- Template Effects of a Clay-Chelate Adduct on the Asymmetric Oxidation of Alkyl Phenyl Sulphide by Sodium Metaperiodate
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Cyclohexyl phenyl sulphide adsorbed by Δ-tris(1,10-phenanthroline)nickel(II)-montmorillonite was oxidized by sodium metaperiodate at 25 deg C in water to give (S)-cyclohexyl phenyl sulphoxide with an optical purity of 78percent.
- Yamagishi, Akihiko
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- Rates and mechanism of the stoichiometric oxidations of organic sulphides to sulphoxides with the peroxomolybdenum complex MoO(O2)2HMPT
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Stoichiometric oxidations of various organic sulfides were performed in 1,2-dichloroethane at -15°C with the oxodiperoxocomplex MoO(O2)2-HMPT in the absence and in the presence of Hg(OCOCF3)2. The oxidation cata
- Ballistreri, Francesco Paolo,Failla, Salvatore,Spina, Emanuela,Tomaselli, Gaetano Andrea
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- Nitrogen donor-controlled chemoselectivity of reaction in oxidation of sulfides with tetra-n-butylammonium hydrogen monopersulfate catalyzed by a partially β-brominated meso-tetraphenylporphyrinatomanganese(III) acetate: A clue to the nature of active oxidant
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Highly efficient and rapid oxidation of different sulfides to the corresponding sulfones with tetra-n- butylammonium hydrogen monopersulfate (TBAO) in the presence of catalytic amounts of Mn(TPPBr2)OAc at room temperature is reported. Contrary to other nitrogen donors, using 4-cyanopyridine as co-catalyst leads to an increase in the ratio of sulfoxide to sulfone in the products. Comparison of the chemoselectivity of reaction in the presence of different nitrogen donors as co-catalyst shows the involvement of a high-valent Mn-oxo species as well as the six-coordinate Mn(TPPBr2)(HSO5)(B) (B = nitrogen donors) complex in sulfide oxidation reactions with TBAO.
- Rayati, Saeed,Zakavi, Saeed,Noroozi, Vahid
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- Effects of the environment on microperoxidase-11 and on its catalytic activity in oxidation of organic sulfides to sulfoxides
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Microperoxidase-11 (MP-11, also known as heme undecapeptide of cytochrome c) was immobilized by encapsulation into sol-gel silica glass and by physisorption, chemisorption, and covalent attachment to silica gel. We then compared these species with one ano
- Kadnikova, Ekaterina N.,Kostic, Nenad M.
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- A mononuclear nonheme cobalt(III)-hydroperoxide complex with an amphoteric reactivity in electrophilic and nucleophilic oxidative reactions
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A mononuclear nonheme cobalt(iii)-hydroperoxide complex bearing a tetramethylated cyclam ligand, [(12-TMC)CoIII(OOH)]2+, was synthesized and characterized spectroscopically and computationally; the cobalt(iii)-hydroperoxide complex exhibited an amphoteric reactivity in electrophilic and nucleophilic oxidative reactions.
- Tcho, Woon-Young,Wang, Bin,Lee, Yong-Min,Cho, Kyung-Bin,Shearer, Jason,Nam, Wonwoo
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- Catalytic Asymmetric Oxidation of Sulfides to Sulfoxides with tert-Butyl Hydroperoxide Using Binaphthol as a Chiral Auxiliary
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The asymmetric oxidation of sulfides to chiral sulfoxides in moderate yield with tert-butyl hydroperoxide (TBHP) was catalyzed very effectively by a titanium complex produced in situ from a titanium alkoxide and a chiral binaphthol.The highest enantioselectivities (up to 96percent ee) were obtained with commercial aqueous 70percent TBHP under atmospheric conditions at 25 deg C with 2.5 mol percent of the catalyst.The presence of more than 1.0 mol equiv of water relative to sulfide was essential for the oxidation, and it was found that the water was necessary not only to produce an effective catalyst for the highly enantioselective oxidation but also to maintain the catalytic activity of the titanium-binaphthol complex for a longer time.The nature of the solvent had a remarkable effect upon the ee of the sulfoxide.Carbon tetrachloride was proven to be the solvent of choice; the use of other chlorinated solvents resulted in low enantioselectivity.A moderate level of asymmetric amplification was observed in this catalytic system.From a mechanistic standpoint, it was revealed that the initial asymmetric oxidation to the chiral sulfoxide (ca. 50percent ee) is followed by the kinetic resolution of the sulfoxide; that is, the titanium-binaphthol complex catalyzes not only the asymmetric oxidation but also the subsequent kinetic resolution.
