- Pd-catalyzed synthesis of biphenyls with methylthio group
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The synthesis of unsymmetrical biaryls with a methylthio group is achieved using the air-stable palladium-phosphinous acid complexes, [(t-Bu)2P(OH)]2 PdCl2 (POPd), as the catalyst. A great variety of substituted bromobenzenes having electron-withdrawing and electron-donating functional groups in para and meta positions have been successfully coupled with 3-methylthiophenylboronic acid. Copyright Taylor & Francis Group, LLC.
- Zhang, Zhiqiang,Hu, Zhizhi,Yu, Zhixiao,Chi, Haijun,Lei, Peng,Wang, Yue,He, Ren
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- Reduction of sulfoxides and pyridine-N-oxides over iron powder with water as hydrogen source promoted by carbon dioxide
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A green process was developed for efficient reduction of sulfoxides and pyridine-N-oxides using the iron powder in the presence of H2O- CO2 to sulfides and pyridines, respectively. Notably, H2O is employed as the terminal hydrogen source, and CO2 could enhance hydrogen generation through in situ formation of carbonic acid. Thus carbonic acid offers simple neutralization by depressurizing CO2 and the system can eliminate unwanted byproducts. The high generality and chemo-selectivity of this protocol were demonstrated by the scope of substrates, in which chlorine, vinyl group and benzene ring can be tolerated.
- Ma, Ran,Liu, An-Hua,Huang, Cheng-Bin,Li, Xue-Dong,He, Liang-Nian
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- Photocatalytic deoxygenation of sulfoxides to sulfides over titanium(IV) oxide at room temperature without use of metal co-catalysts
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Deoxygenation of sulfoxides was examined in acetonitrile suspensions of metal-free titanium(IV) oxide (TiO2) under irradiation of UV light at room temperature. Experimental results indicate that deoxygenation was induced by the TiO2
- Kominami, Hiroshi,Nakanishi, Kousuke,Yamamoto, Satoshi,Imamura, Kazuya,Hashimoto, Keiji
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- Catalytic dehydrogenation of amines to imines and the in-situ reduction of sulfoxides into sulfides
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The catalytic acceptorless dehydrogenation of primary amines into imines and H2 represents one of the most important organic transformations, and the in-situ utilization of the generated H2 for chemical reduction reactions has never
- Li, Bo,Liu, Bing,Liu, Xixi,Wang, Wei,Wang, Yanxin,Xiang, Nian,Zhang, Zehui
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- Impregnated palladium on magnetite as catalyst for multicomponent reductive amination reactions and other related reducing processes
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The impregnated palladium on magnetite catalyst is a versatile system for different reduction processes using inexpensive polymehtylhydrosiloxane, including multicomponent reductive amination reactions, and aldehyde, imine, sulfinimide and sulfoxide reductions. This catalyst avoids the use of any type of expensive and quite expensive organic ligand, showing excellent yields, under mild reaction conditions. The catalyst is easily removed from the reaction medium, just by using a magnet. The catalytic system is very selective permitting the discrimination between ketones and aldehydes in the reductive amination process.
- Cano, Rafael,Yus, Miguel,Ramón, Diego J.
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- Gas-phase S-alkylation of benzenethiol with aliphatic alcohols, ethers, esters, alkyl halides and olefins over halide cluster catalysts of Groups 5 and 6 transition metals
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Benzenethiol was reacted with methanol under a hydrogen stream over [(Nb6Cl12)Cl2(H2O) 4]·6H2O supported on silica gel. Catalytic activity of the cluster commenced above 250 °C, yielding methyl phenyl sulfide. The selectivity was 98% at 400 °C. Molybdenum, tantalum and tungsten halide clusters with the same octahedral metal framework also catalyzed the reaction. Primary alcohols with shorter alkyl chains were effective reagents for the S-alkylation. Aliphatic ethers, dialkyl carbonates, orthoesters and alkyl halides were effective reagents for the S-alkylation. When 1-hexene was applied to the reaction, spontaneous and catalytic S-alkylation proceeded simultaneously above 200 °C, yielding n-hexyl phenyl sulfide. When alkyl acetates were subjected to this reaction, the niobium cluster afforded S-phenyl thioacetate, and the other clusters afforded alkyl phenyl sulfides selectively. A Br?nsted acid site attributable to a hydroxo ligand, which is formed on the cluster complex by thermal activation, is proposed as the active site of the catalysts.
- Nagashima, Sayoko,Kudo, Kentaro,Yamazaki, Hitomi,Kamiguchi, Satoshi,Chihara, Teiji
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- Efficient reduction of sulfoxides with NaHSO3 catalyzed by I2
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An efficient method for the deoxygenation of sulfoxides into their corresponding sulfides at room temperature using NaHSO3 in the presence of catalytic I2 has been reported.
- Abbasi, Mohammad,Mohammadizadeh, Mohammad Reza,Moradi, Zahra
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- Reactivity of Substituted Phenyldimethylsulfonium Ions with Common Nucleophiles. A Test of pKlgMe for Phenyldimethylsulfonium Salts and a Comparison with Methyl Arenesulfonates
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The correlations of nucleophilic rate data for phenyldimethylsulfonium ions with common nucleophiles with pKlgMe values shows that the slopes of the line, βlgMe, correlate qualitatively with Edwards hardness parameter for the nucleophile, and not with the Swain-Scott no parameter. Comparison with substituted methyl arenesulfonates shows different leaving group behavior in the two systems. These results support Shaik's hypothesis that leaving group behavior consists of some SET character.
- Fountain,Dunkin, Timothy W.,Patel, Kamlesh D.
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- Selective deoxygenation of sulfoxides to sulfides with phosphites catalyzed by dichlorodioxomolybdenum(VI)
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Chemoselective deoxygenation of sulfoxides to sulfides was carried out by P(OPh)3 in mild conditions catalyzed by dichlorodioxomolybdenum(VI).
- Sanz, Roberto,Escribano, Jaime,Aguado, Rafael,Pedrosa, Maria R.,Arnaiz, Francisco J.
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- Rapid, efficient and chemoselective deoxygenation of sulfoxides to thioethers using NaBH4/I2
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Sodium borohydride in the presence of iodine in anhydrous THF converts a range of structurally different sulfoxides to their thioethers in excellent yields. It has been found that chemoselective deoxygenation of sulfoxides can be achieved in the presence of other reducible functional groups such as esters, nitriles and double bonds.
- Karimi, Babak,Zareyee, Daryoush
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- Unprecedented synthesis of iron-NHC complexes by C-H activation of imidazolium salts. Mild catalysts for reduction of sulfoxides
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A direct synthesis of bidentate cyclopentadienyl-functionalised NHC-iron(ii) complexes by using imidazolium salts and commercially available Fe3(CO)12 is developed. These well-defined iron-NHC complexes efficiently catalyse the reduction of sulfoxides under mild conditions. Radical scavenging experiments indicate the presence of free radicals in the catalytic reaction. The Royal Society of Chemistry 2012.
- Cardoso, Joao M.S.,Royo, Beatriz
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- SCAVENGING OF RADICALS FROM THE GAS PHASE BY FREEZING WITH DIMETHYL DISULFIDE: 2. RADICALS FROM DISCHARGES AND A FLAME OF ACETYLENE.
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The method of detecting radicals from low-pressure gas-phase systems by scavenging with dimethyl disulfide (DMD) has been applied to microwave discharges in C//2H//2/He mixtures and to a C//2H//2/O//2 flame. It was accomplished by condensing a supersonic nozzle beam from the reaction system together with a beam of DMD on a liquid-N//2 cooled surface. The scavenging products were measured by GC/MS after warming-up. Radicals measured in the discharge were C//2H, C//4H, C//6H, C//3H//2, C//2 besides H atoms. Preliminary measurements on the flame showed that C//6H//5 (phenyl), CH//2, C//3H//2, besides H and O atoms were prominent radicals at the end of the oxidation zone. The concentration of phenyl is of the same order as that of e. g. naphthalene.
- Kubitza,Schottler,Homann
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- Zinc-catalyzed deoxygenation of sulfoxides to sulfides applying [B(Pin)]2 as deoxygenation reagents
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In the present study, the zinc-catalyzed deoxygenation of aliphatic and aromatic sulfoxides in the presence of 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi-1, 3, 2-dioxaborolane [B(Pin)]2 as reducing reagent to produce the corresponding sulfides has been investigated. After examination of various reaction parameters the abilities of catalytic amounts of Zn(OTf)2 has been proven in the deoxygenation of various sulfoxides. Especially, a high functional group tolerance was noticed for the Zn(OTf)2/ B(Pin) 2 system. Springer Science+Business Media, LLC 2012.
