- Facile synthesis of Pd nanoparticles supported on a novel Schiff base modified chitosan-kaolin: Antibacterial and catalytic activities in Sonogashira coupling reaction
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The present work studies the Sonogashira coupling reaction (SCR) between aryl halides and acetylenes under aerobic conditions using the catalytic complex of Pd nanoparticles (NPs) supported on a novel Schiff base modified chitosan-kaolin (Pd NPs@CS-Kao) in ethanol solvent. The prepared catalyst was characterized by TEM, SEM, FT-IR, XRD, EDS, XPS, elemental mapping, and Raman analyses. The products were formed in high yields. At the end of the reaction, Pd NPs@CS-Kao can be filtered and reused for five consecutive cycles. The advantages of this catalytic process include simple methodology, high yields, and easy work-up. In addition, Pd NPs@CS-Kao exhibited effective antibacterial performance against E. coli gram-negative bacteria.
- Nasrollahzadeh, Mahmoud,Shafiei, Nasrin,Baran, Talat,Pakzad, Khatereh,Tahsili, Mohammad Reza,Baran, Nuray Y?lmaz,Shokouhimehr, Mohammadreza
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- Method for synthesizing terminal alkyne by utilizing 1, 2-dihaloalkane
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The invention discloses a method for synthesizing terminal alkyne by utilizing 1, 2-dihaloalkane. According to the method, 1, 3-dihaloalkane is used as a raw material and terminal alkyne is synthesized under the action of alkali and a catalyst, wherein the molar ratio of the alkali to the 1, 2-dihaloalkane is 2: 1-5: 1, the use amount of the catalyst is 2%-10% of the mass of the 1, 2-dihaloalkane,the reaction temperature is 100-150 DEG C and the reaction time is 3-10 h. The method has the advantages of environmental protection, high selectivity, high yield and the like.
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Paragraph 0028-0030
(2020/04/29)
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- Bimolecular vinylation of arenes by vinyl cations
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Styrene derivatives can be easily synthesized from vinyl triflates and arenes under mild reaction conditions, using [Li][Al(OC(CF3)3)4] as a catalyst and LiHMDS as a base. This transformation is likely to involve a vinyl cation intermediate as an electrophile, which is corroborated by DFT calculations, deuterium-labeling and other control experiments. The use of an inert weakly coordinating anion is a decisive factor in this bimolecular vinylation process. This journal is
- Bour, Christophe,Gandon, Vincent,Li, Zhilong
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supporting information
p. 6507 - 6510
(2020/07/02)
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- Synthesis and Reactivity of Phosphine-Quinolinolato Rhodium Complexes: Intermediacy of Vinylidene and (Amino)carbene Complexes in the Catalytic Hydroamination of Terminal Alkynes
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We report here on the syntheses of rhodium(I) complexes bearing a phosphine-quinolinolate ligand and the isolation of two classes of important intermediates in the anti-Markovnikov hydroamination of terminal alkynes with secondary amines: vinylidene-bridged dirhodium complexes and (amino)carbene complexes. We first prepared various rhodium(I) complexes bearing a phosphine-quinolinolate ligand and found that some of these complexes had catalytic activity for the anti-Markovnikov hydroamination of terminal alkynes with secondary amines. The reaction of stoichiometric amounts of a (PNO)Rh complex with terminal alkynes provided vinylidene-bridged dirhodium complexes. When the resulting vinylidene complexes were reacted with secondary amines, (amino)carbene complexes were generated, which gave the hydroamination product upon heating with an additive. These results suggest that this anti-Markovnikov hydroamination catalyzed by (PNO)Rh complexes proceeds via vinylidene and (amino)carbene complexes.