- Komatsu, Naoki,Hashizume, Masaya,Sugita, Toshio,Uemura, Sakae
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- Do trinuclear triplesalen complexes exhibit cooperative effects? Synthesis, characterization, and enantioselective catalytic sulfoxidation by chiral trinuclear FeIII triplesalen complexes
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The chiral triplesalen ligand H6chand provides three chiral salen ligand compartments in a meta-phenylene arrangement by a phloroglucinol backbone. The two diastereomeric versions H6chand RR and H 6chand rac have been used to synthesize the enantiomerically pure chiral complex [(FeCl)3-(chand RR)] (3 RR) and the racemic complex [(FeCl)3(chand rac)] (3 rac). The molecular structure of the free ligand H6chand rac exhibits at the terminal donor sides the O-protonated phenol-imine tautomer and at the central donor sides the N-protonated keto-enamine tautomer. The trinuclear complexes are comprised of five-coordinate square-pyramidal Fe III ions with a chloride at the axial positions. The crystal structure of 3 rac exhibits collinear chiral channels of ~11 A in diameter making up 33.6 % of the volume of the crystals, whereas the crystal structure of 3 RR exhibits voids of 560 A 3. Moessbauer spectroscopy demonstrates the presence of Fe III high-spin ions. UV/Vis spectroscopy is in accordance with a large delocalized system in the central backbone evidenced by strong low-energy shifts of the imine π-π * transitions relative to that of the terminal units. Magnetic measurements reveal weak intramolecular exchange interactions but strong magnetic anisotropies of the Fe III ions. Complexes 3 rac and 3 RR are good catalysts for the sulfoxidation of sulfides providing very good yields and high selectivities with 3 RR being enantioselective. A comparison of 3 RR and [FeCl-(salen')] provides higher yields and selectivities but lower enantiomeric excess values (ee values) for 3 RR relative to [FeCl(salen')]. The low ee values of 3 RR appeared to be connected to a strong ligand folding in 3 RR, opening access to the catalytically active high-valent Fe-O species. The higher selectivity is assigned to a cooperative stabilization of the catalytically active high-valent Fe-O species through the phloroglucinol backbone in the trinuclear complexes.
- Mukherjee, Chandan,Stammler, Anja,Boegge, Hartmut,Glaser, Thorsten
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- Ni(II) and V(IV) Schiff base complexes derived from 2,2′-dimethylpropandiamine: the crystal structure, electrochemical properties and catalytic activities in oxidation of sulfides
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Tetradentate Schiff base (H2L) derived from 2,2′-dimethylpropandiamine and its nickel(II) and oxo-vanadium(IV) complexes (NiL, VOL) have been prepared and characterized. The crystal structure of NiL has been determined. The reported structure c
- Rayati, Saeed,Khodaei, Elham,Jafarian, Majid,Bahrami, Arezo,Wojtczak, Andrzej,Kozakiewicz, Anna
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- Synthesis, structural studies, and oxidation catalysis of the late-first-row-transition-metal complexes of a 2-pyridylmethyl pendant-armed ethylene cross-bridged cyclam
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The first 2-pyridylmethyl pendant-armed ethylene cross-bridged cyclam ligand has been synthesized and successfully complexed to Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+ cations. X-ray crystal structures were obtained for all six complexes and demonstrate pentadentate binding of the ligand with the requisite cis-V configuration of the cross-bridged cyclam ring in all cases, leaving a potential labile binding site cis to the pyridine donor for interaction of the complex with oxidants and/or substrates. The electronic properties of the complexes were evaluated using solid-state magnetic moment determination and acetonitrile solution electronic spectroscopy, which both agree with the crystal structure determination of high-spin divalent metal complexes in all cases. Cyclic voltammetry in acetonitrile revealed reversible redox processes in all but the Ni2+ complex, suggesting that catalytic reactivity involving electron-transfer processes is possible for complexes of this ligand. Kinetic studies of the dissociation of the ligand from the copper(II) complex under strongly acidic conditions and elevated temperatures revealed that the pyridine pendant arm actually destabilizes the complex compared to the parent cross-bridged cyclam complex. Screening for oxidation catalysis using hydrogen peroxide as the terminal oxidant for the most biologically relevant Mn2+, Fe2+, and Cu2+ complexes identified the Mn2+ complex as a potential mild oxidation catalyst worthy of continued development.
- Jones, Donald G.,Wilson, Kevin R.,Cannon-Smith, Desiray J.,Shircliff, Anthony D.,Zhang, Zhan,Chen, Zhuqi,Prior, Timothy J.,Yin, Guochuan,Hubin, Timothy J.
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- Direct evidence for oxygen-atom exchange between nonheme oxoiron(IV) complexes and isotopically labeled water
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Rates of exchange: Evidence that non-heme oxoiron(IV) complexes exchange their oxygen atoms with H218O was obtained for the first time, by monitoring electrospray ionization mass spectral changes of the oxoiron(IV) species. The oxyge
- Seo, Mi Sook,In, Jun-Hee,Kim, Sun Ok,Oh, Na Young,Hong, Jongki,Kim, Jinheung,Que Jr., Lawrence,Nam, Wonwoo
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- Synthesis and Characterization of Glucose Derived Dioxo-molybdenum (VI) Complexes and Their Application in Sulphide Oxidation
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Three new molybdenum (VI) complexes of 4,6-O-ethylidene-β-D-glucopyranosylamine derived ligands has been synthesized and the same has been used in the oxidation of thioanisole along with an earlier reported analogous complex. A selective oxidation of thio
- Sah, Ajay K.,Baig, Noorullah
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- Chiral ionic liquids for catalytic enantioselective sulfide oxidation
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A new class of catalytic ionic liquids, containing chiral tungstate(VI) anions, gives enantiomeric excesses up to 96% for sulfide oxidation to sulfoxides.
- Bigi, Franca,Nimal Gunaratne,Quarantelli, Carla,Seddon, Kenneth R.
