic activity. This activity increase results from the generation of hot charge carriers or hot surfaces, or a combination of both. We have studied the light‐induced Suzuki‐Miyaura cross‐coupling reaction of bromobenzene and m‐tolylboronic acid using Pd‐decorated Au nanorods as plasmonic catalyst in order to assess which physical effect dominates. Comparative experiments under laser illumination and in dark were performed, demonstrating that under the experimental conditions applied in our study the catalytic activity achieved upon illumination is dominantly based on the conversion of light to heat by the plasmonic catalyst. Pd leached from the catalyst also plays a significant role in the reaction mechanism.

Heck arylation of allyl alcohol catalyzed by Pd(0) nanoparticles

Pd(0) nanoparticles ca. 2 nm in diameter were obtained by the reduction of PdCl2 and Pd(OAc)2 in water at 80 °C in the presence of a PVP-stabilizing polymer. Pd(0) NPs were successfully used in the Heck coupling of allyl alcohol with iodo- and bromobenzenes. Iodobenzenes reacted under solventless conditions or in DMF solution producing 3-arylpropanals and 2-arylpropanals as the main products. The same products were obtained in the reaction of bromobenzene in TBAB as the reaction medium. The stability of Pd(0) NPs was evidenced in recycling experiments. Similar Heck coupling results were also obtained with the palladium compounds PdCl2(cod) and Pd(OAc)2 under the same conditions.

ChemInform Abstract: An Efficient and Simple Ligand from Phthalandione for Palladium‐Catalyzed Suzuki Reaction in Aqueous Media.

Abstract An efficient and simple ligand derived from phthalandione was used for palladium catalyzed Suzuki coupling reaction in water/ethanol (V/V = 2/1) under aerobic conditions. The reaction exhibited a high catalytic efficiency even with lower Pd loading (0.002 mol %). In this work, the catalyst could be successfully used in coupling reaction between various aryl halides with phenylboronic acid in excellent yields with high turnover number (TON) (the maximal TON was up to 49,000 for the reaction of bromobenzene with phenylboronic acid). Moreover, this new ligand had been elucidated by 1H NMR, 13C NMR and X-ray crystal diffraction.

Iminophosphine palladium(II) complexes: synthesis, characterization, and application in Heck cross‐coupling reaction of aryl bromides

Palladium(II) complexes containing phosphorus and nitrogen donor atoms (iminophosphine), dichlorido{N‐[2‐(diphenylphosphino)benzylidene]‐2‐trifluoromethylaniline}palladium(II) 1, dichlorido{N‐[2‐(diphenylphosphino)benzylidene]‐3‐trifluoromethylaniline}palladium(II) 2, dichlorido{N‐[2‐(diphenylphosphino)benzylidene]‐2‐methylaniline}palladium(II) 3, dichlorido{N‐[2‐(diphenylphosphino)benzylidene]‐3‐methylaniline}palladium(II) 4 have been successfully synthesized and fully characterized by FT‐IR and NMR (1H, 31P, 19F, and 13C) spectroscopy techniques. These complexes were first step tested in the reaction of bromobenzene and styrene to determine the optimal coupling reaction conditions and then successfully applied as catalysts for Heck cross‐coupling reactions of activated and deactivated aryl bromides with styrene derivatives and several acrylates. Copyright © 2014 John Wiley & Sons, Ltd.

Synthesis, characterization and catalytic activity of three palladium(II) complexes containing Schiff base ligands

Three new Pd(II) complexes of Schiff base ligands, namely, [Pd4(L1)4] (1), [Pd2(L2)2Cl2] (2) and [Pd(L3)2Cl2] (3) [HL1 = N-(benzylidene)-2-aminophenol; L2 = N-(2,4-dichlorobenzylidene)-2,6-diethylbenzenamine, L3 = 4-(2,4-dichlorobenzylide-neamino)phenol] have been synthesized using solvothermal methods and characterized by elemental analysis, spectroscopy and single crystal X-ray diffraction. The crystal structures of the free ligands were also determined. The μ-oxygen-bridged tetranuclear cyclometallated Pd(II) complex (1) contains four nearly planar units, in which PdII is four-coordinate. Complex 2 is a μ-chloro-bridged dinuclear cyclometallated Pd(II) complex, whereas complex 3 is mononuclear. The Heck reactions of bromobenzene with acrylic acid catalyzed by complexes 1–3 have also been studied.

