- Vinylalumination of fluoro-carbonyl compounds
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Ethyl acrylate and acrylonitrile fail to undergo efficient Baylis- Hillman reaction with fluoral, but provide good yields of products with pentafluorobenzaldehyde. Alternately, unsubstituted and β-substituted [α- (ethoxycarbonyl)vinyl]aluminum react with perfluoroalkyl and -aryl aldehydes and ketones to provide the α-hydroxyalkenylated fluoro-organic compounds in good to excellent yields.
- Ramachandran, P. Veeraraghavan,Reddy, M. Venkat Ram,Rudd, Michael T.,De Alaniz, Javier Read
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- Unusual temperature dependence of salt effects for "on water" Wittig reaction: Hydrophobicity at the interface
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An unusual variation with temperature of the salt effects in aqueous Wittig reaction is observed, suggesting that hydrophobic acceleration of reactions comprising "on water" reactants is fundamentally different from that for reactions with small non-polar solutes. The Royal Society of Chemistry.
- Tiwari, Shraeddha,Kumar, Anil
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- Pd/Cu-Free Cobalt-Catalyzed Suzuki and Heck Using Green Bio-Magnetic Hybrid and DFT-Based Theoretical Study
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Abstract: Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds (Co-ligand@MNPs/Ch). The structure of these nanocomposites was confirmed by various physicochemical techniques such as FT-IR, XRD, TGA, VSM, TEM, SEM, CHNS and ICP-OES. These nano composites exhibit remarkable catalytic efficiency for Suzuki and Heck cross-coupling reactions in mild and green reaction conditions. The facile accessibility of starting materials, possible performance in air and eco-friendly conditions are merits of our catalysts. In addition, to describe and go insight to role and effect of ligands present in these catalysts, electrostatic interactions, density functional theory (DFT) model in molecular method were employed. Graphic Abstract: [Figure not available: see fulltext.]
- Hajipour, Abdol R.,Khorsandi, Zahra,Ahmadi, Mehnoosh,Jouypazadeh, Hamidreza,Mohammadi, Bahareh,Farrokhpour, Hossein
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- Meta -Selective C-H functionalisation of aryl boronic acids directed by a MIDA-derived boronate ester
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N-Methyliminodiacetic acid (MIDA) boronates are boronic acid derivatives which are stable to reduction, oxidation and transmetalation. This has led to their widespread use as boronic acid protecting groups (PGs) and in iterative cross-couplings. We describe herein the development of a novel MIDA derivative that acts in a dual manner, as a protecting group and a directing group (DG) for meta C(sp2)-H functionalisation of arylboronic acids. Palladium catalysed C-H alkenylations, acetoxylations and arylations are possible, at room temperature and under aerobic conditions. Deprotection to reveal the functionalised boronic acids is rapid and allows for full recovery of the DG. The technique allows the facile diversification of aryl boronic acids and their subsequent use in a range of reactions or in iterative processes.
- Cordier, Christopher J.,Spivey, Alan C.,White, Andrew J. P.,Williams, Alexander F.
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- Magnetically recoverable nanostructured Pd complex of dendrimeric type ligand on the MCM-41: Preparation, characterization and catalytic activity in the Heck reaction
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A palladium complex of a dendrimer type ligand of aminoethylacrylamide immobilized onto the mesoporous channels of MCM-41 with magnetic core was prepared and characterized using various techniques such as XRD, TEM, BET, FT-IR, TGA, and VSM. The prepared nanostructured material was found as a magnetically recoverable catalyst for Heck reaction of aryl halides and vinylic C-H. The catalyst is easily recoverable with an external magnet and is reusable with different leaching amounts depending to loading of Pd. A hot filtration test was also performed and gave evidence that Palladium in heterogeneous samples can dissolve and then redeposit on the surface of the support material.
- Abdollahi-Alibeik, Mohammad,Gharibpour, Najmeh,Ramazani, Zahra
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- Palladium(II) oxide impregnated on magnetite as a catalyst for the synthesis of 4-arylcoumarins: Via a Heck-arylation/cyclization process
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Heck-arylation/cyclization was achieved using heterogeneous palladium(ii) oxide impregnated on magnetite catalyst (2.5 mol%) with a lower catalyst loading than that reported for similar processes. Ethanol was used as a non-toxic and bio-renewable solvent. Good yields were afforded using a broad range of substrates (40-98%). The catalyst could be partially recycled, and analyses confirmed the almost total reduction of palladium(ii) oxide to palladium(0) as well as the iodine poissoning effect, which is the main barrier to complete recyclability.
- Pérez, Juana M.,Cano, Rafael,McGlacken, Gerard P.,Ramón, Diego J.
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- Mesoporous Borated Zirconia: A Solid Acid-Base Bifunctional Catalyst
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The development and use of reusable solid catalysts for the selective organic transformation in solvent-free or environmentally benign solvent media is the key interest of modern frontier science. Herein a facile low temperature aqueous solution based chemical route for the synthesis of mesoporous borated zirconia, an acid-base bifunctional solid catalyst, using aqueous zirconium ammonium carbonate complex and borax in presence of cetyltrimethylammonium bromide is presented. The material has a very high surface area and acidity with weak basicity. The catalytic activity of the material was investigated for the solvent-free Knoevenagel condensation reaction of benzaldehyde/substituted benzaldehyde and malononitrile/cyano ethylacetate to confirm the acid-base bifunctionality. High yield (>90%) of the corresponding benzylidene was obtained within 15-30min at room temperature. The evidence that the high catalytic activity is a result of acid-base bifunctionality of the synthesized borated zirconia material was further supported by performing Claisen-Schmidt condensation of benzaldehyde and acetophenone. The methodology was also extended for targeted synthesis of cinnamyl ethyl ester and coumarin or coumarin ester; and resulted in a good yield.
- Sinhamahapatra, Apurba,Pal, Provas,Tarafdar, Abhijit,Bajaj, Hari C.,Panda, Asit Baran
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- A sequential tetra-n-propylammonium perruthenate (TPAP)-Wittig oxidation olefination protocol
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A convenient sequential oxidation-olefination protocol is reported using tetra-n-propylammonium perruthenate (TPAP) as oxidant and phosphonium salts as olefin source. The oxidation reaction mixture is added directly to the phosphorane facilitating an efficient method for this transformation that avoids work-up of potentially sensitive aldehyde intermediates.
- MacCoss, Rachel N.,Balskus, Emily P.,Ley, Steven V.
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- Controlling reactivity in the Fujiwara–Moritani reaction: Examining solvent effects and the addition of 1,3-dicarbonyl ligands on the oxidative coupling of electron rich arenes and acrylates
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A palladium-catalysed direct alkenation of electron rich arenes in the presence of K2S2O8 with an acetic acid/1,4-dioxane solvent combination has been developed. The 1,4-dioxane co-solvent dramatically influences the rate of reaction, giving selectively disubstituted alkenes, while the addition of acetylacetone ligands was shown to increase site selectivity for the alkenation of monofunctionalized arenes. The participation of these carbonyl ligands has been confirmed by ESI-MS studies, with some key in situ intermediates in the catalytic cycle identified. A variety of electron rich arenes and olefinic substrates can be utilised in the direct oxidative coupling to give disubstituted alkenes in moderate to good yields.
- Jones, Roderick C.
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- A photoredox catalysed Heck reaction: Via hole transfer from a Ru(ii)-bis(terpyridine) complex to graphene oxide
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The attachment of homoleptic Ru bis-terpy complexes on graphene oxide significantly improved the photocatalytic activity of the complexes. These straightforward complexes were applied as photocatalysts in a Heck reaction. Due to covalent functionalization on graphene oxide, which functions as an electron reservoir, excellent yields were obtained. DFT investigations of the charge redistribution revealed efficient hole transfer from the excited Ru unit towards the graphene oxide. This journal is
- Rosenthal, Marta,Lindner, J?rg K. N.,Gerstmann, Uwe,Meier, Armin,Schmidt, W. Gero,Wilhelm, René
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- Direct substitution of the hydroxy group in alcohols with silyl nucleophiles catalyzed by indium trichloride
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Straightforward substitution: An excellent combination of a silyl nucleophile and indium catalyst was used to accomplish the dehydroxylation/ alkylation of alcohols under nearly neutral conditions (see scheme, Si = silyl group) even though this type of reaction usually requires at least an equimolar amount of acid.
- Yasuda, Makoto,Saito, Takahiro,Ueba, Masako,Baba, Akio
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- Synthesis, structure, and catalytic activity of complexes of 1,1′-bisisoquinoline with PdCl2 and NiCl2
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New complexes of 1,1′-bisisoquinoline with PdCl2 and NiCl2 were synthesized. The structures of the complexes were established by X-ray diffraction. The PdII complex acts as a catalyst for the Suzuki and Heck reactions and the hydroarylation of norbornene. As exemplified by the Suzuki reaction, the NiII complex can also be used as a catalyst.
- Khrushcheva,Bulygina,Starikova,Sokolov
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- A computational triage approach to the synthesis of novel difluorocyclopentenes and fluorinated cycloheptadienes using thermal rearrangements
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Electronic structure calculations have been used for the effective triage of substituent effects on difluorinated vinylcyclopropane precursors and their ability to undergo vinyl cyclopropane rearrangements (VCPR). Groups which effectively stabilised radicals, specifically heteroarenes, were found to result in the lowest energy barriers. Ten novel precursors were synthesised to test the accuracy of computational predictions; the most reactive species which contained heteroarenes underwent thermal rearrangements at room temperature to afford novel difluorocyclopentenes and fluorinated benzocycloheptadienes through competing VCPR and [3,3]-rearrangement pathways, respectively. More controlled rearrangement of ethyl 3-(1′(2′2′-difluoro-3′-benzo[d][1,3]dioxol-5-yl)cyclopropyl)propenoate (22) allowed these competing pathways to be monitored at the same time and activation energies for both reactions were determined; Ea(VCPR) = (23.4 ± 0.2) kcal mol-1 and Ea([3,3]) = (24.9 ± 0.3) kcal mol-1. Comparing our calculated activation energies with these parameters showed that no single method stood out as the most accurate for predicting barrier heights; (U)M05-2X/6-31+G? methodology remained the best for VCPR but M06-2X/6-31G? was better for the [3,3]-rearrangement. The consistency observed with (U)B3LYP/6-31G? calculations meant that it came closest to a universal method for dealing with these systems. The developed computational design model correctly predicted the observed selectivity of rearrangement pathways for both our system and literature compounds.