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- Titanium(IV)-salan catalysts for asymmetric sulfoxidation with hydrogen peroxide
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We report the synthesis and the solution and solid-phase characterization of several titanium(IV)-salan complexes. The structures of the ligands H 2sal(R,R-chan), H2ovan(S,S-chan), and H 6pyr(R,R-chan)4+·4Cl-·H 2O were determined by single-crystal X-ray diffraction and their main features are compared and discussed. Single crystals suitable for X-ray diffraction studies were also obtained for [Ti4{sal(R,R-chan)} 4(μ-O)4] and showed a tetranuclear core bearing μ-oxo bridges between the titanium atoms and the ligand wrapped around the Ti in a fac-mer geometry. The Ti-salan complexes were tested as catalysts in the benchmark oxidation of thioanisole with H2O2 as oxidant in organic solvents. High H2O2 conversion and moderate enantioselectivities (up to 51 % ee) were obtained. In an effort to perform greener catalysis the complexes were tested in selected ionic liquids with several oxidants. [Ti{5-MeO-sal(R,R-chan)}] was also covalently bound to a polystyrene matrix. tert-Butyl hydroperoxide was found to be the most suitable oxidant for use in ionic liquids (100 % conversion vs. 80 % with H 2O2) and in general the Ti-salan complexes showed better activity in ILs at 25 °C although with reduced induced asymmetry (up to 18 % ee). The solution and solid-phase characterization of several titanium(IV)-salan complexes is reported. The Ti-salan complexes were tested as catalysts in the benchmark oxidation of thioanisole with several oxidants in organic solvents and ionic liquids. The best catalyst bears no substituents on the aromatic groups and tert-butyl hydroperoxide is the most suitable oxidant for use in ILs. Copyright
- Adao, Pedro,Avecilla, Fernando,Bonchio, Marcella,Carraro, Mauro,Costa Pessoa, Joao,Correia, Isabel
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- α-Fluorination of Sulfoxides Bearing α-Hydrogens by Molecular Fluorine. A Novel Method for the Synthesis of α-Fluorosulfones
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Direct formation of α-fluorosulfones from sulfoxides bearing α-hydrogens merely by reacting molecular fluorine (5percent F2/N2) is reported and a possible mechanism for this novel α-fluorination reaction is proposed.
- Chiba, Jun,Sugihara, Takumichi,Kaneko, Chikara
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- New metal complexes supported on Fe3O4 magnetic nanoparticles as recoverable catalysts for selective oxidation of sulfides to sulfoxides
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Fe3O4 nanoparticles were coated with aminopropyltriethoxysilane and subsequently reacted with isatin to obtain imine-bonded Fe3O4 nanoparticles. The addition of ZrOCl2·8H2O or CuCl2 led to the formation of complexes of Zr(IV)/isatin@Fe3O4 or Cu (II)/isatin@Fe3O4 as new magnetically separable catalysts. The synthesized catalysts were characterized using various techniques. These catalysts are shown to be efficient for chemo-selective oxidation of sulfides to sulfoxides using hydrogen peroxide as oxidative agent. This system has many advantages, such as excellent level of reusability of magnetic catalysts, high yields, simplicity of separation of catalysts using an external magnet, environmental benignity and ease of handling.
- Hajjami, Maryam,Kolivand, Somaye
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- Structure and Reactivity of a Mononuclear Nonheme Manganese(III)-Iodosylarene Complex
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Transition metal-iodosylarene complexes have been proposed to be key intermediates in the catalytic cycles of metal catalysts with iodosylarene. We report the first X-ray crystal structure and spectroscopic characterization of a mononuclear nonheme manganese(III)-iodosylarene complex with a tetradentate macrocyclic ligand, [MnIII(TBDAP)(OIPh)(OH)]2+ (2). The manganese(III)-iodosylarene complex is capable of conducting various oxidation reactions with organic substrates, such as C-H bond activation, sulfoxidation and epoxidation. Kinetic studies including isotope labeling experiments and Hammett correlation demonstrate the electrophilic character on the Mn-iodosylarene adduct. This novel intermediate would be prominently valuable for expanding the chemistry of transition metal catalysts.
- Jeong, Donghyun,Ohta, Takehiro,Cho, Jaeheung
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- On the nature of the chain-extending species in organolithium initiated stereospecific reagent-controlled homologation reactions using α-chloroalkyl aryl sulfoxides
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The reaction of an organolithium with an α-chloroalkyl aryl sulfoxide ostensibly generates an α-chloroalkyllithium by sulfoxide-lithium exchange, but the actual identity of the chain-extending species in chlorosulfoxide-based StReCH reactions is not certain. To explore this issue, racemic 2-cyclohexyl (4R?,5R?)-4,5-diphenyl-1,3,2-dioxaborolane was homologated by treatment with scalemic (S)-chloromethyl phenyl sulfoxide and n-BuLi (THF, -78 °C). The reaction proceeded without a detectable level of kinetic resolution, a finding consistent with chloromethyllithium being the active chain-extending species rather than a chiral sulfurane intermediate.
- Hoyt, Amanda L.,Blakemore, Paul R.
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- Enzyme-catalysed oxygenation and deoxygenation routes to chiral thiosulfinates
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Enantioenriched thiosulfinates have been obtained by dioxygenase- and chloroperoxidase-catalysed oxidation of 1,2-disulfides and dimethyl sulfoxide reductase- catalysed deoxygenation.
- Boyd, Derek R.,Sharma, Narain D.,Kennedy, Martina A.,Shepherd, Steven D.,Malone, John F.,Alves-Areias, Andre,Holt, Robert,Allenmark, Stig G.,Lemurell, Malin A.,Dalton, Howard,Luckarift, Heather
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- Enantioselective oxidation of thioanisole with an alcohol oxidase/peroxidase bienzymatic system
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Optimization of a new bienzymatic couple alcohol oxidase/peroxidase for the asymmetric oxidation of thioanisole was realized. The main advantages in the application of this system is the use of inexpensive and easily available enzymes and substrates, perm
- Pezzotti, Fabio,Therisod, Michel
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- Immobilized Sandwich-Type Polyoxometalates [Mn4(XW9O34)2]n? on Tb-Doped TiO2 Nanoparticles as Efficient and Selective Catalysts in the Oxidation of Sulfides and Alcohols
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Abstract: Sandwich-type polyoxometalates of [M4(XW9O34)2]n?(M = Mn2+, Cu2+, Zn2+, X = Ge4+, P5+, As5+) supported on Ln-doped TiO2(Ln = Nd3+, Sm3+, Tb3+and Dy3+) nanoparticles were prepared and their catalytic activities examined for oxidation of sulfides and alcohols. Results show that the catalytic activities of new nanocomposites were significantly higher than homogeneous conditions with corresponding sandwich-type polyoxometalates. The best results obtained by [Mn4(XW9O34)2]10?(X = P5+, As5+) supported on Tb/TiO2which were characterized by various techniques. The catalysts can be easily recovered and reused for at least five times without obvious decrease of catalytic activities and the structures of the catalysts remain unchanged after recycling and the yields for catalyst recovery are all above 95%. Graphical Abstract: [Figure not available: see fulltext.]
