100-13-0Relevant articles and documents
Elimination in sulfobetaine micelles: Effects of head group bulk
Brinchi, Lucia,Germani, Raimondo,Savelli, Gianfranco,Bunton, Clifford A.
, p. 890 - 894 (1999)
Zwitterionic micelles of tetradecyldimethylammoniopropanesulfonate and tetradecyldibutylammoniopropanesulfonate, SB3-14 and SBBu3-14, respectively, accelerate the E2 reaction of OH- with 4-nitrophenethyl bromide (1b), but the reaction of phenet
EFFECT OF CYCLIC ACETAL-TYPE CATIONIC SURFACTANTS ON THE BASIC DEHYDROBROMINATION REACTION
Wilk, Kazimiera A.,Bieniecki, Albert,Matuszewska, Barbara
, p. 646 - 651 (1994)
The reaction of 2-(p-nitrophenyl)ethyl bromide with hydroxide ion was studied at 50 and 25 deg C in the presence of cationic chemodegradable surfactants, i.e. trimethylammonium bromides Ia-c (alkyl: a = n-C9H19, b = n-C11H23, c = n-C13H27).The kinetic data were interpreted with the pseudo-phase ion-exchange (PIE) formalzm at both temperatures.The results indicate that the major source of rate enhancement is the increased reactant concentration in the small micellar reaction volume.The surfactant stability in micellar conditions was probed by means of a hydrolysis reaction of the surfactant 1,3-dioxolane ring.The kinetics of acid hydrolysis of Ia-c micelles, as a result of specific hydronium ion concentration, is one order of magnitude smaller than that of unaggregated systems.
P(CH3NCH2CH2)3N: A Nonionic Superbase for Efficient Dehydrohalogenation
Arumugam, Subramaniam,Verkade, John G.
, p. 4827 - 4828 (1997)
The commercially available nonionic Superbase P(CH3NH2CH2)3N (1) is far superior to DBU for the conversion of primary and secondary alkyl halides to alkenes. A reason for the efficacy of acetonitrile as a solvent for the halides requiring extended reaction times is presented.
Metal-free and base-free decarboxylation of substituted cinnamic acids in a deep eutectic solvent
Chen, Chen,Jian, Yuqing,Lei, Yuxin,Li, Bin,Peng, Caiyun,Sheng, Wen-Bing,Sumera, Yasmin,Wang, Wei,Zhang, Ming
, p. 558 - 563 (2020)
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.
Pd-grafted periodic mesoporous organosilica: An efficient heterogeneous catalyst for Hiyama and Sonogashira couplings, and cyanation reactions
Modak, Arindam,Mondal, John,Bhaumik, Asim
, p. 2840 - 2855 (2012)
The high surface area of 2D-hexagonal periodic mesoporous organosilica (PMO) containing a phloroglucinol-diimine moiety inside the pore wall has been utilized for grafting Pd(ii) at the surface of the mesopores. This Pd-containing PMO material (Pd-LHMS-3) shows excellent catalytic activity in fluoride-free Hiyama cross-coupling reactions in water at alkaline pH conditions. Sonogashira cross-couplings between terminal alkynes and aryl halides take place in the presence of water and hexamine as base in the absence of any Cu co-catalyst. Cyanation of aryl halides is equally promoted with K4[Fe(CN) 6] as the cyanide source (in the absence of poisonous KCN, NaCN or Zn(CN)2) over Pd-LHMS-3. Excellent yield of the products, reusability and the facile work-up could make this Pd-grafted PMO material a unique catalyst for the synthesis of substituted benzonitriles, unsymmetrical biphenyls and di-substituted alkynes under environmentally benign reaction conditions. Further good yield of products and no evidence of leached Pd from the catalyst surface during the reaction and its smooth recovery confirm the true heterogeneity in these catalytic reactions.