- Takano, Shotaro,Kochi, Takuya,Kakiuchi, Fumitoshi
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p. 4112 - 4125
(2017/01/10)
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- Chemo-, regio-, and stereoselective hydroboration of conjugated enyne alcohol/amine: Facile synthesis of Z,Z-/Z,E-1,3-dien-1/2-ylboronic ester bearing hydroxyl/amino group
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Hydroboration of conjugated enyne alcohol/amine is studied by using copper salts and bis(pinacolato)diboron as pre-catalysts and boron source respectively. It is suggested that the chemo-selectivity is derived from a combined electronic influence of the heteroatoms on the substrate and the ligand on the transition metal. The regioselectivity is probably dominated mainly by electronic effect of the alkyne substituent. This study resulted in a highly selective protocol to access Z,Z-/Z,E-1,3-dien-1/2-ylboronic ester bearing hydroxyl/amino group.
- Xu, Hua-Dong,Wu, Hao,Jiang, Chun,Chen, Peng,Shen, Mei-Hua
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supporting information
p. 2915 - 2918
(2016/06/14)
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- Tandem Claisen Rearrangement/6-endo Cyclization Approach to Allylated and Prenylated Chromones
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Allyl, dimethylallyl and prenyl ethers derived from o-acylphenols reacted upon microwave irradiation to form C-allylated or -prenylated chromone derivatives, depending on the substitution pattern of the arene and the allyl substituent. The reaction proceeds through a tandem Claisen rearrangement and 6-endo-trig or 6-endo-dig cyclization sequence. For prenyl ethers, the tandem sequence can be extended by a Cope rearrangement to furnish 6-prenylchromones. The method is potentially useful for the synthesis of natural products and drugs.
- Schmidt, Bernd,Riemer, Martin,Schilde, Uwe
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supporting information
p. 7602 - 7611
(2016/01/25)
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- "quick and click" assembly of functionalised indole rings via metal-promoted cyclative tandem reactions
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An efficient and convenient synthesis of a variety of decorated indoles using a three-component tandem metal-catalysed process is described. We propose here a new "synthetic kit" that allows for the "quick and click" assembly of indole rings using readily available, and inexpensive starting materials under environmentally friendly reaction conditions. This journal is
- Capitta, Francesca,De Luca, Lidia,Porcheddu, Andrea
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p. 59297 - 59301
(2015/02/19)
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- Synthesis of acetylenes via dehydrobromination using solid anhydrous potassium phosphate as the base under phase-transfer conditions
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Phase-transfer catalyzed preparation of acetylenes from the corresponding vicinal dibromo compounds via double dehydrobromination using the mild solid base, anhydrous potassium phosphate, under very mild conditions is reported.
- Shenawi-Khalil, Sanaa,Sonavane, Sachin U.,Sasson, Yoel
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experimental part
p. 2295 - 2297
(2012/07/27)
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- InCl3-catalyzed synthesis of 1,2-dimetallic compounds by direct insertion of aluminum or zinc powder
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In-sertion of metal: Catalytic amounts of InCl3 allow the insertion of aluminum and zinc into aromatic 1,2-dibromides or 1,2-bromotriflates (see scheme). These 1,2-dimetallic species can undergo Cu or Pd-catalyzed acylations, allylations, or cross-couplings. Copyright
- Bluemke, Tobias D.,Klatt, Thomas,Koszinowski, Konrad,Knochel, Paul
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supporting information
p. 9926 - 9930
(2012/11/07)
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- Stereospecific approach to α,β-disubstituted nitroalkenes via coupling of α-bromonitroalkenes with boronic acids and terminal acetylenes
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(Z)-α-Bromo-β-substituted nitroethylenes undergo facile Suzuki coupling with aryl, heteroaryl, and vinylboronic acids in the presence of Pd(PPh3)4 as catalyst to afford (E)-α,β-disubstituted nitroethylenes in high yield (up to 95%) and complete specificity. Similar coupling of α-bromonitroethylenes with terminal acetylenes (Sonogashira coupling) provides a novel route to (E)-nitroenynes. These Pd-catalyzed coupling methods offer a convenient and stereospecific entry into a diverse array of synthetically and biologically useful α,β-disubstituted nitroethylenes.
- Ganesh, Madhu,Namboothiri, Irishi N.N.