- Orr, David,Percy, Jonathan M.,Harrison, Zo? A.
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- Preparation of active and robust palladium nanoparticle catalysts stabilized by diamine-functionalized mesoporous polymers
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A two-step chemical modification process is designed for synthesizing novel diamine-functionalized mesopolymers, which combine the advantage of organic polymers and mesoporous materials, and serve as an efficient scaffold for supporting highly dispersed, catalytically active and robust Pd nanoparticles (NPs). The Royal Society of Chemistry 2008.
- Xing, Rong,Liu, Yueming,Wu, Haihong,Li, Xiaohong,He, Mingyuan,Wu, Peng
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- Green synthesis of palladium nanoparticles via branched polymers: A bio-based nanocomposite for C-C coupling reactions
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Catalytic process is the key process for many chemical industries. In this study, a novel heterogeneous Pd (CMH-Pd(0)) has been prepared by the deposition of palladium nanoparticles (Pd NPs) onto the surface of carboxymethyl functionalized hemicelluloses using ethanol as solvent and in situ reducing agent. The as prepared catalyst was characterized by TEM, HR-TEM, XRD, FT-IR, TGA and XPS. The loading level of Pd in the CMH-Pd(0) catalyst was 0.38 mmol g-1. The catalyst showed high catalytic activity and versatility towards Heck coupling reactions under aerobic conditions and could be readily recovered and reused in at least five successive cycles without obvious loss in activity. The catalyst is promising for its renewability, environmental benefits, efficient catalytic activity, mild reaction conditions, simple product work-up and easy catalyst recovery.
- Wu, Changyan,Peng, Xinwen,Zhong, Linxin,Li, Xuehui,Sun, Runcang
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- Catalytic properties of chiral terpenoid CN-palladacycle in the C - C bond forming reactions
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Chiral camphor-derived CN-palladacycle exhibits high catalytic activity in the Suzuki crosscouplings and hydroarylation of norbornene under mild conditions.
- Bulygina,Khrushcheva,Gu?eva, Ya. A.,Kutchin,Sokolov
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- Oxorhenium complexes as aldehyde-olefination catalysts
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Several oxorhenium compounds in the formal oxidation states V and VII are examined as catalysts for the aldehyde-olefination starting from diazo compounds, phosphines, and aldehydes. Of these, [ReMeO2(η 2-alkyne)] complexes provide the simplest catalysts to study, although [ReOCl3(PPh3)2] still remains the most efficient rhenium catalyst for aldehydeolefination described to date. Prior to the reaction with the Re catalysts the phosphine and the diazo compound react to form a phosphazine. No catalytic reaction occurs in cases where no phosphazine formation is observed. The first step of the catalytic cycle involves the formation of a carbene intermediate by the reaction of phosphazine and catalyst under extrusion of phosphine oxide and dinitrogen. In a second step the carbene reacts with aldehyde under olefin formation and catalyst regeneration. Excess of alkyne as well as the presence of ketones slows down the catalytic reaction. The olefination of 4-nitrobenzaldehyde with diazomalonate is possible with these Re catalysts. In contrast, this reaction does not take place either in the classical Wittig fashion from Ph3P=C(CO2Et)2 and aldehyde or by use of all other catalysts for aldehyde olefination reactions reported to date. Catalytic ylide formation from diazo compounds seems therefore not to be the only pathway through which catalytic aldehyde-olefination reactions can proceed.
- Santos, Ana M.,Pedro, Filipe M.,Yogalekar, Ameya A.,Lucas, Isabel S.,Romao, Carlos C.,Kuehn, Fritz E.
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- ALKALI METAL FLUORIDE MEDIATED SILYL-REFORMATSKY REACTION IN SOLID-LIQUID MEDIA; ACTIVATION BY MICROWAVES.
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Condensation of trimethylsilylacetonitrile or ethyltrimethylsilylacetate with benzaldehyde, in the presence of dried alkali metal fluorides in heterogeneous media under microwaves leads readily to β-trimethylsilyloxynitrile or ester according to a Reformatsky type reaction.The later products could be hydrolyzed and dehydrated on the wet inorganic salt to give the corresponding alkenes.
- Latouche, Regine,Texier-Boullet, Francoise,Hamelin, Jack
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- Oxidative esterification via photocatalytic C-H activation
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Direct oxidative esterification of alcohol via photocatalytic C-H activation has been developed using VO@g-C3N4 catalyst; an expeditious esterification of alcohols occurs under neutral conditions using visible light as the source of energy.
- Verma, Sanny,Baig, R. B. Nasir,Han, Changseok,Nadagouda, Mallikarjuna N.,Varma, Rajender S.
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- Ruthenium-catalyzed tandem cross-metathesis/wittig olefination: Generation of conjugated dienoic esters from terminal olefins
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In the presence of ruthenium-based olefin metathesis catalysts and triphenylphosphine, α,β-unsaturated aldehydes can be olefinated with diazoacetates. This ruthenium-catalyzed transformation has been employed in tandem with olefin cross-metathesis to convert terminal olefins into 1,3-dienoic esters in a single operation.
- Murelli, Ryan P.,Snapper, Marc L.
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- Immobilization of ruthenium(II) salen complexes on poly(4-vinylpyridine) and their application in catalytic aldehyde olefination
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Two Ru(II)(salen)(PPh3)2 complexes grafted on poly(4-vinylpyridine) have been synthesized and characterized. An elemental analysis shows that both grafted samples contain ca. 0.6 wt % Ru. FTIR spectra confirm the formation of metal-salen complexes attached to the carrier polymer by an interaction between the ruthenium(II) compounds with the pyridine nitrogen atoms of the poly(4-vinylpyridine). Immobilization of both Ru(II) salen complexes on the polymer increases their thermal stability as demonstrated by TG-MS analysis. The grafted materials were applied as catalysts for the olefination of various aldehydes at 60 °C under an inert gas atmosphere, showing comparable yields as their homogeneous congeners and high trans-selectivities. The ruthenium(II) compound with a larger salen ligand shows a better recyclability and selectivity than the derivative with the smaller ligand.
- Syukri, Syukri,Sun, Wei,Kühn, Fritz E.
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- A facile preparation of indium enolates and their Reformatsky-and Darzens-type reactions
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Indium enolates were readily prepared by transmetalation of lithium enolates with indium trichloride, and were subsequently reacted with aldehydes to give β-hydroxy esters in high yields. Indium α-bromo enolates were also prepared and reacted with carbonyl compounds to give Darzens-type α,β-epoxy carbonyl products. The Royal Society of Chemistry 2000.
- Hirashita, Tsunehisa,Kinoshita, Kenji,Yamamura, Hatsuo,Kawai, Masao,Araki, Shuki
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- Acyl transfer reactions of carbohydrates, alcohols, phenols, thiols and thiophenols under green reaction conditions
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Acyl transfer reactions of various carbohydrates, alcohols, phenols, thiols and thiophenols were achieved at room temperature in high yields and catalytic efficiency in the presence of methane sulfonic acid, a green organic acid, under solvent-free conditions over short time periods. The method is mild enough to allow acid labile substituents such as isopropylidene acetals and trityl ethers on the reacting substrates to be left completely unaffected. Esterification of free mono- and dicarboxylic acids such as acetic acid, cinnamic acid, sialic acid and tartaric acid with alcohols such as menthol, ethanol, methanol or propylene glycol has also been achieved efficiently at room temperature. A comparative study of the method with the silica-sulfuric acid is also reported.
- Giri, Santosh Kumar,Kartha, K. P. Ravindranathan
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- Access to well-defined heterogeneous catalytic systems via ring-opening metathesis polymerization (ROMP): Applications in palladium(II)-mediated coupling reactions
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The preparation of a new heterogeneous palladium(II)-based catalyst and its homogeneous analogue and their use for Heck-type, alkyne and amine couplings are described. The heterogeneous catalytic system is based on a polymer-bound dichloropalladium di(pyrid-2-yl)amide and was prepared via ring-opening metathesis copolymerization of norborn-2-ene-5-(N,N-di(pyrid-2-yl))carbamide with 1,4,4a,5,8,8a-hexahydro-1,4,5,8-exoendo-dimethanonaphthalene and subsequent loading of the resulting resin with palladium(II) chloride. The heterogeneous catalyst is air, moisture, and temperature stable up to 150 °C and highly active (94-99% yields) in the vinylation of aryl iodides and aryl bromides (Heck-type couplings) with turn-over numbers (TONs) of up to 210000. Even higher TON's (up to 350000) may be achieved in the arylation of alkynes. High yields (≤95%) and TONs (≤24000) may additionally be achieved in the tetrabutylammonium bromide (TBAB) assisted vinylation of aryl chlorides. Moderate yields (1/n, a = 835.0(1) pm, b = 1494.3(4) pm, c = 1199.3(2) pm, α = 90°, β = 109.05(2)°, γ = 90°, Z = 4. It served as a model compound for the elucidation of the actual geometry of the catalytic species. The unstrained geometry of 2 with almost ideal angles and bond lengths explaines the high stability of the catalytic center. The significantly higher catalytic activity of the heterogeneous system compared to the homogeneous one suggests well-defined ligand-bound catalytic sites rather than polymer-supported palladium colloids.
- Buchmeiser, Michael R.,Wurst
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- Asymmetric Synthesis of γ-Amino Alcohols by Copper-Catalyzed Hydroamination
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Asymmetric synthesis of γ-amino alcohols from unprotected allylic alcohols by a copper-catalyzed hydroamination strategy has been developed. Using easily accessible starting materials, a range of chiral 1,3-amino alcohols were prepared with excellent regio- and enantioselectivity. Further, this protocol provided an efficient one-step method for the enantioselective synthesis of γ-amino alcohols in an intermolecular manner.