- Gholamyan, Sahar,Khoshnavazi, Roushan,Rostami, Amin,Bahrami, Leila
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- Kinetic studies of oxygen atom transfer reactions from trans- dioxoruthenium(VI) porphyrins to sulfides
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The kinetics of the reactions of three trans-dioxoruthenium(VI) porphyrin derivatives with organic sulfides were measured. The dioxo systems studied were 5,10,15,20-tetramesityl porphyrin-dioxoruthenium(VI) (2a), 5,10,15,20- tetraphenylporphyrin-dioxoruthenium(VI) (2b), and 5,10,15,20- tetrakis(pentafluorophenyl)porphyrin-dioxoruthenium(VI) (2c). Species 2 were competent oxidants and reacted rapidly with thioanisoles to generate the corresponding sulfoxides. Typical second-order rate constants determined from pseudo-first-order kinetic studies for sulfoxidation reactions are 8-60 M - 1 s- 1, which are 3 orders of magnitude larger in comparison with those of well studied alkene epoxidations and activated C-H bond oxidations by the same dioxo species. For a given sulfide substrate, the reactivity order for the dioxoruthenium(VI) species was 2a 2b 2c, which is in agreement with expectation on the basis of the electron-withdrawing and steric effects of the porphyrin macrocycles. Various para-substituted thioanisoles react in a narrow kinetic range with the same dioxo species. The kinetic results obtained in this study indicate a concerted oxygen atom transfer and/or electron transfer followed by oxygen transfer mechanism from oxidant to sulfide. Competition kinetic reactions with a catalytic amount of porphyrin ruthenium(II) species and a terminal oxidant give relative rate constants for sulfoxidations of competing substrates that are somewhat smaller than the ratios of absolute rate constants, implying a multiple oxidant model for sulfoxidation reactions.
- Abebrese, Chris,Huang, Yan,Pan, Alice,Yuan, Zhibo,Zhang, Rui
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- Highly enantioselective sulfoxidation with vanadium catalysts of Schiff bases derived from bromo- and iodo-functionalized hydroxynaphthaldehydes
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Two series of chiral Schiff bases, 4a-e and 5a-e, prepared from the condensation of the mono-, di-, tribromohydroxynaphthaldehyde or monoiodohydroxynaphthaldehyde with chiral amino alcohols, were used in combination with VO(acac)2 for the asymmetric oxidation of aryl methyl sulfides using H2O2 as terminal oxidant. Among these Schiff bases, dibromo-functionalized 4d and iodo-functionalized 5e gave high yields (91-93%) with good enantioselectivities (80-82% ee) for the oxidation of thioanisole in dichloromethane. The asymmetric oxidation of thioanisole in toluene using these Schiff bases gave methyl phenyl sulfoxide in satisfactory isolated yields (48-62%) with high enantioselectivities (91-94% ee), which were further improved by a modified procedure with the ee value up to 98% in 62% yield. The oxidations of other aryl methyl sulfides in toluene with dibromo- and iodo-functionalized Schiff bases 5d and 5e as ligands using the modified procedure afforded the corresponding sulfoxides in 55-67% isolated yields with 95-99% ee.
- Wang, Ying,Wang, Mei,Wang, Yu,Wang, Xiuna,Wang, Lin,Sun, Licheng
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- Eaton's reagent-mediated metal-free and efficient synthesis of NH-sulfoximines
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NH-sulfoximines can be prepared efficiently from corresponding sulfoxides in the presence of sodium azide and Eaton's reagent. This metal-free and efficient methodology is applicable to a wide variety of functionalized sulfoxides to afford NH-sulfoximines in good to excellent yields with shorter reaction time than previously reported methods.
- Wang, Jianping,Zhang, Jian,Miao, Kun,Yun, Hongying,Shen, Hong C.,Zhao, Weili,Liang, Chungen
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- Synthesis and catalytic properties of niobium indenyl peroxo complexes
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Synthesis of four niobium sandwich peroxo complexes containing fragments of substituted indenes was performed and their structure was proved by NMR spectroscopy and ESI-MS mass spectrometry. Catalytic activity of the complexes in the oxidation of sulfides
- Rakhmanov, E. V.,Sinyan, Zhong,Tarakanova, A. V.,Anisimov, A. V.,Akopyan, A. V.,Baleeva, N. S.
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- The activation of molecular oxygen by horseradish peroxidase with sodium sulfite
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Horseradish peroxidase (HRP) utilizes molecular oxygen (O2) with sodium sulfite (Na2SO3) to oxidize thioanisole and styrene at the exterior of the heine pocket.
