103-36-6Relevant articles and documents
Vinylalumination of fluoro-carbonyl compounds
Ramachandran, P. Veeraraghavan,Reddy, M. Venkat Ram,Rudd, Michael T.,De Alaniz, Javier Read
, p. 8791 - 8794 (1998)
Ethyl acrylate and acrylonitrile fail to undergo efficient Baylis- Hillman reaction with fluoral, but provide good yields of products with pentafluorobenzaldehyde. Alternately, unsubstituted and β-substituted [α- (ethoxycarbonyl)vinyl]aluminum react with perfluoroalkyl and -aryl aldehydes and ketones to provide the α-hydroxyalkenylated fluoro-organic compounds in good to excellent yields.
Pd/Cu-Free Cobalt-Catalyzed Suzuki and Heck Using Green Bio-Magnetic Hybrid and DFT-Based Theoretical Study
Hajipour, Abdol R.,Khorsandi, Zahra,Ahmadi, Mehnoosh,Jouypazadeh, Hamidreza,Mohammadi, Bahareh,Farrokhpour, Hossein
, p. 2842 - 2850 (2021)
Abstract: Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds (Co-ligand@MNPs/Ch). The structure of these nanocomposites was confirmed by various physicochemical techniques such as FT-IR, XRD, TGA, VSM, TEM, SEM, CHNS and ICP-OES. These nano composites exhibit remarkable catalytic efficiency for Suzuki and Heck cross-coupling reactions in mild and green reaction conditions. The facile accessibility of starting materials, possible performance in air and eco-friendly conditions are merits of our catalysts. In addition, to describe and go insight to role and effect of ligands present in these catalysts, electrostatic interactions, density functional theory (DFT) model in molecular method were employed. Graphic Abstract: [Figure not available: see fulltext.]
Magnetically recoverable nanostructured Pd complex of dendrimeric type ligand on the MCM-41: Preparation, characterization and catalytic activity in the Heck reaction
Abdollahi-Alibeik, Mohammad,Gharibpour, Najmeh,Ramazani, Zahra
, p. 184 - 199 (2020)
A palladium complex of a dendrimer type ligand of aminoethylacrylamide immobilized onto the mesoporous channels of MCM-41 with magnetic core was prepared and characterized using various techniques such as XRD, TEM, BET, FT-IR, TGA, and VSM. The prepared nanostructured material was found as a magnetically recoverable catalyst for Heck reaction of aryl halides and vinylic C-H. The catalyst is easily recoverable with an external magnet and is reusable with different leaching amounts depending to loading of Pd. A hot filtration test was also performed and gave evidence that Palladium in heterogeneous samples can dissolve and then redeposit on the surface of the support material.
Mesoporous Borated Zirconia: A Solid Acid-Base Bifunctional Catalyst
Sinhamahapatra, Apurba,Pal, Provas,Tarafdar, Abhijit,Bajaj, Hari C.,Panda, Asit Baran
, p. 331 - 338 (2013)
The development and use of reusable solid catalysts for the selective organic transformation in solvent-free or environmentally benign solvent media is the key interest of modern frontier science. Herein a facile low temperature aqueous solution based chemical route for the synthesis of mesoporous borated zirconia, an acid-base bifunctional solid catalyst, using aqueous zirconium ammonium carbonate complex and borax in presence of cetyltrimethylammonium bromide is presented. The material has a very high surface area and acidity with weak basicity. The catalytic activity of the material was investigated for the solvent-free Knoevenagel condensation reaction of benzaldehyde/substituted benzaldehyde and malononitrile/cyano ethylacetate to confirm the acid-base bifunctionality. High yield (>90%) of the corresponding benzylidene was obtained within 15-30min at room temperature. The evidence that the high catalytic activity is a result of acid-base bifunctionality of the synthesized borated zirconia material was further supported by performing Claisen-Schmidt condensation of benzaldehyde and acetophenone. The methodology was also extended for targeted synthesis of cinnamyl ethyl ester and coumarin or coumarin ester; and resulted in a good yield.
Controlling reactivity in the Fujiwara–Moritani reaction: Examining solvent effects and the addition of 1,3-dicarbonyl ligands on the oxidative coupling of electron rich arenes and acrylates
Jones, Roderick C.