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p. 11973 - 11983
(2008/03/13)
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- Palladium-Catalyzed Cross-Coupling Reaction of Organoindiums with Aryl Halides in Aqueous Media
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(matrix presented) Diaryl-, divinyl-, and dialkylindium proved to be stable in aqueous media and to undergo a palladium-catalyzed cross-coupling reaction with aryl halides in aqueous THF. Treatment of 3-iodophenol with diphenylindium compound, generated from indium trichloride and two equimolar amounts of a phenyl Grignard reagent, in aqueous media under palladium catalysis provided the corresponding coupling product in excellent yield. Divinyl- and diethlindium can be used for the coupling reaction in the presence of water. A wide range of functional groups, including a hydroxy group and a formyl group, are compatible with this reaction.
- Takami, Kazuaki,Yorimitsu, Hideki,Shinokubo, Hiroshi,Matsubara, Seijiro,Oshima, Koichiro
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p. 1997 - 1998
(2007/10/03)
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- Nickel-catalysed electroreductive cleavage of propargyl compounds
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The selective reduction of propargyl esters and aryl ethers, involving the cleavage of the propargyl-oxygen bond, affords the corresponding carboxylic acids and phenols in good yields. The reaction proceeds through electrosynthesis combined with the catalysis by Ni(II)-bipyridine complexes, under mild conditions.
- Olivero, Sandra,Dunach, Elisabet
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p. 6193 - 6196
(2007/10/03)
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- Synthesis and Nuclear Magnetic Resonance Studies on a Series of Synthesis Long-chain Tellurophene Fatty Esters
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The synthesis and the results of the 1H and 13C NMR spectroscopic analyses of thirteen 2,5-disubstituted tellurophene fatty esters, containing substituents of different chain lengths, and of a monosubstituted tellurophene ester are repported.The tellurophene esters are obtained by cyclization of the corresponding conjugated intermediates with Na2Te in the presence of AgOAc in methanol.The tellurophene moiety in the alkyl chain induces a deshielding effect on the protons of the adjacent methylene prtons.The shift parameters of the tellurophene moiety on the shifts of the adjacent methylene carbon atoms are also determined.
- Jie, Marcel S. F. Lie Ken,Chau, Sherman H.
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p. 2642 - 2657
(2007/10/03)
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- Photo-induced ditelluration of acetylenes with diphenyl ditelluride
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Diphenyl ditelluride (PhTeTePh) adds to a variety of acetylenes upon irradiation with visible light in the absence of solvent to provide vic-bis(phenyltelluro)alkenes in good yields. The reaction may proceed by a radical-chain mechanism that includes the addition to acetylenes of phenyltelluro radical (phTe·) generated in situ by photolysis of diphenyl ditelluride, followed by the S(H)2 reaction between thus formed β-(phenyltelluro)alkenyl radicals and diphenyl ditelluride. In the cases of unactivated acetylenes such as 1-octyne, the addition proceeds stereoselectively to provide only (E)-vic-bis(phenyltelluro)alkenes. Contrary to this, activated acetylenes like phenylacetylene give rise to a mixture of E- and Z-isomers of vic-bis(phenyltelluro)alkenes. Since the obtained vic-bis(phenyltelluro)alkenes indicate absorption in the near-UV, irradiation with near-UV light in solvent causes a novel reverse reaction of the adducts to the starting acetylenes and diphenyl ditelluride. Accordingly, irradiation with visible light (> 400 nm) under high concentrations of the substrates induces the addition of (PhTe)2 to acetylenes, whereas irradiation with near-ultraviolet (> 300 nm) under dilution condition causes the reverse reaction.
- Ogawa,Yokoyama,Obayashi,Han,Kambe,Sonoda
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p. 1177 - 1188
(2007/10/02)
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- Generation of Alkylidenecarbenes from 1,1-Dibromoalk-1-enes by the Reaction with Samarium Diiodide in Hexamethylphosphoric Triamide-Benzene
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Reaction of 1,1-dibromoalk-1-enes with samarium diiodide in benzene containing 10percent of hexamethylphosphoric triamide (HMPA) affords rearranged alkynes; generation of alkylidenecarbenes is probably involved.