- Ichikawa, Saki,Buchwald, Stephen L.
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- Grafting of cyclopentadienyl ruthenium complexes on aminosilane linker modified mesoporous SBA-15 silicates
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Cyclopentadienyl ruthenium phosphane and carbene complexes are grafted on the surface of mesoporous SBA-15 molecular sieves through an aminosilane linker. The nature of the support after the grafting is examined by powder XRD, TEM and N2 adsorption/desorption analysis. Elemental analysis, FT-IR, DRIFTS, TG-MS and MAS-NMR studies confirm the successful grafting of the complexes on the surface. The grafted materials are applied for catalytic aldehyde olefination and cyclopropanation. The Royal Society of Chemistry.
- Sakthivel, Ayyamperumal,Pedro, Filipe M.,Chiang, Anthony S. T.,Kuehn, Fritz E.
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- Br?nsted acidic ionic liquid as an efficient and recyclable promoter for hydroesterification of olefins catalyzed by a triphenylphosphine-palladium complex
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Several Br?nsted acidic ionic liquids (BAILs) with different acidic scales were synthesized and employed as acid promoters for the hydroesterification of olefins catalyzed by a triphenylphosphine-palladium complex. The results showed that catalysts with BAIL promoters resulted inmoderate to high conversions to the ester product with excellent selectivity, depending on the acidity of BAIL used. The reaction conversion reached a plateau when the catalyst was promoted using BAIL with a Hammett acidity function less than or equal to-0.11. This catalyst system could be reused several times for the hydroesterification of 1-hexene without a considerable decrease in the catalytic performance.
- Yang, Jing,Zhou, Hancheng,Lu, Xinning,Yuan, Youzhu
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- An organometallic analogue of the Wittig reaction. A one-pot reaction for C=C bond formation catalyzed by a molybdenum complex
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An olefinic bond is formed by the one-pot reaction of an aldehyde, diazoacetate and triphenylphosphine in the presence of a catalytic amount of MoO2(S2CNEt2)2.The mechanism of this reaction is discussed.
- Lu, Xiyan,Fang, Hong,Ni, Zhijie
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- Amine Base Promoted β-Elimination in α-Bromo Ester Substrates. Evidence for Permutational Isomerism in the TBP Carbon Intermediate
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Amine bases show reaction rates and activation parameters that suggest close similarity to the E2C mechanism previously identified for the Br(1-)-promoted reaction with α-bromo ester.Proton Sponge (PS), an amine base, which cannot participate in an SN2 process, nonetheless, is an effective promoter of the E2C.This is confirmed by applying the temperature-dependent isotope effect (TDKIE) criteria of transition-state geometry to PS and other amine reactions with α-bromo esters with the general result that a>DH is found to be temperature independent and AH/AD >> 1.2.The α-secondary deuterium isotope effect, (kH/kD)α = 1.27, is the largest value ever found (thus far) for either SN2-like or β-elimination processes.On these and other grounds it is concluded that the E2C mechanism is not SN2 like but is regarded as a precedented nucleophilic trigger mechanism.The virtual identity of intra- and intermolecular isotope effects among amine base promoters cannot be explained by the formation of a symmetrical trigonal-bipyramid (TBP) intermediate, as was the case for the Br(1-)-promoted reaction with α-bromo ester substrates.But the obviously equal availability of abstractable H and D in the transition states of the intramolecular competition isotope effect is possibly to be explained by invoking permutational isomerism in the precursor trigonal-bipyramid (TBP) intermediate.The reasoning which seems to justify this proposal is considered in detail.
- Kwart, Harold,Gaffney, Anne,Wilk, Kazimiera A.
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- OXIDATION OF α-HYDROXYKETONES WITH TRIPHENYLANTIMONY DIBROMIDE AND ITS CATALYTIC CYCLE
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α-Hydroxyketones were oxidized into α-diketones with triphenylantimony dibromide in the presence of two equiv. of base.Antimony-catalyzed debromination and oxidation cycle was devised for the system of ethyl 2,3-dibromo-3-phenylpropionate and α-hydroxyketones.
- Akiba, Kin-ya,Ohnari, Hideyuki,Ohkata, Katsuo
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- Direct Preparation of Organocadmium Compounds from Highly Reactive Cadmium Metal Powders
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Highly reactive cadmium metal powders and a cadmium-lithium alloy were prepared and were used to prepare organocadmium reagents directly from organic halides.
- Burkhardt, Elizabeth R.,Rieke, Reuben D.
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- Highly active homoleptic nickel(II) bis-N-heterocyclic carbene catalyst for Suzuki–Miyaura and Heck cross-coupling reactions
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New homoleptic nickel(II) biscarbene complex was synthesized and structurally characterized. The complex depicted the excellent catalytic activities with only 3 mol% catalyst loading along with wide substrate scope for the Suzuki–Miyaura cross-coupling reactions (twenty six examples) and Heck coupling reactions (eighteen examples).
- Nirmala, Muthukumaran,Arruri, Sathyanarayana,Vaddamanu, Moulali,Karupnaswamy, Ramesh,Mannarsamy, Maruthupandi,Adinarayana, Mannem,Ganesan, Prabusankar
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- POSS-Based Covalent Networks: Supporting and Stabilizing Pd for Heck Reaction in Aqueous Media
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Abstract: Palladium nanoparticles supported on Incompletely Condensed Polyhedral Oligomeric Silsesquioxane (IC-POSS) based poly (Acrylamide-co-Hydroxy ethyl methacrylate) as a novel nanohybrid catalyst were synthesized and characterized. This catalyst was found to be an efficient and reusable heterogeneous catalyst for the Heck reaction using water as the solvent in the absence of a phosphine ligand and phase transfer catalyst. Graphical Abstract: [Figure not available: see fulltext.]
- Arsalani, Nasser,Akbari, Ali,Amini, Mojtaba,Jabbari, Esmaiel,Gautam, Sanjeev,Chae, Keun Hwa
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- Pd nanoparticles catalyzed ligand-free Heck reaction in ionic liquid microemulsion
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The H2O/TX-100/1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) microemulsion is a new green medium, in which the Pd nanoparticles were prepared in situ for the first time. Surfactant TX-100 served as the reductant and the
- Zhang, Guoping,Zhou, Haihui,Hu, Jiaqi,Liu, Mei,Kuang, Yafei
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- A palladacyclic azobenzene derivative as a catalyst for carbon-carbon bond formation reactions
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A bis-chelated palladacycle in which the Pd atom is [(C, N)(C, N)]-tetracoordinated to two azobenzene ligands proved to be a moderately active catalyst for the Suzuki and Heck reactions. A voltammetric study revealed that the two-electron oxidation of this complex is accounted for by the irreversible PdII/PdIV transition.
- Bulygina,Khrushcheva,Peregudova,Sokolov
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- Triethylsilane-indium(III) chloride system as a radical reagent
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(Chemical Equation Presented) A novel generation method of indium hydride (Cl2InH) was found by the transmetalation of InCl3 with Et3SiH. In the intramolecular cyclization of enynes, the previously reported system (NaBH4-InCl3) has a problem of side reactions with the coexistent borane. In contrast, the problem was solved by the presented system, which affords effective hydroindation of alkynes.
- Hayashi, Naoki,Shibata, Ikuya,Baba, Akio
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- Condensation of orthoacetates with aldehydes: A new strategy for the preparation of α,β-unsaturated esters
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α,β-Unsaturated esters are formed in good yields when aldehydes are heated with orthoacetates in the presence of a catalytic amount of phenol.
- Sampath Kumar,Rao, M. Shesha,Joyasawal, Sipak,Yadav
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- Myoglobin-catalyzed olefination of aldehydes
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The olefination of aldehydes constitutes a most valuable and widely adopted strategy for constructing carbon-carbon double bonds in organic chemistry. While various synthetic methods have been made available for this purpose, no biocatalysts are known to mediate this transformation. Reported herein is that engineered myoglobin variants can catalyze the olefination of aldehydes in the presence of α-diazoesters with high catalytic efficiency (up to 4,900 turnovers) and excellent Ediastereoselectivity (92-99.9 % de). This transformation could be applied to the olefination of a variety of substituted benzaldehydes and heteroaromatic aldehydes, also in combination with different alkyl α-diazoacetate reagents. This work provides a first example of biocatalytic aldehyde olefination and extends the spectrum of synthetically valuable chemical transformations accessible using metalloprotein-based catalysts.
- Tyagi, Vikas,Fasan, Rudi
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- The controllable preparation of electrospun carbon fibers supported Pd nanoparticles catalyst and its application in Suzuki and Heck reactions
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The palladium nanoparticles/carbon nanofibers (Pd NPs/CNFs) catalyst was prepared by the electrospinning method, the hydrazine hydrate solution reduction in an ice bath environment, the high temperature carbonization. The catalyst was characterized by X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and transmission electron microscopy (TEM). The nanofibers are not cross-linked and arranged in order. The surface of Pd NPs/CNFs is smooth, and it can be observed that a large number of particles were loaded and well-dispersed in carbon fiber matrix, and the particle distribution is uniform. The activity center of catalyst is Pd(0). The Pd NPs/CNFs exhibited a high efficiency, good reusability and stability in the Suzuki and Heck reactions. It can be used for at least five consecutive runs without significant loss of its catalytic activity. The good recyclability of Pd NPs/CNFs provides a way to greatly reduce the cost of the catalyst.
