- Photoredox Catalyzed Sulfonylation of Multisubstituted Allenes with Ru(bpy)3Cl2 or Rhodamine B
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A highly regio- and stereoselective sulfonylation of allenes was developed that provided direct access to α, β-substituted unsaturated sulfone. By means of visible-light photoredox catalysis, the free radicals produced by p-toluenesulfonic acid reacted with multisubstituted allenes to obtain Markovnikov-type vinyl sulfones with Ru(bpy)3Cl2 or Rhodamine B as photocatalyst. The yield of this reaction could reach up to 91%. A series of unsaturated sulfones would be used for further transformation to some valuable compounds.
- Chen, Jingyun,Chen, Shufang,Jiang, Jun,Lu, Qianqian,Shi, Liyang,Xu, Zekun,Yimei, Zhao
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supporting information
(2021/11/09)
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- Clean protocol for deoxygenation of epoxides to alkenes: Via catalytic hydrogenation using gold
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The epoxidation of olefin as a strategy to protect carbon-carbon double bonds is a well-known procedure in organic synthesis, however the reverse reaction, deprotection/deoxygenation of epoxides is much less developed, despite its potential utility for the synthesis of substituted olefins. Here, we disclose a clean protocol for the selective deprotection of epoxides, by combining commercially available organophosphorus ligands and gold nanoparticles (Au NP). Besides being successfully applied in the deoxygenation of epoxides, the discovered catalytic system also enables the selective reduction N-oxides and sulfoxides using molecular hydrogen as reductant. The Au NP catalyst combined with triethylphosphite P(OEt)3 is remarkably more reactive than solely Au NPs. The method is not only a complementary Au-catalyzed reductive reaction under mild conditions, but also an effective procedure for selective reductions of a wide range of valuable molecules that would be either synthetically inconvenient or even difficult to access by alternative synthetic protocols or by using classical transition metal catalysts. This journal is
- Fiorio, Jhonatan L.,Rossi, Liane M.
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p. 312 - 318
(2021/01/29)
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- Polymerization of Allenes by Using an Iron(II) β-Diketiminate Pre-Catalyst to Generate High Mn Polymers
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Herein, we report an iron(II)-catalyzed polymerization of arylallenes. This reaction proceeds rapidly at room temperature in the presence of a hydride co-catalyst to generate polymers of weight up to Mn=189 000 Da. We have determined the polymer structure and chain length for a range of monomers through a combination of NMR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) analysis. Mechanistically, we postulate that the co-catalyst does not react to form an iron(II) hydride in situ, but instead the chain growth is proceeding via a reactive Fe(III) species. We have also performed kinetic and isotopic experiments to further our understanding. The formation of a highly unusual 1,3-substituted cyclobutane side-product is also investigated.
- Durand, Derek J.,Webster, Ruth L.,Woof, Callum R.
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supporting information
p. 12335 - 12340
(2021/07/19)
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- Controlling the Lewis Acidity and Polymerizing Effectively Prevent Frustrated Lewis Pairs from Deactivation in the Hydrogenation of Terminal Alkynes
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Two strategies were reported to prevent the deactivation of Frustrated Lewis pairs (FLPs) in the hydrogenation of terminal alkynes: reducing the Lewis acidity and polymerizing the Lewis acid. A polymeric Lewis acid (P-BPh3) with high stability was designed and synthesized. Excellent conversion (up to 99%) and selectivity can be achieved in the hydrogenation of terminal alkynes catalyzed by P-BPh3. This catalytic system works quite well for different substrates. In addition, the P-BPh3 can be easily recycled.
- Geng, Jiao,Hu, Xingbang,Liu, Qiang,Wu, Youting,Yang, Liu,Yao, Chenfei
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p. 3685 - 3690
(2021/05/31)
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- Preparation of Recyclable and Versatile Porous Poly(aryl thioether)s by Reversible Pd-Catalyzed C–S/C–S Metathesis
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Porous organic materials (polymers and COFs) have shown a number of promising properties; however, the lability of their linkages often limits their robustness and can hamper downstream industrial application. Inspired by the outstanding chemical, mechanical, and thermal resistance of the 1D polymer poly(phenylene sulfide) (PPS), we have designed a new family of porous poly(aryl thioether)s, synthesized via a mild Pd-catalyzed C–S/C–S metathesis-based method, that merges the attractive features common to porous polymers and PPS in a single material. In addition, the method is highly modular, allowing to easily introduce application-oriented functionalities in the materials for a series of environmentally relevant applications including metal capture, metal sensing, and heterogeneous catalysis. Moreover, despite their extreme chemical resistance, the polymers can be easily recycled to recover the original monomers, offering an attractive perspective for their sustainable use. In a broader context, these results clearly demonstrate the untapped potential of emerging single-bond metathesis reactions in the preparation of new, recyclable materials.
- Morandi, Bill,Rivero-Crespo, Miguel A.,Toupalas, Georgios
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supporting information
p. 21331 - 21339
(2021/12/17)
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- Phenylacetylene semihydrogenation over a palladium pyrazolate hydrogen-bonded network
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The palladium azolate/carboxylate network (Pd-dmpzc) catalyses the selective hydrogenation of phenylacetylene to styrene in water. Under optimised conditions, at a Pd:NaBH4 ratio of 1:100 at 40 °C, Pd-dmpzc provided much better results than Pd(OAc)2 or PdCl2(CH3CN)2. Analysis of the recovered catalyst revealed the presence of different Pd2+ species and Pd0 NPs which contributed in the catalytic reaction.
- Augustyniak, Adam W.,Trzeciak, Anna M.
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- Phosphorus and nitrogen-doped palladium nanomaterials support on coral-like carbon materials as the catalyst for semi-hydrogenation of phenylacetylene and mechanism study
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In this work, two types of polyporous and coral-like materials (CN) with high specific surface area are prepared using sodium glutamate as a carrier. At the same time, a CN-supported phosphorus-nitrogen-doped palladium nanomaterial CN-P-Pd is synthesized and applied to the preparation of styrene by selective hydrogenation of phenylacetylene under mild conditions. As shown in the TEM images, Pd nanoparticles with a particle size of about 4.4 nm are uniformly dispersed on the surface of the carrier. The results of N2 adsorption–desorption reveal that the surface area of the prepared catalyst (CN-P-Pd) is 1307 m2g?1. In addition, the experimental exploration shows the intervention of P in carbon-nitrogen materials can contribute to improve the selectivity of the reaction, which can be attributed to the fact that P element can change the electron density of Pd. Meanwhile, it is found that the solvent not only affects the activity of catalyst, but also the selectivity of the reaction. Kinetic study shows the activation energy of the reaction is 4.5 kJ/mol. With the increase of the reaction temperature, the dissolution rate of hydrogen in the solvent gradually slows down, which inhibits the progress of the reduction reaction. Mechanistic studies demonstrate that the carbon-nitrogen materials have strong adsorption capacity for substrates, and also provide more adsorption sites for phenylacetylene. Additionally, the optimal catalyst (CN-P-Pd) also has high reaction activity to other alkynes and the conversion can reach at 95%. Moreover, the optimal catalyst can be reused several times without significant reduction in reaction activity.