C–Br Activation of Aryl Bromides at Ni0(NHC)2: Stoichiometric Reactions, Catalytic Application in Suzuki–Miyaura Cross-Coupling, and Catalyst Degradation

Complex [Ni2(iPr2Im)4(COD)] (1) (iPr2Im = 1,3-diisopropylimidazolin-2-ylidene) is a very efficient catalyst for the Suzuki–Miyaura cross-coupling reaction of 4-bromotoluene with phenylboronic acid and also mediates the Ullmann-type homo-cross-coupling reaction of bromobenzene with a moderate efficiency. Stoichiometric reactions of complex 1 with aryl bromides (ArBr) at room temperature lead to mixtures of aryl bromo complexes of the type trans-[Ni(iPr2Im)2(Br)(Ar)] and the bis(bromo) complex trans-[Ni(iPr2Im)2(Br)2] 2. The complexes trans-[Ni(iPr2Im)2(Br)(Ar)] (for Ar = Ph 3, 4-MeC6H44, 4-Me(O)CC6H45, 4-MeOC6H46, 4-MeSC6H47, 4-Me2NC6H48, 2-C5NH49) can be selectively synthesized by working at low temperatures and using a high dilution of the starting materials. A major deactivation pathway for trans-[Ni(iPr2Im)2(Br)(Ar)] was identified in the presence of aryl bromides. This deactivation process includes (i) the formation of trans-[Ni(iPr2Im)2(Br)2] from trans-[Ni(iPr2Im)2(Br)(Ar)] (2) and ArBr and (ii) the formation of an imidazolium salt of the type 2[iPr2Im-Ar]+[NiBr4]2– from trans-[Ni(iPr2Im)2(Br)2] (2) and ArBr. The reactions of complex 2 with a series of aryl halides at higher temperatures lead to the decomposition of the bis(carbene) nickel moiety with formation of the imidazolium salts 2[iPr2Im-Ar]+[NiBr2X2]2– (for X = I, Ar = Ph 10 and X = Br, Ar = Ph 11, 4-MeC6H412, 4-FC6H413, 4-OSi(CH3)3-C6H414) in high yields.

ChemInform Abstract: Synthesis and X-Ray Structure of cis-4b,9b-Diphenyl-4b,5,9b,10- tetrahydroindeno(2,1-a)indene-5,10-dione.

The X-ray structure of the title compound 3 and a possible mechanism for its formation from the reaction of bromobenzene and the trimethylsilyl enolate of methyl phenylacetate 2 with lithium diisopropylamide in tetrahydrofuran are presented.

Phosphane-free C–C Heck couplings catalyzed by Pd(II) fluorinated aniline complexes of the type trans-[PdCl 2(NH 2Ar F) 2

A series of palladium fluoro-aniline complexes of the trans-[PdCl 2(NH 2Ar F ) 2] type were synthesized in good yields by direct reaction of trans-[PdCl 2(C 6H 5CN)] with Ar F NH 2; Ar F = C 6H 3-2,3-F 2 ( 1), C 6H 3-2,5-F 2 ( 2), C 6H 3-3,4-F 2 ( 3), C 6H 3-3,5-F 2 ( 4), C 6H 2-2,3,4-F 3 ( 5), C 6H 2-2,3,6-F 3 ( 6), C 6H 2-2,4,5-F 3 ( 7), C 6H 2-2,4,6-F 3 ( 8), C 6F 4-4-H ( 9), C 6F 5 ( 10). The crystal structures of complexes 3, 4 and 5 were determined. Heck coupling reactions were carried out using complexes 1–10 as catalysts in order to examine the effect of the fluorinated anilines in the reaction of bromobenzene and styrene.