- Kunishima, Munetaka,Hioki, Kazuhito,Ohara, Takashi,Tani, Shohei
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p. 219 - 220
(2007/10/02)
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- SYMMETRICAL AND UNSYMMETRICAL COUPLING OF ALKYL HALIDES MEDIATED BY GRIGNARD REACTION
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A simple method for extending the carbon chain via the coupling of alkyl or aryl halides has been developed.The versatility of this reaction has been demonstrated by symmetrical and unsymmetrical coupling of alkyl, alkenyl or alkynyl halides.
- Herendeen, Barbara L.,Bhatia, Suresh K.,Singh, Alok
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p. 2899 - 2908
(2007/10/02)
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- An Unprecedented Intramolecular Migration of Carbon Groups from Aluminum to an Adjacent Vinylic Center and Its Application to the Synthesis of Stereodefined Olefins
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Hydroalumination of 1-chloro-1-alkynes by sodium trialkylaluminum hydrides furnishes stereo- and regioselectively the respective (E)-1-chloro-1-alkenylalanates, which, in the presence of NaOMe, undergo a novel 1,2-migration of a carbon group from Al to the adjacent vinylic center to generate a useful synthesis of di- and trisubstituted olefins of defined geometry.
- Miller, Joseph A.
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p. 998 - 1000
(2007/10/02)
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- Studies on the Thermal Conversion of Long-chain Alkynes at High Temperatures in the Gas Phase
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In the gas phase pyrolysis of long-chain alkynes C5 to C9 at 773 to 873 K, a remarkable portion of molecular reaction (retro-ene analogous decompositions as well as cycloisomerizations of the parent alkynes to cyclopentenes alkylated in 3-position) takes place besides the thermal conversion of the starting compounds via radical chain processes.The different products were separated by GC and the main products identified by means of different methods.The mechanisms of formation of the major products are discussed.
- Ondruschka, B.,Zimmermann, G.,Ziegler, U.,Kopinke, F.-D.,Teuber, M.
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p. 273 - 284
(2007/10/02)
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- DIOLS AS EFFECTIVE COCATALYSTS IN THE PHASE TRANSFER CATALYZED PREPARATION OF 1-ALKYNES FROM 1,2-DIHALIDES
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Bis-tertiary diols accelerate bis-eliminations of HX from 1,2-dihalides in the presence of an onium salt as phase transfer catalyst and potassium hydroxyde as base.PEG 400 catalyzes the same elimination, but isomerizations from 1-alkyne to mixtures with the 2-alkyne and the 1,2-diene occur easily.
- Dehmlow, Eckehard V.,Thieser, Rainer,Sasson, Yoel,Neumann, Ronny
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p. 3569 - 3574
(2007/10/02)
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- General Base Catalyzed Hydrogen Exchange of 1-Octyne, 4-Nitrophenylacetylene, and 3-(Phenyldimethylammonio)-1-propyne. Broensted Relations and Normal Acid Behavior
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Rates of loss of tritium from the title compounds labeled at the acetylenic hydrogen position were measured in aqueous primary amine buffer solutions at 25 deg C.These data give Broensted relations with essentially unit exponents: β = 0.97 +/- 0.06 for 1-octyne, β = 0.97 +/- 0.05 for 4-nitrophenylacetylene, and β = 0.98 +/- 0.05 for 3-(phenyldimethylammonio)-1-propyne, which indicates that these acetylenes are "normal" rather than pseudo carbon acids.
- Kresge, A. J.,Powell, M. F.
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p. 822 - 824
(2007/10/02)
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- Selective Synthesis of Alkynes by Catalytic Dehydrogenation of Alkenes over Polymer-supported Palladium Acetate in the Liquid Phase
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A heterogenized palladium acetate catalyst, in the presence of oxygen and perchloric acid in ethanol-water caused the direct conversion of terminal and internal monoalkenes into the corresponding alkynes, under mild conditions and in high yields; Wacker-type ketonization occurs with the same reagents in dioxane-water.