- Ma, Lei,Jiang, Pengbo,Wang, Kaizhi,Lan, Kai,Huang, Xiaokang,Yang, Ming,Gong, Li,Jia, Qi,Mu, Xiao,Xiong, Yucong,Li, Rong
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- Selective reduction of alkynes to alkenes with hydrogen or formic acid catalyzed by cis,mer-[IrH2Cl(mtppms)3]
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In this work we have found, that the water-soluble cis,mer-[IrH2Cl(mtppms)3] (mtppms = monosulfonated triphenylphosphine Na-salt) was an excellent catalyst for reduction of terminal alkynes by hydrogen transfer from aqueous HCOOH/HCOONa mixtures. The conversions strongly depended on the pH of the reaction mixtures, and the highest rate of phenylacetylene transfer hydrogenation was observed at pH 3. The same dihydrido-Ir(III) complex actively catalyzed also the hydrogenation of terminal alkynes under mild conditions (T = 50 °C; P(H2) = 2–10 bar). Importantly, both the hydrogenation and hydrogen transfer reductions afforded exclusively the corresponding alkenes as products. Phenylacetylene and its substituted derivatives reacted smoothly, while benzylic and aliphatic alkynes were less reactive or did not react at all. It was also found, that an excess of the mtppms ligand inhibited the reaction. This was rationalized by formation of cisz-[IrH2(mtppms)4]+ which was also confirmed with multinuclear NMR spectroscopy. On the basis of the experimental results, a joint mechanism was suggested for both the hydrogenation and transfer hydrogenation pathways. The mechanism of hydrogenation and transfer hydrogenation of phenylacetylene was also studied by DFT calculations, which revealed several possibilities for protonation of a vinyl intermediate as the crucial step in formation of the styrene product.
- Hankó, Gy?rgy,Márton, Richárd,Udvardy, Antal,Purgel, Mihály,Kathó, ágnes,Joó, Ferenc,Papp, Gábor
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supporting information
(2021/04/09)
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- Recoverable palladium-catalyzed carbon-carbon bond forming reactions under thermomorphic mode: Stille and suzuki-miyaura reactions
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The reaction of [PdCl2(CH3CN)2] and bis-4,40-(RfCH2OCH2)-2,2'-bpy (1a-d), where Rf = n- C11F23 (a), n-C10F21 (b), n-C9F19 (c) and n-C8F17 (d), respectively, in the presence of dichloromethane (CH2Cl2) resulted in the synthesis of Pd complex, [PdCl2[4,4'-bis-(RfCH2OCH2)-2,2'-bpy] (2a-d). The Pd-catalyzed Stille arylations of vinyl tributyltin with aryl halides were selected to demonstrate the feasibility of recycling usage with 2a as the catalyst using NMP (N-methyl-2-pyrrolidone) as the solvent at 120-150 °C. Additionally, recycling and electronic effect studies of 2a-c were also carried out for Suzuki-Miyaura reaction of phenylboronic acid derivatives, 4-X-C6H4-B(OH)2, (X = H or Ph) with aryl halide, 4-Y-C6H4-Z, (Y = CN, H or OCH3; Z = I or Br) in dimethylformamide (DMF) at 135-150 °C. At the end of each cycle, the product mixtures were cooled to lower temperature (e.g., -10 °C), and then catalysts were recovered by decantation with Pd leaching less than 1%. The products were quantified by gas chromatography/mass spectrometry (GC/MS) analysis or by the isolated yield. The complex 2a-catalyzed Stille reaction of aryl iodides with vinyl tributyltin have good recycling results for a total of 8 times, with a high yield within short period of time (1-3 h). Similarly, 2a-c-catalyzed Suzuki-Miyaura reactions also have good recycling results. The electronic effect studies from substituents in both Stille and Suzuki-Miyaura coupling reactions showed that electron withdrawing groups speed up the reaction rate. To our knowledge, this is the first example of recoverable fluorous long-chained Pd-catalyzed Stille reactions under the thermomorphic mode.
- Chan, Ka Long,Chiu, Chiao-Fan,Elakkat, Vijayanath,Lu, Norman,Shen, Chia-Rui,Su, Han-Chang,Tessema, Eskedar,Tsai, Zong-Lin
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- Indene formation upon borane-induced cyclization of arylallenes, 1,1-carboboration, and retro-hydroboration
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We herein report the reaction of arylallenes with tris(pentafluorophenyl)borane that yields pentafluorophenyl substituted indenes. The tris(pentafluorophenyl)borane induces the cyclization of the allene and transfers a pentafluorophenyl ring in the course of this reaction. A Hammett plot analysis and DFT computations indicate a 1,1-carboboration to be the C-C bond-forming step.
- Hasenbeck, Max,Wech, Felix,Averdunk, Arthur,Becker, Jonathan,Gellrich, Urs
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supporting information
p. 5518 - 5521
(2021/06/12)
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- Electrochemical fluorosulfonylation of styrenes
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An environmentally friendly and efficient electrochemical fluorosulfonylation of styrenes has been developed. With the use of sulfonylhydrazides and triethylamine trihydrofluoride, a diverse array of β-fluorosulfones could be readily obtained. This reaction features mild conditions and a broad substrate scope, which could also be conveniently extended to a gram-scale preparation.
- Jiang, Yi-Min,Wu, Shao-Fen,Yan, Hong,Ye, Ke-Yin,Yu, Yi,Yuan, Yaofeng
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supporting information
p. 11481 - 11484
(2021/11/16)
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- Electrochemistry enabled selective vicinal fluorosulfenylation and fluorosulfoxidation of alkenes
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Both sulfur and fluorine play important roles in organic synthesis, the life science, and materials science. The direct incorporation of these elements into organic scaffolds with precise control of the oxidation states of sulfur moieties is of great significance. Herein, we report the highly selective electrochemical vicinal fluorosulfenylation and fluorosulfoxidation reactions of alkenes, which were enabled by the unique ability of electrochemistry to dial in the potentials on demand. Preliminary mechanistic investigations revealed that the fluorosulfenylation reaction proceeded through a radical-polar crossover mechanism involving a key episulfonium ion intermediate. Subsequent electrochemical oxidation of fluorosulfides to fluorosulfoxides were readily achieved under a higher applied potential with the adventitious H2O in the reaction mixture.
