- Palladium nanoparticles on β-cyclodextrin functionalised graphene nanosheets: A supramolecular based heterogeneous catalyst for C-C coupling reactions under green reaction conditions
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The use of functional properties of native cyclodextrins in palladium nanoparticle-β-cyclodextrin-graphene nanosheet (Pd@CD-GNS) catalyzed carbon-carbon (C-C) coupling reactions have been investigated under green reaction conditions. The supramolecular catalyst was prepared by deposition of Pd nanoparticles (Pd NPs) on CD-GNS using ethanol as the greener solvent and in situ reducing agent. The catalyst was characterised by FTIR, XRD, RAMAN, UV-Vis spectroscopy, TEM, SAED, XPS and ICP-AES. The catalytic activity of these catalysts is investigated in C-C coupling reactions such as Suzuki-Miyaura and Heck-Mizoroki reactions of aryl bromides and aryl chlorides containing functional groups under green reaction conditions i.e. in water, under phosphine free and aerobic conditions. This catalyst afforded excellent selectivities for the products in good to excellent yields under low Pd loadings (0.2-0.05 mol%), while ensuring the recovery and reusability of the catalysts. The reused catalyst was characterized by FTIR, TEM, XPS and ICP-AES. The CD supramolecular mediators loaded on GNS act as stabilising agents for the Pd NPs. The excellent catalytic activity of this system was attributed to the presence of CDs, excellent dispersibility in water, hydrophobic nature of the GNS support for the accumulation of organic substrates in water, "Breslow effect", the presence of PTC to overcome the mass transfer limitation onto the surface of GNS and formation of ternary CD/substrate/additive complexes on the Pd-GNS surface.
- Putta, Chandrababu,Sharavath, Vittal,Sarkar, Suprabhat,Ghosh, Sutapa
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- 2-Pyridyl substituents enhance the activity of palladium-phospha-adamantane catalysts for the methoxycarbonylation of phenylacetylene
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The synthesis of a series of CgPAr ligands is reported, where CgP is the 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamant-6-yl moiety and Ar = 2-pyridyl (L2), 3-pyridyl (L3), 2-pyrimidyl (L4), 4-R-2-pyridyl [R = Me (L5a), CF3 (L6a), SiMe3 (L7a)] or 6-R-2-pyridyl [R = Me (L5b), CF3 (L6b), SiMe3 (L7b). Testing of these ligands in the Pd-catalysed methoxycarbonylation of phenylacetylene reveals that the activity and branched selectivity of the catalysts derived from these ligands varies as a function of the N-heterocycle, with the catalyst derived from L5b being the most active of those tested. This, together with the poor performance of catalysts derived from L3 supports the hypothesis that the catalysis proceeds by a “proton shuttling” mechanism, an idea that previously had only been applied to arylphosphines. Reaction of [PtCl2(cod)] with L where L = L2 or L4-7 yields a rac/meso mixture of the trans-[PtCl2(L)2] (1a-h) complexes, three of which are structurally characterised. 31P NMR spectroscopy shows that reaction of L3 with [PtCl2(cod)] gives a mixture of mononuclear and binuclear metal complexes in solution. The complex trans-[PdCl2(L2)2] (4) reacts with AgBF4 to give the [PdCl(κ1-L2)(κ2-L2)]BF4 (5) with spectroscopic and structural characterisation confirming the presence of a P,N-chelate. 1H and 31P NMR evidence supports the assignment of a pyridyl-protonated species being formed upon treatment of 4 with TsOH·H2O in CD2Cl2; both the protonated species and chelate 5 are observed when the reaction is carried out in MeOH.
- Shuttleworth, Timothy A.,Miles-Hobbs, Alexandra M.,Pringle, Paul G.,Sparkes, Hazel A.
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- Chalcone and cinnamate synthesis via one-pot enol silane formation-Mukaiyama aldol reactions of ketones and acetate esters
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Aryl alkyl ketones, acetate esters, and acetamides undergo facile one-pot enol silane formation, Mukaiyama aldol addition, and dehydrosilyloxylation in the presence of an amine base and excess trimethylsilyl trifluoromethanesulfonate. The chalcone and cinnamate products are generally recovered in high yield. The relative stoichiometry of the trimethylsilyl trifluoromethanesulfonate and amine base reagents determines whether the reaction yields the β-silyloxy carbonyl product or the α,β-unsaturated carbonyl.
- Downey, C. Wade,Glist, Hadleigh M.,Takashima, Anna,Bottum, Samuel R.,Dixon, Grant J.
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- Highly reactive heterogeneous Heck and hydrogenation catalysts constructed through 'bottom-up' nanoparticle self-assembly
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Polymer-mediated self-assembly of functionalized Pd and SiO2 nanoparticles provides highly active hydrogenation and Heck coupling catalysts.
- Galow, Trent H.,Drechsler, Ulf,Hanson, Jarrod A.,Rotello, Vincent M.
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- Simultaneous immobilization of a matrix containing palladium and phase transfer catalyst on silica nanoparticles: Application as a recoverable catalyst for the Heck reaction in neat water
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Simultaneous covalent anchoring of a phosphonium-palladium complex/phase transfer catalyst matrix on the surface of silica nanoparticles and the application of the resulting catalyst in the Heck reaction of a variety of different haloarenes in neat aqueous media is described. This journal is the Partner Organisations 2014.
- Hajipour, Abdol R.,Azizi, Ghobad
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- Palladium(II)-catalyzed phenylation of unsaturated compounds using phenylantimony chlorides under air
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Diphenylantimony chloride and phenylantimony dichloride, mainly the former, react smoothly with alkenes in acetonitrile at r.t. in the presence of a catalytic amount of Pd(OAc)2 under air to afford the corresponding phenylated alkenes (Heck-type reaction). The addition of AgOAc as reoxidant is not necessary for this reaction in sharp contrast to similar reactions using triarylstibines. The oxygen absorption is confirmed in this catalytic reaction and the reaction does not proceed catalytically in palladium(II) under inert gases, such as nitrogen or argon. Even under air the addition of a radical scavenger stopped the reaction. The regeneration of PhPdOAc species from Ph2SbCl, HPdOAc species and oxygen is proposed as a key step in the catalytic cycle where oxygen-containing radical species might be present as intermediates.
- Matoba, Kazutaka,Motofusa, Shin-Ichi,Sik Cho, Chan,Ohe, Kouichi,Uemura, Sakae
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- Highly active Pd(II) cyclometallated imine catalysts for the Heck reaction
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The new cyclopalladated, phosphine-free imine complexes 1-3 are exceptional catalysts for the Heck arylation, leading to more than a million turnovers in some cases; the catalysts are very thermally and air stable and are recovered unchanged after the catalysis.
- Ohff, Manuela,Ohff, Andreas,Milstein, David
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- Silica hybrid material containing Pd-NHC complex as heterogeneous catalyst for Mizoroki-Heck reactions
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A silica hybrid material containing palladium-N-heterocyclic carbene complexes was prepared by the sol-gel transformation of a molecular triethoxysilylated Pd-NHC complex. The material showed high activity as heterogeneous catalyst in Mizoroki-Heck reaction of aryl bromides and -iodides with styrene and methyl acrylate and could be re-used in at least five reaction cycles with unchanged catalytic properties.
- Polshettiwar, Vivek,Hesemann, Peter,Moreau, Jo?l J.E.
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- Magnetic dendritic polymer nanocomposites as supports for palladium: A highly efficient and reusable catalyst for Mizoroki-Heck and Suzuki-Miyaura coupling reactions
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A novel catalyst Fe3O4@SiO2-Dendrimer-Pd based on palladium immobilized on magnetic dendritic polymer nanocomposites was successfully synthesized and characterized by FT-IR, EA, XRD, TEM, EDX, VSM and XPS. This nanocatalyst showed excellent catalytic activity for solvent-free Mizoroki-Heck reaction and Suzuki-Miyaura reaction in EtOH/H2O at a palladium loading of only 0.009 mol%. Moreover, the Fe3O4@SiO2-Dendrimer-Pd catalyst could be conveniently recovered by an external magnet and used consecutively five times with excellent yields. The remarkable catalytic performances and convenient magnetic separability of the Fe3O4@SiO2-Dendrimer-Pd catalyst make it promising for practical application.
- Ma, Rong,Yang, Pengbo,Bian, Fengling
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- Synthesis of novel palladacycles and their application in heck and Suzuki reactions under aerobic conditions
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(Chemical Equation Presented) Design and synthesis of a novel family of furancarbothioamide-based palladacycles are reported herein. These palladacycles are thermally stable, not sensitive to air or moisture, and are applied effectively in the Heck reaction of aryl halides with terminal olefins and in the Suzuki reaction of aryl halides with arylboronic acids. These reactions were performed under aerobic conditions, leading to turnover numbers (TONs) up to 1 × 105.
- Xiong, Zhengchang,Wang, Nengdong,Dai, Mingji,Li, Ang,Chen, Jiahua,Yang, Zhen
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- Sulfilimine palladacycles: Stable and efficient catalysts for carbon-carbon coupling reactions
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A new family of sulfilimine-based palladacycles (1-4) has been synthesized in high yields from easily accessible starting materials and is found to exhibit high catalytic activities for carbon-carbon bond-formation in Suzuki, Heck, Sonogashira and Ullmann-type reactions, affording coupled products in excellent yields.
- Thakur, Vinay V.,Ramesh Kumar,Sudalai
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- Pd nanosized particles supported on chitosan and 6-deoxy-6-amino chitosan as recyclable catalysts for Suzuki-Miyaura and Heck cross-coupling reactions
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Several chitosan and 6-deoxy-6-amino chitosan-Schiff base ligands (1-4) were prepared by condensation of either 2-pyridinecarboxaldehyde or 2-(diphenylphosphino)benzaldehyde with the amino group(s) on chitosan and its derivative (6-deoxy-6-amino chitosan). The supported ligands were reacted with [PdCl2(COD)] to form chitosan-supported PdII catalysts (5-8). All the supported catalysts were air- and moisture-stable and have been characterized using elemental analysis, ICP-MS, UV-vis, FT-IR, PXRD, TGA, 31P solid state NMR and TEM. As models for the heterogenized catalysts (5 and 6), mononuclear PdII complexes (9 and 10) were also prepared via the Schiff-base condensation reaction of 1,3,4,6-tetra-O-acetyl- β-d-glucosamine hydrochloride to form 1,3,4,6-tetra-O-acetyl-β-d- glucos-2-pyridylimine and 1,3,4,6-tetra-O-acetyl-β-d-glucos-2- (diphenylphosphino)imine which were subsequently reacted with [PdCl 2(COD)]. Complexes (9 and 10) and their precursors were characterized by 1H and 31P NMR, UV-vis, FT-IR spectroscopy and elemental analysis. Catalytic Suzuki-Miyaura and Heck carbon-carbon cross-coupling reactions were carried out using the supported Pd catalysts and their mononuclear analogues. The immobilized and homogeneous catalysts showed high activity for both the Suzuki-Miyaura and Heck cross-coupling reactions in organic and aqueous media. Homogeneous catalysts (9 and 10) decomposed during the first run, while the supported catalysts could be recycled and reused up to five times.
- Makhubela, Banothile C.E.,Jardine, Anwar,Smith, Gregory S.
