Palladium-Catalyzed C-Phenylation of Methyl Acrylate with Triphenylbismuth Dicarboxylates

A new catalytic reaction of C-phenylation of methyl acrylate with bismuth derivatives Ph₃Bi(O₂CR)₂ (R = H, Me, Et, Bu, CF₃, Ph) or Ph₃BiCl₂ in a 3 : 1 ratio was studied. The reaction was performed in the presence of 4 mol % palladium compounds PdCl₂, Pd(OAc)₂, Pd₂(dba)₃, Pd(Ph₃P)₂Cl₂, and PdLCl₂ (L = dppm, dppe, dppp, dppb, dppf, binap, xantphos) at 50°C in CH₃CN, DMF, THF, or CH₂Cl₂ and gave methyl cinnamate (yield up to 85% based on the starting bismuth compound), diphenyl (up to 138%), and benzene (up to 59%).     

Catalytic C-phenylation of methyl acrylate with triphenylantimony(v) dicarboxylates

Triphenylantimony dicarboxylates Ph₃Sb(OAc)₂ and Ph₃Sb(O₂CEt)₂ are efficient C-phenylating agents for methyl acrylate. In the presence of the Pd(OAc)₂, Li₂PdCl₄ or Pd₂(dba)₃(CHCl₃) catalysts in MeCN at 50 °C, methyl cinnamate forms in 70—150% yield with respect to Sb^V. Copper(ii) salts do not increase the reaction yield.     

Phenyl Derivatives of Antimony(III,V) and Bismuth(III,V) in the Presence of Palladium Salts,as C-Phenylating Agents for Methyl Acrylate

The C-phenylation of methyl acrylate to methyl cynnamate with Ph₃Sb, Ph₃SbX₂ (X = Cl, OAc), Ph₃Bi, and Ph₃BiX₂ (X = OAc, O₂CEt) in the presence of PdCl₂, Pd(OAc)₂, Li₂PdCl₄, NaPd(OAc)Cl₂, and Na₂Pd(OAc)₂Cl₂ was studied to show that the reactions with Ph₃Sb and Ph₃Sb(OAc)₂ are more selective and give higher yields of the target product than those with Ph3Bi and Ph₃Bi(OAc)₂, while Ph₃M(OAc)₂ are preferred over Ph₃M. Copper(II) alkanecarboxylate additives have no effect on the yield of methyl cynnamate in the reactions with Ph₃Sb.     

Competing reactions of hydrophenylation and phenylation in tetraphenylantimony chloride methyl acrylate palladium chloride system

A new catalytic reaction of the competing phenylation and hydrophenylation in air of methyl acrylate with tetraphenylantimony chloride in the presence of PdCl₂ (0.04 mol per 1 mol of organometallic compound) in acetonitrile at 50°C for 6 h was studied. The yields of methyl cynnamate and methyl hydrocynnamate were 0.73 and 0.27 mol mol^?1 respectively. The products ratio obtained depends slightly on the process duration, the Ph₄SbCl and methyl acrylate ratio, and the structure of Pd salt [PdCl₂, Pd(OAc)₂, Li₂PdCl₄], but significantly on the nature of a solvent (MeCN > DMF > THF). The use of Ph₄SbCl instead of Ph₄SbBr leads to decrease in the yield of methyl hydrocynnamate to 0.04 mol mol^?1. In the reactions of Ph₄SbX (X = F, I, OAc, O₂CEt) the product is not formed at all.     

Dephenylation of triphenylbismuth(v) and antimony(v) derivatives in a methyl acrylate—methanol system in the presence of copper and palladium salts

The influence of the central metal atom and acid residue in a molecule of organometallic compound Ph₃MX₂ (M = Bi, Sb; X = Cl, Br, OAc, O₂CEt) on the direction and yield of dephenylation products in a methyl acrylate— methanol system in the presence of Cu(OAc)₂ and Na₂PdCl₂(OAc)₂ was studied at 50 °C in acetonitrile. The main product of dephenylation of the antimony compounds is methyl cinnamate (yield 0.31–1.59 moles per mole of the starting Ph₃SbX₂), while anisole (0.55–0.97 mol) and halobenzene (0.67–1.04 mol) are those for compounds Ph₃Bi(O₂CR)₂ and Ph₃BiHal₂, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 655–658, April, 2006.     