Phosphane-free hiyama cross-coupling of aryl and heteroaryl halides catalyzed by palladium nanoparticles in ionic liquids
Premi, Chanchal,Jain, Nidhi
, p. 5493 - 5499 (2013)
Palladium nanoparticles (NPs) 2-5 nm in size and preformed by thermal reduction in nitrile-functionalized 3-(3-cyanopropyl)-1-methyl-1H-imidazol-3-ium hexafluorophosphate {[CN-bmim]PF6} act as an in situ catalyst for carbon-carbon bond-forming reactions of aromatic and heterocyclic halides with aryl- and vinyltrimethoxysilanes. A variety of biphenyl derivatives, substituted styrenes, and aromatic heterocycles were obtained in 76 to 98 % yield. We demonstrate for the first time the use of 1-butyl-3-methylimidazolium fluoride as an activator of the organosilanes with easy handling, storage, and workup in comparison to conventional fluorine sources such as tetrabutylammonium fluoride, which is indispensable for Hiyama coupling. Pd NPs immobilized in [CN-bmim]PF6 gave high yields of the cross-coupled products at a low catalyst loading of only 4 mol-%, and the catalyst could be reused and recycled up to four times with only a slight loss in catalytic activity. Phosphane-free Hiyama coupling of aryl- and vinyltrimethoxysilanes with aromatic and heterocyclic halides catalyzed by palladium nanoparticles in nitrile-functionalized ionic liquids to yield a range of biphenyl derivatives, substituted styrenes, and aromatic heterocycles is reported. The catalytic system can be recycled at least four times with only a slight loss in catalytic activity. Copyright
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Basler
, p. 3003 (1883)
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Salt Effects upon the Basic Dehydrobromination Reactions in Nonfunctional Micelles
Wilk, Kazimiera A.
, p. 7432 - 7435 (1989)
It was found that the effects of added univalent salts, NaX (X = Cl-, Br-, NO3-) upon the reaction of para-substituted 2-phenylethyl bromides with hydroxide ion in aqueous micellar solutions of hexadecyltrimethylammonium i
Generation of the CF3 radical from trifluoromethylsulfonium triflate and its trifluoromethylation of styrenes
Zhang, Cheng-Pan,Wang, Zong-Ling,Chen, Qing-Yun,Zhang, Chun-Tao,Gu, Yu-Cheng,Xiao, Ji-Chang
, p. 6632 - 6634 (2011)
The CF3 radical was generated from the reaction of S-(trifluoromethyl)diphenylsulfonium triflate with Na2S 2O4 or HOCH2SO2Na under suitable conditions without further reduction. Based on this, a method for the synthesis of α-trifluoromethylated ketones has been successfully developed.
A Change in the Rate-Determining Step in the E1cB Reactions of N-(2-(4-Nitrophenyl)ethyl)pyridinium Cations
Bunting, John W.,Kanter, James P.
, p. 6950 - 6954 (1991)
Second-order rate constants have been measured (aqueous solution, I = 1.0, 25 deg C) for the hydroxide ion catalyzed elimination reactions of 12 N-(2-(4-nitrophenyl)ethyl)pyridinium cations (3) bearing a variety of substituents in the pyridine ring.Broensted plots as a function of the basicity of the pyridine leaving group are concave-down, which is consistent with a change in rate-determining step within an E1cB mechanism.These plots are characterized by βlg = -0.17 for the rate-determining deprotonation for pKBH lg = -0.39 for the rate-determining expulsion of the pyridine nucleofuge from the carbanionic intermediate for pKBH > 6.5.Elimination reactions in basic D2O occur without any significant incorporation of deuterium into the 4-nitrostyrene product, and require the presence of a hydrogen-bonded carbanionic intermediate in which nucleofuge expulsion occurs faster than exchange of hydrogen-bonding water molecules.Rate-determining deprotonation in these elimination reactions occurs 50-fold more slowly than for the corresponding reactions of the N-quinuclidinium cations that have also been reported to have βlg = -0.17, but which do not show an analogous change in the rate-determining step upon variation of the nucleofuge basicity.The analogous elimination of the 1-methyl-3-imidazolium cation occurs a further 30-fold more slowly than that predicted for 3 having a pyridine leaving group of the same basicity as 1-methylimidazole.The E1cB reactions of 3 are similar to the analogous reactions of N-(2-cyanoethyl)pyridinium cations (1) in displaying a change in the rate-determining step with nucleofuge basicity; however, theβlg values for 1 and 3 are quite different for both k1 and k2/k-1.
Wittig reaction by using DBU as a base
Okuma, Kentaro,Sakai, Osami,Shioji, Kosei
, p. 1675 - 1676 (2003)
The reaction of methyltriphenylphosphonium bromide with DBU in refluxing dichloromethane or toluene afforded methylenetriphenylphosphorane, which further reacted with benzaldehydes to give styrenes in good yields. Semistabilized ylide, benzylidenetriphenylphosphorane was also synthesized by using DBU, which reacted with aldehydes to afford olefins in nearly quantitative yields.