- Enthaler, Stephan
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- Dealkylation of Quaternary Ammonium Salts by Thiolate Anions: A Model of the Cobalamin-independent Methionine Synthase Reaction.
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The reactions of thiolate ions derived from thiophenol and homocysteine with substituted quaternary ammonium salts result in alkyl transfer from nitrogen to sulfur.A radical mechanism for this transalkylation, accounts for the reactivity pattern of the substrate salts.In a model study of the cobalamin-independent methionine synthase reaction, 5,5,6,7-tetramethyl-5,6,7,8-tetrahydropteridinium salt (25), which can be considered as a model for the natural coenzyme 5-CH3H4-folate (1), was allowed to react with the thiolate of homocysteine, whereupon the formation of methionine was observed in good yield.These results suggest that in the enzymatic process the N(5)-CH3 bond may be activated for the methyl transfer step, by coordination of the N(5) with an electrophile or a proton at the active site.
- Hilhorst, Ellen,Chen, Tjoe B. R. A.,Iskander, Atef S.,Pandit, Upendra K.
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- One-pot reduction of sulfoxides with NaBH4, CoCl2. 6H2O catalyst, and moist alumina
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Sulfoxides are reduced by a combination of sodium borohydride, a catalytic amount of cobalt(II) chloride hexahydrate, and chromatographic neutral alumina preloaded with a small amount of water (moist alumina) in hexane to produce the corresponding sulfides in good to excellent yields under mild conditions. An interesting structural influence of sulfoxides on their reactivity is observed. Copyright
- Yakabe, Shigetaka,Hirano, Masao,Morimoto, Takashi
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- Convenient synthesis of electron-donating substituted benzonitriles by photolysis of phenyl halides and esters
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Irradiation of electron-donating substituted phenyl halides (fluorides and chlorides) or esters (mesylates, triflates and phosphates) in aqueous MeCN in the presence of KCN gives the corresponding benzonitriles in 48 to 100% yield through an ArSN1 reaction with the intermediacy of a triplet phenyl cation. The Royal Society of Chemistry 2006.
- Dichiarante, Valentina,Fagnoni, Maurizio,Albini, Angelo
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- An unprecedented use for glycerol: Chemoselective reducing agent for sulfoxides
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A new application for glycerol that expands its possibilities beyond a green solvent and a precursor of value-added products has been demonstrated. Simple, easily available, and environmentally friendly dioxomolybdenum(vi) complexes are highly efficient catalysts for the chemoselective sulfoxide deoxygenation with this biomass-derived chemical feedstock. Both refined glycerol and crude glycerin can be used, thus expanding the potential application of this reaction. Subsequent transformation of glycerol during this reductive process has also been investigated.
- Garcia, Nuria,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Garcia, Daniel,Pedrosa, Maria R.,Arnaiz, Francisco J.,Sanz, Roberto
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- Photoredox catalysis for oxygenation/deoxygenation between sulfides and sulfoxides by visible-light-responsive polyoxometalates
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In this paper, we report the unique visible-light-responsive photoredox catalysis of a divacant lacunary silicotungstate TBA4H4[γ-SiW10O36] (SiW10) for functional group transformations of sulfur-containing compounds; namely, (i) aerobic oxygenation of sulfides to sulfoxides and (ii) deoxygenation of sulfoxides to sulfides. In the presence of suitable additives, such as Ce3+ (electron transfer mediator for oxygenation) and an alcohol (electron and proton donor for deoxygenation), SiW10 shows visible-light-induced charge transfers by using the newly formed highest occupied molecular orbitals derived from the coordinating Ce3+ or alcohol at the vacant site of SiW10. Consequently, oxygenation of sulfides and deoxygenation of sulfoxides can selectively proceed by irradiation with visible light (λ > 400 nm) to afford the corresponding desired products in high yields. The SiW10 photocatalysts can readily be recovered and reused for these transformations. Based on evidence from several experiments, the roles of the additives as well as the reaction mechanisms for these transformations are also discussed.
- Suzuki, Kosuke,Jeong, Jinu,Yamaguchi, Kazuya,Mizuno, Noritaka
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- Phosphonate Decomposition-Induced Polyoxomolybdate Dumbbell-Type Cluster Formation: Structural Analysis, Proton Conduction, and Catalytic Sulfoxide Reduction
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The reaction of MoO42- with a number of phosphonic acids [bis(phosphonomethyl)glycine, R,S-hydroxyphosphonoacetic acid, 1-hydroxyethane-1,1-diphosphonic acid, phenylphosphonic acid, aminotris(methylene phosphonic acid), and 1,2-ethylenediphosphonic acid] under oxidizing (H2O2) hydrothermal conditions at low pH leads to rupture of the P-C bond, release of orthophosphate ions, and generation of the octanuclear, phosphate-bridged, polyoxometalate molybdenum cluster (NH4)5[Mo8(OH)2O24(μ8-PO4)](H2O)2 (POMPhos). This cluster has been fully characterized and its structure determined. It was studied as a proton conductor, giving moderate values of σ = 2.13 × 10-5 S·cm-1 (25 °C) and 1.17 × 10-4 S·cm-1 (80 °C) at 95% relative humidity, with Ea = 0.27 eV. The POMPhos cluster was then thermally treated at 310 °C, yielding (NH4)2.6(H3O)0.4(PO4Mo12O36) together with an amorphous impurity containing phosphate and molybdenum oxide. This product was also studied for its proton conductivity properties, giving rise to an impressively high value of σ = 2.43 × 10-3 S·cm-1 (25 °C) and 6.67 × 10-3 S·cm-1 (80 °C) at 95% relative humidity, 2 orders of magnitude higher than those corresponding to the "as-synthesized" solid. The utilization of POMPhos in catalytic reduction of different sulfoxides was also evaluated. POMPhos acts as an efficient homogeneous catalyst for the reduction of diphenyl sulfoxide to diphenyl sulfide, as a model reaction. Pinacol was used as a low-cost, environmentally friendly, and highly efficient reducing agent. The effects of different reaction parameters were investigated, namely the type of solvent and reducing agent, presence of acid promoter, reaction time and temperature, loading of catalyst and pinacol, allowing to achieve up to 84-99% yields of sulfide products under optimized conditions. Substrate scope was tested on the examples of diaryl, alkylaryl, dibenzyl, and dialkyl sulfoxides and excellent product yields were obtained.
- Armakola, Eirini,Salcedo, Inés R.,Bazaga-García, Montse,Olivera-Pastor, Pascual,Mezei, Gellert,Cabeza, Aurelio,Fernandes, Tiago A.,Kirillov, Alexander M.,Demadis, Konstantinos D.
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- Thiophenol-Promoted Radical Chain Reduction of α-Substituted Isobutyrophenones by 1,3-Dimethyl-2-phenylbenzimidazoline
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The reduction of α-haloacetophenones and α-halopropiophenones by 1,3-dimethyl-2-phenylbenzimidazoline (DMBI) have been reported to proceed via an electron-transfer free-radical chain mechanism.The reduction of α-haloisobutyrophenones did not proceed by the chain sequence.We mow report that initiated reductions of α-bromo- and α-chloroisobutyrophenones (IIIa,b) have been found to be promoted by the addition of thiophenol.Isobutyrophenone was formed as the major product via a free-radical chain process.During the PhSH-promoted DMBI reduction of IIIa,b a minor product, α-(phenylthio)isobutyrophenone (IV), was also formed via nucleophilic substitution.The chain propagation steps involve the efficient hydrogen atom transfers between PhCOCMe2. and PhSH and between PhS. and DMBI.The facile hydrogen transfer between PhS. and DMBI was comfirmed by carrying out the radical-chain reduction of PhSSPh with DMBI.
- Tanner, Dennis D.,Chen, Jian Jeffrey
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- A Model of the Cobalamin-independent Methionine Synthase Reaction
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Homocysteine is converted to methionine via a nonenzymatic methyl transfer from a 5-methyltetrahydrofolate model bearing a positive charge at N(5).
- Hilhorst, Ellen,Chen, Tjoe B. R. A.,Pandit, Upendra K.
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- Facile and mild reduction of sulfoxides to sulfides with TiCl4/Sm system
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TiCl4/Sm system reduces sulfoxides rapidly to the corresponding sulfides in good yields in THF at room temperature.
- Wang,Zhang
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- A CONVENIENT SYNTHESIS OF VINYL SULFIDES
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Dithioketals are converted in good yields to vinyl sulfides by action of diethylzinc and methylene iodide.The reaction has been successfully applied to dialkyl and diaryl dithioketals, to spirocyclic analogs, and to a dithioacetal.A monothioketal produced a vinyl ether (enol ether) with the same reagent.