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- Cellulose supported Pd(II) complex catalyzed carbon-carbon bonds formation
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Corn-cobs are an agro-industrial waste and composed of cellulose mostly. In this study cellulose was isolated from the waste corn-cobs and modified to polymeric hydroxamic acid palladium complex 1 and characterized by using a variety of spectroscopic methods such as field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The complex 1 exhibited high catalytic activity towards Suzuki and Heck coupling reactions of activated and deactivated aryl halides to give the respective coupling products with high yield. Moreover, the complex 1 was recovered and recycled five times with no considerable loss of catalytic overall performance.
- Sarkar, Shaheen M.,Rashid,Karim, Kaykobad Md. Rezaul,Mustapha, Siti Noor Hidayah,Lian, Yuen Mei,Zamri, Normaiza,Khan, Md. Maksudur Rahman,O'Reilly, Emmet J.,Rahman, Md. Lutfor
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- Preparation of microcapsule-supported palladium catalyst using SPG (Shirasu Porous Glass) emulsification technique
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A new method for the preparation of microcapsule-supported palladium catalyst was described. The highly monodisperse crosslinked polystyrene microcapsules containing phosphine ligand were synthesized by the self-assembling of phase separated polymer (SaPSeP) method using diphenyl(4-vinylphenyl)phosphine and divinylbenzene as a monomer and crosslinking agent, respectively, and 2,2′-azobisisobutyronitrile (AIBN) as an initiator within the droplets of oil-in-water (O/W) emulsions, which were prepared by using the Shirasu Porous Glass (SPG) membrane emulsification technique. The prepared microcapsule-supported palladium catalyst exhibited high catalytic activity for Heck reaction and can be reused several times without loss of activity.
- Liu, Ying,Feng, Xiu Juan,Bao, De Cai,Li, Kai Xiao,Bao, Ming
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- Catalysis of the Heck-type reaction of alkenes with arylboronic acids by silica-supported rhodium: An efficient phosphine-free reusable catalytic protocol
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A 3-aminopropyl-functionalized silica-supported rhodium(0) catalyst (SiO2-Rh0) was prepared and employed in the Heck-type coupling of arylboronic acids and alkenes, affording good-to-excellent yields of substituted alkenes; the catalyst was recovered by filtration and reused for several cycles. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Trivedi, Rajiv,Roy, Sarabindu,Roy, Moumita,Sreedhar,Kantam, M. Lakshmi
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- Direct Oxidation of Acetals and Aldehydes to Esters
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One step conversion of acetals and aldehydes to esters was achieved with hydrogen peroxide (35wt% solution in water) and hydrochloric acid in alcohol. This procedure was proved to be simple and effective.
- Takeda, Takanobu,Watanabe, Hidenori,Kitahara, Takeshi
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- A convenient synthesis of 2-(6-methoxy-2-naphthyl)propenoic acid (a naproxen precursor)
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The title compound has been synthesised via the quantitative hydrocabonylation of the corresponding 1-alkyne in the presence of a palladium catalyst. The reaction proceeds at best under 30 bar of CO, but for the purposes of a laboratory scale synthesis it can be carried out successfully even at atmospheric pressure.
- Scrivanti,Matteoli
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- Pd–Schiff base complex supported on Fe3O4 magnetic nanoparticles: A new and highly efficient reusable catalyst for C–C bond formation in water
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A protocol is introduced for the preparation of a new cage-like Pd–Schiff base organometallic complex supported on Fe3O4 nanoparticles (Fe3O4@Schiff-base-Pd). The structure of the nanomagnetic catalyst was comprehensively characterized using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller measurements, scanning electron microscopy (SEM), transmission electron microscopy, X-ray mapping, thermogravimetric analysis, vibrating sample magnetometry and inductively coupled plasma atomic emission spectroscopy. In the second stage, the catalytic activity of this catalyst was studied in the Suzuki and Heck cross-coupling reactions in water as a green solvent. In this sense, simple preparation of the catalyst from commercially available materials, high catalytic activity, simple operation, short reaction times, high yields and use of green solvent are some advantages of this protocol. Finally, the nanocatalyst was easily recovered, using an external magnet, and reused several times without significant loss of its catalytic efficiency. In addition, the stability of the catalyst after recycling was confirmed using SEM, XRD and FT-IR techniques.
- Lei, Lei
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- PALLADIUM-CATALYZED OXIDATIVE COUPLING OF AROMATIC COMPOUNDS WITH OLEFINS USING t-BUTYL PERBENZOATE AS A HYDROGEN ACCEPTER
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Benzene and furans undergo oxidative coupling with olefins with an aid of t-butyl perbenzoate and a catalytic amount of Pd salts.The perbenzoate acts as a hydrogen accepter.In the absence of olefins, Pd catalyzed benzoxylation of aromatic compounds takes place.
- Tsuji, Jiro,Nagashima, Hideo
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- Palladium-catalyzed Mizoroki-Heck type reaction with aryliodine diacetates using hydrazone ligand
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We developed a palladium-catalyzed Mizoroki-Heck type reaction of olefins with such hypervalent iodine reagents as iodobenzene diacetate in good to high yields using 2 mol% of a heterocyclic hydrazone (1b)-Pd(OAc)2 system in NMP under air at 90 °C. The Japan Institute of Heterocyclic Chemistry.
- Mino, Takashi,Watanabe, Kohei,Abe, Taichi,Kogure, Taketo,Sakamoto, Masami
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- Palladium-catalyzed Mizoroki-Heck-type reactions of [Ph2SRfn][OTf] with alkenes at room temperature
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The first Pd-catalyzed Mizoroki-Heck-type reaction of [Ph2SRfn][OTf] with alkenes is described. The reaction of [Ph2SRfn][OTf] (Rfn = CF3, CH2CF3) with alkenes in the presence of 10 mol% Pd[P(t-Bu)3]2 and TsOH at room temperature provided the corresponding phenylation products in good to high yields. The bases that benefit the traditional Mizoroki-Heck reactions severely inhibited the transformation with [Ph2SRfn][OTf], whereas acids significantly improved the reaction. This protocol supplies a new class of cross-coupling partners for Mizoroki-Heck-type reactions and gains important insights into the reactivity of phenylsulfonium salts either with or without fluorine-containing alkyl groups as the promising phenylation reagents in organic synthesis.
- Wang, Shi-Meng,Song, Hai-Xia,Wang, Xiao-Yan,Liu, Nan,Qin, Hua-Li,Zhang, Cheng-Pan
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- Crystalline hybrid solid materials of palladium and decamethylcucurbit[5] uril as recoverable precatalysts for heck cross-coupling reactions
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A series of M-Pd-Me10CB[5] (M=Li, Na, K, Rb, and Cs; Me 10CB[5]=decamethylcucurbit[5]uril) hybrid solid materials have been successfully synthesized for the first time through a simple diffusion method. These as-prepared hybrid solids have been applied as phosphine-free precatalysts for Heck cross-coupling reactions with excellent catalytic performance and good recyclability. In the processes of the catalytic reactions, the activated PdII species were released from the crystalline hybrid precatalysts and transformed into catalytically active Pd nanoparticles, which have been demonstrated as key to carry on the catalytic reactions for the recoverable precatalysts M-Pd-Me10CB[5] (M=K, Rb, and Cs). It has also been rationalized that the introduction of different alkali metals afforded crystalline hybrid precatalysts with different crystal structures, which are responsible for their diversified stability and reusability presented in Heck reactions. Hybrid cats: A series of crystalline hybrid solid materials of palladium and decamethylcucurbit[5]uril (M-Pd-Me10CB[5], in which M=Li, Na, K, Rb, and Cs) have been successfully synthesized for the first time by means of a simple diffusion method. These as-prepared hybrid solids have been applied as phosphine-free precatalysts for Heck cross-coupling reactions with excellent catalytic performance and good recyclability (see figure). Copyright
- Li, Hongfang,Lue, Jian,Lin, Jingxiang,Huang, Yuanbiao,Cao, Minna,Cao, Rong
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- A click strategy for the immobilization of palladium nanoparticles onto silica: Efficient and recyclable catalysts for carbon-carbon bond formation under mild reaction conditions
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An interesting silica-supported nano-palladium catalyst was successfully prepared through "click" reaction of azide-functionalized silica with methylpropargylimidazolium bromide followed by immobilization of palladium nanoparticles (NPs), in which the click-triazole as an important functional entity acts as both a stable linker and a good chelator. The palladium-NPs are stabilized by synergistic effect of coordination and electrostatic interactions. The as-prepared nanocatalyst was well characterized and found to be highly efficient in Heck and Suzuki-Miyaura coupling in terms of activity and recyclability in aqueous ethanol under phosphine-free and low Pd loading (0.1 mol%) conditions.
- Hajipour, Abdol R.,Abolfathi, Parisa,Mohammadsaleh, Fatemeh
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- A NOVEL ROUTE TO α,β-UNSATURATED ESTERS VIA A REFORMATSKY-TYPE REACTION USING SODIUM TELLURIDE
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Sodium telluride, prepared by heating tellurium and sodium hydride in a 1:2 molar ratio in dry N,N-dimethylformamide, readily debrominates a bromoacetic ester at low temperatures to generate an enolate anion, which undergoes a Reformatsky-type reaction with various non-enolizable aldehydes to give the corresponding α,β-unsaturated esters in good to moderate yields.Ketones remain almost unaffected under the same conditions.
- Suzuki, Hitomi,Inouye, Masahiko
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- In-situ-generated palladium nanoparticles in novel ionic liquid: an efficient catalytic system for Heck–Matsuda coupling
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Abstract: A green, convenient, ecological and recyclable method comprising dual functionalized, task-specific, ionic liquid (IL)-triggered, in situ-generated Pd nanoparticles (NPs) and their catalytic application for Heck–Matsuda coupling of olefins is described. Both arenediazonium tetrafluoroborate and silica sulphate salts are coupled with olefins under ligand-free and aerobic conditions at ambient temperature furnishing excellent yields of products. The Ionic liquid used acts as a reducing as well as stabilizing agent for in situ-generated Pd NPs. The formed NPs were characterized by transmission electron microscopy (TEM) analysis, having a size below 50?nm, and exhibited high catalytic activity. The catalytic system can be reused for eight times effectively without any significant loss of activity. The method was found to be highly stereo-specific, giving exclusively the ‘E’ isomer.
- Gaikwad,Undale,Patil,Pore,Korade,Kamble
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- Chemoselective and stereoselective debromination of vicinal-dibromides with sodium dithionite
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A simple and efficient procedure for the quantitative debromination of vic-dibromides has been reported with sodium dithionite at ambient temperature. These eliminations are chemoselective and also stereoselective.
- Khurana, Jitender M.,Sehgal, Arti
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- Sodium 2-(2-pyridin-3-ylethylamino)sulfonate: an efficient ligand and base for palladium-catalyzed Heck reaction in aqueous media
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The first successful Pd(OAc)2, N-donor ligand and base mediated Heck coupling reaction of aryl halides and alkenes in water is described. The corresponding Heck products were obtained in good to excellent yields.
- Pawar, Shivaji S.,Dekhane, Deepak V.,Shingare, Murlidhar S.,Thore, Shivaji N.
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- A dithizone-functionalized polystyrene resin-supported Pd(II) complex as an effective catalyst for Suzuki, Heck, and copper-free Sonogashira reactions under aerobic conditions in water
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A novel polystyrene-supported palladium(II) dithizone complex is found to be a highly active catalyst for the Suzuki, Heck, and Sonogashira reactions of aryl halides in water. By this protocol, aryl halides, coupled with phenyl boronic acid (Suzuki reaction), alkenes (Heck reaction) or terminal alkyne (Sonogashira reaction), smoothly affords the corresponding cross-coupling products in good to excellent yields. Furthermore, the catalyst shows good thermal stability and recyclability. The catalyst was recycled for the Suzuki, Heck, and Sonogashira reactions for five runs without appreciable loss of its catalytic activity and negligible metal leaching.