- Cum, Giampietro,Gallo, Raffaele,Ipsale, Salvatore,Spadaro, Agatino
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p. 1571 - 1573
(2007/10/02)
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- REGIO ET STEREOCHIMIE DE LA REDUCTION DE DERIVES D'ALCOOLS PROPARGYLIQUES CATALYSEE PAR UN COMPLEXE DE PALLADIUM (O)
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Regio and stereoselectivity of the palladium catalyzed reduction of propargylic halides and esters is greatly influenced by the nature of the hydride donor as by the leaving group.Best results in allene formation are observed in the reduction by lithium triethylborohydride of mesylates and phosphates.In the former case, reaction occurs with anti displacement of the sulfonyl group.
- Colas, Yann,Cazes, Bernard,Gore, Jacques
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p. 845 - 848
(2007/10/02)
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- DIRECT PHOTOLYSIS AT 185 nm OF 1-ALKENES IN SOLUTION. MOLECULAR ELIMINATION OF TERMINAL HYDROGENS
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Direct irradiations at 185 nm of 1-octene and 2-methyl-1-pentene in pentane gave alkylidene carbenes through the molecular elimination of terminal hydrogens, as well as double-bond migration products via 1,3-shift of allylic hydrogen and radical-derived products.
- Inoue, Yoshihisa,Mukai, Toshio,Hakushi, Tadao
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p. 1725 - 1728
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF UNSYMMETRICAL BIBENZYLS, HOMOALLYLARENES, AND HOMOPROPARGYLARENES VIA PALLADIUM-CATALYZED CROSS COUPLING
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The palladium-catalyzed homobenzyl-aryl, homobenzyl-alkenyl, homoallyl-aryl, and homopropargyl-aryl cross coupling reactions provide the desired coupling products in high yields, whereas similar reactions involving akynyl halides lead to low product yields.
- Negishi, Ei-ichi,Matsushita, Hajime,Kobayashi, Makoto,Rand, Cynthia L.
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p. 3823 - 3824
(2007/10/02)
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- Organic Photochemistry with 6.7-ev Photons: γ,δ-Unsaturated Ketones
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The photochemistry of a series of acyclic, aliphatic γ,δ-unsaturated ketones in pentane solution with 185-nm light has been investigated.The variety of products formed can be rationalized as arising from discrete reactions of the individually excited chromophores.Neither intramolecular energy transfer nor internal conversion leading to population of the lowest (n,?*) singlet state are competitive with product formation at 185 nm.The mechanism of alkyne formation in the solution-phase photolysis of these and terminal alkenes at 185 nm is elucidated by using a deuterated derivative, and the reaction is postulated to proceed from the olefinic ?,?* singlet state.
- Leigh, William J.,Srinivasan, R.
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p. 4424 - 4429
(2007/10/02)
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- A CONVENIENT ROUTE TO ALKYNES VIA PHASE TRANSFER CATALYSIS; ( APPLICATIONS OF PHASE TRANSFER CATALYSIS, PART 19 )
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High yield, rapid formations of alkynes from vic-dibromides are possible using powered potassium hydroxide and catalytic amounts of lipophilic phase transfer catalysts.Reasons are given why molar amounts of expensive catalysts were necessary in earlier procedures.
- Dehmlow, Eckehard V.,Lissel, Manfred
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p. 1653 - 1658
(2007/10/02)
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- Application of Phase Transfer Catalysis, 14.- Preparation of Alkynes from Halides with Solid Potassium tert-Butoxide and Crown Ether
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Preparatively very simple and mild HX eliminations with solid potassium tert-butoxide in petroleum ether in the presence of catalytic amounts of crown-6 are described. 1,2-Dihalides (from alkenes) and 1,1-dihalides (from aldehydes) yield 1-alkynes; internal geminal dihalides (from symmetric ketones) give internal alkynes in excellent yields. 2,2-Dihalides (from methyl ketones) yield homogeneous 1-alkynes only if the 3-position is blocked. (E)-Haloalkenes lead also to alkynes in a syn-elimination process.
- Dehmlow, Eckehard V.,Lissel, Manfred
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