- Jiang, Yimin,Shi, Zhaojiang,Wu, Jinnan,Wu, Shaofen,Ye, Keyin,Yu, Yi,Yuan, Yaofeng
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supporting information
(2021/11/17)
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- Rapid synthesis method of biomass-based olefin
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The invention discloses a rapid synthesis method of biomass-based olefin, which comprises the following steps: by taking a biomass ketone compound as a substrate and 2-pentanol as a hydrogen source and a solvent at the same time, under the action of hafnium/zirconium-based catalysts such as hafnium phenylphosphonate and Zirconium phenylphosphonate, hafnium phytate andzirconium phytate and hafnium polydivinylphenylphosphonate and zirconium polydivinylphenylphosphonate, selectively converting a biomass-based ketone compound into a corresponding alcohol compound, and continuously dehydrating to prepare olefin. According to the present invention, the time required by the system reaction is substantially shortened and is at least 2 h, the target product selectivity is significantly improved, the conversion rate of the representative reaction 4 '-methoxypropiophenone can at least achieve 99.8%, and the anethole yield can achieve 98.1%.
- -
-
Paragraph 0020; 0041-0046; 0051-0052
(2021/07/31)
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- Switchable Chemoselectivity of Reactive Intermediates Formation and Their Direct Use in A Flow Microreactor
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A chemoselectivity switchable microflow reaction was developed to generate reactive and unstable intermediates. The switchable chemoselectivity of this reaction enables a selection for one of two different intermediates, an aryllithium or a benzyl lithium, at will from the same starting material. Starting from bromo-substituted styrenes, the aryllithium intermediates were converted to the substituted styrenes, whereas the benzyl lithium intermediates were engaged in an anionic polymerization. These chemoselectivity-switchable reactions can be integrated to produce polymers that cannot be formed during typical polymerization reactions.
- Ashikari, Yosuke,Tamaki, Takashi,Kawaguchi, Tomoko,Furusawa, Mai,Yonekura, Yuya,Ishikawa, Susumu,Takahashi, Yusuke,Aizawa, Yoko,Nagaki, Aiichiro
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supporting information
p. 16107 - 16111
(2021/10/12)
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- Metal-free and base-free decarboxylation of substituted cinnamic acids in a deep eutectic solvent
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A metal-free and base-free strategy was developed in DES to synthesize styrenes for the first time by decarboxylation of cinnamic acid derivatives, which provided a renewable and cost efficiently protocol to access various styrenes including those with functional groups such as 4-vinylphenol and 1-chloro-4-vinylbenzene.
- Chen, Chen,Jian, Yuqing,Lei, Yuxin,Li, Bin,Peng, Caiyun,Sheng, Wen-Bing,Sumera, Yasmin,Wang, Wei,Zhang, Ming
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p. 558 - 563
(2020/01/24)
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- Palladium-catalyzed proaromatic C(Alkenyl)-H olefination: Synthesis of densely functionalized 1,3-dienes
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An example of proaromatic C(alkenyl)-H olefination is reported. This protocol utilized a free carboxylic acid as a directing group for C(alkenyl)-H activation of 1,4-cyclohexadiene and coupled with various alkenes. Direct and sequential bisolefinations of proaromatic acids were achieved. The synthetic applicability has been exhibited by [4 + 2] cycloaddition and decarboxylative aromatization of the resulting proaromatic 1,3-dienes. Additionally, several kinetic studies also have been carried out to elucidate the reaction mechanism.
- Wang, Yu-Chun,Huang, Yen-Hsiang,Tsai, Hung-Chang,Sidick Basha,Chou, Chih-Ming
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supporting information
p. 6765 - 6770
(2020/09/15)
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- Exhaustive Reduction of Esters Enabled by Nickel Catalysis
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We report a one-step procedure to directly reduce unactivated aryl esters into their corresponding tolyl derivatives. This is achieved by an organosilane-mediated ester hydrosilylation reaction and subsequent Ni/NHC-catalyzed hydrogenolysis. The resulting conditions provide a direct and efficient alternative to multi-step procedures for this transformation that often require the use of hazardous metal hydrides. Applications in the synthesis of -CD3-containing products, derivatization of bioactive molecules, and chemoselective reduction in the presence of other C-O bonds are demonstrated.
- Cook, Adam,Prakash, Sekar,Zheng, Yan-Long,Newman, Stephen G.
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supporting information
p. 8109 - 8115
(2020/05/20)
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- Novel nickel nanoparticles stabilized by imidazolium-amidinate ligands for selective hydrogenation of alkynes
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The main challenge in the hydrogenation of alkynes into (E)- or (Z)-alkenes is to control the selective formation of the alkene, avoiding the over-reduction to the corresponding alkane. In addition, the preparation of recoverable and reusable catalysts is of high interest. In this work, we report novel nickel nanoparticles (Ni NPs) stabilized by three different imidazolium-amidinate ligands (ICy·(Ar)NCN; L1: Ar = p-tol, L2: Ar = p-anisyl and L3: Ar = p-ClC6H4). The as-prepared Ni NPs were fully characterized by (HR)-TEM, XRD, WASX, XPS and VSM. The nanocatalysts are active in the hydrogenation of various substrates. They present a remarkable selectivity in the hydrogenation of alkynes towards (Z)-alkenes, particularly in the hydrogenation of 3-hexyne into (Z)-3-hexene under mild reaction conditions (room temperature, 3% mol Ni and 1 bar H2). The catalytic behaviour of Ni NPs was influenced by the electron donor/acceptor groups (-Me, -OMe, -Cl) in the N-aryl substituents of the amidinate moiety of the ligands. Due to the magnetic character of the Ni NPs, recycling experiments were successfully performed after decantation in the presence of an external magnet, which allowed us to recover and reuse these catalysts at least 3 times preserving both activity and chemoselectivity.
- López-Vinasco, Angela M.,Martínez-Prieto, Luis M.,Asensio, Juan M.,Lecante, Pierre,Chaudret, Bruno,Cámpora, Juan,Van Leeuwen, Piet W. N. M.
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p. 342 - 350
(2020/02/04)
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- Method for preparing alkene compound from alkyne compound
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The invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing an alkene compound from an alkyne compound. The method comprises the following step: reacting an alkyne compound in the presence of a photocatalyst and alkali under illumination to obtain an alkene compound. A sacrificial agent used in the invention can be used as a reaction solvent. The preparation method provided by the invention can inhibit the over-reduction of the alkyne compound to obtain an alkene compound. The method has the advantages of mild reaction conditions and simple operation, and can efficiently and greenly synthesize an alkene compound.