- Bakherad, Mohammad,Jajarmi, Saeideh
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- Cobalt supported on dendronized magnetic nanoparticles: A new highly efficient and recyclable catalyst for the Mizoroki–Heck cross-coupling reaction
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Polyamidoamine (PAMAM) is one of the most interesting types of hyperbranched polymers that carry a large number of amino groups on its surface. PAMAM has gained significant attention from synthetic organic chemists due to its structural characteristics, controllable structure, inner porosity, and ability to trap a wide range of ions and molecules. So, in this work, the PAMAM dendrimer was synthesized, grafted onto the surface of magnetite nanoparticles, and the resulting hybrid nanoparticles were then employed as suitable host for immobilizing cobalt nanoparticles. The newly developed catalyst was well characterized by Fourier transform-infrared, X-ray diffraction, thermogravimetric analysis, field emission-scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, element mapping and energy-dispersive X-ray analysis. The efficiency of the as-prepared nanocatalyst was evaluated for the Mizoroki–Heck cross-coupling reactions. The MNP@PAMAM-Co represented perfect catalytic efficiency and high selectivity for the Mizoroki–Heck cross-coupling reaction compared with previously reported catalysts. The catalyst separation from the reaction mixture was easily achieved with the assistance of an external magnetic field, and its recycling was also investigated for five consecutive runs. Hot filtration confirmed no leaching of the active metal during the Heck coupling.
- Arghan, Maryam,Koukabi, Nadiya,Kolvari, Eskandar
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- Methoxylation of Acyl Fluorides with Tris(2,4,6-trimethoxyphenyl)phosphine via C-OMe Bond Cleavage under Metal-Free Conditions
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Acyl fluorides are subjected to methoxylation with tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) to afford the corresponding methyl esters in good to excellent yields. This transformation is featured by C(sp2)-OMe bond cleavage under metal-free conditions. Unprecedented utilization of TMPP as a methoxylating agent realized the installation of an OMe group into the desired products.
- Ishida, Takumi,Nishihara, Yasushi,Wang, Xiu,Wang, Zhenhua
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- Silica-Supported Ni(II)–DABCO Complex: An Efficient and Reusable Catalyst for the Heck Reaction
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Abstract: An interesting nickel-based catalyst supported on DABCO-functionalized silica was successfully prepared and evaluated as heterogeneous nanocatalyst in Heck cross coupling reaction of various aryl halides and methyl acrylate. The as-prepared nanocatalyst was well characterized by FT-IR, FE-SEM, TEM, XRD, SEM-EDX, ICP and TGA techniques and found to be highly efficient in the reaction system in terms of activity and recyclability. Graphical Abstract: This work provides an economical and heterogeneous catalytic system based nickel nanoparticle supported on DABCO functionalized silica for the Heck cross-coupling reaction of various aryl halides with methyl acrylate. [Figure not available: see fulltext.]
- Hajipour, Abdol R.,Abolfathi, Parisa
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- Fluorapatite-supported palladium catalyst for Suzuki and Heck coupling reactions of haloarenes
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A fluorapatite-supported palladium catalyst (PdFAP) was synthesized by treatment of fluorapatite (prepared by incorporating the basic species fluoride ion into apatite in situ by co-precipitation) with bis(benzonitrile) palladium(II) chloride in acetone. The catalyst displayed high catalytic activity for Suzuki coupling of aryl iodides and bromides with boronic acids at room temperature and chloroarenes at 130°C in the presence of tetrabutylammonium bromide to give biaryls in excellent yields. Heck olefination of chloroarenes was also successfully carried out by this catalyst. PdFAP was recovered quantitatively by simple filtration and reused with consistent activity. PdFAP was well characterized by XRD, FTIR, XPS, ICP-AES, CO 2 TPD and CHN elemental analysis.
- Kantam, M. Lakshmi,Kumar, K. B. Shiva,Srinivas,Sreedhar
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- DIRECT SYNTHESIS OF Z-UNSATURATED ESTERS. A USEFUL MODIFICATION OF THE HORNER-EMMONS OLEFINATION.
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New phosphonoester reagents and reaction conditions are described which yield Z-alpha,beta-unsaturated esters stereoselectively and in high yield from aliphatic and aromatic aldehydes.
- Still, W. Clark,Gennari, Cesare
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- Pd complex of an NNN pincer ligand supported on γ-Fe2O3@SiO2 magnetic nanoparticles: A new catalyst for Heck, Suzuki and Sonogashira coupling reactions
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In this study, a Pd complex of bis(imino)pyridine as an NNN pincer ligand supported on γ-Fe2O3@SiO2 magnetic nanoparticles (Pd-BIP-γ-Fe2O3@SiO2) was synthesized and characterized by SEM, TEM, FT-IR, TGA, ICP, XRD, XPS, VSM and elemental analysis. The synthesized catalyst was used successfully as a new air- and moisture-stable phosphine-free Pd catalyst for Heck, Suzuki and Sonogashira coupling reactions of aryl iodides, bromides and chlorides with alkyl acrylates, styrene, phenylboronic acid and phenylacetylene. The true heterogeneous magnetically-recyclable catalyst can be separated easily using a magnetic bar and reused ten times without any drastic loss of its catalytic activity.
- Sobhani, Sara,Zeraatkar, Zohre,Zarifi, Farzaneh
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- Palladium-catalysed Vinylation of Organic Halides under Solid-Liquid Phase Transfer Conditions
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Heck-type reactions involving organic halides proceed readily at or near room temperature when performed under solid-liquid phase transfer conditions.
- Jeffery, Tuyet
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- Arylation and Alkylation of Olefins by Arylamines or Hydrazines via Carbon-Nitrogen Bond Cleavage in the Presence of Palladium(II) Salts
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Arylamines (ArNH2) have been found to function as arylating agents by way of C-N bond cleavage to give aryl-substituted olefins when treated with palladium salts and acetic acid.The reactivity of various amines and olefins has been investigated.Hydrazines such as phenylhydrazine and methylhydrazine are also able to act as arylating and alkylating agents, respectively.The addition of tert-butyl nitrite greatly increases the yields.
- Akiyama, Fumitaka,Miyazaki, Hiroshi,Kaneda, Kiyotomi,Teranishi, Shiichiro,Fujiwara, Yuzo,et al.
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- Salen-porphyrin-based conjugated microporous polymer supported Pd nanoparticles: Highly efficient heterogeneous catalysts for aqueous C-C coupling reactions
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The salen-porphyrin based conjugated microporous polymer (SP-CMP) was first constructed by polycondensation reaction of a salen-dialdehyde derivative and pyrrole. Due to the outstanding chemical and thermal stability, abundant micropores with a reasonable pore size, and ordered salen-porphyrin arrays in the A4B4-type polymer framework, the functional CMP was further applied as a Pd nanoparticle support by the coordinate interactions between the polydentate chelating sites with Pd(OAc)2 and subsequent reduction with NaBH4. The as-synthesized composite material (Pd@SP-CMP) was fully characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and solid-state 13C nuclear magnetic resonance (NMR). The porous property of Pd@SP-CMP was also characterized by N2 adsorption/desorption isotherms and the obtained material exhibited a Brunauer-Emmett-Teller (BET) surface area of 266 m2 g-1, together with a pore volume of 0.192 cm3 g-1. The microscopic morphology of Pd@SP-CMP was further evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Pd@SP-CMP material with highly dispersed Pd nanoparticles exhibited excellent catalytic activity towards Suzuki-Miyaura and Heck-Mizoroki coupling reactions in water or in the dioxane/water mixture. In addition, Pd@SP-CMP also displayed outstanding stability and recyclability, and it can be reused without loss of activity in ten successive reactions. More importantly, the salen-porphyrin based CMPs could be the promising candidates for developing high-performance heterogeneous catalysts.
- Ju, Pengyao,Wu, Shujie,Su, Qing,Li, Xiaodong,Liu, Ziqian,Li, Guanghua,Wu, Qiaolin
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- Palladium-catalysed cross-coupling reactions in supercritical carbon dioxide
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Heck and Suzuki reactions proceed in good yield in supercritical carbon dioxide in the presence of palladium acetate and tri-tert-butylphosphine with both free and polymer-tethered substrates.
- Early,Gordon,Carroll,Holmes,Shute,McConvey
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- Amidoxime modified PAN supported palladium complex: A greener and efficient heterogeneous catalyst for heck reaction
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Development of a facile and greener approach for Heck reaction using a modified PAN supported palladium catalyst is described. The preparation of the catalyst involves a simple process through amidoxime modification of nitrile group in Polyacrylonitrile (PAN), followed by the complexation with Palladium chloride (PdCl2). The resulting supported catalyst was characterized by spectroscopic analyses and further by computational studies. This polymer supported Palladium complex displayed excellent catalytic activity in Heck coupling reaction of a series of activated alkenes and aryl halides and afforded the corresponding coupling products upto 96% isolated yield. After the reaction, the catalyst was easily recovered by simple filtration and recycled with excellent stability and activity even after 5 runs. This is the first report on the use of amidoxime functionalized PAN- Palladium (II) complex as a heterogeneous catalyst in Heck coupling reaction.
- Sruthi, Pambingal Rajan,Sarika, Vijayalekshmi,Suku, Arya,Krishnan, Aravind,Anas, Saithalavi
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- Manganese phthalocyanine immobilized on silica gel: Efficient and recyclable catalyst for single-step oxidative esterification of aldehydes with alcohols
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The functionalization of silica gel was carried out using 3-aminopropyltriethoxysilane as a reactive surface modifier followed by covalent grafting of novel tetrakis-(2-methoxy-4-formylphenoxy)phthalocyaninato manganese(III) acetate complex. The resulting inorganic-organic hybrid material was found to be a highly selective and recyclable catalyst for the single-step synthesis of esters. The catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV-visible, 13C CPMAS and 29Si CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier-transform infrared (FT-IR) and atomic absorption spectroscopy (AAS) techniques, which demonstrates the covalent grafting of the complex onto functionalized silica gel. The catalytic performance of the novel inorganic-organic hybrid catalyst was evaluated in the direct oxidative esterification of aldehydes with alcohols, at ambient temperature, using hydrogen peroxide as an environment friendly oxidant. The hybrid catalyst presented up to 100% of substrate conversion with high turn-over numbers (TONs), up to 100% of selectivity toward the ester product, and can be recovered and reused for multiple cycles without appreciable loss in its catalytic activity.
- Sharma,Gulati, Shikha
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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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- Poly(hydroxamic acid) palladium catalyst for heck reactions and its application in the synthesis of Ozagrel
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Bio-waste corn-cob cellulose supported poly(hydroxamic acid) palladium complex was synthesized and it is characterized using some different techniques such as FTIR, FESEM, HRTEM, EDX, XPS, UV–vis, TGA and ICP-AES analyses. The cellulose supported heterogeneous palladium complex showed high stability and catalytic activity toward Mizoroki-Heck reaction of aryl/heteroaryl halides and arenediazonium tetrafluoroborate with a variety of olefins to give the corresponding coupling products in up to 97% yield. The palladium complex was also applied to the synthesis of Ozagrel a thromboxane A2-synthetase inhibitor with excellent yield. The complex was separated from the reaction mixture by simple filtration and repeatedly used up to seven times without significant loss of its catalytic performance.