, (2020)
A palladium-catalysed direct alkenation of electron rich arenes in the presence of K2S2O8 with an acetic acid/1,4-dioxane solvent combination has been developed. The 1,4-dioxane co-solvent dramatically influences the rate of reaction, giving selectively disubstituted alkenes, while the addition of acetylacetone ligands was shown to increase site selectivity for the alkenation of monofunctionalized arenes. The participation of these carbonyl ligands has been confirmed by ESI-MS studies, with some key in situ intermediates in the catalytic cycle identified. A variety of electron rich arenes and olefinic substrates can be utilised in the direct oxidative coupling to give disubstituted alkenes in moderate to good yields.
Direct substitution of the hydroxy group in alcohols with silyl nucleophiles catalyzed by indium trichloride
Yasuda, Makoto,Saito, Takahiro,Ueba, Masako,Baba, Akio
, p. 1414 - 1416 (2004)
Straightforward substitution: An excellent combination of a silyl nucleophile and indium catalyst was used to accomplish the dehydroxylation/ alkylation of alcohols under nearly neutral conditions (see scheme, Si = silyl group) even though this type of reaction usually requires at least an equimolar amount of acid.
A computational triage approach to the synthesis of novel difluorocyclopentenes and fluorinated cycloheptadienes using thermal rearrangements
Orr, David,Percy, Jonathan M.,Harrison, Zo? A.
, p. 6369 - 6380 (2016)
Electronic structure calculations have been used for the effective triage of substituent effects on difluorinated vinylcyclopropane precursors and their ability to undergo vinyl cyclopropane rearrangements (VCPR). Groups which effectively stabilised radicals, specifically heteroarenes, were found to result in the lowest energy barriers. Ten novel precursors were synthesised to test the accuracy of computational predictions; the most reactive species which contained heteroarenes underwent thermal rearrangements at room temperature to afford novel difluorocyclopentenes and fluorinated benzocycloheptadienes through competing VCPR and [3,3]-rearrangement pathways, respectively. More controlled rearrangement of ethyl 3-(1′(2′2′-difluoro-3′-benzo[d][1,3]dioxol-5-yl)cyclopropyl)propenoate (22) allowed these competing pathways to be monitored at the same time and activation energies for both reactions were determined; Ea(VCPR) = (23.4 ± 0.2) kcal mol-1 and Ea([3,3]) = (24.9 ± 0.3) kcal mol-1. Comparing our calculated activation energies with these parameters showed that no single method stood out as the most accurate for predicting barrier heights; (U)M05-2X/6-31+G? methodology remained the best for VCPR but M06-2X/6-31G? was better for the [3,3]-rearrangement. The consistency observed with (U)B3LYP/6-31G? calculations meant that it came closest to a universal method for dealing with these systems. The developed computational design model correctly predicted the observed selectivity of rearrangement pathways for both our system and literature compounds.
Preparation of active and robust palladium nanoparticle catalysts stabilized by diamine-functionalized mesoporous polymers
Xing, Rong,Liu, Yueming,Wu, Haihong,Li, Xiaohong,He, Mingyuan,Wu, Peng
, p. 6297 - 6299 (2008)
A two-step chemical modification process is designed for synthesizing novel diamine-functionalized mesopolymers, which combine the advantage of organic polymers and mesoporous materials, and serve as an efficient scaffold for supporting highly dispersed, catalytically active and robust Pd nanoparticles (NPs). The Royal Society of Chemistry 2008.
Catalytic properties of chiral terpenoid CN-palladacycle in the C - C bond forming reactions
Bulygina,Khrushcheva,Gu?eva, Ya. A.,Kutchin,Sokolov
, p. 436 - 438 (2015)
Chiral camphor-derived CN-palladacycle exhibits high catalytic activity in the Suzuki crosscouplings and hydroarylation of norbornene under mild conditions.
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Shimoji,K. et al.
, p. 1620 - 1621 (1974)
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ALKALI METAL FLUORIDE MEDIATED SILYL-REFORMATSKY REACTION IN SOLID-LIQUID MEDIA; ACTIVATION BY MICROWAVES.
Latouche, Regine,Texier-Boullet, Francoise,Hamelin, Jack
, p. 1179 - 1182 (1991)
Condensation of trimethylsilylacetonitrile or ethyltrimethylsilylacetate with benzaldehyde, in the presence of dried alkali metal fluorides in heterogeneous media under microwaves leads readily to β-trimethylsilyloxynitrile or ester according to a Reformatsky type reaction.The later products could be hydrolyzed and dehydrated on the wet inorganic salt to give the corresponding alkenes.