- Guo, Shou-Jun,Bai, Jie,Liang, Hai-Ou,Li, Chun-Ping
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- Continuous Radio Amplification by Stimulated Emission of Radiation using Parahydrogen Induced Polarization (PHIP-RASER) at 14 Tesla
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Nuclear Magnetic Resonance (NMR) is an intriguing quantum-mechanical effect that is used for routine medical diagnostics and chemical analysis alike. Numerous advancements have contributed to the success of the technique, including hyperpolarized contrast agents that enable real-time imaging of metabolism in vivo. Herein, we report the finding of an NMR radio amplification by stimulated emission of radiation (RASER), which continuously emits 1H NMR signal for more than 10 min. Using parahydrogen induced hyperpolarization (PHIP) with 50 % para-hydrogen, we demonstrated the effect at 600 MHz but expect that it is functional across a wide range of frequencies, e.g. 101–103 MHz. PHIP-RASER occurs spontaneously or can be triggered with a standard NMR excitation. Full chemical shift resolution was maintained, and a linewidth of 0.6 ppb was achieved. The effect was reproduced by simulations using a weakly coupled, two spin-1/2 system. All devices used were standard issue, such that the effect can be reproduced by any NMR lab worldwide with access to liquid nitrogen for producing parahydrogen.
- H?vener, Jan-Bernd,Pravdivtsev, Andrey N.,S?nnichsen, Frank D.
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- Synthesis, structure, computational and catalytic activities of palladium complexes containing hydrazide based amino-phosphine ligands
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Two new N, N-bis(diphenylphosphino)-amine ligands [where amine = N-Aminophthalimide (in L1) and Hydrazine dihydrochloride (in L2)] and their Pd(II) complexes, C1 and C2 have been synthesized and characterized by IR and NMR spectroscopies. Single crystal X-ray diffraction techniques have been used to determine the crystal structures of the complexes. Moreover, the catalytic activities of mentioned complexes in Heck coupling reactions have been assessed. The NBO analysis has been used to investigate the nature of the metal-ligand interactions. In the case of L2, preparation route could have produced two different products (Pro.1 and Pro.2), but only one structure has been gained which has been prepared in high purity. To address the reason for this manner, kinetics and thermodynamics of two different pathways that could have led to possible products have been investigated theoretically.
- Gholivand, Khodayar,Kahnouji, Mohammad,Maghsoud, Yazdan,Hosseini, Mahdieh,Mark Roe, Stephen
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- Use of ferrocenyl chelated palladacycles as catalysts for the Heck reaction
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Two ferrocenyl palladacycles with bi-and tridentate (C,N) and (C,N,N) ligands were tested as possible catalysts for the Heck reaction. The latter complex efficiently catalyzed reactions of aryl halides with ethyl acrylate.
- Sokolov,Bulygina,Khrushcheva,Ikonnikov
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- Ionic liquid immobilized palladium nanoparticle-Graphene hybrid as active catalyst for heck reaction
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We engineered, graphene based Pd-Nano composites (Pd/RGO) and tested them to catalyze the Heck reaction in [bmim] NTf2 solvent system. High yield, easy product isolation, recycling of the catalytic system and ligand free approach are the main outcomes of this proposed protocol. The proposed protocol was further exploited for the successful synthesis of 3-styryl coumarins in good yield.
- Srivastava, Vivek
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- One-pot chemoenzymatic reactions in water enabled by micellar encapsulation
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The use of micellar conditions to enable one-pot reactions involving both transition metal and enzymatic catalysts is reported. Representative enzymatic transformations under micellar conditions are unaffected by the presence of non-ionic surfactants, including designer surfactants such as TPGS-750-M. Furthermore, the presence of enzymes has a negligible effect on transition metal catalysis under micellar conditions in water. Finally, three one-pot chemoenzymatic reactions in water are reported in which the micelle-forming surfactant TPGS-750-M is a crucial factor for reaction efficiency.
- Adams, Nicholas P.,Bushi, Jurgen,Hastings, Courtney J.,Kolb, Samuel J.
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- N-heterocyclic carbene–palladium(II) complex supported on magnetic mesoporous silica for Heck cross-coupling reaction
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Magnetic mesoporous silica was prepared via embedding magnetite nanoparticles between channels of mesoporous silica (SBA-15). The prepared composite (Fe3O4@SiO2-SBA) was then reacted with 3-chloropropyltriethoxysilane, sodium imidazolide and 2-bromopyridine to give 3-(pyridin-2-yl)-1H-imidazol-3-iumpropyl-functionalized Fe3O4@SiO2-SBA as a supported pincer ligand for Pd(II). The functionalized magnetic mesoporous silica was further reacted with [PdCl2(SMe2)2] to produce a supported N-heterocyclic carbene–Pd(II) complex. The obtained catalyst was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, vibrating sample magnetometry, Brunauer–Emmett–Teller surface area measurement and X-ray diffraction. The amount of the loaded complex was 80.3?mg?g?1, as calculated through thermogravimetric analysis. The formation of the ordered mesoporous structure of SBA-15 was confirmed using low-angle X-ray diffraction and transmission electron microscopy. Also, X-ray photoelectron spectroscopy confirmed the presence of the Pd(II) complex on the magnetic support. The prepared magnetic catalyst was then effectively used in the coupling reaction of olefins with aryl halides, i.e. the Heck reaction, in the presence of a base. The reaction parameters, such as solvent, base, temperature, amount of catalyst and reactant ratio, were optimized by choosing the coupling reaction of 1-bromonaphthalene and styrene as a model Heck reaction. N-Methylpyrrolidone as solvent, 0.25?mol% catalyst, K2CO3 as base, reaction temperature of 120°C and ultrasonication of the catalyst for 10?min before use provided the best conditions for the Heck cross-coupling reaction. The best results were observed for aryl bromides and iodides while aryl chlorides were found to be less reactive. The catalyst exhibited noticeable stability and reusability.
- Nuri, Ayat,Mansoori, Yagoub,Bezaatpour, Abolfazl
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- Harnessing Thorpe–Ingold Dialkylation to Access High-Hill-Percentage pH Probes
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Sensitivity is an important parameter for a molecular probe. Hill-type pH probes exhibit improved detection sensitivity compared to the traditional pH probes following the Henderson–Hasselbalch equation. Exploiting positive cooperativity, we recently devised a novel molecular scaffold (PHX) to offer such an unconventional Hill-type pH titration profile. We previously confirmed that PHX is not a pure Hill-type probe yet. Only 64% of its absorbance/fluorescence turn-on is the result of a Hill-type pathway. The remaining 36% is from an undesired Henderson–Hasselbalch-type pathway (HH pathway). In this work, the Thorpe–Ingold dialkylation was harnessed to further suppress the percent contribution of the HH pathway down to 16%. We also propose that PHX is a viable molecular model for assessing the efficacy of the steric compressing effect induced by different Thorpe–Ingold dialkylations.
- Huang, Yunxia,Luo, Xiao,Qian, Xuhong,Xiao, Yansheng,Yang, Youjun,Zeng, Zhenhua
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- Preparation of Recyclable and Versatile Porous Poly(aryl thioether)s by Reversible Pd-Catalyzed C–S/C–S Metathesis
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Porous organic materials (polymers and COFs) have shown a number of promising properties; however, the lability of their linkages often limits their robustness and can hamper downstream industrial application. Inspired by the outstanding chemical, mechanical, and thermal resistance of the 1D polymer poly(phenylene sulfide) (PPS), we have designed a new family of porous poly(aryl thioether)s, synthesized via a mild Pd-catalyzed C–S/C–S metathesis-based method, that merges the attractive features common to porous polymers and PPS in a single material. In addition, the method is highly modular, allowing to easily introduce application-oriented functionalities in the materials for a series of environmentally relevant applications including metal capture, metal sensing, and heterogeneous catalysis. Moreover, despite their extreme chemical resistance, the polymers can be easily recycled to recover the original monomers, offering an attractive perspective for their sustainable use. In a broader context, these results clearly demonstrate the untapped potential of emerging single-bond metathesis reactions in the preparation of new, recyclable materials.
- Morandi, Bill,Rivero-Crespo, Miguel A.,Toupalas, Georgios
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supporting information
p. 21331 - 21339
(2021/12/17)
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- Green and sustainable palladium nanomagnetic catalyst stabilized by glucosamine-functionalized Fe3O4@SiO2 nanoparticles for Suzuki and Heck reactions
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A novel magnetic and heterogeneous palladium-based catalyst stabilized by glucosamine-functionalized magnetic Fe3O4@SiO2 nanoparticle was synthesized. The strategy relies on the covalently bonding of glucosamine to cyanuric chloride-functionalized magnetic nanoparticles followed by complexation with palladium. The structure of magnetic nanocatalyst was fully determined by FT-IR, XRD, DLS, FE-SEM, TEM, ICP, UV-Vis, TGA, VSM, and EDX. The obtained results confirmed that the palladium nanoparticles stabilized by glucosamine immobilized onto the magnetic support exhibited high activity in cross-coupling reactions of Suzuki-Miyaura and Mizoroki-Heck. Various aryl halides were coupled with arylboronic acid (Suzuki cross-coupling reaction) and olefins (Heck reactions) under the green conditions to provide corresponding products in high to excellent yields. Interestingly, the catalyst can be easily isolated from the reaction media by magnetic decantation and can subsequently be applied for consecutive reaction cycles (at least seven times) with no notable reduction in the catalytic activity.
- Eslahi, Hassan,Sardarian, Ali Reza,Esmaeilpour, Mohsen
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- A magnetic palladium nickel carbon nanocomposite as a heterogeneous catalyst for the synthesis of distyrylbenzene and biphenyl derivatives
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A magnetic palladium nickel carbon (Fe3O4@Pd@Ni/C) nanocomposite has been synthesized using a simple one-pot procedure via a hydrothermal approach. Ferric nitrate, palladium acetate, and nickel nitrate were dissolved in water together with glucose, and the mixture was heated in an autoclave. The Fe3O4@Pd@Ni/C nanocomposite was characterized via XRD, TEM, FE-SEM, VSM, EDS, and XPS studies. The catalytic abilities of the Fe3O4@Pd@Ni/C nanocomposite were investigated for the synthesis of distyrylbenzene and 9,10-distyrylanthracene derivatives. This method shows obvious advantages, such as the recyclability of the catalyst, simple experimental operation, and the obtaining of good to excellent yields.