- Ozaki,Watanabe,Hayasaka,Konuma
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- C3-symmetric Ti(IV) triphenolate amino complexes as sulfoxidation catalysts with aqueous hydrogen peroxide
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(Chemical Equation Presented) The Ti(IV) complex 2c bearing a C 3-symmetric triphenolate amine ligand is an air and moisture tolerant complex that efficiently catalyzes sulfoxidation reactions at room temperature without previous activation (catalyst loading down to 0.01%, TONs up to 8000, TOFs up to 1700 h-1, quantitative yields). Reactions were performed with aqueous hydrogen peroxide as oxidant, which adds value to the methodology from the environmental viewpoint.
- Mba, Myriam,Prins, Leonard J.,Licini, Giulia
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- A new method for oxidation of tertiary amine by molecular oxygen/aldehyde/Fe2O3 system
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Oxidation of tertiary amines to tertiary amine N-oxides was achieved in moderate to high yields, by using Fe2O3 as catalyst, with molecular oxygen in the presence of isovaleraldehyde under mild conditions.
- Wang, Fan,Zhang, Hao,Song, Guoqiang,Lu, Xiaoling
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- Enantioselective sulfoxidation mediated by vanadium-incorporated phytase: A hydrolase acting as a peroxidase
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Phytase (E.C. 3.1.3.8), which in vivo mediates the hydrolysis of phosphate esters, catalyses the enantioselective oxidation of thioanisole with H2O2, both in the presence and absence of vanadate ion, affording the S-sulfoxide in up t
- Van De Velde, Fred,Koenemann, Lars,Van Rantwijk, Fred,Sheldon, Roger A.
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- Guest dependent inversion of enantiomeric recognition in dehydrocholic acid host-guest enclathration
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A guest dependent inversion of enantiomeric recognition operated by the host dehydrocholic acid on a second guest is observed during host-guest dehydrocholic acid-sulfoxide assembly formation.
- Bortolini, Olga,Fantin, Giancarlo,Fogagnolo, Marco,Perrone, Daniela
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- Sulfoxidation inside a C3-vanadium(V) bowl-shaped catalyst
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The confined enantiopure oxido-vanadium complex SSS-RRR-1 was synthesized and tested as a catalyst for the oxidation of sulfides into sulfoxides. This catalyst is very efficient with a reaction rate more than 300 times higher than that of the model compound SSS-RRR-3, and a turnover number (TON) close to 105 was reached in combination with a good selectivity (more than 90%) in the sulfoxide product. Moreover, enantiomerically enriched sulfoxide can be obtained, breaking through the major limitation of the previous chiral vanatrane catalysts that show no detectable enantiomeric excess (ee). Further investigations revealed that the complex SSS-RRR-1 adopts a bowl-shaped structure with an open hydrophobic pocket. The microenvironment of the chiral pocket above the metal center accounts for the strong improvement in catalytic activity and enantioselectivity.
- Zhang, Dawei,Dutasta, Jean-Pierre,Dufaud, Veronique,Guy, Laure,Martinez, Alexandre
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- Facile synthesis of a 3D flower-like SiO2-MOF architecture with copper oxide as a copper source for enantioselective capture
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A facile self-template synthetic approach for the facile synthesis of a 3D flower-like SiO2-CuLBH architecture with copper oxide as a copper source has been demonstrated. The resulting composite as a sorbent showed a certain selective separation capability for phenyl methyl sulfoxide enantiomers (PMS) with an enantiomeric excess (ee) value of 31%.
- Li, Xinglin,Gao, Yu,Wang, Cuijie,Cui, Jiting,Yu, Ajuan,Zhang, Shusheng
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- Gold(III) catalyzed oxidation of sulfides to sulfoxides with hydrogen peroxide
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Au(III) catalyzed oxidation of sulfides to sulfoxides with 30% hydrogen peroxide in good yields and chemoselectivities was developed. It was shown that the catalyst loading can be decreased to 0.01 mol % with the good activity and chemoselectivity. Meanwhile, the catalyst was stable in the reaction system, which can be reused at least six cycles with similar activity and chemoselectivity.
- Yuan, Yu,Bian, Yubo
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- Enantiopure 24-armed dendritic polyoxometalates: Synthesis and evaluation as recoverable catalysts for asymmetric sulfide oxidation
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Enantiopure 24-armed dendritic polyoxometalate (DENDRI-POM) hybrids were prepared by ionic coupling of enantiopure 8-armed n-propyl dendritic ammoniums with a catalytically active peroxophosphotungstate trianion {PO4[WO(O2)2]4}3-. The catalytic properties of these DENDRI-POM hybrids were evaluated in the oxidation of thioanisole as a model reaction and compared to those of the 12-armed n-propyl analogous previously reported in our group. Up to 10% enantiomeric excess (ee) was obtained, indicating a negative effect on the reaction rate and the enantioselectivity, whereas the selectivity to the chiral sulfoxide versus sulfone was improved. This study AIDS understanding of how the structure and size of the dendritic wedge around the POM can influence its catalytic properties, especially regarding enantioselectivity. Four catalytic cycles were performed without any obvious change in the activity, selectivity and enantioselectivity.
- Jahier, Claire,Touzani, Rachid,El Kadiri, Sghir,Nlate, Sylvain
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- DIASTEREOSELECTIVE OXIDATION OF SULFIDES TO SULFOXIDES WITH POTASSIUM PEROXYMONOSULFATE
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Potassium peroxymonosulfate oxidation of sulfides to sulfoxides occurs with high diastereoselectivity.
- Quallich, George J.,Lackey, J. William
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- Catalytic asymmetric oxidation of sulfides to sulfoxides using R-(+)-binaphthol
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An asymmetric oxidation system using R-(+)-binaphthol as a chiral auxiliary catalyzes the oxidation of sulfides to chiral sulfoxides in good enantiomeric excess ( up to 73% e.e. ) and in a high chemical yield.