Ruthenium-catalyzed tandem cross-metathesis/wittig olefination: Generation of conjugated dienoic esters from terminal olefins
Murelli, Ryan P.,Snapper, Marc L.
, p. 1749 - 1752 (2007)
In the presence of ruthenium-based olefin metathesis catalysts and triphenylphosphine, α,β-unsaturated aldehydes can be olefinated with diazoacetates. This ruthenium-catalyzed transformation has been employed in tandem with olefin cross-metathesis to convert terminal olefins into 1,3-dienoic esters in a single operation.
A facile preparation of indium enolates and their Reformatsky-and Darzens-type reactions
Hirashita, Tsunehisa,Kinoshita, Kenji,Yamamura, Hatsuo,Kawai, Masao,Araki, Shuki
, p. 825 - 828 (2000)
Indium enolates were readily prepared by transmetalation of lithium enolates with indium trichloride, and were subsequently reacted with aldehydes to give β-hydroxy esters in high yields. Indium α-bromo enolates were also prepared and reacted with carbonyl compounds to give Darzens-type α,β-epoxy carbonyl products. The Royal Society of Chemistry 2000.
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Takahashi et al.
, p. 1498 (1962)
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Asymmetric Synthesis of γ-Amino Alcohols by Copper-Catalyzed Hydroamination
Ichikawa, Saki,Buchwald, Stephen L.
, p. 8736 - 8739 (2019)
Asymmetric synthesis of γ-amino alcohols from unprotected allylic alcohols by a copper-catalyzed hydroamination strategy has been developed. Using easily accessible starting materials, a range of chiral 1,3-amino alcohols were prepared with excellent regio- and enantioselectivity. Further, this protocol provided an efficient one-step method for the enantioselective synthesis of γ-amino alcohols in an intermolecular manner.
Br?nsted acidic ionic liquid as an efficient and recyclable promoter for hydroesterification of olefins catalyzed by a triphenylphosphine-palladium complex
Yang, Jing,Zhou, Hancheng,Lu, Xinning,Yuan, Youzhu
, p. 1200 - 1204 (2010)
Several Br?nsted acidic ionic liquids (BAILs) with different acidic scales were synthesized and employed as acid promoters for the hydroesterification of olefins catalyzed by a triphenylphosphine-palladium complex. The results showed that catalysts with BAIL promoters resulted inmoderate to high conversions to the ester product with excellent selectivity, depending on the acidity of BAIL used. The reaction conversion reached a plateau when the catalyst was promoted using BAIL with a Hammett acidity function less than or equal to-0.11. This catalyst system could be reused several times for the hydroesterification of 1-hexene without a considerable decrease in the catalytic performance.
Amine Base Promoted β-Elimination in α-Bromo Ester Substrates. Evidence for Permutational Isomerism in the TBP Carbon Intermediate
Kwart, Harold,Gaffney, Anne,Wilk, Kazimiera A.
, p. 4509 - 4513 (1983)
Amine bases show reaction rates and activation parameters that suggest close similarity to the E2C mechanism previously identified for the Br(1-)-promoted reaction with α-bromo ester.Proton Sponge (PS), an amine base, which cannot participate in an SN2 process, nonetheless, is an effective promoter of the E2C.This is confirmed by applying the temperature-dependent isotope effect (TDKIE) criteria of transition-state geometry to PS and other amine reactions with α-bromo esters with the general result that a>DH is found to be temperature independent and AH/AD >> 1.2.The α-secondary deuterium isotope effect, (kH/kD)α = 1.27, is the largest value ever found (thus far) for either SN2-like or β-elimination processes.On these and other grounds it is concluded that the E2C mechanism is not SN2 like but is regarded as a precedented nucleophilic trigger mechanism.The virtual identity of intra- and intermolecular isotope effects among amine base promoters cannot be explained by the formation of a symmetrical trigonal-bipyramid (TBP) intermediate, as was the case for the Br(1-)-promoted reaction with α-bromo ester substrates.But the obviously equal availability of abstractable H and D in the transition states of the intramolecular competition isotope effect is possibly to be explained by invoking permutational isomerism in the precursor trigonal-bipyramid (TBP) intermediate.The reasoning which seems to justify this proposal is considered in detail.
Direct Preparation of Organocadmium Compounds from Highly Reactive Cadmium Metal Powders
Burkhardt, Elizabeth R.,Rieke, Reuben D.