Catalytic system based on triphenylantimony and tert-butyl hydroperoxide for the Heck reaction

Triphenylantimony was used as an efficient agent for C-phenylation of methyl acrylate in the presence of Bu^tOOH (1 to 2 mol) and a palladium salt (PdCl₂, Li₂PdCl₄; 0.04 mol) in AcOH at 50 °C. The yield of methyl cinnamate is two moles per mole of the starting Ph₃Sb.     

Synthesis of regioregular poly(3‐octylthiophene)s via Suzuki polycondensation and end‐group analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Regioregular poly(3‐octylthiophene)s were synthesized through a palladium‐catalyzed Suzuki polycondensation of 2‐(5‐iodo‐4‐octyl‐2‐thienyl)‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolane. The effects of the palladium catalyst {tetrakis(triphenylphosphine)palladium(0) [Pd(PPh₃)₄], palladium(II) acetate [Pd(OAc)₂], [1, 1′‐bis(diphenylphosphino)ferrocene]dichloropalladium(II) [Pd(dppf)Cl₂], tris(dibenzylideneacetone)dipalladium(0), or bis(triphenylphosphine)palladium(II) dichloride [Pd(PPh₃)₂Cl₂]} and the reaction conditions (bases and solvents) were investigated. NMR spectroscopy revealed that poly(3‐octylthiophene)s prepared via this route were essentially regioregular. According to size exclusion chromatography, the highest molecular weights were obtained with in situ generated Pd(PPh₃)₄ and tetrakis(tri‐o‐tolylphosphine]palladium(0) {Pd[P(o‐Tol)₃]₄} catalysts or more reactive, phosphine‐free Pd(OAc)₂. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry was used to analyze end groups and allowed the determination of some mechanistic aspects of the Suzuki polycondensation. The polymers were commonly terminated with hydrogen or iodine as a result of deboronation and some deiodination. Pd(PPh₃)₄, Pd(PPh₃)₂Cl₂, and Pd[P(o‐Tol)₃]₄ induced aryl–aryl exchange reactions with the palladium center and resulted in some chains having phenyl‐ and o‐tolyl‐capped chain ends. Pd(dppf)Cl₂ yielded only one type of chain, and it had hydrogen end groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1454–1462, 2005     

Hydrocarbobutoxylation of Phenylacetylene on Palladium Complexes: A Solvent Effect

Data on changes in the activity of the Pd(dba)₂/2TsOH/10Ph₃P (dba is dibenzylideneacetone) and PdCl₂(Ph₃P)₂/8Ph₃P catalytic systems in the reaction of phenylacetylene with CO and n-butanol under the action of a solvent (aromatic hydrocarbons, chloroalkanes, ethers, esters, ketones, and dipolar aprotic media) are presented. The differences found in the response of either of the systems to changes in the properties of the medium are discussed in terms of a scheme of the catalytic cycle of reaction. It is noted that activity does not correlate with the physicochemical characteristics (polarity, basicity, and electron-acceptor ability) of solvents.     

Synthese und Struktur der Komplexe [(n‐Bu)4N]2[{(THF)Cl4Re≡N}2PdCl2], [Ph4P]2[(THF)Cl4Re≡N‐PdCl(μ‐Cl)]2 und [(n‐Bu)4N]2[Pd3Cl8]