- Sarkar, Shaheen M.,Rahman, Md. Lutfor,Chong, Kwok Feng,Yusoff, Mashitah Mohd
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- Homoleptic cis- and trans-palladium(II) bis(guanidinato) complexes derived from N-aryl-N′,N″-di(pyridin-2-yl)- and N-aryl-N′,N″-bis(6-methylpyridin-2-yl)guanidines: Catalysts for Heck-Mizoroki coupling reactions
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N-Aryl-N′,N″-di(pyridin-2-yl)- and N-aryl-N′,N″-bis(6-methylpyridin-2-yl)guanidines (1–4 and 5–7) were isolated in 75%–81% yields. Reactions of Pd(OAc)2 with guanidines 2–7 carried out separately in toluene at 60 °C for 3 h afforded 8–13 respectively in 69%–80% yields. Compounds 1–13 were characterized by elemental analyses, HR-MS, IR and NMR (1H and 13C) spectroscopy. Molecular structures of guanidines 1, 4, 5 and 6 and those of 8–13 were determined by single crystal X-ray diffraction. The Pd(II) atom in 8–10 revealed trans geometry while that in 11–13 revealed cis geometry. DFT calculations were carried out on model compounds 9a (trans) and its hypothetical cis isomer, 9b and 12a (cis) and its hypothetical trans isomer 12b which indicated a very small energy difference between the 9a/9b pair (1.28 kcal/mol) whereas a large energy difference was observed between the 12a/12b pair (26.38 kcal/mol) in CH2Cl2. The catalytic utility of 9 in Heck-Mizoroki coupling reactions involving styrene and methyl acrylate and aryl bromides/aryl chlorides in the presence of NaOAc and excess of tetrabutylammonium bromide (TBAB) at 120 °C was explored. Both activated and de-activated aryl bromides and aryl chlorides were coupled with styrene and in addition, the aryl chlorides were coupled with methyl acrylate in the presence of 9 to afford the respective coupling products in 68% ? >99% yields. Neat reaction carried out with 9 and TBAB under the optimized condition released the colloidal Pd black as verified by EDAX, PXRD and SEM techniques thereby implying the heterogeneous nature of catalysis.
- Mishra, Vishwesh,Thomas, Jisha Mary,Chinnappan, Sivasankar,Thirupathi, Natesan
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- Thiophene Methanimine–Palladium Schiff Base Complex Anchored on Magnetic Nanoparticles: A Novel, Highly Efficient and Recoverable Nanocatalyst for Cross-Coupling Reactions in Mild and Aqueous Media: Γ-Fe2O3/AEPH2-TC-Pd Catalyzed Suzuki–Miyaura and Heck–Mizoroki Reactions
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Abstract: In this study, a novel thiophene methanimine–palladium Schiff base complex anchored on decorated γ-Fe2O3 with 2-aminoethyl dihydrogen phosphate (γ-Fe2O3/AEPH2-TC-Pd) was synthesized as a new magnetically separable nanocatalyst. Characterization of the new designed nanocatalyst was performed successfully using different techniques such as FT-IR, XRD, XPS, TEM, TGA, VSM, ICP and elemental analysis. This nanocatalyst presented a superb catalytic activity for Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions. The most important features of the prepared catalytic system which makes the current protocol more beneficial from both industrial and environmental viewpoints are its ease of recovery and reusability up to nine cycles without appreciable loss of the catalytic performance, as well as accomplishing the reactions under mild conditions in aqueous media which is a great challenge in some cross-coupling reactions. Graphical Abstract: [Figure not available: see fulltext.].
- Jahanshahi, Roya,Akhlaghinia, Batool
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- A heterometal (Pd–Pb) organic framework: synthesis, structure and heterogeneous catalytic application
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A heterometallic organic framework {Pb[Pd(bpydc)Cl2]DMF}n (1) (H2bpydc = 2,2′-bipyridine-5,5′-dicarboxylic acid) was synthesized via a one-pot solvothermal method and characterized using thermogravimetric analysis, X-ray photoelectron spectroscopy as well as powder and single-crystal X-ray diffraction. The crystal structure of 1 indicates that, in metalloligand Pd(bpydc)Cl2, every Pd atom adopts a square planar coordination mode with two chloride ions and two nitrogen atoms from bpydc, and the carboxyl groups of Pd(bpydc)Cl2 connect Pb atoms to form a one-dimensional chain along the crystallographic a-axis, which is interlinked via metalloligands to form a two-dimensional layer structure. This complex is highly active, stable and recyclable as a catalyst for the Suzuki–Miyaura and Heck reactions of a wide range of aryl halides including electron-rich and electron-poor aryl iodides/bromides, affording the corresponding products in good to excellent yields.
- Ren, Yanwei,Jiang, Ou,Li, Jiawei,Zeng, Hang
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- Aminophosphine Palladium(0) Complex Supported on ZrO2 Nanoparticles (ZrO2@AEPH2-PPh2-Pd(0)) as an Efficient Heterogeneous Catalyst for Suzuki–Miyaura and Heck–Mizoroki Reactions in Green Media
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Abstract: A new aminophosphine palladium(0) complex supported on ZrO2nanoparticles (ZrO2@AEPH2-PPh2-Pd(0)) was successfully synthesized and characterized using FT-IR, XRD, XPS, SEM, TEM, EDS, TGA and ICP techniques. Characterization results revealed that the synthesized catalyst had tetragonal and monoclinic structure with spherical morphology. The prepared nanocatalyst was showed excellent reactivity in the Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions. Moreover, this nanocatalyst can be easily recovered and reused for at least six cycles without deterioration in catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]
- Razavi, Nasrin,Akhlaghinia, Batool,Jahanshahi, Roya
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- Piperazine-derived palladium complexes immobilised on a Merrifield resin as a catalyst for the Heck reaction
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A palladium catalyst supported on a Merrifield resin was prepared by a simple procedure and exhibited high activity and stability for the phosphine-free Heck reaction of activated and non-activated aryl or heteroaryl substrates with olefins to afford substituted cinnamic acids, stilbenes and their hetero-aromatic relatives.
- Wu, Xiang-Mei,Pei, Wen
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- Synthesis and crystal structures of a series of (μ-thiophenolato)(μ-pyrazolato-N,N′) double bridged dipalladium(II) complexes and their application in Mizoroki-Heck reaction as highly efficient catalysts
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Three new binucleating S-protected ligand precursors, 2-(N,N-dimethylthiocarbamato)-5-methylisophthalaldehyde di-2′-hydroxy 5′-methylanil (1b), 2-(N,N-dimethylthiocarbamato)-5-tert-butylisophthalaldehyde di-2′-hydroxyanil (2a) and 2-(N,N-dimethylthiocarbamato)-5-tert-butylisophthalaldehyde di-2′-hydroxy 5′-methylanil (2b), have been synthesized. The reaction of these ligand precursors with PdCl2 in the presence of pyrazole under Pd-mediated S-C cleavage yielded a series of binuclear palladium(II) complexes of general formula [LPd2(pz)], where pz is the exogenous bridging pyrazolyl ligand and L3- represents a series of pentadentate thiophenol-based bridging ligands originated from their corresponding ligand precursors. All the compounds were characterized by elemental analysis, IR, 1H NMR and UV-Vis spectroscopies. The binuclear μ-thiophenolato-μ-pyrazolato palladium(II) complexes have also been characterized by single crystal X-ray diffraction analysis. Crystal structure analyses of the complexes show that two PdII centers are located in distorted square-planar environments, arranged in binuclear units with PdPd distance of 3.57 ?. The catalytic activity of these new binuclear palladium complexes was studied in Mizoroki-Heck C-C coupling reaction of methyl- and n-butyl acrylate with various types of aryl iodides and bromides. All reactions were completed for very short times with very excellent yield. Reactions were stereoselective and only trans isomers were obtained in each case.
- Khadir, Narjes,Tavakoli, Ghazal,Assoud, Abdeljalil,Bagherzadeh, Mojtaba,Boghaei, Davar M.
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- Novel diphosphine-modified palladium catalysts for oxidative carbonylation of styrene to methyl cinnamate
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The oxidative carbonylation of styrene has been achieved in MeOH with known and new palladium(II) catalysts of general formulae [Pd(P-P)(MeCN)2][PF6]2, [Pd(P-P)(bipy)][PF6]2, Pd(P-P)(OAc)2, [Pd2(cyclo-tetraphos)(MeCN)4]-[PF6]4 , [Pd2(cyclo-tetraphos)(bipy)2][PF6]4, Pd2(cyclo-tetraphos)(OAc)4 (P-P = 1,2-bis(diphenylphosphino)ethane), meso-2,3-bis(diphenylphosphino)butane or rac-2,3-bis(diphenylphosphino)butane; cyclo-tetraphos = cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane; bipy = 2,2′-bipyridine; OAc = acetate). The influence of various catalytic parameters on the overall conversion of styrene into carbonylated products and on the product selectivity has been studied by systematically varying the type of palladium initiator, the concentrations of organic oxidant (1,4-benzoquinone) and protic acid (p-toluenesulfonic acid), and the CO pressure. This investigation has allowed a partial optimization of the process so as to obtain the largely predominant formation of either methyl cinnamate (highest selectivity 99%) or dimethyl phenylsuccinate (highest selectivity 88%).
- Bianchini, Claudio,Mantovani, Giuseppe,Meli, Andrea,Oberhauser, Werner,Brueggeller, Peter,Stampfl, Thomas
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- A Straightforward, Purification-Free Procedure for the Synthesis of Ando and Still-Gennari Type Phosphonates
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Z-Selective Still-Gennari and Ando modifications of the typically E-selective Horner-Wadsworth-Emmons reaction are highly valuable synthetic tools in organic chemistry. These procedures are based on application of bis(2,2,2-trifluoroethyl) phosphonates or diaryl phosphonates, respectively, for the olefination of carbonyl groups. In our research, we present an improved, straightforward, purificationfree procedure for the synthesis of these reagents. The key step of our procedure is the reaction of phosphonic dichlorides with the appropriate sodium alkoxides, which results in 52-97% isolated yields of the desired products on a gram scale. The whole three-step process is performed in one pot. Most importantly, the product is obtained in over 95% purity after simple extraction, avoiding column chromatography and distillation. Moreover, we present the synthesis of a novel Still-Gennari type reagent, bis(1,1,1,3,3,3-hexafluoroisopropyl) phosphonates, which may exhibit improved Z-selectivity in Still-Gennari olefinations.
- Janicki, Ignacy,Kie?basiński, Piotr
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p. 378 - 382
(2021/10/21)
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- Visible-Light-Driven Isocyanide Insertion to o-Alkenylanilines: A Route to Isoindolinone Synthesis
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A visible-light-mediated intermolecular radical insertion of isocyanides to electron-deficient o-alkenylanilines leading to isoindolinone is reported. Deuterium (D2O) and H2O18 labelling experiments suggest H and O incorporation in the product. The formation of an N-centered radical (NCR) via stepwise PT/ET process was confirmed by radical trapping experiments, photoluminescence, cyclic voltammetry and DFT studies. This photo cascade methodology is overall a redox neutral process featuring metal-free condition and broad substrate scope (32 examples). The synthesis of analogue of GABA receptor antagonist shows the practical utility of this method. (Figure presented.).
- Dahiya, Anjali,Das, Bubul,Sahoo, Ashish Kumar,Patel, Bhisma K.