- Rodriguez, Abimael D.,Nickon, Alex
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- Discovery and application of methionine sulfoxide reductase B for preparation of (S)-sulfoxides through kinetic resolution
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Here we report a methionine sulfoxide reductase B (MsrB) enzymatic system for the preparation of (S)-sulfoxides through kinetic resolution of racemic (rac) sulfoxides. Eight MsrB homologue recombinant proteins were expressed and their activities on asymmetric reduction of rac-sulfoxides were analyzed. Among these MsrB homologue proteins, one protein from Acidovorax species showed good activity and enantioselectivity towards several aryl-alkyl sulfoxides. The (S)-sulfoxides were prepared with 93–98% enantiomeric excess through kinetic resolution at initial substrate concentration up to 50 mM. The establishment of MsrB catalytic kinetic resolution system provides a new efficient green strategy for preparation of (S)-sulfoxides.
- Wen, Yuanmei,Peng, Liaotian,Zhou, Yang,Peng, Tao,Chen, Yu,Cheng, Xiaoling,Chen, Yongzheng,Yang, Jiawei
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- Reduction of Sulfoxides with Sodium or Benzyl Bromide
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The reduction of dimethyl and diphenyl sulfoxides, and of alkyl and arylbenzyl sulfoxides to the corresponding sulfides can be carried out using sodium bromide without solvent or benzyl bromide in dimethylformamide, mostly through an oxidation-reduction cycle catalyzed by developing hydrobromic acid.
- Bernard, Angela M.,Caredda, Maria G.,Piras, P. Paolo,Serra, Ermanno
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- Formation of σ- and π-type dimer radical cations by the photochemical one-electron oxidation of aromatic sulfides
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The formation of dimer radical cations from aromatic sulfides has been studied by photochemical one-electron oxidation in acetonitrile. When dicyanonaphthalene and thioanisole in acetonitrile were irradiated with nanosecond laser flash (308 nm), two types of dimer radical cations were detected at 470 and 800 nm at the expense of the monomer radical cation (520 nm). The intramolecular formation of similar radical ion complexes was observed for the cases of 1,n-bis(phenylthio)alkanes with n = 3 and 4, while bissulfides with n = 2, 6, and 8 showed radical cation spectra quite different from the above cases of n = 3 and 4. These facts indicate that dimer radical cations absorbing at around 460-500 nm are assigned as the σ- type complex of the sulfur-sulfur three-electron bond and that radical cations absorbing at around 800 nm are of the π-type complex associated with two phenylthio groups. For the case of p-methylthioanisole the formation of π-type dimer was shown to be reduced owing to the steric hindrance of two methyl groups. No formation of dimer radical cations was observed for cases of p-methoxythioanisole and diphenyl sulfide where the corresponding monomer radical cations are stabilized by the delocalization of positive charge on the sulfur atom. The density functional BLYP/6-31G* calculations on thioanisole predicted the existence of σ- and π-type dimer radical cations, in accordance with the experimental observation of approximately equal stability.
- Yokoi, Hajime,Hatta, Akio,Ishiguro, Katsuya,Sawaki, Yasuhiko
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- Metal-free S-methylation of diaryl disulfides with di-tert-butyl peroxide
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An efficient approach for S-methylation of diaryl disulfides with di-tert-butyl peroxide under metal-free and neutral conditions was established. The present protocol shows good functional group tolerance to afford aryl methyl sulfides in moderate to good
- Wu, Xiangmei,Wang, Yan
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- α-Effect with Substituted N-Methylbenzohydroxamates and Substituted Phenyldimethylsulfonium Salts: Toward Understanding of an Intrinsic α-Effect
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Increasing electron demand in the reactions of G-NMBH anions with substituted phenyldimethylsulfonium ions decreases the α-effect for the methyl transfers toward 1.0 (zero effect). An extrapolation shows the possibility of an inverse effect (3 group. These correlations indicate inclusion of some SET character into the wavefunction of the SN2 transition state for these reactions, in agreement with the Shaik and Pross SCD model of the SN2 reaction.
- Fountain,Dunkin, Timothy W.,Patel, Kamlesh D.
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- Reversible Intramolecular P-S Bond Formation Coupled with a Ni(0)/Ni(II) Redox Process
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P-S bond formation/cleavage mediated by a nickel ion supported by a PPP ligand (PPP = P[2-PiPr2-C6H4]2-) has been investigated herein. To gain an entry into this chemistry, a mononuclear thiolato nickel complex, (PPP)Ni(SAr) (1a,b) was prepared by treating the chloride starting material with NaSPh. Upon carbonylation, this complex produces a nickel(0) monocarbonyl species, (PPSArP)Ni(CO) (2a,b), in which the thiolate migrates onto the central P of the ligand to give a P-S bond and two-electron reduction of a nickel(II) center. The reaction undergoes via a pseudo-first-order decay with respect to consumption of a nickel(II) thiolato species, suggesting an intramolecular reaction under the excess CO(g) conditions. The reverse reaction involving P-S bond cleavage with concomitant decarbonylation occurs to regenerate 1a,b in benzene. Reaction of 2a with trityl chloride results in Ph3CSPh formation, whereas the reaction with MeI gives methylation at a phosphide moiety or a thiolate group.
- Oh, Seohee,Lee, Yunho
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- Application of alkoxy-λ6-sulfanenitriles as strong alkylating reagents
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Alkoxy-λ6-sulfanenitriles were found to be versatile alkylating reagents toward various nucleophiles bearing at least one proton such as methanol, phenol, thiophenols, carboxylic acids, ptoluenesulfonic acid, hydrochloric acid, and primary and secondary amines. Reactivity of the alkoxy group of the λ6-sulfanenitriles showed an opposite trend to the usual SN2 character, i.e. Me (la), Pr (1b), and Bu (1d) ? i-Pr (1c). In the presence of p-TsOH, alkyl tosylates were predominantly formed instead of the alkylation products of nucleophiles. In addition, even a sterically hindered substrate, neopentyloxy-λ6-sulfanenitrile, was found to undergo an SN2 reaction toward thiophenol without any rearrangement product to give neopentyl phenyl sulfide in good yield.
- Hao, Wei,Fujii, Takayoshi,Dong, Tiaoling,Wakai, Youko,Yoshimura, Toshiaki
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- A chemical model for the enzymatic mono de-alkylation of (methyl and ethyl) parathion by glutathione-S-transferase
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The NMR study of the reaction of methylparathion with thiol (glutathione) and a tertiary amine shows unambiguously a sequential transfer of the methyl group firstly to the amine and secondly to the thiol. The reaction stops after a single demethylation. This observation may account for regiospecificity of some glutathione S-transferases.
- Maturano, Marie Dolores,Bongibault, Véronique,Willson, Michèle,Klaébé, Alain,Fournier, Didier
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- Domino reaction of 2,3-dichloroprop-1-ene with diphenyl disulfide in the system hydrazine hydrate-potassium hydroxide
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2,3-Dichloroprop-1-ene reacted with diphenyl disulfide in the system hydrazine hydrate-potassium hydroxide at 30-35 C to give three products: 2-chloro-3-phenylsulfanylprop-1-ene, 1-phenylsulfanylpropadiene, and 1-phenylsulfanylprop-1-yne. Variation of tem
- Levanova,Grabel'Nykh,Elaev,Russavskaya,Klyba,Albanov,Tarasova,Korchevin
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- Hydrodediazoniation of dry arenediazonium o-benzenedisulfonimides with hydrogen peroxide
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This report describes the hydrodediazoniation of dry arenediazonium o-benzenedisulfonimides 1 with hydrogen peroxide (2) in THF at reflux. The new procedure is general, giving positive results in the presence of both electron-donating and electron-withdrawing substituents. Furthermore, it does not suffer from steric effects and always gives the pure reduction products 3 in excellent yields (15 examples, average yield = 93%). All the reactions show over 90% recovery of o-benzenedisulfonimide (4) that can be reused to prepare the salts 1. The collateral proofs we performed led us to hypothesize, for this reaction, a free-radical chain mechanism in which 2 is the exclusive hydrogen source in the arenes Ar-H 3.