Synthesis and Crystal Structure of the Complexes [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}₂PdCl₂], [Ph₄P]₂[(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂ and [(n‐Bu)₄N]₂[Pd₃Cl₈] The threenuclear complex [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}₂ PdCl₂] ( 1 ) is obtained in THF by the reaction of PdCl₂(NCC₆H₅)₂ with [(n‐Bu)₄N][ReNCl₄] in the molar ration 1:2. It forms orange crystals with the composition 1· THF crystallizing in the monoclinic space group C2/c with a = 2973.3(2); b = 1486.63(7); c = 1662.67(8)pm; β = 120.036(5)° and Z = 4. If the reaction is carried out with PdCl₂ instead of PdCl₂(NCC₆H₅)₂, orange crystals of hitherto unknown [(n‐Bu)₄N]₂[Pd₃Cl₈] ( 3 ) are obtained besides some crystals of 1· THF. 3 crystallizes with the space group P1¯ and a = 1141.50(8), b = 1401.2(1), c = 1665.9(1)pm, α = 67.529(8)°, β = 81.960(9)°, γ = 66.813(8)° and Z = 2. In the centrosymmetric complex anion [{(THF)Cl₄Re≡N}₂PdCl₂]^2— a linear PdCl₂ moiety is connected in trans arrangement with two complex fragments [(THF)Cl₄Re≡N]^— via asymmetric nitrido bridges Re≡N‐Pd. For Pd(II) thereby results a square‐planar coordination PdCl₂N₂. The linear nitrido bridges are characterized by distances Re‐N = 163.8(7)pm and Pd‐N = 194.1(7)pm. The crystal structure of 3 contains two symmetry independent, planar complexes [Pd₃Cl₈]^2— with the symmetry 1¯, in which the Pd atoms are connected by slightly asymmetric chloro bridges. By the reaction of equimolar amounts of [Ph₄P][ReNCl₄] and PdCl₂(NCC₆H₅)₂ in THF brown crystals of the heterometallic complex, [Ph₄P]₂[(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂ ( 2 ) result. 2 crystallizes in the monoclinic space group P2₁/n with a = 979.55(9); b = 2221.5(1); c = 1523.1(2)pm; β = 100.33(1)° and Z = 2. In the central unit ClPd(μ‐Cl)₂PdCl of the centrosymmetric anionic complex [(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂^2— the coordination of the Pd atoms is completed by two nitrido bridges Re≡N‐Pd to nitrido complex fragments [(THF)Cl₄Re≡N]^— forming a square‐planar arrangement for Pd(II). The distances in the linear nitrido bridges are Re‐N = 163.8(9)pm and Pd‐N = 191.5(9)pm.     

Phenylethenyl-substituted silicones via Heck coupling reaction

Systematic studies of several palladium complexes (Pd(OAc)₂, [PdCl₂(cod)], [Pd₂(dba)₃], [Pd(PPh3)4], [PdCl(SnCl₃)(P{p-Tol}₃)₂], [Pd₂Cl₂(SnCl₃)₂(P{p-Tol}₃)₂]) as potential catalytic systems for arylation of vinylsiloxanes via Heck coupling reactions are described. Catalytic activity and selectivity were studied for a model reaction of trimethylvinylsilane with PhBr and m-ClC₆H₆Br and then the most effective systems were applied for functionalisation of tetramethyltetravinylcyclotetrasiloxane and poly(dimethylsiloxane-co-methylvinylsiloxane), leading to the silicone fluids having high refractive index (1.5–1.6).     

A Highly Versatile Catalyst System for the Cross‐Coupling of Aryl Chlorides and Amines

The syntheses of 2‐(di‐tert‐butylphosphino)‐N,N‐dimethylaniline ( L1 , 71 %) and 2‐(di‐1‐adamantylphosphino)‐N,N‐dimethylaniline ( L2 , 74 %), and their application in Buchwald–Hartwig amination, are reported. In combination with [Pd(allyl)Cl]₂ or [Pd(cinnamyl)Cl]₂, these structurally simple and air‐stable P,N ligands enable the cross‐coupling of aryl and heteroaryl chlorides, including those bearing as substituents enolizable ketones, ethers, esters, carboxylic acids, phenols, alcohols, olefins, amides, and halogens, to a diverse range of amine and related substrates that includes primary alkyl‐ and arylamines, cyclic and acyclic secondary amines, N? H imines, hydrazones, lithium amide, and ammonia. In many cases, the reactions can be performed at low catalyst loadings (0.5–0.02 mol % Pd) with excellent functional group tolerance and chemoselectivity. Examples of cross‐coupling reactions involving 1,4‐bromochlorobenzene and iodobenzene are also reported. Under similar conditions, inferior catalytic performance was achieved when using Pd(OAc)₂, PdCl₂, [PdCl₂(cod)] (cod=1,5‐cyclooctadiene), [PdCl₂(MeCN)₂], or [Pd₂(dba)₃] (dba=dibenzylideneacetone) in combination with L1 or L2 , or by use of [Pd(allyl)Cl]₂ or [Pd(cinnamyl)Cl]₂ with variants of L1 and L2 bearing less basic or less sterically demanding substituents on phosphorus or lacking an ortho‐dimethylamino fragment. Given current limitations associated with established ligand classes with regard to maintaining high activity across the diverse possible range of C? N coupling applications, L1 and L2 represent unusually versatile ligand systems for the cross‐coupling of aryl chlorides and amines.     