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p. 966 - 973
(2022/02/07)
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- Synthesis of α-diazoesters from α-hydrazonoesters: Utilization of α-hydrazonoesters and α-diazoesters for convenient interconversion
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We have developed a novel method to synthesize α-diazoesters from α-hydrazonoesters with a catalytic amount of Cu(OAc)2 in acetonitrile. When the reaction was carried out under an argon atmosphere, the reaction stopped halfway, suggesting that this reaction required oxygen to reoxidize the catalyst. Since hydrazonoesters can be obtained by reduction of α-diazoesters with P(n-Bu)3 in diisopropyl ether, these 2 compounds are mutually interconvertible with ease. Whereas α-diazoesters are unstable and unsuitable for storage, hydrazonoesters are more stable, especially crystalline hydrazonoesters. Thus, hydrazonoesters, which are suitable for long-term storage, could be conveniently used as precursors for α-diazoesters.
- Yasui, Eiko,Ishimine, Kanako,Nitanai, Sohta,Hatakeyama, Nanami,Nagumo, Shinji
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- Pd-Catalyzed desulfitative arylation of olefins by: N -methoxysulfonamide
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A novel Pd-catalyzed protocol for the desulfitative Heck-type reaction of N-methoxy aryl sulfonamides with alkenes was reported. The cross-coupling reaction was performed successfully with a variety of olefins to obtain aryl alkenes. Different substituents on the aromatic ring of N-methoxysulfonamides were also found to be compatible with the reaction conditions. Expectedly, the reaction proceeds through CuCl2-promoted generation of the nitrogen radical and subsequent desulfonylation under thermal conditions to afford the aryl radical for the Pd-catalyzed coupling reaction. N-Methoxysulfonamide was further exploited for the synthesis of symmetrical biaryls in the presence of CuCl2. This journal is
- Ojha, Subhadra,Panda, Niranjan
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supporting information
p. 1292 - 1298
(2022/02/19)
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- Synthesis of novel 1-phenyl-benzopyrrolizidin-3-one derivatives and evaluation of their cytoneuroprotective effects against NMDA-induced injury in PC12 cells
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A range of novel 1-phenyl-benzopyrrolizidin-3-one derivatives were synthesized and evaluated for neuroprotective effects against N-methyl-?-aspartate (NMDA)-induced injury in PC12 cells. Interestingly, derivatives that 1-phenyl moiety bearing electron-donating group, especially benzyloxy, and the trans-forms exhibited better protective activity against NMDA-induced neurotoxicity. Compound 11 m demonstrated the best neuroprotective potency and shown a dose-dependent prevention. The increased intracellular calcium (Ca2+) influx caused by NMDA in PC12 cells was reversed in the case of compound 11 m pretreatment at 15 μM. These results suggested that the synthesized 1-phenyl-benzopyrrolizidin-3-one derivatives exerted neuroprotective effect on NMDA-induced excitotoxicity in PC12 cells associated with inhibition of Ca2+ overload and can be further optimized for the development of neuroprotective agents.
- Cao, Jiafu,Li, Qiji,Liao, Xiu,Wang, Enhua,Wang, Li,Yang, Juan,Yang, Lishou,Yang, Qian,Yang, Xiaosheng,Yang, Yan
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supporting information
(2022/02/23)
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- Click amidations, esterifications and one–pot reactions catalyzed by Cu salts and multimetal–organic frameworks (M–MOFs)
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Amides and esters are prevalent chemicals in Nature, industry and academic laboratories. Thus, it is not surprising that a plethora of synthetic methods for these compounds has been developed along the years. However, these methods are not 100% atom economical and generally require harsh reagents or reaction conditions. Here we show a “spring–loaded”, 100% atom–efficient amidation and esterification protocol which consists in the ring opening of cyclopropenones with amines or alcohols. Some alkyl amines react spontaneously at room temperature in a variety of solvents and reaction conditions, including water at different pHs, while other alkyl amines, aromatic amines and alcohols react in the presence of catalytic amounts of simple Cu2+ salts or solids. A modular reactivity pattern (alkyl amines >> alkyl alcohols >> phenols >> aromatic amines) enables to design orthogonal and one–pot reactions on well–defined catalytic Multimetal–Organic Frameworks (M–MOFs, M= Cu, Ni, Pd), to easily functionalize the resulting cinnamides and cinnamic esters to more complex molecules. The strong resemblance of the amidation and esterification reaction conditions here reported with the copper–catalyzed azide–alkyne cycloaddition (CuAAC) allows to define this fast, clean and flexible protocol as a click reaction.
- Armentano, Donatella,Ferrando-Soria, Jesús,Greco, Rossella,Leyva-Pérez, Antonio,Palomar-De Lucas, Brenda,Pardo, Emilio,Tiburcio, Estefanía
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- Heterogeneous Isomerization for Stereoselective Alkyne Hydrogenation to trans-Alkene Mediated by Frustrated Hydrogen Atoms
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Stereoselective production of alkenes from the alkyne hydrogenation plays a crucial role in the chemical industry. However, for heterogeneous metal catalysts, the olefins in cis-configuration are usually dominant in the products due to the most important and common Horiuti-Polanyi mechanism involved over the metal surface. In this work, through combined theoretical and experimental investigations, we demonstrate a novel isomerization mechanism mediated by the frustrated hydrogen atoms via the H2 dissociation at the defect on solid surface, which can lead to the switch in selectivity from the cis-configuration to trans-configuration without overhydrogenation. The defective Rh2S3 with exposing facet of (110) exhibits outstanding performance as a heterogeneous metal catalyst for stereoselective production of trans-olefins. With the frustrated hydrogen atoms at spatially separated high-valence Rh sites, the isolated hydrogen mediated cis-to-trans isomerization of olefins can be effectively conducted and the overhydrogenation can be completely inhibited. Furthermore, the bifunctional Rh-S/Pd nanosheets have been synthesized through the surface modification of Pd nanosheets with rhodium and sulfide. With the selective semihydrogenation of alkynes into cis-olefins catalyzed by the small surface PdSx ensembles, the bifunctional Rh-S/Pd nanosheets exhibit excellent activity and stereoselectivity in the one-pot alkyne hydrogenation into trans-olefin, which surpasses the most reported homogeneous and heterogeneous catalysts.
- Zhang, Weijie,Qin, Ruixuan,Fu, Gang,Zheng, Nanfeng
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supporting information
p. 15882 - 15890
(2021/10/02)
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- Pd supported on clicked cellulose-modified magnetite-graphene oxide nanocomposite for C-C coupling reactions in deep eutectic solvent
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Cellulose-modified magnetite-graphene oxide nanocomposite was prepared via click reaction and utilized for immobilization of palladium (Pd) nanoparticles without using additional reducing agent. The abundant OH groups of cellulose provided the uniform dispersion and high stability of Pd nanoparticles, while magnetite-graphene oxide as a supporting material offered high specific surface area and easy magnetic separation. The as-prepared nanocomposite served as a heterogeneous catalyst for the Heck and Sonogashira coupling reactions in various hydrophilic and hydrophobic deep eutectic solvents (DESs) as sustainable and environmentally benign reaction media. Among the fifteen DESs evaluated for coupling reactions, the hydrophilic DES composed of dimethyl ammonium chloride and glycerol exhibited the best results. Due to the low miscibility of catalyst and DES in organic solvents, the separated aqueous phase containing both of the catalyst and DES can be readily recovered by evaporating water and retrieved eight times with negligible loss of catalytic performance.
- Karimi, Sabah,Masteri-Farahani, Majid,Niakan, Mahsa,Shekaari, Hemayat
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- Immobilizing palladium on melamine-functionalized magnetic nanoparticles: An efficient and reusable phosphine-free catalyst for Mizoroki–Heck reaction
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A highly efficient and stable heterogeneous catalyst was successfully prepared by anchoring palladium(0) onto melamine-functionalized Fe3O4 magnetic nanoparticles (MNPs-Mel-Pd). With the aid of amine functional groups, melamine was covalently bonded on epoxy functionalized magnetic nanoparticles and then Pd(0) was immobilized on this support with high dispersion. The prepared nanocatalyst exhibits excellent catalytic activity for C-C cross coupling (Mizoroki–Heck) of various aryl halides (iodide, bromides, and chrlorides) with olefins under mild reaction condition in relatively short reaction times. The synthesized nanocatalyst was characterized using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and X-ray photoelectron spectroscopy (XPS) techniques. The loading level of Pd in MNPs-Mel-Pd catalyst was measured to be 1.26 × 10?3 mol g?1 by atomic absorption spectroscopy (AAS). In addition, the catalyst can be easily separated and recovered from the reaction mixture by using an external magnet. The heterogeneity of the catalyst was confirmed by the hot filtration test, which was reused for at least six times under the optimized conditions without any significant loss of its activity.
- Aryanasab, Fezzeh,Shabanian, Meisam,Laoutid, Fouad,Vahabi, Henri
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- Synthesis of new adamantyl-imine palladium(II) complexes and their application in Mizoroki-Heck and Suzuki-Miyaura C[sbnd]C cross-coupling reactions
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Improving carbon–carbon cross-coupling reactions is an ongoing process and finding the most versatile and stable catalyst precursors has been of great interest. Ligand design has been proven to be important since it is responsible for providing electron density and steric saturation around the metal centre, thus contributing towards the stereo-electronic properties. The adamantyl moiety has been used to generate highly bulky and electron-rich ligands for application in palladium-catalysed cross-coupling reactions. Accordingly, we have prepared some Schiff-base adamantyl ligands (L1-L3) and complexed them with [PdCl2(MeCN)2] to afford the (pre)catalysts C1-C3, which were successfully applied in Mizoroki-Heck and Suzuki-Miyaura carbon–carbon cross-coupling reactions. The cross-coupling reaction products were obtained in good yields using 0.5 mol % Pd catalyst loading. C2 and C3 showed remarkable activity in the Mizoroki-Heck coupling reactions involving substrates with substituents on the olefin and aryl halide (including 4-Cl, 4-CH3, -CO2Me and -CO2Et). We also, observed that the Suzuki-Miyaura cross-coupling system was active towards challenging activated and deactivated aryl chlorides, with to up 70% conversions recorded. The mercury poisoning tests conducted revealed that the catalysts act as homogenous molecular active species in the Mizoroki-Heck reactions and act as both homogenous and heterogeneous catalysts in the Suzuki-Miyaura cross-coupling reactions.
- Makhubela, Banothile C. E.,Matsheku, Asanda C.,Maumela, Munaka C.
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- Immobilized Pd on a NHC-functionalized metal-organic FrameworkMIL-101(Cr): An efficient heterogeneous catalyst in the heck and copper-free Sonogashira coupling reactions
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A heterogeneous palladium catalyst system based on immobilization of palladium moieties on a N-heterocyclic carbene (NHC) modified metal organic framework (MOF) was developed for the Heck and copper-free Sonogashira coupling reactions. In order to prepare this catalyst system, first, MIL-101(Cr) was functionalized with NHC moieties through a post synthetic modification (PSM) approach, and then Pd metal was stabilized on the prepered MIL-101(Cr)-NHC substrate. This material was characterized using various microscopic and spectroscopic techniques and then was used as an efficient heterogeneous Pd catalyst system in the Heck and copper-free Sonogashira reactions. Results of the heterogeneity tests showed that the Pd-NHC-MIL-101(Cr) catalyst can efficiently catalyzed these coupling reactions heterogeneously and no remarkable changes observed in the morphology and structure of MIL-101(Cr) template during the reaction progress. Also, existence of palladium nanoparticles immobilized on the MOF structure affirmed by the TEM and XPS analysis confirmed the oxidation state of Pd. A variety of alkene and alkyne derivatives were synthesized in good to excellent yields using this heterogeneous Pd catalyst system under normal conditions. More importantly Pd-NHC-MIL-101(Cr) catalyst was simply recovered from the reaction medium without remarkable decreasing in its catalytic activities after five times of reusability. The ICP analysis showed the very low Pd and Cr metals leaching, representing high stability and applicability of this catalyst in Pd coupling reactions.