- Barbero, Margherita,Degani, Iacopo,Dughera, Stefano,Fochi, Rita
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- KINETICS AND MECHANISM OF OXIDATION OF SUBSTITUTED PHENYL METHYL SULPHIDES BY N-BROMOACETAMIDE
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The kinetics of oxidation of several substituted phenyl methyl sulphides by N-bromoacetamide (NBA) in 80percentacetonitrile-20percentwater (v/v) mixture are presented.The reaction is first order with respect to both sulphide and NBA and second order in Hg(II).The rate of the reaction exhibits inverse dependence on both and .Electron-releasing substituents present in the phenyl ring of the sulphides accelerate the rate while electron-withdrawing ones retard it.The results are in accord with a mechanism involving the reaction between NBA-Hg(II) and sulphide-Hg(II) complexes in the slow rate-limiting step affording a sulphonium ion which hydrolyses in a subsequent fast step to the sulphoxide.
- Perumal, Subbu,Alagumalai, Sakkiah,Selvaraj, Sangavanaicker,Arumugam, Natesan
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- Reductive deamination of aromatic amines with nitric oxide (NO)
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Aromatic amines were treated with nitric oxide in tetrahydrofuran or chloroform under argon atmosphere to afford deaminated aromatic compounds in good yields. The reaction is suggested to proceed via aryl radicals, which are supposed to be formed by reduction of aryldiazonium salts with NO.
- Itoh, Takashi,Matsuya, Yuji,Nagata, Kazuhiro,Ohsawa, Akio
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- A simple and efficient method for reduction of sulfoxide under solvent-free conditions
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Benzyl DABCO bromide was found to be an efficient and mild reagent for the reduction of sulfoxides to the corresponding sulfide using sulfuric acid adsorbed silica gel under solvent-free conditions at room temperature.
- Pourmousavi, Seied Ali,Salehi, Parvin
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- Identification of MsrA homologues for the preparation of (R)-sulfoxides at high substrate concentrations
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Here we report a methionine sulfoxide reductase A (MsrA) homologue with extremely high substrate tolerance and a wide substrate scope for the biocatalytic preparation of enantiopure sulfoxides. This MsrA homologue which was obtained from Pseudomonas alcaliphila (named paMsrA) showed good activity and enantioselectivity towards a series of aryl methyl/ethyl sulfoxides 1a-1k, with electron-withdrawing or electron-donating substituents at the aromatic ring. Chiral sulfoxides in the R configuration were prepared with approximately 50% of yield and up to 99% enantiomeric excess through the asymmetric reductive resolution of racemic sulfoxide catalyzed by the recombinant paMsrA protein. More importantly, kinetic resolution has been successfully accomplished with high enantioselectivity (E > 200) at initial substrate concentrations up to 320 mM (approximately 45 g L-1), which represents a great improvement in the aspect of the substrate concentration for the biocatalytic preparation of chiral sulfoxides.
- Yang, Jiawei,Wen, Yuanmei,Peng, Liaotian,Chan, Yu,Cheng, Xiaoling,Chen, Yongzheng
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- Mild and efficient deoxygenation of sulfoxides with titanium(IV) chloride/sodium iodide reagent system
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Dialkyl, diaryl and alkyl aryl sulfoxides were readily deoxygenated to the corresponding sulfides in excellent yields with titanium(IV) chloride/sodium iodide reagent system at room temperature.
- Balicki
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- Efficient deoxygenation of sulfoxides to thioethers and reductive coupling of sulfonyl chlorides to disulfides with tungsten hexachloride
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Tungsten hexachloride (WCI6) in the presence of NaI in anhydrous acetonitrile or zinc powder in anhydrous THF converts sulfoxides to their thioethers in high yields. Reductive coupling of sulfonyl chlorides to their corresponding disulfides is also achieved efficiently with the above reagent in anhydrous acetonitrile in high yields. Sodium benzene sulfinate as a model compound for sulfinate salts is also converted to diphenyl disulfide in almost quantitative yield.
- Firouzabadi, Habib,Karimi, Babak
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- A mild, efficient, and selective procedure for the deoxygenation of sulfoxides with the TaCl5/indium system
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The TaCl5/In systemwas found to be a new reagent for reducing a wide range of structurally diverse sulfoxides to the corresponding sulfides with high yields under mild conditions. This protocol is chemoselective and tolerates several functional groups, such as Br, Cl, OCH3, CHO, and CH= CH2.
- Yoo, Byung Woo,Lee, Min Kyung,Yoon, Cheol Min
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- N-bromosuccinimide/HCl mediated reduction of sulfoxides to sulfides
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An efficient reduction of sulfoxides to sulfides mediated by N-bromosuccinimide (NBS)/HCl system has been developed. This protocol shows good functional group compatibility as well as broad substrates scope with operational simplicity.
- Wang, Jianqiang,Shi, Fangmin,Dai, Dongyan,Xiong, Liping,Yang, Yongpo
-
supporting information
p. 439 - 443
(2021/02/03)
-
- Ceramic boron carbonitrides for unlocking organic halides with visible light
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Photochemistry provides a sustainable pathway for organic transformations by inducing radical intermediates from substrates through electron transfer process. However, progress is limited by heterogeneous photocatalysts that are required to be efficient, stable, and inexpensive for long-term operation with easy recyclability and product separation. Here, we report that boron carbonitride (BCN) ceramics are such a system and can reduce organic halides, including (het)aryl and alkyl halides, with visible light irradiation. Cross-coupling of halides to afford new C-H, C-C, and C-S bonds can proceed at ambient reaction conditions. Hydrogen, (het)aryl, and sulfonyl groups were introduced into the arenes and heteroarenes at the designed positions by means of mesolytic C-X (carbon-halogen) bond cleavage in the absence of any metal-based catalysts or ligands. BCN can be used not only for half reactions, like reduction reactions with a sacrificial agent, but also redox reactions through oxidative and reductive interfacial electron transfer. The BCN photocatalyst shows tolerance to different substituents and conserved activity after five recycles. The apparent metal-free system opens new opportunities for a wide range of organic catalysts using light energy and sustainable materials, which are metal-free, inexpensive and stable. This journal is
- Yuan, Tao,Zheng, Meifang,Antonietti, Markus,Wang, Xinchen
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p. 6323 - 6332
(2021/05/19)
-
- Synthesis and Reactivity Studies of a Series of Nickel(II) Arylchalcogenolates
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Two series of high-spin nickel complexes, [TpPh,Me]Ni(EAr) (E = O, Se, Te; Ar = C6H5) and [TpPh,Me]Ni(SeC6H4-4-X) (X = H, Cl, Me, OMe), were prepared by metathetical reaction of the nickel(II) halide precursor with sodium salts of the corresponding chalcogen, NaEAr. X-ray crystallographic characterization and spectroscopic studies have established the geometric and electronic structures of these complexes. The observed spectroscopic and structural characteristics reveal distinct trends in accordance with the variation of the identity of the arylchalcogenolate and para substituent. Reaction of the [TpPh,Me]Ni(EAr) complexes with methyl iodide proceeded readily, producing the corresponding methylarylchalcogen and [TpPh,Me]NiI. A kinetic and computational analysis of the reaction of [TpPh,Me]Ni(SeC6H5) with MeI supports that the electrophilic alkylation reactions occur via an associative mechanism via a classical SN2 transition state.
- Cordeiro, Lauren L.,Dmitrenko, Olga,Yap, Glenn P. A.,Riordan, Charles G.
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p. 6327 - 6338
(2021/05/06)
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- Nickel-Catalyzed Reversible Functional Group Metathesis between Aryl Nitriles and Aryl Thioethers
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We describe a new functional group metathesis between aryl nitriles and aryl thioethers. The catalytic system nickel/dcype is essential to achieve this fully reversible transformation in good to excellent yields. Furthermore, the cyanide- and thiol-free reaction shows high functional group tolerance and great efficiency for the late-stage derivatization of commercial molecules. Finally, synthetic applications demonstrate its versatility and utility in multistep synthesis.
- Delcaillau, Tristan,Boehm, Philip,Morandi, Bill
-
supporting information
p. 3723 - 3728
(2021/04/07)
-
- Trialkylammonium salt degradation: Implications for methylation and cross-coupling
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Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse. This journal is
- Assante, Michele,Baillie, Sharon E.,Juba, Vanessa,Leach, Andrew G.,McKinney, David,Reid, Marc,Washington, Jack B.,Yan, Chunhui
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p. 6949 - 6963
(2021/06/02)
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- Mechanistic Investigation of a Synthetic Route to Biaryls by the Sigmatropic Rearrangement of Arylsulfonium Species
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A comprehensive mechanistic investigation was conducted on the coupling reaction of aryl sulfoxides with phenols by using trifluoroacetic anhydride to yield biaryls. NMR experiments revealed that our previously proposed mechanism, which consists of a cascade of an interrupted Pummerer reaction and a rate-determining [3,3] sigmatropic rearrangement, is reasonable. The electronic effects of the substrates were also evaluated to elucidate the nature of the rearrangement step. Based on experimental observations and theoretical calculations, we conclude that the rearrangement is highly asynchronous and stepwise rather than concerted when electron-rich phenols are employed for the reaction.