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Paragraph 0059-0060
(2020/07/03)
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- An Annelated Mesoionic Carbene (MIC) Based Ru(II) Catalyst for Chemo- And Stereoselective Semihydrogenation of Internal and Terminal Alkynes
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The catalytic utility of [RuL1(CO)2I2] (1), containing an annelated π-conjugated imidazo-naphthyridine-based mesoionic carbene (MIC) ligand (L1), is evaluated for E-selective alkyne semihydrogenation. The precatalyst 1, in combination with 2 equiv of AgBArF, semihydrogenates a broad range of internal alkynes with molecular hydrogen (5 bar) in water. (E)-Alkenes are accessed in high yields, and a number of reducible functional groups are tolerated. A chelate MIC ligand and two cis carbonyls provide a well-defined platform at the Ru center for hydrogenation and isomerization. The loss of two iodides and the presence of two carbonyls render the Ru center electron deficient and thus the formation of metal vinylidenes with terminal alkynes is avoided. This is leveraged for the semihydrogenation of terminal alkynes by the same catalytic system in isopropyl alcohol. Reaction profile, isomerization, kinetic, and DFT studies reveal initial alkyne hydrogenation to a (Z)-alkene, which further isomerizes to an (E)-alkene via metal-catalyzed Z → E isomerization.
- Bera, Jitendra K.,Choudhury, Joyanta,Das, Shubhajit,Dutta, Indranil,Pati, Swapan K.,Saha, Sayantani,Yadav, Suman
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p. 3212 - 3223
(2020/10/02)
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- Piperazine-promoted gold-catalyzed hydrogenation: The influence of capping ligands
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Gold nanoparticles (NPs) combined with Lewis bases, such as piperazine, were found to perform selective hydrogenation reactions via the heterolytic cleavage of H2. Since gold nanoparticles can be prepared by many different methodologies and using different capping ligands, in this study, we investigated the influence of capping ligands adsorbed on gold surfaces on the formation of the gold-ligand interface. Citrate (Citr), poly(vinyl alcohol) (PVA), polyvinylpyrrolidone (PVP), and oleylamine (Oley)-stabilized Au NPs were not activated by piperazine for the hydrogenation of alkynes, but the catalytic activity was greatly enhanced after removing the capping ligands from the gold surface by calcination at 400 °C and the subsequent adsorption of piperazine. Therefore, the capping ligand can limit the catalytic activity if not carefully removed, demonstrating the need of a cleaner surface for a ligand-metal cooperative effect in the activation of H2 for selective semihydrogenation of various alkynes under mild reaction conditions.
- Barbosa, Eduardo C. M.,Camargo, Pedro H. C.,Fiorio, Jhonatan L.,Hashmi, A. Stephen K.,Kikuchi, Danielle K.,Rossi, Liane M.,Rudolph, Matthias
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p. 1996 - 2003
(2020/04/22)
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- Fast and Selective Semihydrogenation of Alkynes by Palladium Nanoparticles Sandwiched in Metal–Organic Frameworks
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The semihydrogenation of alkynes into alkenes rather than alkanes is of great importance in the chemical industry. Unfortunately, state-of-the-art heterogeneous catalysts hardly achieve high turnover frequencies (TOFs) simultaneously with almost full conversion, excellent selectivity, and good stability. Here, we used metal–organic frameworks (MOFs) containing Zr metal nodes (“UiO”) with tunable wettability and electron-withdrawing ability as activity accelerators for the semihydrogenation of alkynes catalyzed by sandwiched palladium nanoparticles (Pd NPs). Impressively, the porous hydrophobic UiO support not only leads to an enrichment of phenylacetylene around the Pd NPs but also renders the Pd surfaces more electron-deficient, which leads to a remarkable catalysis performance, including an exceptionally high TOF of 13835 h?1, 100 % phenylacetylene conversion 93.1 % selectivity towards styrene, and no activity decay after successive catalytic cycles. The strategy of using molecularly tailored supports is universal for boosting the selective semihydrogenation of various terminal and internal alkynes.
- Choe, Kwanghak,Li, Guodong,Qiu, Xueying,Ri, Myonghak,Shi, Xinghua,Tang, Zhiyong,Wang, Hui,Wang, Yinglong,Xue, Guangxin,Yuan, Yi,Zhao, Wenshi,Zheng, Fengbin
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supporting information
p. 3650 - 3657
(2020/02/04)
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- Accelerating Chemo- And Regioselective Hydrogenation of Alkynes over Bimetallic Nanoparticles in a Metal-Organic Framework
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Selective semihydrogenation of alkynes has been a long-term and significant target, yet it remains a great challenge. Herein, bimetallic nanoparticles in a metal-organic framework (MOF), i.e., CuPd&at;ZIF-8 composite, featuring a cubic CuPd core and a porous ZIF-8 shell, have been rationally fabricated for this end. Given the unique physicochemical properties, the Cu nanocubes can not only convert solar energy into heat to accelerate the reaction but also serve as the seed for in situ formation of Pd nanoparticles (NPs) on their external surface to regulate the chemoselectivity of Pd active sites. The additional growth of the MOF shell is helpful to stabilize the CuPd core and offer regioselectivity via the steric hindrance effect. Ammonia borane provides active hydrogen species to significantly boost the hydrogenation and ensure the high selectivity. As a result, the CuPd&at;MOF exhibits high efficiency, featuring a turnover frequency (TOF, 6799 min-1) of 5-105 times higher than that in previous reports, and high chemo- and regioselectivity toward the semihydrogenation of alkynes, in the presence of NH3BH3 as a hydrogen source, under visible-light irradiation at ambient temperature.
- Guan, Qiaoqiao,Jiang, Hai-Long,Li, Luyan,Lu, Junling,Yang, Qihao,Yang, Weijie,Yu, Shu-Hong
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p. 7753 - 7762
(2020/08/21)
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- Selective Transfer Semihydrogenation of Alkynes with H2O (D2O) as the H (D) Source over a Pd-P Cathode
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We reported a selective semihydrogenation (deuteration) of numerous terminal and internal alkynes using H2O (D2O) as the H (D) source over a Pd-P alloy cathode at a lower potential. P-doping caused the enhanced specific adsorption of alkynes and the promoted intrinsic activity for producing adsorbed atomic hydrogen (H*ads) from water electrolysis. The semihydrogenation of alkynes could be accomplished at a lower potential with up to 99 % selectivity and 78 % Faraday efficiency of alkene products, outperforming pure Pd and commercial Pd/C. This electrochemical semihydrogenation of alkynes might proceed via a H*ads addition pathway rather than a proton-coupled electron transfer process. The decreased amount of H*ads at a lower potential and the more preferential adsorption of the Pd-P to C≡C π bond than C=C moiety resulted in the excellent alkene selectivity. This method was capable of producing mono-, di-, and tri-deuterated alkenes with up to 99 % deuterium incorporation.