- Niknam, Esmaeil,Panahi, Farhad,Khalafi-Nezhad, Ali
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supporting information
(2021/01/12)
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- Oxoammonium-Mediated Allylsilane–Ether Coupling Reaction
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A new C(sp3)?H functionalization reaction consisting of the oxidative α-allylation of allyl- and benzyl- methyl ethers has been developed. The C?C coupling could be carried out under mild conditions thanks to the use of cheap and green oxoammonium salts. The scope of the reaction was studied over 27 examples, considering the nature of the substituents on the two coupling partners.
- Carlet, Federica,Bertarini, Greta,Broggini, Gianluigi,Pradal, Alexandre,Poli, Giovanni
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supporting information
p. 2162 - 2168
(2021/04/02)
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- Heteroleptic copper(I) complexes as energy transfer photocatalysts for the intermolecular [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides
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The [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides can be effectively catalyzed by heteroleptic copper(I) complexes. The reactions were carried out under mild reaction conditions and the products were obtained in 20–72% yield under visible light irradiation. The copper-based photocatalyst comprised of the rigid phenanthroline ligand with substituents at the 2,9-positions and the 4,7-positions showed high activity in the photodimerization via an energy transfer pathway.
- Wu, Qing-An,Ren, Chen-Chao,Chen, Feng,Wang, Tian-Qi,Zhang, Yu,Liu, Xue-Fen,Chen, Jian-Bin,Luo, Shu-Ping
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supporting information
(2021/05/10)
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- Mizoroki-Heck Reaction of Unstrained Aryl Ketones via Ligand-Promoted C-C Bond Olefination
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Mizoroki-Heck reaction of unstrained aryl ketone with acrylate/styrene is accomplished via palladium-catalyzed ligand-promoted C-C bond cleavage. Various (hetero)aryl ketones are compatible in the reaction, affording the alkene product in good to excellent yields. Further applications in the late-stage olefination of some drugs, natural products, and fragrance-derived aryl ketones demonstrate the synthetic utility of this protocol. By employing ketone as both the directing group and the leaving group, 1,2-bifunctionalization is achieved via sequential ortho-C-H alkylation/ipso-Heck olefination.
- Wang, Mei-Ling,Xu, Hui,Li, Han-Yuan,Ma, Biao,Wang, Zhen-Yu,Wang, Xing,Dai, Hui-Xiong
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supporting information
p. 2147 - 2152
(2021/04/05)
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- Exploring the synthetic potential of a marine transaminase including discrimination at a remote stereocentre
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The marine transaminase, P-ω-TA, can be employed for the transamination from 1-aminotetralins and 1-aminoindanes with differentiation of stereochemistry at both the site of reaction and at a remote stereocentre resulting in formation of ketone products with up to 93% ee. While 4-substituents are tolerated on the tetralin core, the presence of 3- or 8-substituents is not tolerated by the transaminase. In general P-ω-TA shows capacity for remote diastereoselectivity, although both the stereoselectivity and efficiency are dependent on the specific substrate structure. Optimum efficiency and selectivity are seen with 4-haloaryl-1-aminotetralins and 3-haloaryl-1-aminoindanes, which may be associated with the marine origin of this enzyme. This journal is
- Schwarz, Maria,Murphy, Edel J.,Foley, Aoife M.,Woods, David F.,Castilla, Ignacio Abreu,Reen, F. Jerry,Collins, Stuart G.,O'gara, Fergal,Maguire, Anita R.
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supporting information
p. 188 - 198
(2021/01/18)
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- Preparation method for catalytically synthesizing methyl cinnamate based on deep eutectic solvent
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The invention discloses a preparation method for catalytically synthesizing methyl cinnamate based on a eutectic solvent. A eutectic solvent prepared by mixing choline chloride and p-toluenesulfonic acid is used as a catalyst and a solvent for reaction, cinnamic acid and methanol are used as reaction raw materials for esterification reaction, and methyl cinnamate is obtained through processes of phase separation, neutralization, crystallization, drying and the like. In the preparation process of the eutectic solvent, the atom utilization rate is 100%, compared with a traditional protonic acid catalyst, the reaction condition is mild, the reaction time is short, equipment is not prone to corrosion, recycling can be achieved, and the requirement of a green catalytic reaction process is met. By adjusting and controlling the reaction conditions, a high yield can be obtained at a low cost.
- -
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Paragraph 0012-0018
(2021/04/14)
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- Privileged scaffolds in medicinal chemistry: Studies on pyrazolo[1,5-a]pyrimidines on sulfonamide containing Carbonic Anhydrase inhibitors
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We report for the first time a small series of compounds endowed in vitro with inhibitory properties for the human (h) expressed Carbonic Anhydrase (CAs, E.C. 4.2.1.1) enzymes of physiological interest (i.e. I, II, VA, IX and XII) and bearing the pyrazolo[1,5-a]pyrimidine (PP) scaffold at the tail section. Among the series reported, 1a-3a, 7a, 8a, 1b and 2b resulted effective ligands and with good selectivities for the hCAs II, IX or XII. In consideration of the nearly matching KI values of 7a for both the hCA II and IX (i.e. 26.4 and 23.0 nM respectively) we explored its binding mode within the CA IX mimic isoform by means of X-ray crystal experiments on the corresponding adduct.
- Angeli, Andrea,Bozdag, Murat,Carta, Fabrizio,Gumus, Arzu,Peat, Thomas S.,Selleri, Silvia,Supuran, Claudiu T.
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supporting information
(2021/08/16)
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- Carboxylic Acid Reductase Can Catalyze Ester Synthesis in Aqueous Environments
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Most of the well-known enzymes catalyzing esterification require the minimization of water or activated substrates for activity. This work reports a new reaction catalyzed by carboxylic acid reductase (CAR), an enzyme known to transform a broad spectrum of carboxylic acids into aldehydes, with the use of ATP, Mg2+, and NADPH as co-substrates. When NADPH was replaced by a nucleophilic alcohol, CAR from Mycobacterium marinum can catalyze esterification under aqueous conditions at room temperature. Addition of imidazole, especially at pH 10.0, significantly enhanced ester production. In comparison to other esterification enzymes such as acyltransferase and lipase, CAR gave higher esterification yields in direct esterification under aqueous conditions. The scalability of CAR catalyzed esterification was demonstrated for the synthesis of cinoxate, an active ingredient in sunscreen. The CAR esterification offers a new method for green esterification under high water content conditions.
- Pongpamorn, Pornkanok,Kiattisewee, Cholpisit,Kittipanukul, Narongyot,Jaroensuk, Juthamas,Trisrivirat, Duangthip,Maenpuen, Somchart,Chaiyen, Pimchai
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supporting information
p. 5749 - 5753
(2021/02/01)
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- Palladium and silk fibroin-containing magnetic nano-biocomposite: a highly efficient heterogeneous nanocatalyst in Heck coupling reactions
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Supported metal catalysts, for instance, palladium, are one of the foundations of chemical reactions, especially in C–C bond formation. The present study reports preparation of a magnetically separable palladium-supported nano-biocomposite with a low cost and easy immobilization technique. Fibroin, a natural biodegradable polymer, was used through an in situ method to cover the Fe3O4 nanoparticles to make a nano-biocomposite followed by anchoring palladium on the fibroin surface. The morphology and the structure of palladium-supported nano-biocomposite Fe3O4@fibroin-Pd were characterized by FT-IR, XRD, TGA, SEM, EDX, and TEM techniques. Consequently, the nanocatalyst activity was evaluated in the Heck coupling reactions. Only a very small amount of the nanocatalyst was employed in the reaction, and it showed excellent catalytic activity; in most cases more than 90% efficiency. The significant advantages of employing this nanocatalyst include high catalytic activity, short reaction times, easy separation of the nanocatalyst with an external magnet and great reusability. The results demonstrated that the used nanocatalysts were very active for four consecutive reaction rounds.
- Nouri Parouch, Ahmad,Koukabi, Nadiya,Abdous, Elham,Shobeiri, Seyed Amin
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p. 3165 - 3177
(2021/05/21)
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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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- Pd salen complex@CPGO as a convenient, effective heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions
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A Pd(II) Schiff base complex supported on graphene oxide nanosheets (Pd(II) salen@CPGO) has been synthesized and characterized by FT-IR, ICP-AES, XRD, SEM/EDX and TEM. The synthesized nanocatalyst has been found to be an efficient heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki coupling reactions. Pd(II) salen@CPGO could be separated and recovered easily from the reaction mixture and recycled several times without a discernible decrease in its catalytic activity. The construction of a solid sheet-supported Pd catalyst would be expected to be a promising system to perform heterogeneous catalytic reactions.
- Ghabdian, Mahdieh,Nasseri, Mohammad Ali,Allahresani, Ali,Motavallizadehkakhky, Alireza
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p. 1713 - 1728
(2018/05/25)
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- Triazine-hyperbranched polymer-modified magnetic nanoparticles-supported nano-cobalt for C–C cross-coupling reactions
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Design of hyperbranched polymers (HBPs) and crafting them in catalytic systems especially in organic chemistry are a relatively unexplored domain. This paper reports the utilization of triazine-hyperbranched polymer (THBP)-coated magnetic chitosan nanoparticles (MCs) as stabilizing matrix for cobalt nanoparticles. Cobalt nanoparticles were fabricated by coordination cobalt(II) ions with amine-terminated triazine polymer and then reduced into Co(0) using sodium borohydride in aqueous medium. The Co(0)-THBP@MCs were fully characterized by FT-IR, SEM–EDX, TEM, and TGA analyses. The presence of metallic cobalt was determined by ICP and XRD techniques. This novel hyperbranched polyaromatic polymer-encapsulated cobalt nanoparticles showed high catalytic activity in Mizoroki–Heck and Suzuki–Miyaura cross-coupling reactions. Heck and Suzuki reactions were carried out using 0.35 and 0.4?mol% of cobalt nanoparticles in which the turnover number (TON) values were calculated as 271 and 225, respectively. In addition, the produced heterogeneous catalyst could be recovered and reused without considerable loss of activity. Oxygen stability and high reusability over 7 runs with trace leaching of the cobalt into the reaction media as well as moisture stability of the immobilized cobalt nanoparticles are their considerable worthwhile advantages.
- Hajipour, Abdol R.,Sadeghi, Shaghayegh
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p. 3219 - 3233
(2021/08/06)
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- Olefin Metathesis, p-Cresol, and the Second Generation Grubbs Catalyst: Fitting the Pieces
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p-Cresol as additive to the Grubbs second generation catalyst (GII) allows the cross-metathesis of acrylates with prop-1-en-1-ylbenzenes under conditions that only give the prop-1-en-1-ylbenzene self-metathesis product in the absence of cresol. NMR and IR spectroscopy, MALDI-TOF MS and XPS supported the formation of a ruthenium benzylidene with hydrogen bonds between p-cresol and the chloride ligands of GII. XPS furthermore confirmed p-cresol to increase the binding energies of the GII Ru 3d5/2, 3d3/2, 3p3/2 and 3p1/2 photoelectron lines, whereas 1H NMR spectroscopy indicated the carbene carbon and hydrogen to be shielded. It is thus postulated that p-cresol allows for more facile interaction between electron-deficient compounds and the ruthenium benzylidene by decreasing the electron density on the metal center and increasing the electron density on the carbene.