Syntheses,characterization and anti‐microbial activities of palladium(II) and palladium(IV) complexes of 3,10‐C‐meso‐Me8[14]diene (L1) and its reduced isomeric anes (LA,LB and LC). Crystal and molecular structure of [PdL1][Pd(SCN)4]

The reactions of 3,10‐C‐meso‐3,5,7,7,10,12,14,14‐octamethyl‐1,4,8,11‐tetraazacyclotetradecadiene, L¹, and two isomers (L_B and L_C, differing in the orientation of methyl groups on the chiral carbon atoms) of its reduced form with PdCl₂ and K₂[Pd(SCN)₄], produce square‐planar tetrachloro‐ and tetrathiocyano‐palladium(II) complexes of general formulae [PdL′][PdCl₄] and [PdL′][Pd(SCN)₄] (L′ = L¹, L_B and L_C), respectively. By contrast, the third ane isomer, L_A, upon reaction with the same reagents, PdCl₂ and K₂[Pd(SCN)₄], formed octahedral tetrachloro‐ and tetrathiocyanato‐palladium(IV) complexes [PdL_ACl₂]Cl₂ and [PdL_A(SCN)₂](SCN)₂, respectively. The [PdL′][PdCl₄] and [PdL_ACl₂]Cl₂ complexes undergo substitution reactions with KSCN to form square‐planar and octahedral tetrathiocyanato complexes [PdL′][Pd(SCN)₄] and [PdL_A(SCN)₂](SCN)₂, respectively. All complexes have been characterized on the basis of analytical, spectroscopic, conductometric and magnetochemical data. The anti‐fungal and anti‐bacterial activities of these complexes have been studied against some phytopathogenic fungi and bacteria. The crystal structure of [PdL¹][Pd(SCN)₄] has been confirmed by X‐ray crystallography and shows with square‐planar PdN₄ and PdS₄ geometries [monoclinic, space group C2/c, a = 17.884(3) Å, b = 14.734(2) Å, c = 11.4313(18) Å, β = 104.054(5)° ]. Copyright © 2008 John Wiley & Sons, Ltd.     

Silicon–oxygen bonding on diphenylsilane through palladium(II)‐catalysed reactions

The reactions of phenols with diphenylsilane are catalysed by palladium(II) catalysts such as Pd(TMEDA)Cl₂ (TMEDA = tetramethylethylenediamine), Pd(DEED)Cl₂ (DEED = N,N′‐diethylethylenediamine), Pd(TEEDA)Cl₂ (TEEDA = N,N′‐tetraethylethylenediamine) or PdCl₂ to form hydrated silanols with molecular formula Ph₂Si(OR)OH·nH₂O (when R = C₆H₅, n = 3; when R = p‐CH₃C₆H₄ or o‐CH₃C₆H₄, n = 1). The reaction of hydroquinone with diphenylsilane in the presence of catalytic amounts of Pd(TMEDA)Cl₂ forms an Si–O‐bonded hydrated aggregate of composition [(C₆H₅)₂Si(OC₆H₄O).0.5H₂0] _n. p‐Benzoquinone reacted with diphenylsilane in the presence of a catalytic amount of Pd(TMEDA)Cl₂ and the reaction proceeded via a multiple pathway involving quinhydrone as an intermediate charge‐transfer complex which reacted further with diphenylsilane to give a linear siloxane. Copyright ­© 2000 John Wiley & Sons, Ltd.     