- Yanagi, Tomoyuki,Yorimitsu, Hideki
-
supporting information
p. 13450 - 13456
(2021/08/23)
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- Synthesis of Aryl Methyl Sulfides from Arysulfonyl Chlorides with Dimethyl Carbonate as the Solvent and C1 Source
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A new procedure for the synthesis of aryl methyl sulfides from dimethyl carbonate (DMC) and arylsulfonyl chlorides has been achieved. In this strategy, DMC plays a dual role as both, C1 building block and green solvent. Arylsulfonyl chlorides served as the sulfur precursors, and a variety of aryl methyl sulfides were obtained in moderate to excellent yields with good functional group tolerance. Additionally, alkylsulfonyl chloride and dibenzyl carbonate are proven to be suitable substrates as well.
- Miao, Ren-Guan,Qi, Xinxin,Wu, Xiao-Feng
-
supporting information
p. 5219 - 5221
(2021/10/19)
-
- Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
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An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
- Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
-
supporting information
p. 8413 - 8418
(2021/11/01)
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- Palladium complex containing meta-position carborane triazole ligand and preparation method and application of palladium complex
-
The invention relates to a palladium complex containing a meta-position carborane triazole ligand and a preparation method and application of the palladium complex. The palladium complex is prepared by the following steps: (1) dropwise adding an n-BuLi solution into a meta-position carborane m-C2B10H12 solution, carrying out stirring and reacting, then adding 3-propargyl bromide for a reaction again, and after the reaction is finished, carrying out separating to obtain 1,3-dipropargyl meta-carborane; and (2) under the catalytic condition of a catalyst CuI, carrying out a reaction on 1,3-dipropargyl meta-carborane and aryl azide, then adding PdCl2 into a reaction system, continuing the reaction, and after the reaction is finished, carrying out separation to obtain the palladium complex containing the meta-carborane triazole ligand. Compared with the prior art, the preparation method provided by the invention is simple and green; the complex can efficiently catalyze a coupling reaction of mercaptan and halogenated hydrocarbon to synthesize thioether compounds; reaction conditions are mild, substrate universality is good, catalytic efficiency is high, and few byproducts are produced;and the catalyst has high stability and is not sensitive to air and water.
- -
-
Paragraph 0041-0043
(2020/08/07)
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- Gas-liquid-solid three-phase catalyzed S-Methylation of thiophenol with dimethyl carbonate in a fixed-bed reactor: Catalytic performances of activated alumina supported alkali metal carbonate catalysts
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The catalytic performances of activated alumina and its supported alkali metal carbonate catalysts for the reaction of thiophenol with dimethyl carbonate to prepare thioanisole (PhSMe) were investigated on a fixed bed reactor under the condition of atmospheric pressure. The properties of activated alumina and its loading alkali metal carbonate catalysts were characterized via IR, BET and XRD. The effect of loading amount of alkali metal carbonate, calcination temperature, reaction temperature and liquid volume hourly space velocity (LVHSV) of reactants on the catalytic performances of the catalysts was also examined. The yield of PhSMe was 93.5% when activated alumina was used as catalyst alone at 120 °C, however, the catalytic activities of the catalysts after loading 5-15 wt% K2CO3were greatly improved, and the yield of PhSMe was 99-100%. Compared to activated alumina, the catalytic performances of catalysts after loading different alkali metal carbonate are greatly improved. The improvement of catalytic performance can be attributed to that carbonate may occupy the Lewis acid sites of the activated alumina surface, making it easier for the catalyst to activate thiophenol, thus giving benzenethiolate a stronger nucleophilic attack ability. The results of FTIR analysis show that the characteristic peaks of carbonate are blue shifted, also indicating that carbonate reacted with the surface of activated alumina. The Lewis basic site on the surface of the activated alumina is believed to play a crucial role.
- Wu, Yuchen,Zhang, Fenghua,Li, Fei,Jiang, Heng,Wang, Rui,Gong, Hong
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p. 846 - 855
(2021/02/26)
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- Copper-Catalyzed Methylthiolation of Aryl Iodides and Bromides with Dimethyl Disulfide in Water
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An efficient route to aryl methyl sulfides through the copper-catalyzed coupling reaction of aryl iodides or bromides with dimethyl disulfide in water is described. Electron-donating and electron-withdrawing functional groups in the substrates were tolerated, and the corresponding products were obtained in moderate to good yields.
- Wang, Ying-Yu,Wu, Xiang-Mei,Yang, Ming-Hua
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supporting information
(2020/07/20)
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- Novel and facile procedure for the synthesis of Ni(II) and Pd(II) PSCOP pincer complexes. Evaluation of their catalytic activity on C-S, C-Se and C-C cross coupling reactions
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A new and facile procedure for the synthesis of non-symmetric phosphinito-thiophosphinito PSCOP pincer complexes based on Ni(II) and Pd(II) was developed. The synthesis of the complexes was carried out in a single step, starting from 3,3-dihydroxydiphenyldisulfide. The Ni(II) complexes were tested as catalysts in C-S and C-Se coupling reactions, being the tBu derivative 3-Ni the one exhibiting the best performance in both transformations. In this case, the sterics of the substrates was studied, showing that higher steric hindrance leads to lower yields. Analogously, the Pd(II) complexes were used as catalyst in Suzuki-Miyaura couplings of para-substituted bromobenzenes and phenyl boronic acid, being the analogous tBu derivative complex 3-Pd the best catalysts for this process, exhibiting tolerance to a wide range of functional groups.
- Valderrama-García, Bianca X.,Rufino-Felipe, Ernesto,Valdés, Hugo,Hernandez-Ortega, Simón,Aguilar-Castillo, Bethsy Adriana,Morales-Morales, David
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- Discovery and characterization of an acridine radical photoreductant
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Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
- MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
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- Palladium-catalyzed intermolecular transthioetherification of aryl halides with thioethers and thioesters
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Functional group transfer reactions are an important synthetic tool in modern organic synthesis. Herein, we developed a new palladium-catalyzed intermolecular transthioetherification reaction of aryl halides with thioethers and thioesters. The synthetic utility and practicality of this catalytic protocol are demonstrated in a wide range of successful transformations (>70 examples). This catalytic protocol is applicable in carbonylative coupling processes as well, and the first example of carbonylative methylthioesterification of aryl halides has been achieved. Notably, this work also provides an approach to using natural products, such as methionine and selenomethionine, as the functional group sources.
- Li, Yahui,Bao, Gao,Wu, Xiao-Feng
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p. 2187 - 2192
(2020/03/11)
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- Cobalt-Catalyzed Reductive Carboxylation of Aryl Bromides with Carbon Dioxide
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Cobalt-catalyzed reductive carboxylation of aryl bromides with carbon dioxide has been developed. The reaction proceeded under one atm pressure of CO2 at 40 °C in the presence of cobalt iodide/2,2′-bipyridine catalysts and zinc dust as a reducing reagent. Various aryl bromides could be converted to the corresponding carboxylic acids in good to high yields. Preliminary mechanistic experiments ruled out intervention of intermediate organozinc species for carboxylation with CO2, thus suggesting a direct CO2 insertion into the corresponding ArCoBr species. (Figure presented.).
- Hang, Wei,Yi, Yaping,Xi, Chanjuan
-
supporting information
p. 2337 - 2341
(2020/04/30)
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- K2S as Sulfur Source and DMSO as Carbon Source for the Synthesis of 2-Unsubstituted Benzothiazoles
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We describe a three-component reaction of o-iodoanilines with K2S and DMSO that provides 2-unsubstituted benzothiazoles in moderate to good isolated yields with good functional group tolerance. Electron-rich aromatic amines and o-phenylenediamines instead of o-iodoanilines provided 2-unsubstituted benzothiazoles and 2-unsubstituted benzimidazoles with and without K2S under similar conditions. Notably, DMSO plays three vital roles: carbon source, solvent, and oxidant.