- Swart, Marthinus R.,Twigge, Linette,Erasmus, Elizabeth,Marais, Charlene,Bezuidenhoudt, Barend C. B.
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supporting information
p. 1752 - 1762
(2021/05/06)
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- A donor-acceptor complex enables the synthesis of: E -olefins from alcohols, amines and carboxylic acids
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Olefins are prevalent substrates and functionalities. The synthesis of olefins from readily available starting materials such as alcohols, amines and carboxylic acids is of great significance to address the sustainability concerns in organic synthesis. Metallaphotoredox-catalyzed defunctionalizations were reported to achieve such transformations under mild conditions. However, all these valuable strategies require a transition metal catalyst, a ligand or an expensive photocatalyst, with the challenges of controlling the region- and stereoselectivities remaining. Herein, we present a fundamentally distinct strategy enabled by electron donor-acceptor (EDA) complexes, for the selective synthesis of olefins from these simple and easily available starting materials. The conversions took place via photoactivation of the EDA complexes of the activated substrates with alkali salts, followed by hydrogen atom elimination from in situ generated alkyl radicals. This method is operationally simple and straightforward and free of photocatalysts and transition-metals, and shows high regio- and stereoselectivities.
- Chen, Kun-Quan,Shen, Jie,Wang, Zhi-Xiang,Chen, Xiang-Yu
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p. 6684 - 6690
(2021/05/31)
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- Z-Selective phosphine promoted 1,4-reduction of ynoates and propynoic amides in the presence of water
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Phosphine-mediated reductions of substituted propynoic esters and amides in the presence of water yield the partially reduced α,β-unsaturated esters and amides with highZ-selectivity. The competitivein situ ZtoE-isomerization of the product in some cases lowers theZtoEratios of the isolated α,β-unsaturated carbonyl products. Reaction time and the amounts of phosphine and water in the reaction mixture are the key experimental factors which control the selectivity by preventing or reducing the rates ofZ- toE-product isomerization. Close reaction monitoring enables isolation of theZ-alkenes with high selectivities. The computational results suggest that the reactions could be highlyZ-selective owing to the stereoselective formation of theE-P-hydroxyphosphorane intermediate.
- Drikermann, Denis,Kupfer, Stephan,Seifert, Fabian,Steinmetzer, Johannes,Vilotijevic, Ivan,Zi, You
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supporting information
p. 6092 - 6097
(2021/07/21)
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- Transition Metal-Free C-H Thiolation via Sulfonium Salts Using β-Sulfinylesters as the Sulfur Source
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We disclose a direct C(sp)-, C(sp2)-, and C(sp3)-H thiolation reaction using β-sulfinylesters as the versatile sulfur source. The key step of this protocol is chemoselective C-S bond cleavage of the sulfonium salts that are formed in situ from the corresponding alkenes, alkynes, and 1,3-dicarboxyl compounds with β-sulfinylesters. The successful capture of the acrylate byproduct supports a retro-Michael reaction mechanism.
- Chen, Yanhui,Wen, Si,Tian, Qingyu,Zhang, Yuqing,Cheng, Guolin
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supporting information
p. 7905 - 7909
(2021/10/20)
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- Synthesis of Functionalized Dihydrocoumarins by NHC-Catalyzed [3 + 3] Annulation of Enals with 2-Substituted Naphthoquinones
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The [3 + 3] annulation of α,β-unsaturated aldehydes with 2-substituted 1,4-naphthoquinones allowing the facile synthesis of functionalized dihydrocoumarins catalyzed by N-heterocyclic carbene (NHC) is reported. The initially formed NHC-homoenolates underwent an efficient Michael-isomerization-lactonization cascade to furnish the products. Preliminary studies on mechanism shed light on the homoenolate pathway over the intermediacy of the α,β-unsaturated acylazolium intermediates. Moreover, using chiral NHCs, the desired products were formed in up to 49% yield and 99:1 er.
- Shee, Sayan,Barik, Soumen,Ghosh, Arghya,Biju, Akkattu T.
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supporting information
p. 8039 - 8044
(2021/10/20)
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- PCl3-mediated transesterification and aminolysis of tert-butyl esters via acid chloride formation
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A PCl3-mediated conversion of tert-butyl esters into esters and amides in one-pot under air is developed. This novel protocol is highlighted by the synthesis of skeletons of bioactive molecules and gram-scale reactions. Mechanistic studies revealed that this transformation involves the formation of an acid chloride in situ, which is followed by reactions with alcohols or amines to afford the desired products.
- Wu, Xiaofang,Zhou, Lei,Li, Fangshao,Xiao, Jing
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p. 491 - 497
(2021/01/20)
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- Method for synthesizing methyl cinnamate based on eutectic solvent catalyst
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The invention discloses a method for catalytically synthesizing methyl cinnamate by adopting a benzyltrimethylammonium chloride eutectic solvent, which comprises the following steps of: performing esterification reaction by taking an acidic eutectic solvent benzyltrimethylammonium chloride p-toluenesulfonic acid (BTAC-PTSA) as a catalyst and cinnamic acid and methanol as raw materials; and carrying out phase separation, neutralization, crystallization purification and other processes to obtain methyl cinnamate. The eutectic solvent used in the invention has an atom utilization rate of 100% inthe preparation process, and has the advantages of mild reaction conditions, small corrosivity to equipment, easy recovery, reusability and the like compared with traditional catalysts such as sulfuric acid and the like.
- -
-
Paragraph 0014-0018
(2021/03/30)
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- Synthesis, characterization and study of mesomorphic behavior of new bent and linear core compounds containing heterocyclic rings
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The article presents the synthesis and liquid crystalline properties of some of new bent and linear core compounds containing a 1,3,4-oxadiazole, piperazine and thiazolidin-4-one rings as a central core. The new synthesized compounds were characterized by elemental analysis and FTIR, 1HNMR and mass spectroscopy). The liquid crystalline properties were studied by polarized optical microscopy and differential scanning calorimetry. All Schiff bases compounds with 1,3,4-oxadiazole and piprzaine ring in central core presented liquid crystalline properties. The liquid crystallinity of compounds containing 1,3,4-oxadiazole and thiazolidin-4-one rings as a central core were found depending on the type of terminal substituents.
- Al-Dujaili, Ammar H.,Karam, Nisreen H.,Shanshal, Alaa K.
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- Electrochemical esterification via oxidative coupling of aldehydes and alcohols
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An electrolytic method for the direct oxidative coupling of aldehydes with alcohols to produce esters is described. Our method involves anodic oxidation in presence of TBAF as supporting electrolyte in an undivided electrochemical cell equipped with graphite electrodes. This method successfully couples a wide range of alcohols to benzaldehydes with yields ranging from 70 to 90%. The protocol is easy to perform at a constant voltage conditions and offers a sustainable alternative over conventional methods.
- Smeyne, Dylan,Verboom, Katherine,Bryan, Maria,LoBue, James,Shaikh, Abid
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supporting information
(2021/03/26)
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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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- Coordination from Heteroscorpionate Ligand Towards Pd(II) via Pd???Hδ?C(sp3) Interaction: Structural and Catalytic Studies
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The coordination ability of the heteroscorpionate ligand 2,2-bis(3,5-dimethylpyrazol-1-yl)-1-p-tolylethanol (1) towards palladium (II) dihalides was evaluated. The structures of the respective palladium complexes (2 and 3) were elucidated in solution by NMR spectroscopy, and their molecular structures were established by single crystal X-ray diffraction analyses. Both studies revealed the existence of Pd???Hδ?C(sp3) anagostic interactions. The molecular structure of complexes 2 and 3 displays coordination of ligand 1 to palladium in a κ3-NNH tridentate fashion via two nitrogen atoms and one δ-anagostic H???Pd interaction. The metal center exhibits a square pyramidal geometry. The distances of anagostic Hδ???Pd interactions ranged from 2.566 to 2.576 ?. The δ-anagostic H???Pd interactions in complexes 2 and 3 were also identified by Bader's quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analysis. The catalytic efficiencies of complexes 2 and 3 in the Suzuki-Miyaura cross-coupling reactions were evaluated and the results showed that palladium (II) dibromide complex is the most efficient of the series. Complex 3 was also evaluated in Mizoroki-Heck cross-coupling reactions.
- Castillo-Moreno, Miguel ángel,Cruz-Borbolla, Julián,González-Montiel, Simplicio,Ignacio Sandoval-Chávez, César,Manuel Vásquez-Pérez, José,Mendoza-Espinosa, Daniel,Salazar-Pereda, Verónica
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supporting information
p. 2661 - 2668
(2021/07/06)
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- NiFe2O4@SiO2@ZrO2/SO42-/Cu/Co nanoparticles: A novel, efficient, magnetically recyclable and bimetallic catalyst for Pd-free Suzuki, Heck and C-N cross-coupling reactions in aqueous media
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The novel heterogeneous bimetallic nanoparticles of Cu-Co were synthesized based on magnetic nanoparticles, and the magnetic nanocatalyst was characterized by XRD, FE-SEM, EDX mapping, BET, TEM, HRTEM, FTIR, TGA, and VSM. This catalyst was successfully applied as a recyclable magnetically catalyst in Heck, Suzuki, and C-N cross-coupling reactions with various aryl halides (iodides, bromides, and chlorides as challengeable substrates), with olefins, phenylboronic acid, and amines, respectively. We considered the rise of synergetic effects from the different Lewis acid and Br?nsted acid sites present in the catalyst. The catalyst was synthesized with cheap, available materials and a simple synthesis method. The catalyst can be separated easily using an external magnet. It was recycled for more than ten runs without a sensible loss of its catalytic activity, and no significant leaching of the Cu and Co quantity was observed. The significant benefits of the method are high-level generality, simple operation, and there are no heavy metals and toxic solvents. This is a quick, easy, efficacious and environmentally friendly protocol, and no by-products are formed in the reaction. These features make it an appropriate practical alternative protocol. In comparison with recent works, the other advantage of this catalyst is the synthesis of a wide variety of C-C and C-N bond derivatives (more than 40 derivatives). The other significant advantage is the low temperature of the reaction and the use of the least possible amount of the catalyst (0.003 g). The efficiency was good to excellent and the catalyst selectivity has been high. We aspire that our study inspires more interest to design novel catalysts based on using low-cost metal ions (such as cobalt and copper) in the cross-coupling reactions. This journal is
- Alavi G., Seyyedeh Ameneh,Nasseri, Mohammad Ali,Kazemnejadi, Milad,Allahresani, Ali,Hussainzadeh, Mahdi
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p. 7741 - 7757
(2021/05/13)
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- Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst
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The direct esterification of alcohols with non-noble metal-based catalytic systems faces great challenges. Here, we report a new chrome-based catalyst stabilized by a single pentaerythritol decorated Anderson-type polyoxometalate, [N(C4H9)4]3[CrMo6O18(OH)3C{(OCH2)3CH2OH}], which can realize the efficient transformation from alcohols to esters by H2O2oxidation in good yields and high selectivity without extra organic ligands. A variety of alcohols with different functionalities including some natural products and pharmaceutical intermediates are tolerated in this system. The chrome-based catalyst can be recycled several times and still keep the original configuration and catalytic activity. We also propose a reasonable catalytic mechanism and prove the potential for industrial applications.