Cocatalysis by tetravalent tin compounds in phase-transfer catalyzed fluorination of alkyl halides and sulfonates
Ma?kosza, Mieczys?aw,Bujok, Robert
, p. 2761 - 2763 (2002)
Phase-transfer catalyzed fluorination of alkyl halides or sulfonates is co-catalyzed efficiently by triorganotin halides. The cocatalytic action is due to continuous formation of lipophilic hypervalent triorganodifluorostannate anions, which act as fluori
Rapid Access to Ortho-Alkylated Vinylarenes from Aromatic Acids by Dearomatization and Tandem Decarboxylative C-H Olefination/Rearomatization
Tsai, Hung-Chang,Huang, Yen-Hsiang,Chou, Chih-Ming
, p. 1328 - 1332 (2018)
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.
Methyltriphenylphosphonium Methylcarbonate, an All-In-One Wittig Vinylation Reagent
Cattelan, Lisa,Noè, Marco,Selva, Maurizio,Demitri, Nicola,Perosa, Alvise
, p. 3963 - 3966 (2015)
The methyltriphenylphosphonium methylcarbonate salt [Ph3PCH3][CH3OCO2], obtained directly by quaternarization of triphenylphosphine with dimethylcarbonate, is a latent ylide that promotes Wittig vinylation of aldehydes and ketones. Alkenes are obtained simply by mixing [Ph3PCH3][CH3OCO2] and the carbonyl and heating in a solvent (no base, no halides, and no inorganic byproducts). Deuterium exchange experiments and the particularly short anion-cation distance measured by XRD in [Ph3PCH3][CH3OCO2] allowed to explain the nature and reactivity of this species. Green chemistry metrics (atom economy, mass index, environmental factor) indicate that this vinylation procedure is more efficient than comparable ones. Deuterated [Ph3PCD3][CH3OCO2] promoted the synthesis of deuterated olefins. Add carbonyl and go! The Wittig reaction is widely applied, despite having shortcomings such as low atom economy (AE), the necessity to use solvents, and stoichiometric amounts of waste from generating the ylide. [Ph3PCH3][CH3OCO2] is a latent phosphorous ylide that promotes Wittig vinylation of aldehydes and ketones by simply heating with the carbonyl. No external base and no halides involved, and the protocol offers good AE, environmental factor, and mass index.
Heterogeneous One-Pot Carbonylation and Mizoroki–Heck Reaction in a Parallel Manner Following the Cleavage of Cinnamaldehyde Derivatives
Hattori, Tomohiro,Ueda, Shun,Takakura, Ryoya,Sawama, Yoshinari,Monguchi, Yasunari,Sajiki, Hironao
, p. 8196 - 8202 (2017)
Carbon monoxide (CO) and styrene derivatives that can be both generated by a palladium on carbon (Pd/C)-catalyzed carbon–carbon (C?C) bond cleavage reaction of cinnamaldehyde derivatives were effectively utilized in further palladium-catalyzed C?C bond forming reactions in a direct and practical way. CO derived from simple and affordable CO carriers such as cinnamaldehyde or terephthalaldehyde was efficiently employed in the in situ CO fixation with various aromatic iodides through a palladium-catalyzed carbonylation followed by an inter- or intramolecular coupling reaction with alcohols to afford the corresponding esters or lactones, respectively. Styrene derivatives were also efficient substrates in an in situ Mizoroki–Heck-type cross-coupling reaction with aryl iodides, leading to the effective formation of asymmetric stilbenes. The decarbonylation of cinnamaldehyde derivatives and the subsequent independent syntheses of both esters/lactones and 1,2-diarylethenes could be achieved in a virtual one-pot and in situ reaction using a H-shaped pressure-tight glass-sealed tube consisting of two independent but laterally connected reaction tubes in the gas space.
OIL-IN-WATER MICROEMULSIONS BASED ON CHEMODEGRADABLE SURFACTANTS AS REACTION MEDIA
Bieniecki, Albert,Wilk, Kazimiera A.