- Shafie, Habiballah,Niknam, Khodabakhsh
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supporting information
p. 11697 - 11704
(2021/07/12)
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- A new Pd(II)-supported catalyst on magnetic SBA-15 for C-C bond formation via the Heck and Hiyama cross-coupling reactions
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Magnetic mesoporous silica composite (MNP@SiO2-SBA) was obtained via embedding magnetite nanoparticles between SBA-15 channels. It was silylated with N-(3-(trimethoxysilyl)propyl)picolinamide (TMS-PCA) and then complexed with Pd(II). The obtained supported Pd(II) catalyst (MNP@SiO2-SBA-PCA) was characterized by conventional methods. The prepared magnetic catalyst showed high activity in the Heck and Hiyama reactions under optimal reaction conditions, including solvent, amount of catalyst, base, and temperature. Aryl bromides and iodides showed better results than aryl chlorides, and the catalyst exhibited noticeable stability and reused several times.
- Rahimi, Leila,Mansoori, Yagoub,Nuri, Ayat,Koohi-Zargar, Behzad,Esquivel, Dolores
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- A New Nitrogen Pd(II) Complex Immobilized on Magnetic Mesoporous Silica: A Retrievable Catalyst for C–C Bond Formation
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Abstract: A new nitrogen ligand, i.e. 1,3-di-(o-aminophenoxy)-2-propyl propargyl ether (DPPE), has been synthesized and characterized. Magnetic mesoporous silica composite (MNP@SiO2-SBA) was obtained via embedding magnetite nano-particles (MNPs) between SBA-15 channels. DPPE palladium dichloride (MNP@SiO2-SBA-DPPE-Pd(II)) was then prepared via click chemistry and fully characterized. The activity and recyclability of supported magnetic Pd(II) catalyst were evaluated in Heck coupling reaction after optimizing the optimal reaction conditions including solvent, amount of catalyst, base and temperature. Aryl iodides and aryl bromides showed enhanced activity compared to those of aryl chlorides in the Heck reaction. The catalyst was easily separated magnetically, reused in five runs sequentially, and no significant loss of activity was observed. Graphic Abstract: [Figure not available: see fulltext.]
- Mousavi, Samira,Mansoori, Yagoub,Nuri, Ayat,Koohi-Zargar, Behzad
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p. 1923 - 1936
(2020/11/30)
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- Pd Nanoparticles Stabilized on the Cross-Linked Melamine-Based SBA-15 as a Catalyst for the Mizoroki–Heck Reaction
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Mesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses. Graphic Abstract: [Figure not available: see fulltext.]
- Amiri, Mandana,Bezaatpour, Abolfazl,Mikkola, Jyri-Pekka,Murzin, Dmitry Yu.,Nuri, Ayat,Vucetic, Nemanja
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- The Mizoroki-Heck reaction in mesoionic 1-butyl-3-methyltetrazolium-5-olate
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1-Butyl-3-methyltetrazolium-5-olate (1), a mesoionic compound, exists as a liquid at room temperature and can be used as a polar solvent for the Mizoroki-Heck reaction, wherein it has been proven to be a superior solvent to other solvents. The reaction of iodobenzene with ethyl acrylate in the presence of palladium acetate in mesoionic liquid 1 at 40 °C for 24 h gave ethyl cinnamate in 78% yield in the absence of ligands, while the use of other solvents, such as [bmim][BF4], [bmim][PF6], and DMF gave lower yields (43%, 37%, and 17%, respectively) under the same conditions. Heck-type coupling reactions of electron-deficient or electron-rich aryl iodides and bromobenzenes with olefins (15 examples, 7%–97%) were performed in 1. When a phosphine ligand was added to the reaction mixture, aryl bromides could be used, and the mesoionic liquid containing the catalysts could be reused at least five times.
- Araki, Shuki,Hirashita, Tsunehisa,Kurabayashi, Hideaki
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- Iridium-Catalyzed Regioselective Hydroalkynylation of Internal Alkenes Directed by an Oxime
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We report here an iridium-catalyzed hydroalkynylation of allylic alcohols protected by an oxime group. Catalytic alkynylation occurs exclusively at the distal position of the alkene. This method generates γ-alkynyl alcohol oximes directly from internal alkenes and terminal alkynes. The oxime group can be readily removed to afford a free alcohol, thus providing an indirect route for the catalytic hydroalkynylation of allylic alcohols.
- Gao, Peng-Chao,Li, Bi-Jie,Wang, Zi-Xuan
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supporting information
p. 9500 - 9504
(2021/12/14)
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- Synthesis, in vitro cytotoxicity, and molecular docking study of novel 3,4-dihydroisoquinolin-1(2H)-one based piperlongumine analogues
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With the aim of expanding the scope of SAR on piperlongumine (PL), a naturally occurring anticancer molecule, we have designed a novel hybrid molecule bearing 3,4-dihydroisoquinolin-1(2H)-one and trans-cinnamic acids. The structure, based on hybridization strategy, is used for hybridization of naturally occurring scaffolds. We have synthesized 14 hybrid molecules by coupling 3,4-dihydroisoquinolin-1(2H)-one core with cinnamic acids using the mix anhydride approach. The newly synthesized inhibitors were evaluated for cell viability against breast cancer MCF-7 and cervical cancer HeLa cell lines. Furthermore, the active compounds were screened for their potential in breast cancer MDA-MB-231, cervical cancer C33A cell lines, prostate cancer DU-145, PC-3, and normal VERO cells. From the series, compound 10g was seen to inhibit MCF-7 cell growth significantly with GI50 50 = 20 μM) and C33A (GI50 = 3.2 μM). While the inhibitor 10i inhibits MCF-7 breast cancer cell growth GI50 = 3.42 μM along with inhibition of cell growth in MDA-MB-231 (GI50 = 30 μM), HeLa (GI50 = 7.67 μM), C33A (GI50 = 13 μM), DU-145 (GI50 = 6.45 μM), PC-3 (GI50 = 8.68 μM), and VERO (GI50 = 2.93 μM), respectively. Furthermore, molecular docking study demonstrated these compounds could bind tightly to the colchicine domain of tubulin through a network of favorable steric and electrostatic interactions and thus act as a tubulin polymerization inhibitor.
- Kulkarni, Mahesh R.,Lad, Nitin P.,Khedkar, Vijay M.,Gaikwad, Nitin D.
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p. 1359 - 1370
(2021/04/09)
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- Synthesis method of 2-benzoxepin compound
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The invention discloses a synthesis method of a 2-benzoxepin compound. The method comprises the following specific steps: under the protection of nitrogen, adding N-phenylseleno-phthalimide into a reactor, then adding anhydrous dichloromethane to dissolve the N-phenylseleno-phthalimide, then adding a 1-[(cinnamyl) methyl]-3, 4, 5-trimethoxybenzene compound, taking zinc chloride as a catalyst, reacting at room temperature, adding saturated sodium bicarbonate for quenching after the reaction is finished, extracting by dichloromethane, combining organic phases, drying by anhydrous magnesium sulfate, concentrating under reduced pressure, and performing silica gel rapid chromatographic purification by thin-layer chromatography silica gel to obtain the 2-benzoxepin compound. The method is simple in reaction operation, mild in reaction condition, relatively high in yield, environment-friendly and suitable for large-scale industrialized production.
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Paragraph 0045; 0048
(2021/05/29)
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- Synthesis method of isochroman compound
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The invention discloses a synthesis method of an isochroman compound, which comprises the following steps of adding dichloromethane and phosphorus tribromide into 3, 4, 5-trimethoxy benzyl alcohol, and reacting to obtain 1-bromomethyl-3, 4, 5-trimethoxy benzene, adding tetrahydrofuran, cinnamyl alcohol, sodium hydride and 1-bromomethyl-3, 4, 5-trimethoxybenzene into a reactor, and reacting to obtain 1-[(cinnamyl oxy)methyl]-3, 4, 5-trimethoxybenzene, adding cyanuric acid into a reactor containing a potassium hydroxide aqueous solution to react, dropwise adding a silver nitrate aqueous solution, and reacting to obtain silver isocyanurate, adding silver isocyanurate, phenyl selenium bromide and anhydrous dichloromethane into a reactor, and reacting to obtain N, N, N-triphenyl seleno isocyanurate, reacting N, N, N-triphenyl seleno isocyanurate, dichloromethane, boron trifluoride diethyl etherate and a 1-[(cinnamyl oxy)methyl]-3, 4, 5-trimethoxybenzene compound to obtain a target product. The method is simple in reaction operation, mild in reaction condition, relatively high in yield and environment-friendly.
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Paragraph 0046; 0049
(2021/05/15)
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- Active Base Hybrid Organosilica Materials based on Pyrrolidine Builder Units for Fine Chemicals Production
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The catalytic activity of “pyrrolidine type” fragments included or anchored in the mesoporous silica supports or polymeric frameworks have been fully reported for enantioselective transformation. Nevertheless, low attention was focused on their catalytic abilities to perform base-catalyzed reaction. Accordingly, hybrid materials including pyrrolidine fragments in the mesoporous silica supports were prepared following different synthesis methods, such as micellar and fluoride sol-gel routes in absence of structural directing agents. Their great catalytic performance was explored for various base-catalyzed reactions to the formation of C?C bond through Knoevenagel, Claisen-Schmidt and Henry condensations under microwave irradiation. The benefits of microwave irradiation combined with suitable catalytic properties of pyrrolidine hybrid materials with strong base sites and high accessibility to active centers, allowed carrying out successfully base-catalyzed condensation reactions for the production of fine chemicals. Moreover, the hybrid catalyst exhibited high selectivity and good stability over different catalytic cycles contributing to environmental sustainability.