Synthesis, Characterization of Mixed Ligand Palladium(II) Complexes of Triphenylphosphine and Anilines and their Enzyme Inhibition Studies against β-glucuronidase. The Crystal Structure of trans-dichloro-(m-chloroaniline)(triphenylphosphine)palladium(II)

A number of palladium(II) complexes with Ph₃P and aromatic amines as ligands having the general formula [(Ph₃P)Pd(Ph₃P)(NH₂R)Cl₂] {where R = Ph (1), m-ClC₆H₄ (2), p-ClC₆H₅ (3)} and [Pd(CH₃NHPh)Cl₂] (4), have been synthesized and characterized by elemental analysis, IR, ¹H and ¹³C NMR. The X-ray crystal structure of [(Ph₃P)Pd(m-ClC₆H₄NH₂)Cl₂] · CH₂ Cl₂ (2) shows a distorted square planar environment around the Pd(II) ion with the P–Pd–N and Cl(1)–Pd–Cl(2) bond angles of 174.88(5)° and 176.77(2)° respectively. The complexes were screened for enzyme inhibition activity against β-glucuronidase and found to be active.     

Synthesis of a novel bridged 2-(cyclopentadienyl)-indene system using Pd-catalyzed Negishi-type cross coupling

The palladium-catalyzed Negishi-type C-C-coupling of the nonaromatic systems 2-indenyl and cyclopentadienyl were investigated. The employed catalyst played a decisive role in product formation. Instead of Pd(PPh₃)₄, the more bulky Pd(dppf)Cl₂·CH₂Cl₂ led to the desired system in distinguished yields.     

Synthesis and characterizations of N,N′‐bis(diphenylphosphino)‐2‐(aminomethyl)aniline derivatives: application of a palladium(II) complex as pre‐catalyst in Heck and Suzuki cross‐coupling reactions

The reaction of 2‐(aminomethyl)aniline with 2 equivalents of PPh₂Cl in the presence of Et₃N, proceeds in CH₂Cl₂ to give N,N′‐bis(diphenylphosphino)‐2‐(aminomethyl)aniline 1 in good yield. Oxidation of 1 with aqueous H₂O₂, elemental sulfur or gray selenium gave the corresponding oxide, sulfide and selenide dichalcogenides [Ph₂P(E)NHC₆H₄CH₂NHP(E)Ph₂] (E: O, 2a; S, 2b; Se, 2c), respectively. The reaction of [Ph₂PNHC₆H₄CH₂NHPPh₂] with PdCl₂(cod), PtCl₂(cod) and [Cu(MeCN)₄]PF₆ gave the corresponding chelate complexes, PdCl₂1, PtCl₂1 and [Cu(1)₂]PF₆. The new compounds were fully characterized by NMR, IR spectroscopy and elemental analysis. The catalytic activity of the Pd(II) complex was tested in the Suzuki coupling and Heck reactions. The Pd(II) complex catalyzes the Suzuki coupling and Heck reaction, affording biphenyls and stilbenes respectively, in good yields. Copyright © 2009 John Wiley & Sons, Ltd.     

Reaction of coordinated phosphines: VI. Divalent palladium promoted cleavage of carbon—phosphorus bonds in tertiary phosphines

The important role of divalent palladium in the cleavage of carbon—phosphorus bond of tertiary phosphines is revealed by the study of the phenylation in the Pd(OAc)₂Ph₃P-styrene system under various conditions; reaction atmosphere, ratio of Ph₃P/Pd(OAc)₂, and addition of ethanol or Cu^II(OAc)₂ · H₂O.     