- Liu, Cuibo,Lu, Siyu,Wang, Changhong,Wu, Yongmeng,Zhang, Bin
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supporting information
p. 21170 - 21175
(2020/09/11)
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- Palladium Nanoparticle-Catalyzed Stereoselective Domino Synthesis of 3-Allylidene-2(3 H)-oxindoles and 3-Allylidene-2(3 H)-benzofuranones
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A single-step, stereoselective protocol for the synthesis of unsymmetrically substituted (E)-3-allylideneoxindole and (E)-3-allylidenebenzofuran from readily accessible starting materials using palladium binaphthyl nanoparticles (Pd-BNPs) has been developed. Pd-BNP showing a wide range of functional group tolerance and an immense array of substrate scope have been explored with the successful synthesis of the drug molecule "tubulin polymerization inhibitor" free from trace metal impurities. The model reaction is extended to a gram-scale synthesis, and one of the products is utilized for derivatization. The Pd-BNP has been recycled up to 5 catalytic cycles without any loss in reaction yields and particle size of nanoparticles.
- Parveen, Naziya,Sekar, Govindasamy
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p. 4682 - 4694
(2020/05/08)
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- Design, synthesis of novel 4,5-dihydroisoxazole-containing benzamide derivatives as highly potent FtsZ inhibitors capable of killing a variety of MDR Staphylococcus aureus
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Antibiotic resistance among clinically significant bacterial pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) is becoming a prevalent threat to public health, and new antibacterial agents with novel mechanisms of action hence are in an urgent need. As a part of continuing effort to develop antibacterial agents, we rationally designed and synthesized two series of 4,5-dihydroisoxazol-5-yl and 4,5-dihydroisoxazol-3-yl-containing benzamide derivatives that targeted the bacterial cell division protein FtsZ. Evaluation of their activity against a panel of Gram-positive and -negative pathogens revealed that compound A16 possessing the 4,5-dihydroisoxazol-5-yl group showed outstanding antibacterial activity (MIC, ≤0.125–0.5 μg/mL) against various testing strains, including methicillin-resistant, penicillin-resistant and clinical isolated S. aureus strains. Besides, further mouse infection model revealed that A16 could be effective in vivo and non-toxic to Hela cells. Finally, a detailed discussion of structure-activity relationships was conducted, referring to the docking results. It is worth noting that substituting a 4,5-dihydroisoxazole ring for the isoxazole ring not only broadened the antibacterial spectrum but also resulted in a significant increase in antibacterial activity against S. aureus strains. Taken together, these results suggest a promising chemotype for the development of new FtsZ-targeting bactericidal agents.
- Song, Di,Bi, Fangchao,Zhang, Nan,Qin, Yinhui,Liu, Xingbang,Teng, Yuetai,Ma, Shutao
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supporting information
(2020/09/11)
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- Deoxygenation of Epoxides with Carbon Monoxide
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The use of carbon monoxide as a direct reducing agent for the deoxygenation of terminal and internal epoxides to the respective olefins is presented. This reaction is homogeneously catalyzed by a carbonyl pincer-iridium(I) complex in combination with a Lewis acid co-catalyst to achieve a pre-activation of the epoxide substrate, as well as the elimination of CO2 from a γ-2-iridabutyrolactone intermediate. Especially terminal alkyl epoxides react smoothly and without significant isomerization to the internal olefins under CO atmosphere in benzene or toluene at 80–120 °C. Detailed investigations reveal a substrate-dependent change in the mechanism for the epoxide C?O bond activation between an oxidative addition under retention of the configuration and an SN2 reaction that leads to an inversion of the configuration.
- Maulbetsch, Theo,Jürgens, Eva,Kunz, Doris
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p. 10634 - 10640
(2020/07/30)
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- Pd-Catalyzed Synthesis of Vinyl Arenes from Aryl Halides and Acrylic Acid
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Acrylic acid is presented as an inexpensive, non-volatile vinylating agent in a palladium-catalyzed decarboxylative vinylation of aryl halides. The reaction proceeds through a Heck reaction of acrylic acid, immediately followed by protodecarboxylation of the cinnamic acid intermediate. The use of the carboxylate group as a deciduous directing group ensures high selectivity for monoarylated products. The vinylation process is generally applicable to diversely substituted substrates. Its utility is shown by the synthesis of drug-like molecules and the gram-scale preparation of key intermediates in drug synthesis.
- Gao, Yang,Ou, Yang,Goo?en, Lukas J.
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p. 8709 - 8712
(2019/06/17)
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- Double Functionalization of Styrenes by Cu-Mediated Assisted Tandem Catalysis
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The double functionalization of styrenes through Cu-mediated assisted tandem catalysis was developed. The reaction was initiated by Cu-catalyzed aziridination and the subsequent nucleophilic ring-opening, which was triggered by the addition of (NH4)2S2O8 as an oxidant of Cu-catalyst to form a variety of C–C and C–X bonds. The expansion to three contiguous catalytic cycles led to the synthesis of functionalized indolines by one-pot operation.
- Kawauchi, Daichi,Ueda, Hirofumi,Tokuyama, Hidetoshi
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supporting information
p. 2056 - 2060
(2019/03/13)
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- Method for preparing styrene derivative from ionic liquid
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The invention belongs to the technical field of chemical engineering and pharmaceutical intermediate synthesis and relates to a method for preparing a styrene derivative from ionic liquid. The methodhas advantages that by adoption of the ionic liquid as a solvent, high reaction catalyzing efficiency is achieved; due to reusability of the ionic liquid, industrial production cost is saved, and theenvironment problem caused by traditional solvents can be solved helpfully.
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Paragraph 0035-0037
(2019/04/06)
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- Substituted styrene preparation method
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The invention belongs to the technical field of synthesis of chemical and medical intermediates, and relates to a substituted styrene preparation method, in particular to a method for preparing substituted styrene by using an ionic solution. In the method, the ionic solution is used as a solvent, and the reaction catalyzing efficiency is high. The ionic solution can be repeatedly used, industrialproduction cost is saved, and environment problems caused by a traditional solvent are solved favorably.