- Deng, Guobo,Kuang, Daizhi,Liang, Yun,Yang, Yuan,Yu, Jiangxi,Zhang, Fuxing,Zhu, Xiaoming
-
supporting information
p. 3789 - 3793
(2020/06/04)
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- Exploiting the radical reactivity of diazaphosphinanes in hydrodehalogenations and cascade cyclizations
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The remarkable reducibility of diazaphosphinanes has been extensively applied in various hydrogenations, based on and yet limited by their well-known hydridic reactivity. Here we exploited their unprecedented radical reactivity to implement hydrodehalogenations and cascade cyclizations originally inaccessible by hydride transfer. These reactions feature a broad substrate scope, high efficiency and simplicity of manipulation. Mechanistic studies suggested a radical chain process in which a phosphinyl radical is generated in a catalytic cycle via hydrogen-atom transfer from diazaphosphinanes. The radical reactivity of diazaphosphinanes disclosed here differs from their well-established hydridic reactivity, and hence, opens a new avenue for diazaphosphinane applications in organic syntheses.
- Cheng, Jin-Pei,Yang, Jin-Dong,Zhang, Jingjing
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p. 4786 - 4790
(2020/06/18)
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- Design, synthesis and antiplasmodial evaluation of sulfoximine-triazole hybrids as potential antimalarial prototypes
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Background: Malaria, caused by the deadly Plasmodium falciparum strain, claims the lives of millions of people annually. The emergence of drug-resistant strains of P. falciparum to the artemisinin-based combination therapy (ACT), the last line of defense against malaria, is worrisome and urges for the development of new chemo-types with a new mode of action. In the search of new antimalarial agents, hybrids of triazoles and other known antimalarial drugs have been reported to possess better activity than either of the parent compounds administered individually. Despite their better activity, no hybrid antimalarial drugs have been developed so far. Objective: In the hope of developing new antimalarial prototypes, we propose the design, synthesis and antimalarial evaluation of novel sulfoximine-triazole hybrids owing to their interesting biological and physiological properties. Method: The sulfoximine part of the hybrid will be synthesized via imidation of the corresponding sulfoxide. Propargylation of the NH moiety of the sulfoximine followed by copper-catalyzed click chemistry with benzyl azide was envisaged to provide the target sulfoximine-triazole hybrids. Results: Five novel sulfoximine-triazole hybrids possessing various substituents on the sulfoximine moiety have been successfully synthesized and evaluated for their antiplasmodial and cytotoxicity activities. The results revealed that the co-presence of the sulfoximine and triazole moieties along with a lipophilic alkyl substituent on the sulfur atom impart significant activity. Conclusion: Sulfoximine-triazole hybrids could be used as a prototype for the synthesis of new derivatives with better antiplasmodial activities.
- Mabasa, Tommy Fredrick,Awe, Babatunde,Laming, Dustin,Kinfe, Henok Hadgu
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p. 683 - 690
(2019/08/30)
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- A Manganese N-Heterocyclic Carbene Catalyst for Reduction of Sulfoxides with Silanes
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The first reduction of sulfoxides catalysed by a well-defined manganese complex is described. A variety of sulfoxides are reduced to the corresponding sulfides in high yields using phenylsilane, diphenylsilane, and the economically feasible 1,1,3,3-tetramethyldisiloxane (TMDS) as reducing agents in the presence of a Mn-NHC complex. The reaction is performed under air and without the need of any additive. The involvement of radicals in the catalytic reaction is probed by spin-trap experiments.
- Sousa, Sara C. A.,Carrasco, Carlos J.,Pinto, Mara F.,Royo, Beatriz
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p. 3839 - 3843
(2019/06/24)
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- Visible-light-promoted organic dye-catalyzed sulfidation and phosphorylation of arylhydrazines toward aromatic sulfides and diarylphosphoryl hydrazides
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Visible-light-promoted sulfidation and phosphorylation of arylhydrazines for the synthesis of aromatic sulfides and diarylphosphoryl hydrazides were developed using the organic dyes rose bengal and Na2-eosin Y as photocatalysts, respectively. This strategy offers an efficient and mild transition-metal-free synthetic protocol for the formation of C-S and N-P bonds from arylhydrazines.
- Li, Rui,Shi, Tao,Chen, Xiao-Lan,Lv, Qi-Yan,Zhang, Yin-Li,Peng, Yu-Yu,Qu, Ling-Bo,Yu, Bing
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supporting information
p. 13642 - 13646
(2019/09/06)
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- Transition-Metal-Free Aryl-Heteroatom Bond Formation via C-S Bond Cleavage
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Aryl-heteroatom bonds (C-Het) are almost ubiquitously present in chemical molecules. However, methods for diverse C-Het bond formations from a simple substrate are limited. Herein, we report a convenient and efficient C-S bond transformation of aryl sulfoniums to various C-Het bonds (C-O, C-S, C-Sn, C-Si, C-Se) in the absence of any transition-metal catalyst. These reactions proceeded in mild conditions with a wide substrate scope.
- Zhao, Jian-Nan,Kayumov, Muzaffar,Wang, Dong-Yu,Zhang, Ao
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supporting information
p. 7303 - 7306
(2019/10/02)
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- Visible light-promoted formation of C-B and C-S bonds under metal- A nd photocatalyst-free conditions
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A green, efficient, photoinduced synthesis of arylboronic esters and aryl sulfides has been developed. Bench stable arylazo sulfones were used as radical precursors for a photocatalyst- A nd additive-free carbon-heteroatom bond formation under visible light. The protocols are applicable to a wide range of substrates, providing products in good yields.
- Blank, Lena,Fagnoni, Maurizio,Protti, Stefano,Rueping, Magnus
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p. 1243 - 1252
(2019/02/26)
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- Transalkylation of alkyl aryl sulfides with alkylating agents
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The reaction of methyl iodide with tert-butylphenylsulfide in DMF leads to a transalkylation that produces methylphenylsulfide. This transalkylation reaction was further studied by 1H NMR spectroscopy. The polarity of the solvent, the electron density on the sulfur atom, and the strength of the alkylating agent (MeI, EtI, BuI, dimethyl sulfate, or dimethyl carbonate) played important roles in the reaction. The suggested mechanism of the reaction involves the formation of a dialkyl aryl sulfonium salt that subsequently eliminates the radical. This mechanism was supported by the observation of higher conversion rates for compounds with more branched alkyl groups on the sulfur atom, which may lead to the formation of more stable radicals.
- Nawrot, Daria,Koleni?, Marek,Kune?, Ji?í,Kostelansky, Filip,Miletin, Miroslav,Novakova, Veronika,Zimcik, Petr
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p. 594 - 599
(2018/01/01)
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- Preparation method of clean and environment-friendly phenyl methyl thioether
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The invention relates to a novel method for preparing phenyl methyl thioether. In a temperature range of 110 to 130 DEG C, thiophenol or sodium benzene sulfide is used as a raw material, alkaline substance Y-type zeolite is used as a catalyst, an appropriate amount of surfactant is added, under a specific condition, DMC is used for substituting the toxic DMS which is restricted to use, the reaction yield reaches 96 percent, and the quality of the prepared phenyl methyl thioether can meet the requirement.
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Paragraph 0024; 0025; 0026; 0027; 0028; 0029
(2018/12/13)
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- Application of Silicon-Initiated Water Splitting for the Reduction of Organic Substrates
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The use of water as a donor for hydrogen suitable for the reduction of several important classes of organic compounds is described. It is found that the reductive water splitting can be promoted by several metalloids among which silicon shows the best efficiency. The developed methodologies were applied for the reduction of nitro compounds, N-oxides, sulfoxides, alkenes, alkynes, hydrodehalogenation as well as for the gram-scale synthesis of several substrates of industrial importance.
- Gevorgyan, Ashot,Mkrtchyan, Satenik,Grigoryan, Tatevik,Iaroshenko, Viktor O.
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p. 375 - 382
(2018/06/04)
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- NITROGEN-CONTAINING BIOPOLYMER-BASED CATALYSTS, THEIR PREPARATION AND USES IN HYDROGENATION PROCESSES, REDUCTIVE DEHALOGENATION AND OXIDATION
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The present invention relates to a process for the preparation of a nitrogen containing biopolymer-based catalyst by pyrolysis of a metal complex with a nitrogen-containing biopolymer and to the nitrogen containing biopolymer-based catalysts obtainable by this process. In particular, the invention relates to a nitrogen containing biopolymer-based catalyst comprising metal particles and at least one nitrogen containing carbon layer. The invention also relates to the use of a nitrogen containing biopolymer-based catalyst in a hydrogenation process, preferably in a process for hydrogenation of nitroarenes, nitriles or imines; in a reductive dehalogenation process of C-X bonds, wherein X is CI, Br or I, preferably in a process for dehalogenation of organohalides or in a process for deuterium labelling of arenes via dehalogenation of organohalides; or in an oxidation process. Further, the invention relates to a metal complex with the nitrogen containing biopolymer, wherein the metal is a transition metal selected from the group consisting of manganese, ruthenium, cobalt, rhodium, nickel, palladium and platinum, preferably cobalt or nickel, and wherein the nitrogen containing biopolymer is selected from chitosan, chitin and a polyamino acid, preferably chitosan or chitin.