Pd catalyzed Heck reaction with the catalytic system [Pd(Ph 2PC 6H 4-2-(CH 2NMe 2))(SR F) 2] : Examination of the electronic effects of fluorinated thiolates

A series of palladium thiolate complexes of the [Pd(Ph 2PC 6H 4-2-(CH 2NMe 2))(SR F) 2] type have been synthesized in good yields by metathetical reactions of [Pd(Ph 2PC 6H 4-2-(CH 2NMe 2))Cl 2] ( 1) with [Pb(SR F) 2], (SR F = S − C 6F 5, S − C 6F 4-4-H, S − C 6H 4-2-CF 3, S − C 6H 4-4-F, S − C 6H 4-2-F) and their crystal structures determined. Heck coupling reactions were carried out using [Pd(Ph 2PC 6H 4-2-(CH 2NMe 2))(SR F) 2], SR F = S − C 6F 5 ( 2), S − C 6F 4-4-H ( 3), S − C 6H 4-2-CF 3 ( 4), S − C 6H 4-4-F ( 5), S − C 6H 4-2-F ( 6) complexes as catalysts in order to examine the effect of the thiolates in the reaction of bromobenzene and styrene. The results obtained indicate that the less electron-withdrawing substituents on the thiolate moiety may favor higher yields in the Pd catalyzed Heck reaction using [Pd(Ph 2PC 6H 4-2-(CH 2NMe 2))(SR F) 2] as catalysts.

Palladium(II) Complexes with Chelating P,O-Ligands as Catalysts for the Heck Reaction

We have synthesized a series of palladium(II) complexes derived from chelating phosphino carboxylic and sulfonic acids. These compounds form highly active catalysts for the Heck reaction of bromobenzene with styrene and n-butyl acrylate. High yields and turnover numbers of up to 96,000 have been obtained.

1,1 ′-Bis(diphenylphosphino)ferrocene]palladium(II) complexes with fluorinated benzenethiolate ligands: examination of the electronic effects in the solid state, solution and in the Pd-catalyzed Heck reaction with the catalytic system [Pd(dppf)(SR F) 2

A series of palladium thiolate complexes of the type [Pd(dppf)(SR F) 2] have been synthesized in good yields by metathetical reactions of [Pd(dppf)Cl 2] with [Pb(SR F) 2], (SR F= −SC 6F 5, −SC 6F 4-4-H, −SC 6H 4-2-CF 3, −SC 6H 4-4-F, −SC 6H 4-3-F) and their crystal structures determined. The effect of the different thiolates in the structural properties of the complexes both in the solid state and in solution have been analyzed. Heck coupling reactions were carried out using the complexes [Pd(dppf)(SR F) 2], SR F= −SC 6F 5 ( 1), −SC 6F 4-4-H ( 2), −SC 6H 4-2-CF 3 ( 3), −SC 6H 4-4-F ( 4), −SC 6H 4-3-F ( 5) as catalysts in order to examine both the effect of the thiolates and the P–Pd–P bite angles in the reaction of bromobenzene and styrene. The results obtained indicate that electron-withdrawing substituents may favor higher yields in the Pd catalyzed Heck reaction using [Pd(dppf)(SR F) 2] as catalysts.

Reactions of chlorobenzene and bromobenzene with methyl acrylate using a conventional supported palladium catalyst

Reactions of bromobenzene and chlorobenzene with methyl acrylate were carried out in N-methylpyrrolidone (NMP) over a conventional Pd/C catalyst under Heck coupling conditions indicating both heterogeneous and homogeneous character. Benzene and biphenyl are produced in addition to the Heck coupling product of methyl cinnamate. It is proposed that the formation of methyl cinnamate and biphenyl proceed homogeneously with dissolved palladium species, while the formation of benzene takes place heterogeneously on the surface of supported palladium particles or free colloidal particles formed during the reaction.