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Paragraph 0035-0037
(2019/02/26)
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- A method for the preparation of substituted styrene ion solution method
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The invention belongs to chemical and pharmaceutical intermediate synthesis technology field, relates to a process for preparing a substituted styrene ion solution method. The method takes the ionic liquid as solvent, reaction of high catalytic efficiency. The ionic liquid can be used repeatedly, save the industrialized production cost, and to facilitate the solution of the environmental problem of traditional solvent.
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Paragraph 0035; 0036; 0037
(2019/04/02)
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- Synthesis and Catalytic Applications of [N,N]-Pyrrole Ligands for the Regioselective Synthesis of Styrene Derivatives
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We report the synthesis of two [N,N]-donor ligands (5 a–b) containing a 2-chalcogenazoline as the structural motif. These compounds were synthesized from a common intermediate Fischer type aminocarbene complex (3). The palladium-complexes of these [N,N]-donor ligands were successfully used as catalytic precursors in the Mizoroki-Heck coupling reaction between aryl halides and methyl acrylate, styrene and ethylene. For methyl acrylates, high yields with TOF values between 0.6 and 5.5×105 h?1 were obtained. In the case of ethylene, we reached high regioselectivities to obtain a diversity of styrene derivatives under soft pressure conditions, with good values of TON and TOF. (Figure presented.).
- Hochberger-Roa, Frank,Cortés-Mendoza, Salvador,Gallardo-Rosas, David,Toscano, Ruben A.,Ortega-Alfaro, M. Carmen,López-Cortés, José G.
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p. 4055 - 4064
(2019/07/31)
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- Ligand-controlled iridium-catalyzed semihydrogenation of alkynes with ethanol: highly stereoselective synthesis of E- and Z-alkenes
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A ligand-controlled iridium-catalyzed semihydrogenation of alkynes to E- and Z-alkenes with ethanol was developed. Effective selectivity control was achieved by ligand regulation. The use of 1,2-bis(diphenylphosphino)ethane (DPPE) and 1,5-cyclooctadiene (COD) was critical for the stereoselective semihydrogenation of alkynes. The general applicability of this procedure was highlighted by the synthesis of more than 40 alkenes, with good stereoselectivities. The value of our approach in practical applications was investigated by studying the effects of pinosylvin and 4,4′-dihydroxystilbene (DHS) on zebrafish as a vertebrate model.
- Yang., Jinfei,Wang, Chengniu,Sun, Yufeng,Man, Xuyan,Li, Jinxia,Sun, Fei
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supporting information
p. 1903 - 1906
(2019/05/02)
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- Selective Semi-Hydrogenation of Terminal Alkynes Promoted by Bimetallic Cu-Pd Nanoparticles
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The selective semi-hydrogenation of terminal alkynes was efficiently performed, under mild reaction conditions (H 2 balloon, 110 °C), promoted by a bimetallic nanocatalyst composed of copper and palladium nanoparticles (5:1 weight ratio) supported on mesostructured silica (MCM-48). The Cu-PdNPS@MCM-48 catalyst, which demonstrated to be highly chemoselective towards the alkyne functionality, is readily prepared from commercial materials and can be recovered and reused after thermal treatment followed by reduction under H 2 atmosphere.
- Buxaderas, Eduardo,Volpe, María Alicia,Radivoy, Gabriel
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p. 1466 - 1472
(2019/03/07)
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- Semihydrogenation of phenylacetylene over nonprecious Ni-based catalysts supported on AlSBA-15
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A series of nonprecious monometallic Ni/AlSBA-15 and bimetallic Ni–M (M = Zn, Ga, Cu, or Fe)/AlSBA-15 catalysts were prepared using a urea precipitation method and applied to the semihydrogenation of phenylacetylene. The catalysts were characterized by various techniques, showing that the Ni particle size of catalyst can be tuned by adjusting the Al content, and NiZn and NiGa supported catalysts exhibited geometric and electronic effects that originated from the bimetallic alloy. Among all the catalysts studied, NiZn3/AlSBA-15, with a turnover frequency of 10.89 s?1 comparable to that of precious Pd-based catalysts, presented the highest selectivity to styrene (90.3%) at nearly 100% conversion of phenylacetylene in semibatch operation. This catalyst was further evaluated in a continuous fixed-bed reactor for semihydrogenation of a model C8 aromatic fraction of pyrolysis gasoline (a mixture of phenylacetylene, styrene, ethylbenzene and xylene), which aimed at assessing its practical application of recovering styrene from pyrolysis gasoline. The results showed that at complete conversion of phenylacetylene, the styrene concentration in the product was always kept at a stable level and higher than its initial concentration over 100 h of time on stream, demonstrating high selectivity and good stability of NiZn3/AlSBA-15. Finally, the application of NiZn3/AlSBA-15 was extended to other phenylacetylene derivatives.
- Yang, Lei,Yu, Shiyi,Peng, Chong,Fang, Xiangchen,Cheng, Zhenmin,Zhou, Zhiming
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p. 310 - 320
(2019/01/24)
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- Electrooxidative 1,2-Bromoesterification of Alkenes with Acids and N-Bromosuccinimide
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A simple three-component 1,2-bromoesterification of alkenes with acids and N-bromosuccinimide under electrochemical oxidative conditions is described. This transformation enables the construction of β-bromoalkyl esters via oxidative C-Br/C-O difunctionalization, where a variety of alkenes, including styrenes and cycloolefins, were well tolerated to react efficiently with a wide range of acids, such as aromatic acids, aliphatic acids, and amino acids.
- Wan, Chao,Song, Ren-Jie,Li, Jin-Heng
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supporting information
p. 2800 - 2803
(2019/04/30)
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- Oxidative [4+2] Cycloaddition of α-(N-Arylamino) Carbonyls with Aryl Alkenes by Multiple C-H Functionalizations and [1,2]-Aryl Shifts
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A new, general copper-catalyzed oxidative tandem [4+2] cycloaddition of α-(N-arylamino) carbonyl compounds with aryl alkenes to produce highly substituted quinolines has been developed, which allows the formation of three new C-C bonds through a sequence of multiple C-H functionalizations, annulation, and [1,2]-aryl shifts.