- Komatsu, Naoki,Nishibayashi, Yoshiaki,Sugita, Toshio,Uemura, Sakae
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- Partial and full β-chlorination of meso-tetraphenylporphyrin: effects on the catalytic activity of the manganese complexes for oxidation of organic compounds with periodate
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A series of β-chlorinated meso-tetraphenylporphyrins, H2TPPCIx (x = 2, 4, 6, or 8) have been prepared and the catalytic activity of their manganese(III) complexes in oxidation of cyclooctene, cyclohexene, and methyl phenyl sulfide wi
- Rayati, Saeed,Bohloulbandi, Elaheh,Zakavi, Saeed,Jafarian, Majid,Rashvand Avei, Mehdi
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- Modeling the cis-Oxo-Labile binding site motif of non-heme iron oxygenases: Water exchange and oxidation reactivity of a non-heme iron(IV)-Oxo compound bearing a tripodal tetradentate ligand
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The spectroscopic and chemical characterization of a new synthetic non-heme iron(IV)-oxo species [FeIV(O)(Me,HPytacn)(S)] 2+ (2, Me,HPytacn=1-(2′-pyridylmethyl)-4,7-dimethyl- 1,4,7-triazacyclononane, S=CH3CN or H2O) is described. Complex 2 was prepared by reaction of [FeII(CF3SO 3)2(Me,HPytacn)] (1) with peracetic acid. Complex 2 bears a tetradentate N4 ligand that leaves two cis sites available for binding an oxo group and a second external ligand but, unlike the related iron(IV)-oxo species with tetradentate ligands, it is remarkably stable at room temperature (t1/2>2a h at 288a K). Its ability to exchange the oxygen atom of the oxo ligand with water has been analyzed in detail by means of kinetic studies, and a mechanism is proposed on the basis of DFT calculations. Hydrogen-atom abstraction from C-H bonds and oxygen-atom transfer to sulfides by 2 have also been studied. Despite its thermal stability, 2 proves to be a very powerful oxidant that is capable of breaking the strong C-H bond of cyclohexane (bond dissociation energy=99.3a kcala mol-1). A powerful oxidant: A non-heme oxo-iron(IV) complex (see picture), containing a labile site cis to the terminal oxo group, has been prepared and characterized. The complex is unusually stable (t1/2>2a h at 288a K). Water exchange, oxo transfer, and Ha abstraction reactions have been studied. Despite its thermal stability, the complex is a very powerful oxidant.
- Company, Anna,Prat, Irene,Frisch, Jonathan R.,Mas-Balleste, Dr Ruben,Gueell, Mireia,Juhasz, Gergely,Ribas, Xavi,Muenck, Dr Eckard,Luis, Josep M.,Que Jr., Lawrence,Costas, Miquel
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- The enantioselective oxidation of sulfides to sulfoxides with Acinetobacter sp. NCIMB 9871, Pseudomonas sp. NCIMB 9872, Xanthobacter autotrophicus DSM 431 (NCIMB 10811) and the Black Yeast NV-2
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Whole cell oxidation of aryl alkyl sulfides to sulfoxides with Acinetobacter sp. NCIMB 9871 is only slightly less enantioselective than isolated enzyme transformation with the cyclohexanone monooxygenase (CHMO) from the same species. Pseudomonas sp. NCIMB 9872 oxidises the same substrates with high and mostly opposite enantioselectivity (73-100%ee). CHMO activity was detected in the black yeast NV-2 and Xanthobacter autotrophicus DSM 431 (NCIMB 10811), but contrary to an earlier report this activity could not be detected in cell free extracts of the latter. Both species oxidised methyl phenyl sulfide exclusively to the corresponding (R)-sulfoxide (100% ee).
- Kelly, David R.,Knowles, Christopher J.,Mahdi, Jassem G.,Taylor, Ian N.,Wright, Michael A.
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- Oxidation with mercury(II) oxide-iodine reagent: Selective oxidation of sulfides to sulfoxides
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A new method for selective oxidation of sulfides to sulfoxides with mercury(II) oxide-iodine reagent is reported.
- Orito,Hatakeyama,Takeo,Suginome
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- Asymmetric sulfoxidation of thioanisole by helical Ti(IV) salan catalysts
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A new helix-directing salan ligand (R,R)-2 with the (1R,2R)- diaminocyclohexyl backbone and benz[a]anthryl sidearms was synthesized by borohydride reduction of the corresponding salen ligand. Formylation and reduction of (R,R)-2 yielded the N-Me counterpart, (R,R)-3. Complexation of these flexible ligands to TiCl4 produced the [TiCl 2(salan)] complexes (R,R)-4 and (R,R)-5, which were characterized by NMR, IR, and HRMS techniques. The complexes were tested as catalysts for the asymmetric sulfoxidation of thioanisole with cumene hydroperoxide and hydrogen peroxide as the oxidants. Modest selectivity was observed, with the N-H salan complex showing somewhat better chiral induction.
- Barman, Sanmitra,Patil, Smita,Levy, Christopher J.
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- Constraining titanium tartrate in the interlayer space of layered double hydroxides induces enantioselectivity
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Kagan-Medona and Sharpless titanium tartrate complexes (Ti(IV)TAm, subscript m represents the coordination ratio of l-tartaric acid to the Ti center in the complex) have been intercalated into the interlayer of layered double hydroxides (LDHs) by anionic exchange method using Mg/Al-CO3 LDH as the precursor. Titanium tartrate-intercalated LDHs (designated Mg/Al-Ti(IV)TAm LDHs) with varied interlayer spacing were produced by tuning the area unit charge (Ac) of the brucite-like layer from 0.24 to 0.44 nm2. The interlayer spacing decreases from 1.87 to 1.44 nm with the increase in Ac. The interlayer titanium tartrate anions are present in an interdigitated bilayer arrangement. The bidimensional interlayer space can be swollen, and thus accommodates the reactants in the interlayer. The titanium tartrate complex constrained in the LDH interlayer region shows enhanced asymmetric induction in the heterogeneous sulfoxidation of pro-chiral methyl phenyl sulfide.