The Synthesis and Catalytic Application of a New Class of Imprinted Silica

AbstractThe effect of chemical environment surrounding a synthetic heterogeneous catalyst active site is investigated using the hydrophilic imprinting of silica. Two model reaction systems have been used for this study: (i) Knoevenagel condensation of 3-nitrobenzaldehyde and malononitrile and (ii) Suzuki coupling of bromobenzene and phenylboronic acid. Using a catalyst in which isolated imprinted amines are surrounded by an acidic silanol-rich environment led to rate accelerations of over 120-fold relative to catalysts in which the amines are surrounded by a hydrophobic environment consisting of trimethylsilyl functional groups for system (i). This result parallels our previous study on the effect of the outer sphere composition on rate acceleration of Knoevenagel reactions using isophthalaldehyde as the aldehyde reactant. We also extended our method for the hydrophilic imprinting of bulk silica to organometallic systems, by successfully synthesizing a tethered palladium complex within the imprinted pocket. This material was used as an active catalyst for (ii). Our results show that a hydrophobic framework environment results in higher initial turnover frequencies than an acidic silanol-rich framework for the Suzuki coupling reaction of bromobenzene and phenylboronic acid, albeit with a lower overall effect than observed in the Knoevenagel system (i). Altogether, these results demonstrate the control of chemical reactivity via the rational design of the outer sphere using an imprinting approach.

Synthesis and X-ray structure of cis-4b,9b-diphenyl-4b,5,9b,10-tetrahydroindeno[2,1-a]indene-5,10-dione

The X-ray structure of the title compound 3 and a possible mechanism for its formation from the reaction of bromobenzene and the trimethylsilyl enolate of methyl phenylacetate 2 with lithium diisopropylamide in tetrahydrofuran are presented.

Kinetics and mechanism of a one-step alternative to the Grignard reaction

The kinetics of the ‘one-step alternative to the Grignard reaction’ between bromobenzene, benzaldehyde, and lithium have been studied with tetrahydrofuran as solvent. The rate of formation of the product, diphenylmethanol, is first-order in bromobenzene and in lithium surface area, and zero-order in benzaldehyde. The activation energy is 3.42 ± 0.59 kJ mol–1. These data are consistent with a rate-determining step involving intermediate formation of phenyl-lithium by reaction of bromobenzene with lithium. The one-step process has also been employed with organic bromides to synthesise ketones from nitriles and alkylarylhydroxylamines from 2-methyl-2-nitrosopropane. In the former the yields were poorer than from conventional reactions but in the latter yields compared very favourably with those from the Grignard reaction.

ChemInform Abstract: ELECTRON SPIN RESONANCE STUDY OF GAMMA‐RAY‐INDUCED REACTIONS OF BROMOBENZENE AND P‐BROMOPHENOL, BROMINE ATOM‐AROMATIC COMPLEXES

Chemischer InformationsdienstVolume 5, Issue 43 Physical Organic Chemistry ChemInform Abstract: ELECTRON SPIN RESONANCE STUDY OF GAMMA-RAY-INDUCED REACTIONS OF BROMOBENZENE AND P-BROMOPHENOL, BROMINE ATOM-AROMATIC COMPLEXES J. EDWARDS, J. EDWARDSSearch for more papers by this authorD. J. HILLS, D. J. HILLSSearch for more papers by this authorS. P. MISHRA, S. P. MISHRASearch for more papers by this authorM. C. R. SYMONS, M. C. R. SYMONSSearch for more papers by this author J. EDWARDS, J. EDWARDSSearch for more papers by this authorD. J. HILLS, D. J. HILLSSearch for more papers by this authorS. P. MISHRA, S. P. MISHRASearch for more papers by this authorM. C. R. SYMONS, M. C. R. SYMONSSearch for more papers by this author First published: October 29, 1974 https://doi.org/10.1002/chin.197443054AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume5, Issue43October 29, 1974 RelatedInformation

Electron spin resonance study of γ-ray-induced reactions of bromobenzene and p-bromophenol: bromine atom–aromatic complexes

Radicals exhibiting a large hyperfine interaction with bromine, obtained from solutions of the title compounds by γ-irradiation at 77 K, are identified as cyclohexadienyl radicals with hydrogen added at the bromine site.

The Reaction of Bromobenzene with Copper(I) Chloride - Pyridine Complex in Nitrobenzene

The Reaction of Bromobenzene with Copper(I) Chloride - Pyridine Complex in Nitrobenzene