Palladium-catalyzed reaction of some triphenylbismuth(V) sulfonates and phenolates with methyl acrylate

Triphenylbismuth(V) derivatives Ph₃BiX₂ [X = OC₆H₂(NO₂)₃-2,4,6, OC₆H₂(NO₂-4)Br₂-2,6, OTs, OSO₂C₆H₄OH-4] react with methyl acrylate and PdCl₂ (1:3:0.04 molar ratio) in acetonitrile at 20°C to form the cross-coupling products, methyl cinnamate (0.26–0.51 mol mol^?1 starting bismuth compound) and methyl hydrocinnamate (0–0.17 mol mol^?1); diphenyl, the homocoupling product (0–0.13 mol mol^?1); and benzene (0.02–0.15 mol mol^?1). The reaction of Ph₃Bi(OSO₂C₆H₄OH-4)₂ is characterized by the selective formation of methyl cinnamate, but the reagent activity is low. Ph₃Bi(OTs)₂ exhibits the highest activity among the derivatives studied, but the reaction selectivity is low. The mechanisms of the palladium-catalyzed formation of homo-and cross-coupling products are proposed.     

Palladium(II) Chloride Interaction with Chelating BIS(Phosphine Sulfides). Effect of the Ligand Structure on the Complex Geometry

Abstract

Interaction of PdCl₂ in chloroform with bis(phosphine sulfides) Ph₂P(S)?X?P(S)Ph₂ (X?CH₂, C(CH₃)₂, CH₂CH₂, NH, S, and SCH₂S) has been studied. Mechanism of the reaction has been found to vary dramatically with the identity of X. The structures of the resultant complexes were evaluated by UV and IR spectroscopy. Crystal structures were were determined by X-ray diffraction for two of the compounds (A: [Ph₂P(S)?(CH₂)₂?P(S)Ph₂]PdCl₂ · CH₃CN, P2₁/n, Z = 4, a = 10.104(2), b = 20.939(4), c = 14.034(3) Å, γ = 102.54(2)· B: [Ph₂P(S)?N?P(S)Ph₂]₂Pd · 2CHCl₃, Pl, Z = 1, a = 9.539(1), b = 12.333(3), c = 12.866 Å, α = 111.83(2)°, β = 96.70(3)° γ = 99.84(3)°).     

Palladium (II) complexes with mono-oxide 1,1′-bis(diphenylphosphino)metallocene ligands [Fe(η-C5Me4PPh2)(η-C5Me4P{O}Ph2)] and [Os(η-C5H4PPh2)(η-C5H4P{O}Ph2)]

The monoxides [Fe(η⁵-C₅Me₄PPh₂)(η⁵-C₅Me₄P{O}Ph₂)] (1) and [Os(η⁵-C₅H₄PPh₂)(η⁵-C₅H₄P{O}Ph₂)] (2) have been prepared by treatment of the corresponding diphosphines with CCl₄ and methanol.These ligands react with [Pd(PhCN)₂Cl₂] to give dichloride complexes of different structure.The dimeric complex [{Os(η⁵-C₅H₄PPh₂)(η⁵-C₅H₄P{O}Ph₂)}PdCl(μ-Cl)]₂ (4) contains the monodentate P-coordinated osmocene ligand with the free P{O}Ph₂ group, while the octamethylferrocene ligand gives the chelate k²-P,O complex [{Fe(η⁵-C₅Me₄PPh₂)(η⁵-C₅Me₄P{O}Ph₂)}PdCl₂] (3).The structures of 3 and 4 have been determined crystallographically.Treatment of 3 and 4 with silver salts in CH₂Cl₂ or acetonitrile leads to the corresponding dicationic complexes[{M(η⁵-C₅R₄PPh₂)(η⁵-C₅R₄P{O}Ph₂)}Pd(MeCN)_x]²⁺ (5, M = Fe, R = Me; 6, M = Os, R = H). Complex 5 decomposes upon isolation, in contrast 6 is rather stable, probably due to Os-Pd bonding. The dichlorides 3 and 4 catalyze catalytic amination of p-bromotoluene with N-(4-tolyl)morpholine with lower activity than (dppf)PdCl₂, however they perform comparable to (dppf)PdCl₂ activity in coupling of p-bromotoluene with p-methoxyphenyl boronic acid.