- Wei, Wen-Ting,Teng, Fan,Li, Yang,Song, Ren-Jie,Li, Jin-Heng
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supporting information
p. 6285 - 6288
(2019/09/06)
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- Model Guided Development of a Simple Catalytic Method for the Synthesis of Unsymmetrical Stilbenes by Sequential Heck Reactions of Aryl Bromides with Ethylene
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Stilbenes are important and useful structural moieties, but methods for their preparation typically possess numerous inefficiencies. Presented here is a methodology for the two-step, one pot preparation of unsymmetrical stilbenes via sequential Heck reactions. The first Heck reaction with ethylene gas was analysed as a function of temperature and pressure for electronically differentiated naphthyl bromides and model-aided reaction optimization was utilized to define the system. In addition, reactNMR was utilized to determine ethylene solubility in common organic solvents useful for Heck reactions. Finally, an optimized sequential Heck reaction process was developed and applied to a range of substrates allowing for efficient preparation of unsymmetrical stilbenes, including the natural antioxidant, pterostilbene. (Figure presented.).
- Barlow, Helen,Buser, Jonas Y.,Glauninger, Hendrik,Luciani, Carla V.,Martinelli, Joseph R.,Oram, Niall,Thompson-Van Hook, Nichole,Richardson, Jeffery
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p. 2678 - 2690
(2018/06/04)
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- Rapid Access to Ortho-Alkylated Vinylarenes from Aromatic Acids by Dearomatization and Tandem Decarboxylative C-H Olefination/Rearomatization
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A two-step straightforward method for the preparation of ortho-alkylated vinylarenes from readily available benzoic acids is described. The synthetic route involves the dearomatization of benzoic acids by Birch reduction providing alkylated cyclohexa-2,5-dienyl-1-carboxylic acids. The diene subsequently undergoes a decarboxylative C-H olefination followed by rearomatization to deliver ortho-alkylated vinylarene. Mechanistic studies suggest that a Pd/Ag bimetallic catalytic system is important in the tandem decarboxylative C-H olefination/rearomatization step.
- Tsai, Hung-Chang,Huang, Yen-Hsiang,Chou, Chih-Ming
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supporting information
p. 1328 - 1332
(2018/03/09)
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- Copper-Catalyzed Oxidative Difunctionalization of Terminal Unactivated Alkenes
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The copper(II)-promoted free-radical oxidative difunctionalization of terminal alkenes to access ketoazides by utilizing molecular oxygen has been reported. A series of styrene derivatives have been evaluated and were found to be compatible to give the desired difunctionalized products in moderate to good yields. The role of molecular oxygen both as an oxidant and oxygen atom source in this catalytic transformation has been unquestionably demonstrated by 18O-labeling studies and a radical mechanistic pathway involving the oxidative formation of azidyl radicals is also designed. This environment-friendly catalytic oxidative protocol can transform aldehyde to nitrile.
- Hussain, Muhammad Ijaz,Feng, Yangyang,Hu, Liangzhen,Deng, Qingfu,Zhang, Xiaohui,Xiong, Yan
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p. 7852 - 7859
(2018/05/30)
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- Terminal Alkenes from Acrylic Acid Derivatives via Non-Oxidative Enzymatic Decarboxylation by Ferulic Acid Decarboxylases
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Fungal ferulic acid decarboxylases (FDCs) belong to the UbiD-family of enzymes and catalyse the reversible (de)carboxylation of cinnamic acid derivatives through the use of a prenylated flavin cofactor. The latter is synthesised by the flavin prenyltransferase UbiX. Herein, we demonstrate the applicability of FDC/UbiX expressing cells for both isolated enzyme and whole-cell biocatalysis. FDCs exhibit high activity with total turnover numbers (TTN) of up to 55000 and turnover frequency (TOF) of up to 370 min?1. Co-solvent compatibility studies revealed FDC's tolerance to some organic solvents up 20 % v/v. Using the in-vitro (de)carboxylase activity of holo-FDC as well as whole-cell biocatalysts, we performed a substrate profiling study of three FDCs, providing insights into structural determinants of activity. FDCs display broad substrate tolerance towards a wide range of acrylic acid derivatives bearing (hetero)cyclic or olefinic substituents at C3 affording conversions of up to >99 %. The synthetic utility of FDCs was demonstrated by a preparative-scale decarboxylation.
- Aleku, Godwin A.,Prause, Christoph,Bradshaw-Allen, Ruth T.,Plasch, Katharina,Glueck, Silvia M.,Bailey, Samuel S.,Payne, Karl A. P.,Parker, David A.,Faber, Kurt,Leys, David
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p. 3736 - 3745
(2018/08/03)
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- Method for synthesizing olefin compound by photo-induced one-pot process
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The invention discloses a method for synthesizing an olefin compound by a photo-induced one-pot process. The method comprises the following step of subjecting a halohydrocarbon and an aldehyde compound to a reaction under the condition of irradiation in an inert atmosphere by taking alkali metal carbonate as a base, taking an organic phosphine compound as an adjuvant and taking a photosensitizer as a catalyst, thereby obtaining the olefin compound. According to the method disclosed by the invention, the olefin compound is produced from the halohydrocarbon and the aldehyde compound in a high-yield manner under the condition of irradiation in the inert atmosphere under normal-temperature reaction conditions by taking acetonitrile, DMF (N,N-dimethylformamide) or DMA (N,N-dimethylacetamide) asa solvent, taking an organic phosphine reagent as a reaction adjuvant, taking the alkali metal carbonate as the base and taking the photosensitizer as the catalyst. Compared with the conventional olefin synthesis methods, the method disclosed by the invention has the obvious advantages that the reaction raw materials are readily available, the tolerance to a variety of functional groups on halohydrocarbons and aldehydes is high, the yield is high, the separation and purification of a product are simple and convenient, and the like.
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Paragraph 0053-0055
(2018/11/03)
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- Metal-Free Catalytic Reductive Cleavage of Enol Ethers
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In contrast to the well-known reductive cleavage of the alkyl-O bond, the cleavage of the alkenyl-O bond is much more challenging especially using metal-free approaches. Unexpectedly, alkenyl-O bonds were reductively cleaved when enol ethers were reacted with Et3SiH and a catalytic amount of B(C6F5)3. Supposedly, this reaction is the result of a B(C6F5)3-catalyzed tandem hydrosilylation reaction and a silicon-assisted β-elimination. A mechanism for this cleavage reaction is proposed based on experiments and density functional theory (DFT) calculations.
- Chulsky, Karina,Dobrovetsky, Roman
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supporting information
p. 6804 - 6807
(2018/11/02)
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- Terminal alkyne insertion into a thiolate-bridged dirhodium hydride complex derived from heterolytic cleavage of H2
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Thiolate-bridged dirhodium and diiridium complexes can facilely realize heterolytic cleavage of H2 across the metal-sulfur bond to generate the corresponding hydride bridged complexes. Furthermore, terminal alkynes can insert the Rh-H-Rh fragment to afford σ:π alkenyl bridged complexes and then convert to the corresponding alkenes in the presence of a reductant and an acid.