- Wang, Jingjing,Jiang, Feng,Tao, Chaofu,Yu, Han,Ruhlmann, Laurent,Wei, Yongge
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supporting information
p. 2652 - 2657
(2021/04/21)
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- Efficient synthesis of acrylates bearing an aryl or heteroaryl moiety: One-pot method from aromatics and heteroaromatics using formylation and the horner-wadsworth-emmons reaction
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Acrylates bearing an aryl or heteroaryl moiety were efficiently prepared by a one-pot process employing a sequence of lithiation, formylation and the Horner-Wadsworth-Emmons reaction starting from aromatic and heteroaromatic compounds. This method can efficiently introduce an acrylate moiety into aromatic and heteroaromatic compounds.
- Yasukata, Tatsuro,Matsuura, Takaharu
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p. 527 - 533
(2021/03/22)
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- Mild Copper-Catalyzed Addition of Arylboronic Esters to Di- tert -butyl Dicarbonate: An Easy Access to Methyl Arylcarboxylates
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An efficient copper-catalyzed addition of arylboronic esters to (Boc) 2O was developed. The reaction can be conducted under exceedingly mild conditions and is compatible with a variety of synthetically relevant functional groups. It therefore represents a useful alternative route for the synthesis of methyl arylcarboxylates. A preliminary mechanistic study indicated the involvement of an addition-elimination mechanism.
- Xu, Jin-Di,Su, Xiao-Bo,Wang, Cai,Yao, Li-Wei,Liu, Jing-Hui,Hu, Guo-Qin
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supporting information
p. 833 - 837
(2021/02/26)
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- Stereoselective synthesis of cyclobutanes by contraction of pyrrolidines
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Here we report a contractive synthesis of multisubstituted cyclobutanes containing multiple stereocenters from readily accessible pyrrolidines using iodonitrene chemistry. Mediated by a nitrogen extrusion process, the stereospecific synthesis of cyclobutanes involves a radical pathway. Unprecedented unsymmetrical spirocyclobutanes were prepared successfully, and a concise, formal synthesis of the cytotoxic natural product piperarborenine B is reported.
- Hui, Chunngai,Brieger, Lukas,Strohmann, Carsten,Antonchick, Andrey P.
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supporting information
p. 18864 - 18870
(2021/11/23)
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- Palladium schiff base complex immobilized on magnetic nanoparticles: An efficient and recyclable catalyst for Mizoroki and Matsuda-Heck coupling
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The present work elucidates the catalytic efficiency of palladium Schiff base complex immobilized on amine functionalized magnetic nanoparticles for Heck coupling of structurally different aryl halide/arenediazonium tetrafluoroborate with styrene/acrylate/acrylonitrile. Matsuda-Heck coupling proceeds in aqueous media at room temperature whereas Mizoroki-Heck coupling was carried out at 80 °C. Both reactions were successfully furnished with low catalyst loading. The catalyst was easily separated from reaction mixture and reused up to six times without significant loss of catalytic activity.
- Vibhute, Sandip P.,Mhaldar, Pradeep M.,Shejwal, Rajendra V.,Rashinkar, Gajanan S.,Pore, Dattaprasad M.
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supporting information
(2020/03/23)
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- A photocatalytic ensemble HP-T?Au-Fe3O4: Synergistic and balanced operation in Kumada and Heck coupling reactions
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A supramolecular catalytic ensemble HP-T?Au-Fe3O4 supported by highly branched assemblies of hexaphenylbenzene (HPB) derivatives has been developed. The as-prepared HP-T?Au-Fe3O4 nanohybrid material serves as an efficient catalytic system to prepare biaryl derivatives through the Kumada cross-coupling reaction using aryl chlorides as one of the coupling partners under mild reaction conditions (visible light irradiation, aqueous media, aerial conditions, short reaction time). Through the cooperative effect of Au NPs and Fe3O4 NPs, dual activation of aryl chlorides for the generation of aryl radical intermediates is achieved. On the other hand, oligomeric assemblies contributed significantly to the enhancement of the reaction rate and yield of the product by facilitating the reductive elimination step. Different mechanistic studies confirm the involvement of Au NPs, Fe3O4 NPs and oligomeric assemblies in the synergistic and balanced operation of HP-T?Au-Fe3O4 nanohybrid materials in the efficient completion of the catalytic cycle of the Kumada coupling reaction. Being magnetic, the catalytic ensemble could be recycled for up to five catalytic cycles. The as-prepared supramolecular photocatalytic ensemble also works efficiently in Heck coupling reactions involving aryl chlorides and aryl iodides as the coupling partner.
- Bhalla, Vandana,Kaur, Harpreet,Kumar, Manoj
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supporting information
p. 8036 - 8045
(2020/11/30)
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- Catalytic and antibacterial properties of 3-dentate carboxamide Pd/Pt complexes obtained via a benign route
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The complexes PdII(qcq)(OAc) and PtII(qcq)Cl have been synthesized using environmentally benign synthesized ligands and characterized by elemental analyses: Fourier transform infrared spectroscopy, UV–visible spectroscopy, 1H NMR spectroscopy, and X-ray diffraction. The catalytic activity of the complex was assessed, in different media, for the Mizoroki–Heck coupling reaction for typical aryl halides and terminal olefins under aerobic conditions. Since the base and the solvent were found to influence the efficiency of the reaction, reaction conditions, temperature, time, and the amount of K3PO4 and a mixture of H2O/PEG, were optimized. We found, for the Mizoroki–Heck reaction coupling less reactive aryl chloride derivatives with olefins, promising activity for palladium catalysts. The electrochemical behavior of Hqcq and the Pd(II) complex was investigated by cyclic voltammetry and irreversible PdII/I reductions were observed. Hqcq and the Pd(II) and Pt(II) complexes were also screened for their in vitro antibacterial activity. They showed promising antibacterial activity comparable to that of the antibiotic penicillin.
- Kiani, Mahsa,Bagherzadeh, Mojtaba,Meghdadi, Soraya,Fadaei-Tirani, Farzaneh,Schenk-Jo?, Kurt,Rabiee, Navid
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- Palladium anchored on guanidine-terminated magnetic dendrimer (G3-Gu-Pd): An efficient nano-sized catalyst for phosphorous-free Mizoroki-Heck and copper-free Sonogashira couplings in water
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In this research, a novel type of Fe3O4&at;silica-supported dendrimer capped by guanidine groups for immobilization of palladium was reported. This novel nano-sized catalyst was characterized by FTIR, TGA, XRD, FESEM, EDX, VSM, XPS and HRTEM methods. Enhanced catalytic activity of the prepared catalyst in Mizoroki-Heck and copper-free Sonogashira coupling reactions were evaluated in water as a green solvent. The influence of the various reaction parameters such as catalyst dosage, time and temperature on two mentioned C–C coupling reactions were studied. Results showed that the catalyst could be easily recovered by simple separation by an external magnet and reused for five cycles of recovery without considerable losing of its activity.
- Khalafi-Nezhad, Ali,Moaddeli, Ali,Niknam, Esmaeil
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- Donor-acceptor fluorophores as efficient energy transfer photocatalysts for [2 + 2] photodimerization
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Mild [2 + 2] photodimerization of enone substrates was induced by donor-acceptor fluorophores. Enone substrates were activated efficiently for anti-head to head dimerizations with a high yield (up to 83%) and high selectivity. The adjustable excited state potential also allows donor-acceptor fluorophores to be used for isomerization of the above substrates, confirming the potential of donor-acceptor fluorophores as energy transfer photocatalysts.
- Chen, Feng,Chen, Hao,Liu, Xue-Fen,Luo, Shu-Ping,Ren, Chen-Chao,Wu, Qing-An,Xu, Liang-Xuan,Yu, Xiao-Cong
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p. 3707 - 3716
(2020/06/03)
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- Encapsulating palladium nanoparticles inside ethylenediamine functionalized and crosslinked chlorinated poly(vinyl chloride) nanofibers as an efficient and stable heterogeneous catalyst for coupling reactions
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Palladium chloride and chlorinated poly (vinyl chloride) (CPVC) mixture were prepared into homogeneous solution, followed by electrospinning to make uniform nanofibers with average diameter of ~460 nm. Then, these composite nanofibers were treated in ethy
- Du, Yijun,Qi, Chenze,Qin, Min,Shao, Linjun,Tao, Hongyu,Wang, Qingqing
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- Systematic Study on the Catalytic Arsa-Wittig Reaction
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Efficient catalytic arsa-Wittig reactions have been developed by using 1-phenylarsolane as a catalyst. A wide array of aldehydes was converted to the corresponding olefins in high yields with moderate to excellent E stereoselectivity in the presence of a catalytic amount of 1-phenylarsolane. Moreover, density functional theory calculations were carried out to afford insight into the E/Z selectivity.
- Inaba, Ryoto,Kawashima, Ikuo,Fujii, Toshiki,Yumura, Takashi,Imoto, Hiroaki,Naka, Kensuke
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supporting information
p. 13400 - 13407
(2020/09/21)
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- C–C Cross-Coupling Reactions of Organosilanes with Terminal Alkenes and Allylic Acetates Using PdII Catalyst Supported on Starch Coated Magnetic Nanoparticles
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Starch coated magnetic nanoparticles supported palladium catalyst has been explored to perform C–C cross coupling reactions, such as oxidative Heck coupling and Tsuji–Trost allylic coupling using organosilicon compounds as one of the coupling partners. The biopolymer coated magnetic catalyst was very easy to recover magnetically and was efficiently recycled in the subsequent batches. All the reactions were performed in air and thus the necessity of air and moisture free reaction condition is avoided. The present protocols show wide substrate scope and good yields of the products.
- Patra, Debabrata,Panja, Subir,Saha, Amit
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p. 878 - 883
(2020/02/13)
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- The Importance of 1,5-Oxygen???Chalcogen Interactions in Enantioselective Isochalcogenourea Catalysis
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The importance of 1,5-O???chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N-acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5-O???Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including nitronate conjugate addition and formal [4+2] cycloadditions. A gram-scale synthesis of the most active selenium analogue was developed using a previously unreported seleno-Hugerschoff reaction, allowing the challenging kinetic resolutions of tertiary alcohols to be performed at 500 ppm catalyst loading. Density functional theory (DFT) and natural bond orbital (NBO) calculations support the role of orbital delocalization (occurring by intramolecular chalcogen bonding) in determining the conformation, equilibrium population, and reactivity of N-acylated intermediates.
- Cockroft, Scott L.,Elmi, Alex,Frost, Aileen B.,Ling, Kenneth B.,McLaughlin, Calum,Morris, Rylie K.,Pascoe, Dominic J.,Slawin, Alexandra M. Z.,Smith, Andrew D.,Smith, Terry K.,Willoughby, Patrick H.,Woods, Andrew M.,Young, Claire M.,de la Houpliere, Alix
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supporting information
p. 3705 - 3710
(2020/02/11)
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- PHARMACEUTICAL COMPOSITION FOR PREVENTING OR TREATING AGING-RELATED DISEASES CONTAINING DECURSIN DERIVATIVE AS ACTIVE INGREDIENT
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A composition for preventing or treating an aging-related disease includes a novel decursin derivative as an active ingredient, wherein the novel decursin derivative has exhibited an excellent effect of inhibiting progerin expression and excellent effect of inhibiting binding between progerin and lamin A, and it has been confirmed that the novel decursin derivative prolongs the survival period of animal models in which progerin was induced.
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Paragraph 0048-0050
(2020/02/27)
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