, p. 71 - 76 (1995)
The reaction of 2-(p-nitrophenyl)ethyl bromide with hydroxide ion was studied in oil-in-water (o/w) microemulsions at 50 deg C.The octane-in-water microemulsion systems were stabilized by chemodegradable cyclic acetal-type cationic surfactants as (2-alky
Design and synthesis of water-soluble chelating polymeric materials for heavy metal ion sequestration from aqueous waste
Jacob, Josemon,Tyagi, Reshu
, (2020)
Sequestration and removal of dissolved heavy metal ions from aqueous waste streams is a challenging task. Ethylenediaminetetraacetic acid (EDTA) is a hexadentate chelating ligand capable of forming 1:1 complex with various heavy metal ions while iminodiacetic acid (IDA) is analogous to half a unit of EDTA. A new styrene based monomer M1 bearing dimethyl iminodiacetate group was designed and synthesized in good yield to meet this objective. Free radical polymerization of M1 generated the homopolymer, which upon base hydrolysis generated the water-soluble chelating homopolymer P10, bearing sodium salt of IDA as the chelating group. The overall yield of P10 was 76.80% and the solubility was 5 mg/mL at room temperature. The water soluble polymer P10 was investigated for its ability to bind various heavy metal ions by UV–vis spectroscopy and was found to efficiently sequester Cu2+, Cd2+, Zn2+, Pb2+, Ni2+, Co2+, Cr3+, Fe2+ and Fe3+. The effect of pH on Cu2+ binding with P10 showed that every two IDA bearing monomeric repeat units binds with one Cu2+ ion at pH 7 suggesting that it forms complexes analogous to EDTA. Thermogravimetric analysis showed that the synthesized polymer possesses high thermal stability up to 400 °C. The potential for recovery and reuse of the polymer has been demonstrated with Cu2+ ion. The reported results suggest that this water-soluble chelating homopolymer is an excellent material with very high potential for application in wastewater treatment.
Intramolecular Dehydration of β-Hydroxyalkylphosphonic Acid Monoesters. A Novel Type of Olefin Formation
Kawashima, Takayuki,Nakamura, Mio,Nakajo, Akira,Inamoto, Naoki
, p. 1483 - 1486 (1994)
The title reaction using dicyclohexylcarbodiimide (DCC) gave stereospecifically the corresponding olefins in good yields via tetracoordinate 1,2-oxaphosphetanes.Use of more than one equivalent of DCC afforded better yields of the olefin.
STYRENE DERIVATIVES VIA PALLADIUM-CATALYZED VINYLATION OF ARYL IODIDES
Hallberg, Anders,Westerlund, Christer
, p. 1993 - 1994 (1982)
A new and efficient method for the preparation of styrene derivatives via Pd-catalyzed vinylation of aromatic systems, using vinyltrimethylsilane as an ethylene equivalent, is described.
Hydroxyl Assisted Rhodium Catalyst Supported on Goethite Nanoflower for Chemoselective Catalytic Transfer Hydrogenation of Fully Converted Nitrostyrenes
Hu, Zenan,Ai, Yongjian,Liu, Lei,Zhou, Junjie,Zhang, Gang,Liu, Hongqi,Liu, Xiangyu,Liu, Zhibo,Hu, Jianshe,Sun, Hong-bin,Liang, Qionglin
, p. 3146 - 3154 (2019)
Control of chemoselectivity is a special challenge for the reduction of nitroarenes bearing one or more unsaturated groups. Here, we report a flower-like Rh/α-FeOOH catalyst for the chemoselective hydrogenation of nitrostyrene to vinylaniline over full conversion, which benefits the new functionalized aminostyrene because the multisubstituted aminostyrenes are usually commercially unavailable. This catalyst does not only show desirable selectivity for the vinylanilines, but also exhibits the inertness to various other reducible groups over wide reaction duration. The catalytic selectivity for the reduction of the nitro group towards vinyl group was investigated by the control experiments and FT-IR analysis. We have found that the abundant hydroxyl groups in the α-FeOOH may contribute to the improvement of catalytic activity and selectivity. Furthermore, the catalyst exhibits excellent stability and keeps its catalytic performance even after 6 cycles. (Figure presented.).
Dhami,K.S.,Stothers,J.B.
, p. 510 (1965)
Recoverable palladium-catalyzed carbon-carbon bond forming reactions under thermomorphic mode: Stille and suzuki-miyaura reactions
Chan, Ka Long,Chiu, Chiao-Fan,Elakkat, Vijayanath,Lu, Norman,Shen, Chia-Rui,Su, Han-Chang,Tessema, Eskedar,Tsai, Zong-Lin
, (2021)
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.
Copper-carbene complexes as catalysts in the synthesis of functionalized styrenes and aliphatic alkenes
Lebel, Helene,Davi, Michael,Diez-Gonzalez, Silvia,Nolan, Steven P.
, p. 144 - 149 (2007)
(NHC)-Cu (NHC = N-heterocyclic carbene) complexes efficiently catalyzed the methylenation of a variety of aliphatic and aromatic aldehydes and ketones in the presence of trimethylsilyldiazomethane, triphenylphosphine, and 2-propanol. The copper catalysts are not only inexpensive compared to rhodium complexes, but they also exhibit better functional group compatibility with aromatic aldehydes and ketones. Indeed very high yields were obtained for the formation of styrenes containing nitro, trifluoromethyl, amino, and ester groups, as well as for pyridine-, pyrrole-, and indole-substituted alkenes.