- Zhao, Xiangyu,Yang, Dawei,Zhang, Yahui,Wang, Baomin,Qu, Jingping
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supporting information
p. 11112 - 11115
(2018/10/15)
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- CATALYSTS AND METHODS FOR FORMING ALKENYL AND ALKYL SUBSTITUTED ARENES
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Embodiments of the present disclosure provide for Rh(I) catalysts, methods of making alkenyl substituted arenes (e.g., allyl arene, vinyl arene, and the like), methods of making alkyl substituted arenes, and the like.
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Paragraph 0158
(2018/03/25)
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- An efficient and sustainable catalytic reduction of carbon-carbon multiple bonds, aldehydes, and ketones using a Cu nanoparticle decorated metal organic framework
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Transition metal (Cu, Mn, Ni, Zr) substituted metal organic frameworks (MOFs) are prepared for the reduction of carbon-carbon multiple bonds with hydrazine hydrate in ethanol under mild reaction conditions. Among the MOFs investigated in this study, the Cu framework substituted MOF exhibited the best activity in this study. Further, Cu nanoparticles (CuNPs) are supported on the surface of a Cu framework substituted MOF to achieve excellent reduction activity. The catalyst exhibits efficient recyclability with no appreciable loss in the catalytic activity even after five recycles. In order to establish the reaction mechanism, reactions are performed under N2 and Ar atmospheres. A reaction is also performed under an Ar atmosphere but in the presence of H2O2 to elucidate the mechanism. The catalyst exhibits excellent activity in the reduction of alkynes. Under the optimum reaction conditions, the catalyst is also successful in reducing a wide range of aldehydes and ketones. The present catalytic process demonstrates several key advantages such as mild and convenient reaction conditions, a low substrate to hydrazine ratio, reusability, and cost-effectiveness of the catalyst (Pt or Pd free catalyst).
- Kar, Ashish Kumar,Srivastava, Rajendra
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p. 9557 - 9567
(2018/06/18)
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- Stable Zero-Valent Nickel Nanoparticles in Glycerol: Synthesis and Applications in Selective Hydrogenations
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Small (mean diameter, ca. 1.2 nm) and well-dispersed zero-valent nickel nanoparticles (NiNPs) stabilized by cinchona-based alkaloids and TPPTS (tris(3-sulfophenyl)phosphine trisodium salt), were synthesized from the organometallic precursor [Ni(cod)2] in neat glycerol under hydrogen pressure. NiNPs were fully characterized ((HR)-TEM, EDX, XPS, XRD, IR, magnetization), both at solid state and directly from the corresponding colloidal solutions in glycerol due to its negligible vapour pressure. NiNPs dispersed in glycerol were applied in hydrogenation reactions, in particular in semihydrogenation of alkynes to give (Z)-alkenes under satisfactory conditions (3 bar H2, 1 mol% Ni, 100 °C), showing remarkable activity and selectivity. The catalytic phase was recycled at least ten times without loss of activity, affording in each case metal-free organic products. Other functional groups such as nitro, nitrile and formyl groups were efficiently hydrogenated to the corresponding anilines, benzylamines and benzylalcohols respectively (77–95% yields). (Figure presented.).
- Reina, Antonio,Favier, Isabelle,Pradel, Christian,Gómez, Montserrat
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supporting information
p. 3544 - 3552
(2018/08/01)
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- Selective Hydrogenations and Dechlorinations in Water Mediated by Anionic Surfactant-Stabilized Pd Nanoparticles
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We report a facile, inexpensive, and green method for the preparation of Pd nanoparticles in aqueous medium stabilized by anionic sulfonated surfactants sodium 1-dodecanesulfonate 1a, sodium dodecylbenzenesulfonate 1b, dioctyl sulfosuccinate sodium salt 1c, and poly(ethylene glycol) 4-nonylphenyl-3-sulfopropyl ether potassium salt 1d simply obtained by stirring aqueous solutions of Pd(OAc)2 with the commercial anionic surfactants further treated under hydrogen atmosphere for variable amounts of time. The aqueous Pd nanoparticle solutions were tested in the selective hydrogenation reactions of aryl-alcohols, -aldehydes, and -ketones, leading to complete conversion to the deoxygenated products even in the absence of strong Br?nsted acids in the reduction of aromatic aldehydes and ketones, in the controlled semihydrogenation of alkynes leading to alkenes, and in the efficient hydrodechlorination of aromatic substrates. In all cases, the micellar media were crucial for stabilizing the metal nanoparticles, dissolving substrates, steering product selectivity, and enabling recycling. What is interesting is also that a benchmark catalyst like Pd/C can often be surpassed in activity and/or selectivity in the reactions tested by simply switching to the appropriate commercially available surfactant, thereby providing an easy to use, flexible, and practical catalytic system capable of efficiently addressing a variety of synthetically significant hydrogenation reactions.
- La Sorella, Giorgio,Sperni, Laura,Canton, Patrizia,Coletti, Lisa,Fabris, Fabrizio,Strukul, Giorgio,Scarso, Alessandro
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supporting information
p. 7438 - 7446
(2018/05/29)
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- Accessing Frustrated Lewis Pair Chemistry through Robust Gold@N-Doped Carbon for Selective Hydrogenation of Alkynes
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Pyrolysis of Au(OAc)3 in the presence of 1,10-phenanthroline over TiO2 furnishes a highly active and selective Au nanoparticle (NP) catalyst embedded in a nitrogen-doped carbon support, Au@N-doped carbon/TiO2 catalyst. Parameters such as pyrolysis temperature, type of support, and nitrogen ligands as well as Au/ligand molar ratios were systematically investigated. Highly selective hydrogenation of numerous structurally diverse alkynes proceeded in moderate to excellent yield under mild conditions. The high selectivity toward the industrially important alkene substrates, functional group tolerance, and the high recyclability makes the catalytic system unique. Both high activity and selectivity are correlated with a frustrated Lewis pairs interface formed by the combination of gold and nitrogen atoms of N-doped carbon that, according to density functional theory calculations, can serve as a basic site to promote the heterolytic activation of H2 under very mild conditions. This "fully heterogeneous" and recyclable gold catalyst makes the selective hydrogenation process environmentally and economically attractive.
- Fiorio, Jhonatan Luiz,Gon?alves, Renato Vitalino,Teixeira-Neto, Erico,Ortu?o, Manuel A.,López, Núria,Rossi, Liane Marcia
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p. 3516 - 3524
(2018/04/14)
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