, p. 416 - 417 (1985)
Highly reactive cadmium metal powders and a cadmium-lithium alloy were prepared and were used to prepare organocadmium reagents directly from organic halides.
POSS-Based Covalent Networks: Supporting and Stabilizing Pd for Heck Reaction in Aqueous Media
Arsalani, Nasser,Akbari, Ali,Amini, Mojtaba,Jabbari, Esmaiel,Gautam, Sanjeev,Chae, Keun Hwa
, p. 1086 - 1094 (2017)
Abstract: Palladium nanoparticles supported on Incompletely Condensed Polyhedral Oligomeric Silsesquioxane (IC-POSS) based poly (Acrylamide-co-Hydroxy ethyl methacrylate) as a novel nanohybrid catalyst were synthesized and characterized. This catalyst was found to be an efficient and reusable heterogeneous catalyst for the Heck reaction using water as the solvent in the absence of a phosphine ligand and phase transfer catalyst. Graphical Abstract: [Figure not available: see fulltext.]
A palladacyclic azobenzene derivative as a catalyst for carbon-carbon bond formation reactions
Bulygina,Khrushcheva,Peregudova,Sokolov
, p. 1998 - 2000 (2012)
A bis-chelated palladacycle in which the Pd atom is [(C, N)(C, N)]-tetracoordinated to two azobenzene ligands proved to be a moderately active catalyst for the Suzuki and Heck reactions. A voltammetric study revealed that the two-electron oxidation of this complex is accounted for by the irreversible PdII/PdIV transition.
Triethylsilane-indium(III) chloride system as a radical reagent
Hayashi, Naoki,Shibata, Ikuya,Baba, Akio
, p. 4981 - 4983 (2004)
(Chemical Equation Presented) A novel generation method of indium hydride (Cl2InH) was found by the transmetalation of InCl3 with Et3SiH. In the intramolecular cyclization of enynes, the previously reported system (NaBH4-InCl3) has a problem of side reactions with the coexistent borane. In contrast, the problem was solved by the presented system, which affords effective hydroindation of alkynes.
Myoglobin-catalyzed olefination of aldehydes
Tyagi, Vikas,Fasan, Rudi
, p. 2512 - 2516 (2016)
The olefination of aldehydes constitutes a most valuable and widely adopted strategy for constructing carbon-carbon double bonds in organic chemistry. While various synthetic methods have been made available for this purpose, no biocatalysts are known to mediate this transformation. Reported herein is that engineered myoglobin variants can catalyze the olefination of aldehydes in the presence of α-diazoesters with high catalytic efficiency (up to 4,900 turnovers) and excellent Ediastereoselectivity (92-99.9 % de). This transformation could be applied to the olefination of a variety of substituted benzaldehydes and heteroaromatic aldehydes, also in combination with different alkyl α-diazoacetate reagents. This work provides a first example of biocatalytic aldehyde olefination and extends the spectrum of synthetically valuable chemical transformations accessible using metalloprotein-based catalysts.
Continuous Radio Amplification by Stimulated Emission of Radiation using Parahydrogen Induced Polarization (PHIP-RASER) at 14 Tesla
H?vener, Jan-Bernd,Pravdivtsev, Andrey N.,S?nnichsen, Frank D.
, (2020)
Nuclear Magnetic Resonance (NMR) is an intriguing quantum-mechanical effect that is used for routine medical diagnostics and chemical analysis alike. Numerous advancements have contributed to the success of the technique, including hyperpolarized contrast agents that enable real-time imaging of metabolism in vivo. Herein, we report the finding of an NMR radio amplification by stimulated emission of radiation (RASER), which continuously emits 1H NMR signal for more than 10 min. Using parahydrogen induced hyperpolarization (PHIP) with 50 % para-hydrogen, we demonstrated the effect at 600 MHz but expect that it is functional across a wide range of frequencies, e.g. 101–103 MHz. PHIP-RASER occurs spontaneously or can be triggered with a standard NMR excitation. Full chemical shift resolution was maintained, and a linewidth of 0.6 ppb was achieved. The effect was reproduced by simulations using a weakly coupled, two spin-1/2 system. All devices used were standard issue, such that the effect can be reproduced by any NMR lab worldwide with access to liquid nitrogen for producing parahydrogen.