- Llopis, Sebastián,Velty, Alexandra,Díaz, Urbano
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p. 5012 - 5024
(2021/10/19)
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- Hypervalent iodine(iii) induced oxidative olefination of benzylamines using Wittig reagents
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We have developed hypervalent iodine(iii) induced oxidative olefination of primary and secondary benzylamines using 2C-Wittig reagents, which provides easy access to α,β-unsaturated esters. Mild reaction conditions, good to excellent yields with high (E) selectivity, and a broad substrate scope are the key features of this reaction. We have successfully carried out the gram-scale synthesis of α,β-unsaturated esters.
- Ramavath, Vijayalakshmi,Rupanawar, Bapurao D.,More, Satish G.,Bansode, Ajay H.,Suryavanshi, Gurunath
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p. 8806 - 8813
(2021/05/26)
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- Promising new catalytic properties of a Co (II)-carboxamide complex and its derived Co3O4 nanoparticles for the Mizoroki-Heck and the Epoxidation reactions
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The new Co(II) - carboxamide complex (1) and Co3O4 nanoparticles (2), by way of thermal decomposition of (1) have been efficiently synthesised in the environment-friendly. X-ray diffraction reveals a slightly distorted octahedral coordination of cobalt (four nitrogens and two oxygens) in (1) and regular octahedral or tetrahedral ones (oxygens only) in (2). The investigation of (1) and (2) in the Mizoroki-Heck and epoxidation of alkens reactions showed them both to be powerful, green and inexpensive catalysts.
- Kiani, Mahsa,Bagherzadeh, Mojtaba,Meghdadi, Soraia,Fadaei-Tirani, Farzaneh,Babaie, Maryam,Schenk-Jo?, Kurt
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- Palladium Immobilized on 2,2′-Dipyridyl-Based Hypercrosslinked Polymers as a Heterogeneous Catalyst for Suzuki–Miyaura Reaction and Heck Reaction
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Abstract: 2,2′-Bipyridine was successfully integrated into the skeleton of hypercrosslinked polymers networks (HCPs-bipy) via Friedel–Crafts reaction and Scholl coupling reaction, and PdCl2 was locked in this network polymers by coordination with pyridine motif. The preparation of HCPs-bipy has the advantages of low cost, mild conditions, easy separation and high yield. FT-IR, TGA, N2 sorption, ICP, XPS, SEM, EDX and TEM was employed to characterize the structure and composition of the heterogeneous catalysts. The result indicates that HCPs-bipy-Pd possess high specific surface areas, large microporous volume, thermal stability, and highly dispersion of palladium species. HCPs-bipy-Pd can be applied in Suzuki–Miyaura reactions and Heck reactions as robust heterogeneous catalyst to afford high yield. The reusability test demonstrates that HCPs-bipy-Pd could be recovered and reused for at least five times without losing catalytic activity. Graphic Abstract: [Figure not available: see fulltext.].
- Liu, Cijie,Xu, Wei,Xiang, Dexuan,Luo, Qionglin,Zeng, Shunqin,Zheng, Lijuan,Tan, Yujie,Ouyang, Yuejun,Lin, Hongwei
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p. 2558 - 2565
(2020/03/23)
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- Synthesis of a Cellulosic Pd(salen)-Type Catalytic Complex as a Green and Recyclable Catalyst for Cross-Coupling Reactions
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Abstract: A green recyclable cellulose-supported Pd(salen)-type catalyst was synthesized through sequential three steps: chlorination with thionyl chloride, modification by ethylenediamine, and the formation of Schiff base with salicylaldehyde to immobilize palladium chloride through multiple binding sites. This novel heterogeneous cellulosic Pd(salen)-type catalytic complex was fully characterized by FT-IR, SEM, TEM, XPS, ICP-AES and TG. The traditional cross-coupling chemistry, such as Suzuki, Heck, Sonogashira, Buchwald–Hartwig amination and etherification, was then investigated in the presence of the above cellulose-palladium nanoparticle. Studies have shown that the synthesized catalyst shows high activity and efficiency for all types of transformations, providing the corresponding carbon–carbon or carbon–heteroatom coupling products in a general and mild manner. Furthermore, the catalyst demonstrates high to excellent yields and is easily recycled by simple filtration for up to twelve cycles without any significant loss of catalytic activity. Graphic Abstract: [Figure not available: see fulltext.]
- Sun, Peng,Yang, Jiaojiao,Chen, Chunxia,Xie, Kaijun,Peng, Jinsong
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p. 2900 - 2910
(2020/03/31)
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- Novel and efficient polymer supported copper catalyst for heck reaction
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A novel polymer supported copper complex (m-PAN-Cu) is prepared by immobilizing Cuprous Iodide (CuI) on amidoxime modified Polyacrylonitrile (mPAN) and characterised by FTIR, XRD, EDX, ICP-MS and XPS analyses. This complex was further explored as a general and efficient heterogeneous catalyst for Heck coupling reaction of a series of aryl halides with olefins and afforded the corresponding coupling products in moderate to good yields. This catalyst offers easy preparation, good stability, excellent catalytic activity and reusability. This is the first study involving an amidoxime modified PAN supported copper catalyst towards greener and efficient Heck reaction.
- Anas, Saithalavi,Anjali, Suresh,Sruthi, Pambingal Rajan,Varghese, Nicy
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- Alkali/alkaline earth ion-exchanged and palladium dispersed MCM-22 zeolite as a potential catalyst for eugenol isomerization and Heck coupling reactions
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Abstract: Alkali and alkaline earth metal ions (Na+, K+, Cs+, Mg2+) exchanged MCM-22 zeolites were prepared and subsequently palladium (2 wt.%; Pd) was dispersed on above exchanged MCM-22 zeolite materials. All the MCM-22 materials were systematically characterized by FTIR, powder X-ray diffraction, N2 sorption analysis and temperature-programmed desorption (TPD) of CO2. The XRD pattern and FTIR data confirmed the existence of the MCM-22 framework structure even after exchanging bulky metal ions and palladium loading. TPD studies using CO2 supports that the cesium and magnesium incorporated MCM-22 possess a strong and large number of basic sites. The alkali and alkaline-earth metal ions exchanged MCM-22 catalysts were explored for industrially important eugenol isomerisation, whereas the palladium containing MCM-22 materials were utilised for Heck coupling reaction of styrene with iodobenzene. The Cs-MCM-22 showed the best activity for the eugenol isomerization with the isoeugenol yield of 76%. The Cs/Pd-MCM-22 was shown as promising heterogeneous catalyst for Heck coupling reaction of styrene with iodobenzene and yield 99% stilbene. For both isomerization and Heck coupling reaction, the catalysts retain their activities even after several runs. Graphic Abstract: Among different alkali and alkaline earth ion-exchanged MCM-22 materials, cesium containing MCM-22 was shown as a promising catalyst for isomerization of lignin-derived biomass model compound viz., eugenol. Subsequently, the palladium dispersed CsMCM-22 was found to be the potential catalyst for Heck coupling under ambient conditions.[Figure not available: see fulltext.].
- Augustin, A.,Haripriya, T. V.,Sahu, P.,Sakthivel, A.,Shanbhag, G. V.,Sreenavya, A.
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- Synthesis and characterization of a new bis-NHC palladium complex and its catalytic activity in the Mizoroki–Heck reaction
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A new bis-N-heterocyclic carbene palladium complex, (C13H9N2F2)2PdCl2, is synthesized by a three-step reaction and characterized by 1H NMR and 13C NMR spectroscopy as well as by X-ray crystallography. This new bis-N-heterocyclic carbene palladium complex has excellent stability and is capable of efficiently catalyzing the Mizoroki–Heck coupling reaction of aryl halides with acrylates.
- Cui, Jin,Feng, Can,Liu, Cheng-Xin,Wang, Yu-Fang,Zhang, Ming-Jie
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p. 684 - 688
(2020/05/22)
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- Palladium Ion Catalysed Oxidative C–C Bond Formation Reactions in Arylboronic Acid: Application of Cordierite Monolith Coated Catalyst
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Abstract: Catalytic efficiency of palladium ion substituted in TiO2, Ti0.97Pd0.03O1.97 is successfully exploited for the oxidative homocoupling of arylboronic acid and oxidative Heck coupling reactions between arylboronic acid and olefins. The reaction protocol provides direct approach to synthesize biphenyls and cinnamates from moderate to good yield with good functional group tolerance. As a result, 11 symmetrical biaryls and 14 cinnamates were synthesized from readily available arylboronic acids. Ti0.97Pd0.03O1.97 powder catalyst is synthesized by solution combustion method and characterized by powder X-ray diffraction. The C–C bond formation reactions were carried out by catalyst cartridge method using Ti0.97Pd0.03O1.97 catalyst coated cordierite monolith. Coating of the catalyst on a cordierite monolith enhanced the applicability of the catalyst and made handling and recycling of the catalyst very easy. Catalyst was recovered and recycled for eight times in both homocoupling and oxidative Heck coupling reactions. The turnover number for both the reactions found to be 443 and 424, respectively. Graphic Abstract: [Figure not available: see fulltext.].
- Bhat, Shrikanth K.,Prasanna,Dasappa, Jagadeesh Prasad,Hegde
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p. 2911 - 2927
(2020/03/31)
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- Synergistic Relay Reactions To Achieve Redox-Neutral α-Alkylations of Olefinic Alcohols with Ruthenium(II) Catalysis
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Herein, we report a ruthenium-catalyzed redox-neutral α-alkylation of unsaturated alcohols based on a synergistic relay process involving olefin isomerization (chain walking) and umpolung hydrazone addition, which takes advantage of the interaction between the two rather inefficient individual reaction steps to enable an efficient overall process. This transformation shows the compatibility of hydrazone-type “carbanions” and active protons in a one-pot reaction, and at the same time achieves the first Grignard-type nucleophilic addition using olefinic alcohols as latent carbonyl groups, providing a higher yield of the corresponding secondary alcohol than the classical hydrazone addition to aldehydes does. A broad scope of unsaturated alcohols and hydrazones, including some complex structures, can be successfully employed in this reaction, which shows the versatility of this approach and its suitability as an alternative, efficient means for the generation of secondary and tertiary alcohols.