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Page/Page column 19
(2018/07/29)
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- METHOD FOR PRODUCING SULFIDE
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PROBLEM TO BE SOLVED: To provide a method that performs a deoxygenation reaction of a sulfoxide using hydrogen as a reductant, and produces a corresponding sulfide. SOLUTION: A method for producing a sulfide is characterized by performing a deoxygenation reaction of a sulfoxide in the presence of a platinum-carrying molybdenum trioxide catalyst in which a platinum particle is immobilized to a molybdenum trioxide, and hydrogen, to obtain a corresponding sulfide. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPO&INPIT
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-
Paragraph 0075-0078; 0083
(2018/06/07)
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- Water-soluble NNN-pincer complexes of cobalt, nickel and palladium: Solid-state structures and catalytic activity
-
Neutral NNN-pincer ligand 1 based on a pyridyl core and cyclic amidine pendant arms was synthesized via a straightforward condensation reaction. Its square-planar palladium acetate complex 2 was prepared in methanol and featured a cyclic, hexameric solid-state structure assembled through moderately strong N?H?O hydrogen bonds involving the ligand backbone and the non-coordinated acetate group. The octahedral, diamagnetic Co(III) complex 3 was prepared via in-situ air oxidation of its Co(II) analog. Its solid-state structure confirmed the oxidation state of the metal and revealed the presence of weak bridging and terminal N–H?Cl hydrogen bonds. Paramagnetic nickel complex 4 was prepared in a similar fashion to 1 and was postulated to have a covalent attachment of the acetate moieties to the metal. Derivatives 2 and 3 had excellent water solubility and stability while 4 was sparingly soluble in water. Cyclic voltammetry revealed electrochemically reversible electron transfer steps corresponding to the Co(II)/Co(III) and Ni(II)/Ni(III) redox couples at ?0.31 V and 1.04 V versus SHE, respectively. Complex 4 displayed catalytic competency towards the thiolation of iodobenzene with dimethyldisulfide and zinc in DMF. In water, 4 was able to catalyze the Negishi cross-coupling of iodobenzene.
- Heidebrecht, Joshua,Gendy, Chris,Gelfand, Benjamin S.,Roesler, Roland
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p. 138 - 143
(2017/10/12)
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- SPS–Ni(II) pincer compounds of the type [Ni(phPS2)(P(C6H4-4-R)3)] Synthesis, characterization and catalytic evaluation in C–S cross-coupling reactions
-
The synthesis and characterization of a series of SPS–Ni(II) pincer complexes with different para-substituted triphenylphosphines has been performed. The molecular structure of [Ni(phPS2)(PPh3)] (1) (phPS2H2 = PhP(C6H4-2-SH)2, bis(phenyl-2-thiol)phenylphosphine) was unequivocally determined by single crystal X-ray diffraction analysis. The metal centre exhibited a slightly distorted square planar geometry. The complexes showed a high catalytic activity in the C–S cross-coupling reaction of both alkyl- and aryl-disulfides with iodobenzenes for the production of non-symmetric sulfides. In general, the different para-substituted triphenylphosphine ligands do not affect the catalytic performance of the SPS–Ni(II) complexes. However, activity of the catalyst decreases with the steric hindrance of the different alkyl groups in the disulphide substrates.
- Gómez-Benítez, Valente,Valdés, Hugo,Hernández-Ortega, Simón,Germán-Acacio, Juan Manuel,Morales-Morales, David
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p. 144 - 148
(2017/10/13)
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- Aryl sulfoxide, thioether compound, synthesis method and application thereof
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The invention discloses a method for selective synthesis of an aryl sulfoxide compound (III) and an aryl thioether compound (IV). According to the invention, in a reactive solvent, an aryl high iodinesalt is adopted as the reaction raw material, aryl/alkyl thiosulfate is taken as the vulcanizing reagent, under the catalysis of visible light and a photosensitive reagent, and under the action of lewis acid and alkali, when the reaction atmosphere is nitrogen, the thioether compound (IV) can be generated, and when the reaction atmosphere is air, the sulfoxide compound (III) can be generated. Thesynthesis method provided by the invention has the advantages of easily available and cheap raw materials, simple reaction operation, mild and environment-friendly reaction conditions, high yield, and excellent functional group tolerance. The invention also discloses the new aryl sulfoxide compound (III) and aryl thioether compound (IV), also successfully realizes later modification of drugs andsugar, and realizes the formal synthesis of some drugs, and provides an efficient method for selective construction of thioether and sulfoxide compounds.
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Paragraph 0189-0192
(2018/04/21)
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- Biocatalytic Preparation of Chiral Sulfoxides through Asymmetric Reductive Resolution by Methionine Sulfoxide Reductase A
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Here we report an environmentally friendly method for the preparation of chiral sulfoxides under high substrate concentration using recombinant methionine sulfoxide reductase A from Pseudomonas monteilii (pmMsrA) as a biocatalyst. Our results show that this enzyme can effectively accomplish the preparation of (R)-sulfoxides with approximately 50 % yield and 94–99 % enantiomeric excess through asymmetric reductive resolution of racemic sulfoxide. With the establishment of the enzyme regeneration system, the initial substrate concentration could be increased 40–100 times compared to our original report. The (R)-sulfoxides were obtained with high enantioselectivity under the substrate concentration up to 200 mm (approximately 32 g L?1), representing a quite high substrate concentration in biocatalytic preparation of chiral sulfoxides. Moreover, this system showed fairly good activity and enantioselectivity towards a series of ortho- and para-substituted phenyl methyl sulfoxides under high substrate concentration.
- Peng, Liaotian,Wen, Yuanmei,Chen, Yu,Yuan, Zhimei,Zhou, Yang,Cheng, Xiaoling,Chen, Yongzheng,Yang, Jiawei
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p. 3284 - 3290
(2018/06/04)
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- Investigation of the Nucleophilic Attack of Dichlorvos by Reduced Sulfur Species Using 1H NMR
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The mechanism of the reaction of dichlorvos through hydrolysis reactions and through the reaction with polysulfide (Sn2-) and thiophenolate (PhS-) was investigated by proton nuclear magnetic resonance (1H NMR). The study confirmed product identities of an organophosphorus insecticide reacting with reduced sulfur species using 1H NMR in oxygen sensitive solutions. The experiments of dichlorvos with polysulfide led to the detection of a previously undetected product. The thiophenolate experiments were further advanced to investigate second-order rate kinetics using an internal standard. The experiments provide new evidence for a nucleophilic attack by the reduced sulfur species at the methoxy carbon of dichlorvos. In addition, the observation of in situ reaction dynamics illustrates the applicability of 1H NMR spectroscopy toward kinetic investigations in environmental science.
- Christian, Saumil,Pradhan, Padmanava,Jans, Urs
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p. 424 - 431
(2018/01/26)
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- A catalyst-free and additive-free method for the synthesis of benzothiazolethiones from: O -iodoanilines, DMSO and potassium sulfide
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Under catalyst-free and additive-free conditions, a novel, convenient, eco-friendly method for the synthesis of benzothiazolethiones has been developed. The three-component reaction of o-iodoanilines and K2S with DMSO proceeded smoothly and the corresponding benzothiazolethiones were obtained with good isolated yields. Meanwhile, this method could be used for the synthesis of thioureas from primary diamines. Furthermore, mechanism research showed that DMSO not only functioned as a carbon source, but also as a mild oxidant in this reaction.
- Zhu, Xiaoming,Li, Wenguang,Luo, Xiai,Deng, Guobo,Liang, Yun,Liu, Jianbing
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supporting information
p. 1970 - 1974
(2018/05/23)
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- Palladium-Catalyzed Reductive Conversion of Acyl Fluorides via Ligand-Controlled Decarbonylation
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Ligand-controlled non-decarbonylative and decarbonylative conversions of acyl fluorides were developed using a Pd(OAc)2/Et3SiH combination. When tricyclohexylphosphine (PCy3) was used as the ligand, aldehydes were obtained as simple reductive conversion products. The use of 1,2-bis(dicyclohexylphosphino)ethane (Cy2P(CH2)2PCy2, DCPE) as the ligand, however, favored the formation of hydrocarbons, which are decarbonylative reduction products.