Use of ferrocenyl chelated palladacycles as catalysts for the Heck reaction
Sokolov,Bulygina,Khrushcheva,Ikonnikov
, p. 1400 - 1402 (2010)
Two ferrocenyl palladacycles with bi-and tridentate (C,N) and (C,N,N) ligands were tested as possible catalysts for the Heck reaction. The latter complex efficiently catalyzed reactions of aryl halides with ethyl acrylate.
One-pot chemoenzymatic reactions in water enabled by micellar encapsulation
Adams, Nicholas P.,Bushi, Jurgen,Hastings, Courtney J.,Kolb, Samuel J.
, p. 6187 - 6193 (2020)
The use of micellar conditions to enable one-pot reactions involving both transition metal and enzymatic catalysts is reported. Representative enzymatic transformations under micellar conditions are unaffected by the presence of non-ionic surfactants, including designer surfactants such as TPGS-750-M. Furthermore, the presence of enzymes has a negligible effect on transition metal catalysis under micellar conditions in water. Finally, three one-pot chemoenzymatic reactions in water are reported in which the micelle-forming surfactant TPGS-750-M is a crucial factor for reaction efficiency.
Harnessing Thorpe–Ingold Dialkylation to Access High-Hill-Percentage pH Probes
Huang, Yunxia,Luo, Xiao,Qian, Xuhong,Xiao, Yansheng,Yang, Youjun,Zeng, Zhenhua
, p. 85 - 93 (2022/01/15)
Sensitivity is an important parameter for a molecular probe. Hill-type pH probes exhibit improved detection sensitivity compared to the traditional pH probes following the Henderson–Hasselbalch equation. Exploiting positive cooperativity, we recently devised a novel molecular scaffold (PHX) to offer such an unconventional Hill-type pH titration profile. We previously confirmed that PHX is not a pure Hill-type probe yet. Only 64% of its absorbance/fluorescence turn-on is the result of a Hill-type pathway. The remaining 36% is from an undesired Henderson–Hasselbalch-type pathway (HH pathway). In this work, the Thorpe–Ingold dialkylation was harnessed to further suppress the percent contribution of the HH pathway down to 16%. We also propose that PHX is a viable molecular model for assessing the efficacy of the steric compressing effect induced by different Thorpe–Ingold dialkylations.
Green and sustainable palladium nanomagnetic catalyst stabilized by glucosamine-functionalized Fe3O4@SiO2 nanoparticles for Suzuki and Heck reactions
Eslahi, Hassan,Sardarian, Ali Reza,Esmaeilpour, Mohsen
, (2021/04/26)
A novel magnetic and heterogeneous palladium-based catalyst stabilized by glucosamine-functionalized magnetic Fe3O4@SiO2 nanoparticle was synthesized. The strategy relies on the covalently bonding of glucosamine to cyanuric chloride-functionalized magnetic nanoparticles followed by complexation with palladium. The structure of magnetic nanocatalyst was fully determined by FT-IR, XRD, DLS, FE-SEM, TEM, ICP, UV-Vis, TGA, VSM, and EDX. The obtained results confirmed that the palladium nanoparticles stabilized by glucosamine immobilized onto the magnetic support exhibited high activity in cross-coupling reactions of Suzuki-Miyaura and Mizoroki-Heck. Various aryl halides were coupled with arylboronic acid (Suzuki cross-coupling reaction) and olefins (Heck reactions) under the green conditions to provide corresponding products in high to excellent yields. Interestingly, the catalyst can be easily isolated from the reaction media by magnetic decantation and can subsequently be applied for consecutive reaction cycles (at least seven times) with no notable reduction in the catalytic activity.
A new Pd(II)-supported catalyst on magnetic SBA-15 for C-C bond formation via the Heck and Hiyama cross-coupling reactions
Rahimi, Leila,Mansoori, Yagoub,Nuri, Ayat,Koohi-Zargar, Behzad,Esquivel, Dolores
, (2020/12/01)
Magnetic mesoporous silica composite (MNP@SiO2-SBA) was obtained via embedding magnetite nanoparticles between SBA-15 channels. It was silylated with N-(3-(trimethoxysilyl)propyl)picolinamide (TMS-PCA) and then complexed with Pd(II). The obtained supported Pd(II) catalyst (MNP@SiO2-SBA-PCA) was characterized by conventional methods. The prepared magnetic catalyst showed high activity in the Heck and Hiyama reactions under optimal reaction conditions, including solvent, amount of catalyst, base, and temperature. Aryl bromides and iodides showed better results than aryl chlorides, and the catalyst exhibited noticeable stability and reused several times.