- Kan, Jian,Li, Chao-Jun,Li, Chen-Chen,Li, Jianbin,Lv, Leiyang,Qiu, Zihang
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supporting information
p. 4544 - 4549
(2020/02/04)
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- Preparation method of cinnamate compound
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The invention discloses a preparation method of a cinnamate compound, which comprises the following steps: sequentially adding a diaryl trifluoromethane sulfonic acid iodine compound, an acrylate compound, a palladium complex, an additive and a solvent into a reaction flask, reacting, and stirring at 70-90 DEG C for 15-20 hours; quenching and extracting; drying the extract, filtering, concentrating, and carrying out column chromatography purification to obtain the cinnamate compound. The problems that a traditional reaction catalyst is large in dosage and too high in reaction temperature are effectively solved, the performance of the palladium catalyst can be brought into full play, the palladium catalyst can rapidly conduct coordination reaction on electron-deficient olefin, the use efficiency of the catalyst is improved, the reaction temperature is reduced, a special reaction environment is not needed, raw materials are simple and easy to obtain, and reaction conditions are loose. The preparation method is a low-cost preparation method of the cinnamate compound.
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Paragraph 0024-0025
(2021/01/15)
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- Preparation method of phenyl acrylate compound under palladium catalysis
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The invention relates to a preparation method of an aryl acrylate derivative under palladium catalysis. The structural formula of the prepared aryl acrylate compound is shown as figure 1, wherein R ismethyl, ethyl or tert-butyl. The preparation method comprises the following steps of: reacting sodium benzenesulfinate, an acrylate compound, bis(triphenylphosphine)palladium chloride, silver hexafluoroantimonate and copper acetate monohydrate at 60DEG C for 12 hours by using toluene as a solvent, performing extracting with an organic solvent, and conducting concentrating and purifying to obtainthe phenyl acrylate compound. The method has the characteristics of easily available raw materials, mild reaction conditions, simple operation, good repeatability and the like.
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Paragraph 0006
(2020/11/09)
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- Pd-catalyzed oxidative Heck-type arylation of vinyl ketones, alkenes, and acrylates with Sb-aryl-tetrahydrodibenz[c,f][1,5]azastibocines
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The Pd-catalyzed cross-coupling reactions of Sb-aryl-1,5-azastibocines with alkenes are described. The reactions of azastibocines with alkenes such as vinyl ketones, alkenes, and acrylates in the presence of 10 mol% PdCl2 at 80 °C in DMA under aerobic conditions produced Heck adducts in moderate-to-excellent yields. Single-crystal X-ray and NMR analysis revealed that the aryl donors in this reaction, the Sb-aryl-1,5-azastibocines, are hypervalent compounds that display N–Sb intramolecular non-bonding interaction. These are the first examples of Pd-catalyzed Heck-type arylations using heterocyclic hypervalent organoantimony compounds. Although the reactions proceeded efficiently with the azastibocines, they hardly progressed with trivalent and pentavalent triarylantimony reagents.
- Murata, Yuki,Kakusawa, Naoki,Arakawa, Yukako,Hayashi, Yukako,Morinaga, Shun,Ueda, Masaaki,Hyodo, Tadashi,Matsumura, Mio,Yamaguchi, Kentaro,Kurita, Jyoji,Yasuike, Shuji
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- Visible-light-induced selective aerobic oxidation of sp3 C-H bonds catalyzed by a heterogeneous AgI/BiVO4 catalyst
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An efficient oxidation of sp3 C-H bonds to esters and ketones has been developed using AgI/BiVO4 as the photocatalyst and O2 as the oxidant in water. Various substrates can be transformed into the desired esters and ketones in moderate to good yields. The synthetic utility of this approach has been demonstrated by gram-level experiments and consecutive oxidation experiments. A plausible mechanism has been proposed.
- Jiang, Li-Ya,Ming, Jing-Jing,Wang, Lian-Yue,Jiang, Yuan-Yuan,Ren, Lan-Hui,Wang, Zi-Cheng,Cheng, Wen-Chen
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supporting information
p. 1156 - 1163
(2020/03/11)
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- Threonine stabilizer-controlled well-dispersed small palladium nanoparticles on modified magnetic nanocatalyst for Heck cross-coupling process in water
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We report the synthesis of magnetically separable Fe3O4@Silica-Threonine-Pd0 magnetic nanoparticles with a core–shell structure. After synthesis of Fe3O4@Silica, threonine as an efficient stabilizer/ligand was bonded to the surface of Fe3O4@Silica. Then, palladium nanoparticles were generated on the threonine-modified catalyst. The threonine stabilizer helps to generate palladium nanoparticles of small size (less than 4?nm) with high dispersity and uniformity. Magnetically separable Fe3O4@Silica-Threonine-Pd0 nanocatalyst was fully characterized using various techniques. This nanocatalyst efficiently catalysed the Heck cross-coupling reaction of a variety of substrates in water medium as a green, safe and inexpensive solvent at 80°C. The Fe3O4@Silica-Threonine-Pd0 catalyst was used for at least eight successful consecutive runs with palladium leaching of only 0.05%.
- Sarvi, Iraj,Gholizadeh, Mostafa,Izadyar, Mohammad
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- Palladium catalyst immobilized on functionalized microporous organic polymers for C-C coupling reactions
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Two microporous organic polymer immobilized palladium (MOP-Pd) catalysts were prepared from benzene and 1,10-phenanthroline by Scholl coupling reaction and Friedel-Crafts reaction, respectively. The structure and composition of the catalyst were characterized by FT-IR, TGA, N2 sorption, SEM, TEM, ICP-AES and XPS. MOP-Pd catalysts were found to possess high specific surface areas, large pore volume and low skeletal bone density. Moreover, the immobilized catalyst also had advantages, such as readily available raw materials, chemical and thermal stability, and low synthetic cost. The Pd catalyst is an effective heterogeneous catalyst for carbon-carbon (C-C) coupling reactions, such as the Heck reaction and Suzuki-Miyaura reaction, affording good to high yields. In these reactions, the catalyst was easily recovered and reused five times without significant activity loss.
- Xu, Wei,Liu, Cijie,Xiang, Dexuan,Luo, Qionglin,Shu, You,Lin, Hongwei,Hu, Yangjian,Zhang, Zaixing,Ouyang, Yuejun
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p. 34595 - 34600
(2019/11/11)
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- Ultra-small and highly dispersed Pd nanoparticles inside the pores of ZIF-8: Sustainable approach to waste-minimized Mizoroki–Heck cross-coupling reaction based on reusable heterogeneous catalyst
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The rapid development of nanomaterials, particularly advanced hybrid nanoparticles, has made new opportunities for the design and fabrication of high-performance metal-based catalysts. However, generating metal nanoparticles of desired size without aggregation is an important challenge for enhancing the catalytic activity of metal nanoparticles supported in the host matrix. In this work, a hybrid nanoporous material, namely Pd nanoparticles@N-heterocyclic carbene@ZIF-8, with a high internal surface area was successfully prepared using a dispersed anionic sulfonated N-heterocyclic carbene–Pd(II) precursor inside the cavities of zeolitic imidazolate framework (ZIF-8) using an impregnation approach followed by reduction with NaBH4. The anionic sulfonated N-heterocyclic carbene was found to be a superb ligand for the stabilization of Pd nanoparticles in the pores of ZIF-8. The resulting system was applied to the Mizoroki–Heck cross-coupling reaction, in which the catalyst showed high catalytic activity under mild reaction conditions.
- Azad, Mohammad,Rostamizadeh, Shahnaz,Estiri, Hamid,Nouri, Fatemeh
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- Pd(0) immobilized on Fe3O4@AHBA: an efficient magnetically separable heterogeneous nanocatalyst for C–C coupling reactions
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We have developed a new method to synthesize magnetically separable Fe3O4@AHBA@Pd(0) (AHBA = 3-amino-4-hydroxybenzoic acid) heterogeneous nanocatalyst via anchoring of palladium(0) on the surface of AHBA-coated Fe3O4 nanoparticles. The synthesized nanocatalyst was characterized by FT-IR, PXRD, ICP, XPS, FESEM, EDX, TEM, TGA, BET, and FT-RAMAN analysis. X-ray photoelectron spectroscopy (XPS) indicated the presence of Pd(0) on the surface of Fe3O4@AHBA. BET analysis exhibits high surface area of the prepared nanocatalyst with catalytic activity toward Heck coupling reactions with high turnover frequency (TOF) at 60 °C in water–acetonitrile within 2 h. The nanocatalyst can be easily recovered from the reaction mixture by using an external magnet and recycled six times without significant decrease in its catalytic activity. All the isolated products are obtained as solids or oils, fully characterized by 1H-NMR spectroscopy.
- Chakraborty, Tonmoy,Sarkar, Abani,Chattopadhyay, Tanmay
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p. 3430 - 3443
(2019/11/19)
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- Palladium-melamine complex anchored on magnetic nanoparticles: A novel promoter for C-C cross coupling reaction
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A palladium-melamine complex deposited on Fe3O4@SiO2 nanoparticles (MNPs-Mel-Pd) was considered as an effective catalyst for C-C cross-coupling (Mirozoki-Heck) reaction. Surface and magnetic properties of the prepared core-shell hybrid nanocatalyst was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, energy-dispersive X-ray, vibrating sample magnetometry, transmission and scanning electron microscopy techniques and ICP/OES analysis. It was found that the heterogeneous nanocatalyst could be recovered simply and reused numerous times without loss of its catalytic activity. The advantages of this new methodology are: isolation of highly pure products without chromatography techniques, reusability of the catalyst using a magnet, easy workup procedure and negligible leaching of palladium.