- Ogiwara, Yohei,Sakurai, Yuka,Hattori, Hiroyuki,Sakai, Norio
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supporting information
p. 4204 - 4208
(2018/07/29)
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- Cesium carbonate-promoted synthesis of aryl methyl sulfides using: S -methylisothiourea sulfate under transition-metal-free conditions
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In the presence of cesium carbonate, an efficient synthesis of aryl methyl sulfides by the reactions of aryl halides with commercially available S-methylisothiourea sulfate is developed. This odourless and highly crystalline solid can be used as the subst
- Zhang, Caiyang,Zhou, You,Huang, Jintao,Tu, Canhui,Zhou, Xiaoai,Yin, Guodong
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p. 6316 - 6321
(2018/09/10)
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- Enantioselective copper catalysed intramolecular C-H insertion reactions of α-diazo-β-keto sulfones, α-diazo-β-keto phosphine oxides and 2-diazo-1,3-diketones; the influence of the carbene substituent
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Enantioselectivities in C-H insertion reactions, employing the copper-bis(oxazoline)-NaBARF catalyst system, leading to cyclopentanones are highest with sulfonyl substituents on the carbene carbon, and furthermore, the impact is enhanced by increased steric demand on the sulfonyl substituent (up to 91%ee). Enantioselective intramolecular C-H insertion reactions of α-diazo-β-keto phosphine oxides and 2-diazo-1,3-diketones are reported for the first time.
- Shiely, Amy E.,Slattery, Catherine N.,Ford, Alan,Eccles, Kevin S.,Lawrence, Simon E.,Maguire, Anita R.
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supporting information
p. 2609 - 2628
(2017/04/01)
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- Rapid and efficient deoxygenation of sulfoxides to sulfides with tantalum(V) chloride/sodium iodide system
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TaCl5/NaI system converts a wide range of sulfoxides to the corresponding sulfides in high yields with short reaction times, under mild conditions. It is worth mentioning that this protocol is chemoselective and tolerates various functional groups (such as –Br, –Cl, –OCH3, –CHO, and –NO2) and double bond.
- Yoo, Byung Woo,Park, Jeeyeon,Shin, Hyo Jong,Yoon, Cheol Min
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p. 597 - 603
(2017/10/06)
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- Metal-Free Reduction of Phosphine Oxides, Sulfoxides, and N-Oxides with Hydrosilanes using a Borinic Acid Precatalyst
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The general reduction of phosphine oxides, sulfoxides, and amine N-oxides was achieved by combining bis(2-chlorophenyl)borinic acid with phenylsilane. The reaction was shown to tolerate a wide range of substrates and could be performed under mild conditions, with only 2.5 mol % of the easily synthesized catalyst. Mechanistic investigations pointed to a key borohydride as the real catalyst and at bis(2-chlorophenyl)borinic acid as a precatalyst.
- Chardon, Aurélien,Maubert, Orianne,Rouden, Jacques,Blanchet, Jér?me
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p. 4460 - 4464
(2017/11/22)
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- B(C 6 F 5) 3 -Catalyzed Reduction of Sulfoxides and Sulfones to Sulfides with Hydrosilanes
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B(C 6 F 5) 3 is shown to catalyze the deoxygenation of sulfoxides and sulfones to the corresponding sulfides with Et 3 SiH as the stoichiometric hydride source. While the method is limited in terms of functional group tolerance, it is applicable to the reduction of alkyl/aryl-, aryl/aryl-, and alkyl/alkyl-substituted sulfoxides, including the benzyl/benzyl-substituted derivative. The same protocol converts alkyl/aryl- but not aryl/aryl-substituted sulfones into sulfides.
- Porwal, Digvijay,Oestreich, Martin
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p. 4698 - 4702
(2017/10/05)
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- B(C6F5)3-Catalyzed Deoxygenation of Sulfoxides and Amine N-Oxides with Hydrosilanes
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An efficient strategy for the deoxygenation of sulfoxides and amine N-oxides by using B(C6F5)3 and hydrosilanes was developed. This method provided the corresponding aromatic and aliphatic products in good to high yields and showed good functional-group tolerance under mild conditions.
- Ding, Fangwei,Jiang, Yanqiu,Gan, Shaoyan,Bao, Robert Li-Yuan,Lin, Kaifeng,Shi, Lei
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p. 3427 - 3430
(2017/07/04)
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- Radical Hydrodehalogenation of Aryl Bromides and Chlorides with Sodium Hydride and 1,4-Dioxane
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A practical method for radical chain reduction of various aryl bromides and chlorides is introduced. The thermal process uses NaH and 1,4-dioxane as reagents and 1,10-phenanthroline as an initiator. Hydrodehalogenation can be combined with typical cyclization reactions, proving the nature of the radical mechanism. These chain reactions proceed by electron catalysis. DFT calculations and mechanistic studies support the suggested mechanism.
- Hokamp, Tobias,Dewanji, Abhishek,Lübbesmeyer, Maximilian,Mück-Lichtenfeld, Christian,Würthwein, Ernst-Ulrich,Studer, Armido
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supporting information
p. 13275 - 13278
(2017/10/09)
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- A Biomass-Derived Non-Noble Cobalt Catalyst for Selective Hydrodehalogenation of Alkyl and (Hetero)Aryl Halides
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Hydrodehalogenation is a straightforward approach for detoxifications of harmful anthropogenic organohalide-based pollutants, as well as removal of halide protecting groups used in multistep syntheses. A novel sustainable catalytic material was prepared from biowaste (chitosan) in combination with an earth-abundant cobalt salt. The heterogeneous catalyst was fully characterized by transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy measurements, and successfully applied to hydrodehalogenation of alkyl and (hetero)aryl halides with broad scope (>40 examples) and excellent chemoselectivity using molecular hydrogen as a reductant. The general usefulness of this method is demonstrated by successful detoxification of non-degradable pesticides and fire retardants. Moreover, the potential of the catalyst as a deprotection tool is demonstrated in a multistep synthesis of (±)-peronatin B (alkaloid).
- Sahoo, Basudev,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
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supporting information
p. 11242 - 11247
(2017/09/02)
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- Copper nanoparticles supported on polyaniline-functionalized multiwall carbon nanotubes: An efficient and recyclable catalyst for synthesis of unsymmetric sulfides using potassium ethyl xanthogenate in water
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A new and powerful polyaniline-functionalized carbon nanotube-supported copper(II) nanoparticle catalyst was successfully prepared and evaluated as a heterogeneous catalyst for the one-pot synthesis of unsymmetric thioethers by coupling of aryl, alkyl and benzyl halides using potassium ethyl xanthogenate as source of sulfur in water. All of these reactions gave the desired products in good to excellent yields. The catalyst is available, air-stable and can be reused several times without significant loss in its catalytic activity.
- Hajipour, Abdol R.,Jajarmi, Saeideh,Khorsandi, Zahra
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- A Convenient, Mild, and Green Synthesis of NH-Sulfoximines in Flow Reactors
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NH-sulfoximines are emerging as useful and important targets in drug discovery and synthetic organic chemistry. We report herein the development of an efficient, convenient, and sustainable continuous-flow strategy, for the direct, straightforward preparation of NH-sulfoximines by using sulfides or sulfoxides as suitable starting material. The flow process uses PhI(OAc)2 as the oxidant and aqueous solutions of ammonia as the N source. The scope of the reaction has been demonstrated by using several substituted sulfides and sulfoxides including enantioenriched and biologically relevant starting materials. The flow strategy was found to be more convenient with respect to conventional batch processing.
- Degennaro, Leonardo,Tota, Arianna,De Angelis, Sonia,Andresini, Michael,Cardellicchio, Cosimo,Capozzi, Maria Annunziata,Romanazzi, Giuseppe,Luisi, Renzo
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supporting information
p. 6486 - 6490
(2017/09/13)
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- Supercritical thioanisole synthesis method by using chloromethane
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The invention relates to a method of synthesizing thioanisole by using chloromethane as a methylating reagent, in particular to a method comprising the following steps that thiophenol sodium and chloromethane are used as raw materials; in a high-pressure reaction vessel, the chloromethane takes a contact reaction with the thiophenol sodium in a supercritical state, wherein the mol ratio of the thiophenol sodium to the chloromethane is 1:1 to 1:10, the reaction temperature is 145 DEG C to 300 DEG C, the reaction pressure is 6.7 to 25 MPa, and the reaction time is 1 to 15 hours; after the reaction is completed, water is used for washing a reaction mixture; an oil phase is collected; reduced pressure distillation is performed; fraction (10mmHg, 67 to 69 DEG C) is collected.
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Paragraph 0025; 0026; 0027; 0028; 0029; 0030; 0031-0033
(2017/04/03)
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