- Shi, Huimin,Yu, Chenguang,He, Jing
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- Alkylthio substituted tricarbonyl(η6-arene)chromium(0) complexes as substrates for asymmetric oxidation
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Oxidation of methylthio substituted tricarbonyl(η6-arene)chromium(0) complexes with Ti(OPr(i))4/ diethyl tartrate H2O/ cumene hydroperoxide (2:4:2:1.3) gives methylsulfinyl substituted tricarbonyl(η6-arene)chromium(0) complexes in 60-73% yield and 81-86% e.e. (29-60% yield and 90 ≥ 95% e.e. after crystallisation); diethyl tartrate gives higher optical and chemical yields than dimethyl or diisopropyl tartrates and the reaction conditions are ineffective for other alkylthio and arylthio substituents: diethyl L-(+)-tartrate and diethyl D-(-)-tartrate lead to complexes of R and S configuration respectively; although an attempted kinetic resolution of tricarbonyl[η6-(melhylsulfinyl)benzene] was unsuccessful, subjecting tricarbonyl[η6-1-melhyl-2-(methylthio)benzene]chromium(0) to kinetic resolution conditions led to the isolation of recovered starting material and the corresponding sulfinyl substituted complex with enantiomeric excesses of 59 and 60% respectively.
- Griffiths,Perrio,Thomas
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- Chemoselective and efficient oxidation of sulfides to sulfoxides mediated by trimethylsilyl chloride and superoxide via a trimethylsilylperoxy radical
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Chemoselective and efficient oxidation of various sulfides were mediated by Me3SiCl and KO2 in dry acetonitrile at -15°C to afford corresponding sulfoxides in excellent yields without any interference in the presence of ketone, olefin, ether and hydroxyl functionalities and without further oxidation to the sulfones. A trimethylsilylperoxy radical generated in situ from this new process is proposed. (C) 2000 Elsevier Science Ltd.
- Chen, Yao-Jung,Huang, Yu-Ping
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- ACID CATALYZED OXYGEN TRANSFER FROM AN OXAZIRIDINE TO A THIOETHER
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Oxygen can be transferred from the oxaziridine derived from 3,4-dihydroisoquinoline to a thio-ether.As shown by the different pathways followed on various conditions, the oxygen transfer depends on acid catalysis and on the nucleophilicity and basicity of substrate.
- Hanquet, G.,Lusinchi, X.,Milliet, P.
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- Tungstate supported on magnetic ionic liquid-modi?ed graphene oxide as an efficient and recyclable catalyst for the selective oxidation of sulfides
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An effective and recyclable catalyst based on tungstate ion immobilization on magnetic ionic liquid modified graphene oxide (WO4@Fe3O4/GO-IL) has been synthesized in this research. The catalyst was characterized by various
- Dabiri, Minoo,Tavil, Hassan Esmaielie,Lehi, Noushin Farajinia,Movahed, Siyavash Kazemi,Mnachekanian Salmasi, Aram,Souri, Sepideh
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- Electrochemical Formation and Activation of Hydrogen Peroxide from Water on Fluorinated Tin Oxide for Baeyer-Villiger Oxidation Reactions
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The two-electron oxidation of water (2e-WOR) has been studied in the past as a possible method for the alternative preparation of hydrogen peroxide. Often, fluorinated tin oxide (FTO) is used as an anode and FTO itself was found also to be active for 2e-WOR. Because one use of H2O2is as an oxygen donor for Baeyer-Villiger oxidation of ketones catalyzed by tin compounds and materials, presently we were interested in studying the use of in situ formed H2O2for these reactions. First, the formation of H2O2was verified in an acetonitrile/water solvent in a 2e-WOR reaction, which is more efficient than a comparable reaction in water in terms of the H2O2concentration attained and faradaic efficiency at comparable potentials, that is, ~3 V vs SHE. Second, initial studies on oxygenation of reactive substrates such as sulfides showed normalized reaction rates (NRRs) for two-electron oxidation reactions that were about 3 times higher than the NRR for H2O2formation, indicating the formation of an active oxygen-donating or oxidizing species on the electrode surface prior to the formation and release of H2O2into solution. Third, the Baeyer-Villiger oxygenation of 2-adamantanone at 2.1 V versus SHE in acetonitrile/water showed both the formation of the expected lactone product and hydroxylation at both tertiary and secondary C-H bonds. Hydroxylation is most easily explained by the presence of hydroxyl radical species as supported by the formation of a spin adduct and its identification by electron paramagnetic resonance. However, the potential used, 2.1 V versus SHE, is an underpotential for the formation of a solvated hydroxyl radical in solution, thereby leading to the conclusion that surface-bound hydroxyl species, OH*, are those that are reactive for the apparent one-electron water oxygenation reaction. Fourth, it was shown that although H2O2can be thermally activated on FTO as a catalyst to a minor degree, electrochemical activation is by far more significant, leading to the use of FTO as an electrochemical catalyst for activation of H2O2for the Baeyer-Villiger oxygenation and also alkene epoxidation.