- Bodaghifard, Mohammad Ali
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- Recyclable Pd ionic catalyst coated on cordierite monolith for high TOF Heck coupling reaction
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Abstract : Pd 2 + ionic catalyst, Ti 0.97Pd 0.03O 1.97 was coated over cordierite monolith by solution combustion method. The catalyst coated on the cordierite is nano-crystalline as seen from XRD studies. Coated catalyst was used for Heck coupling reactions with different substrates of aryl halides and olefins. Thus handling nano-crystalline catalyst powder is avoided by fixing it on a solid catalyst cartridge. Heck coupled products were characterized using 1H NMR, 13C NMR, Mass and FTIR spectroscopy. This catalyst showed high selectivity towards Heck coupling reaction. Turnover frequencies (TOF) for each of the reactions were found to be very high. The catalyst was recycled up to 7 times with total TOF 3017 h - 1, which is found to be a new green technique in the Heck coupling reaction. Graphical abstract: Ti 0.97Pd 0.03O 1.97 catalyst is coated on cordierite monolith honeycomb (HC) by solution combustion method and it is used in the Heck coupling reaction. Reactions are done in a specially designed flask. Catalyst is recycled for 7 times. The total turnover frequency (TOF) after 7 cycles was 3017 h - 1. [Figure not available: see fulltext.].
- Bhat, Shrikanth K,Prasad, Jagadeesh D,Hegde
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- Pd-chelated 1,3,5-triazine organosilica as an active catalyst for Suzuki and Heck reactions
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Design of novel functional periodic mesoporous organosilica with molecular level control finds applications in several fields of energy and environmental research including adsorption, catalysis, nanotechnology, and energy harvesting. Herein we present a melamine (1,3,5-triazine) functionalized periodic mesoporous silica (MPMO) by self-assembly of N2,N4,N6-tris(3-(triethoxysilyl)propyl)-1,3,5-triazine-2,4,6-triamine (TTET) with tetraethylorthosilicate (TEOS) via cocondensation strategy. The TTET silsesquioxane precursor was synthesized by the condensation reaction between cyanuric chloride and 3-aminopropyl triethoxysilane. The resultant MPMO material serves as an effective solid chelating agent through amine and triazine functionalities for Pd(II) to provide Pd-MPMO. The Pd-MPMO material was thoroughly characterized by a small-angle XRD, HRTEM, N2 sorption, 13C CP-MAS NMR, 29Si CP-MAS NMR, and ICP analyses. The Pd-MPMO serves as an active catalyst for C–C bond formation reactions by Suzuki- and Heck cross-coupling methodologies under ligand- and cocatalyst-free conditions. Notably, the present catalytic protocol demonstrates a wide spectrum of substrate scope towards Suzuki coupling between aryl halides (I?, Br?, Cl?) and aryl boronic acids with high turn-over-number (TON) in aqueous phase under air ambience. Whereas for Heck-coupling reaction, the phenyl iodides furnished high TON than the other aryl halides. Investigation of Pd-leaching by a hot filtration test as well as reusability experiments confirms the true heterogeneous nature of present Pd-MPMO and its robustness in terms of substrate scope, catalyst stability, and durability.
- Elavarasan,Kala,Muhammad, Ibrahim,Bhaumik,Sasidharan
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- Synthesis of new Pro-PYE ligands as co-catalysts toward Pd-catalyzed Heck-Mizoroki cross coupling reactions
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The present research work describes the synthesis of five new ligands containing pyridinium amine, [H2L1][OTf]2-[H2L5][I]2 from two new precursors, [P3Et][I] and [P2Me][CF3SO3]. The structure elucidations of the compounds were confirmed by multinuclear NMR (1H, 13C), FT-IR and by single crystal XRD techniques. Theoretical DFT studies were carried out to get better insight into the electronic levels and structural features of all the molecules. These synthesized new Pro-PYE ligands [H2L1][OTf]2-[H2L5][I]2 were found to be significantly active as co-catalysts for Pd(CH3CO2)2 toward Heck-Mizoroki coupling reactions with wide substrate scope in the order of [H2L1][OTf]2 ? [H2L2][OTf]2 > [H2L3][OTf]2 > [H2L4][OTf]2 > [H2L5][I]2.
- Munir, Naima,Masood, Sara,Liaqat, Faroha,Tahir, Muhammad Nawaz,Yousuf, Sammer,Kalsoom, Saima,Mughal, Ehsan Ullah,Sumrra, Sajjad Hussain,Maalik, Aneela,Zafar, Muhammad Naveed
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p. 37986 - 38000
(2019/12/03)
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- Boron-Catalyzed C?C Functionalization of Allyl Alcohols
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Tris(pentafluorophenyl)borane-catalyzed C?C bond functionalization of arylallyl alcohols using donor-acceptor carbenes is presented. The allylic hydroxyl group is found to assist the product formation by neighboring group participation providing a clue towards mechanistic understanding. This method can also be employed to effect homologation of allyl alcohols to homoallyl alcohols. Overall, this metal-free transformation presents a novel disconnection strategy towards carbon-carbon bond scission and formation. (Figure presented.).
- Rao, Santhosh,Kapanaiah, Raja,Prabhu, Kandikere Ramaiah
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supporting information
(2019/02/14)
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- Boron-Templated Dimerization of Allylic Alcohols to Form Protected 1,3-Diols via Acid Catalysis
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We report an unprecedented boron-templated dimerization of allylic alcohols that generates a 1,3-diol product with two stereogenic centers in high yield and diastereoselectivity. This acid-catalyzed reaction is achieved via in situ formation of a boronic ester intermediate that facilitates selective cyclization and formation of a cyclic boronic ester product. High yields are observed with a variety of allylic alcohols, and mechanistic studies confirm the role of boron as a template for the reaction.
- Nazari, S. Hadi,Forson, Kelton G.,Martinez, Erin E.,Hansen, Nicholas J.,Gassaway, Kyle J.,Lyons, Nathan M.,Kenney, Karissa C.,Valdivia-Berroeta, Gabriel A.,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 9589 - 9593
(2019/12/02)
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- Arene Trifunctionalization with Highly Fused Ring Systems through a Domino Aryne Nucleophilic and Diels–Alder Cascade
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A convenient and efficient domino aryne process was developed under transition-metal-free conditions to generate a range of tetra- and pentacyclic ring systems. This transformation was realized via a 1,2-benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C?N and two C?C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2-aryne and 2,3-aryne stages. Moreover, in-depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity.
- He, Jia,Jia, Zizi,Tan, Hongcheng,Luo, Xiaohua,Qiu, Dachuan,Shi, Jiarong,Xu, Hai,Li, Yang
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supporting information
p. 18513 - 18518
(2019/11/19)
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- Spectral and crystallography studies of new palladacycle complexes with P,C- and C,C-donor ligands; Application of (OAL16) to optimizing the yield of Mizoroki-Heck reaction
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The new symmetrical diphosphonium salt [Ph2P(CH2)2PPh2(CH2C(O)C6H4Br)2] Br2 (S) was synthesized in the reaction of 1,2-bis (diphenylphosphino) ethane (dppe) and related ketone. Further treatment with NEt3 gave the symmetrical α-keto stabilized diphosphine ylide [Ph2P(CH2)2PPh2(CHC(O)C6H4Br)2] (Y1). The unsymmetrical α-keto stabilized diphosphine ylide [Ph2P(CH2)2PPh2(CHC(O)C6H4Br)] (Y2) was synthesized in the reaction of diphosphine in 1:1 ratio with 2.3′-dibromoacetophenone, then treatment with NEt3. The reaction of dibromo (1,5-cyclooctadiene)palladium (II), [PdBr2(COD)] with this ligand (Y1) in equimolar ratio gave the new C,C-chelated [PdBr2(Ph2P(CH2)2PPh2(C(H)C(O)C6H4Br)2)] (1) and with unsymmetrical phosphorus ylide [Ph2P(CH2)2PPh2C(H)C(O)C6H4Br] (Y2) gave the new P, C-chelated palladacycle complex [PdBr2(Ph2P(CH2)2PPh2C(H)C(O)Br)] (2). These compounds were characterized successfully by FT-IR, NMR (1H, 13C and 31P) spectroscopic methods and the crystal structure of Y1 and 2 were elucidated by single crystal X-ray diffraction. The results indicated that the complex 1 was C, C-chelated whereas complex 2 was P, C-chelated. These air/moisture stable complexes were employed as efficient catalysts for the Mizoroki-Heck cross-coupling reaction of several aryl chlorides, and the Taguchi method was used to optimize the yield of Mizoroki-Heck coupling. The optimum condition was found to be as followed: base; K2CO3, solvent; DMF and loading of catalyst; 0.005?mmol.
- Sabounchei, Seyyed Javad,Badpa, Khadijeh,Hashemi, Ali,Moniriyan, Faezeh,Gable, Robert W.
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- Polystyrene bis[N-(2-pyridyl) sulfonamide] palladium(II): Synthesis, characterization as a catalyst for coupling reactions
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The [N-(2-pyridyl)] para-styrene sulfonamide (PSS) was prepared as a monomer, from the reaction of para-styrene sulfonyl chloride and 2-amino pyridine in the presence of potassium hydroxide solution 0.5?M as a base, and CH3Cl. Polystyrene [N-(2-pyridyl) sulfonamide] (PPSS) was synthesized from the polymerization of [N-(2-pyridyl)] para-styrene sulfonamide (PSS). The Polystyrene bis [N-(2-pyridyl) sulfonamide] palladium (II) as a polymer- supporting palladium complex was also prepared from the reaction of PdCl2 (CH3CN)2 with PPSS in the presence of KOH 0.5?M. Polystyrene bis [N-(2-pyridyl) sulfonamide] palladium (II) is produced as a novel heterogeneous catalyst for coupling reactions for C-C bond formation. This method includes higher yield and has an easier work-up procedure. The structures of the monomer, polymer and its Pd complex were confirmed by using FT-IR and 1H-NMR spectroscopy. Elemental analysis of Pd by inductively coupled plasma (ICP) technique and hot filtration test showed loading of the metal into solution from the catalyst The heterogeneous catalyst was recycled without any loss in its properties.
- Shafieyoon, Parvaneh,Mehdipour, Ebrahim,Tavakol, Hosein
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p. 324 - 328
(2018/01/04)
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