Hetero-Diels-Alder cycloadditions of α,β-unsaturated acyl cyanides. Part 4. Substituent effects in reactions with p-substituted styrenes
Zhuo, Jin-Cong,Wyler, Hugo
, p. 1122 - 1134 (1999)
Cycloadditions of α,β-unsaturated acyl cyanides (=2-oxonitriles) 1-6 to styrene and its p-substituted derivatives 7a-f,h are of inverse electron demand and provide, under mild conditions, regio- and stereo-selectively 2- aryl-3,4-dihydro-2H-pyran-6-carbonitriles 8-13, generally in good yield. Rates for the cycloaddition of acryloyl cyanide 1 to p-substituted styrenes, determined in competition reactions of substrate pairs relative to that of styrene, increase in the order of electron-donating ability NO2 + substituent constants (a Hammett-type plot), gives a reaction constant ρ(p)+ of -1.47 ± 0.17, supporting a concerted mechanism.
Pd?Zn Alloy Nanoparticles Encapsulated into Mesoporous Silica with Confinement Effect for Highly Selective Semi-Hydrogenation of Phenylacetylene
Li, Zhenxing,Hu, Mingliang,Liu, Bowen,Liu, Jiahao,Wang, Ping,Yao, Jiasai,Zhang, Xin,He, Miao,Song, Weiyu
, p. 868 - 873 (2021)
In the process of hydrogenation of phenylacetylene to styrene, it is a crucial step to improve the reaction selectivity of the target product styrene. Herein, we have designed the Pd?Zn alloy nanoparticles encapsulated into mesoporous silica with confinement effect (Pd?Zn@MS) for highly selective semi-hydrogenation of phenylacetylene via annealing the Pd NPs@ZIF-8 in reducing atmosphere. The as-obtained Pd?Zn@MS achieved up to the 95 % of conversion rate and 92 % of selectivity, because the mesoporous silica exhibits a steric hindrance effect for the reactant molecular size, and the Pd?Zn alloy nanoparticles shows the high selectivity for the target product styrene. DFT calculations demonstrates that the PdZn alloy nanoparticles can reduce significantly the desorption energy barrier of styrene from 1.72 eV to 0.95 eV, compared with the Pd nanoparticles. Meanwhile the mesoporous silica in the outer layer greatly guarantees the stability of the catalytic performance of the catalyst, and the catalytic performance did not drop after the five-cycle test. This work provides a new idea for the selective hydrogenation of phenylacetylene and the process of limited-area catalysis.
Tertiary arsine ligands for the Stille coupling reaction
Chishiro, Akane,Imoto, Hiroaki,Inaba, Ryoto,Konishi, Masafumi,Naka, Kensuke,Yumura, Takashi
, p. 95 - 103 (2021/12/27)
The Stille coupling reaction is one of the most important coupling reactions. It is well known that the triphenylarsine ligand can accelerate the reaction rate of Stille coupling. However, other arsine ligands have never been investigated for the Stille c
Cross-Coupling Reactions with 2-Amino-/Acetylamino-Substituted 3-Iodo-1,4-naphthoquinones: Convenient Synthesis of Novel Alkenyl- And Alkynylnaphthoquinones and Derivatives
Demidoff, Felipe C.,Rodrigues Filho, Eduardo José P.,De Souza, Andréa Luzia F.,Netto, Chaquip D.,De Carvalho, Leandro L.
supporting information, p. 4097 - 4109 (2021/08/31)
Functionalized 1,4-naphthoquinones have been employed as versatile synthons in organic synthesis, in addition to presenting a large array of biological activities. Herein, the applications of 2-amino-/ acetylamino-substituted 3-iodo-1,4-naphthoquinones in cross-coupling reactions are described to successfully afford sixteen novel 3-styryl-1,4-naphthoquinones (amino-stilbene-quinone hybrids) and four 3-alkynyl-1,4-naphthoquinone in overall good yields. Interestingly, the alkynylated derivatives could be obtained from ligand- and Pd-free Cu I -mediated cross-coupling reactions, after extensive investigations to exclude Pd as a co-catalyst. Lastly, the desilanized terminal alkyne was subjected to click chemistry reactions to give two novel triazole-1,4-naphthoquinone hybrids.