- Herman, Adi,Mathias, Jenny-Lee,Neumann, Ronny
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p. 4149 - 4155
(2022/04/12)
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- Sulfoxide and Sulfone Synthesis via Electrochemical Oxidation of Sulfides
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The oxidation of diaryl sulfides and aryl alkyl sulfides to the corresponding sulfoxides and sulfones under electrochemical conditions is reported. Sulfoxides are selectively obtained in good yield under a constant current of 5 mA for 10 h in DMF, while sulfones are formed as the major product under a constant current of 10 or 20 mA for 10 h in MeOH. The oxygen of both the sulfoxide and sulfone function is derived from water.
- Lee, Sunwoo,Park, Jin Kyu
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supporting information
p. 13790 - 13799
(2021/10/12)
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- Charge Transfer from Donor to Acceptor in Conjugated Microporous Polymer for Enhanced Photosensitization
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Photosensitization associated with light absorption and energy/electron-transfer represents the central processes for photosynthesis. However, it's still a challenge to develop a heavy-atom-free (HAF) strategy to improve the sensitizing ability of polymeric photosensitizers. Herein, we propose a new protocol to significantly improve the photosensitization by decorating mother conjugated microporous polymer (CMP-1) with polycyclic aromatic hydrocarbons (PAHs), resulting in a series of CMPs (CMP-2–4). Systematic study reveals that covalent modification with PAHs can transfer charge to Bodipy in CMP to further facilitate both intersystem crossing and electron-hole separation, which can dramatically boost energy-/electron-transfer reactions. Remarkably, CMP-2 as a representative CMP can efficiently drive the photosynthesis of methyl phenyl sulfoxide with 92 % yield, substantially higher than that of CMP-1 (32 %). Experiments and theory calculations demonstrate the structure-property-activity relationship of these CMPs, opening a new horizon for developing HAF heterogeneous photosensitizers with highly efficient sensitizing activity by rational structure regulation at a molecular level.
- Guo, Guang-Chen,Guo, Song,Kong, Li-Hui,Lu, Tong-Bu,Peng, Yuan-Zhao,Zhang, Zhi-Ming
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supporting information
p. 22062 - 22069
(2021/08/30)
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- Organocatalytic sulfoxidation
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Treatment of a sulfide with a catalytic amount of a 1,3-diketone in the presence of silica sulfuric acid as a co-catalyst and hydrogen peroxide (50% aq) as the stoichiometric oxidant leads to the corresponding sulfoxide product. The reaction is effective for diaryl, aryl-alkyl and dialkyl sulfides and is tolerant of oxidisable and acid sensitive functional groups. Investigations have shown that the tris-peroxide 2, formed on reaction of pentane-2,4-dione with hydrogen peroxide under acidic reaction conditions, can oxidise two equivalents of sulfide using the exocyclic peroxide groups whereas the endocyclic peroxide remains intact. Calculations provide a mechanism consistent with experimental observations and suggest the reaction proceeds via an initial acid catalysed ring opening of a protonated tris-peroxide prior to oxygen transfer to a sulfur nucleophile.
- Davidson, Stuart C.,Gomes, Gabriel dos Passos,Kuhn, Leah R.,Alabugin, Igor V.,Kennedy, Alan R.,Tomkinson, Nicholas C.O.
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- Copper based on diaminonaphthalene-coated magnetic nanoparticles as robust catalysts for catalytic oxidation reactions and C-S cross-coupling reactions
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In this work, the immobilization of copper(ii) on the surface of 1,8-diaminonaphthalene (DAN)-coated magnetic nanoparticles provides a highly active catalyst for the oxidation reaction of sulfides to sulfoxides and the oxidative coupling of thiols to disulfides using hydrogen peroxide (H2O2). This catalyst was also applied for the one-pot synthesis of symmetrical sulfidesviathe reaction of aryl halides with thiourea as the sulfur source in the presence of NaOH instead of former strongly basic and harsh reaction conditions. Under optimum conditions, the synthesis yields of sulfoxides, symmetrical sulfides, and disulfides were about 99%, 95%, and 96% respectively with highest selectivity. The heterogeneous copper-based catalyst has advantages such as the easy recyclability of the catalyst, the easy separation of the product and the less wastage of products during the separation of the catalyst. This heterogeneous nanocatalyst was characterized by FESEM, FT-IR, VSM, XRD, EDX, ICP and TGA. Furthermore, the recycled catalyst can be reused for several runs and is economically effective.
- Yarmohammadi, Nasrin,Ghadermazi, Mohammad,Mozafari, Roya
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p. 9366 - 9380
(2021/03/16)
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- In situconstruction of phenanthroline-based cationic radical porous hybrid polymers for metal-free heterogeneous catalysis
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Rational design of multifunctional radical porous polymers with redox activity for targeted metal-free heterogeneous catalysis is an important research topic. In this work, we reported a new class of phenanthroline-based cationic radical porous hybrid polymers (Phen˙+-PHPs), which were constructed from the Heck reaction between a newly designed dibromo-substituted phenanthroline ionic monomer (iDBPhen) and a rigid building block, octavinylsilsesquioxane (VPOSS). For the first time, the stable phenanthroline-based radical cation was unexpectedly discovered in these polyhedral oligomeric silsesquioxane (POSS)-based porous hybrid polymers, probably undergoingin situreduction of the dicationic monomer iDBPhen during the alkaline reagent K2CO3-involved Heck reaction. The radical characters of the typical porous polymers Phen˙+-PHP-2 and Phen˙+-PHP-2Br were confirmed from the electron paramagnetic resonance (EPR) spectra and X-ray photoelectron spectra (XPS). The chemical structures and porous geometry were fully characterized by a series of advanced technologies. Surprisingly, the metal-free cationic radical polymer Phen˙+-PHP-2 exhibited high heterogeneous catalytic efficiency in the H2O2-mediated selective oxidation of various sulfides to sulfoxides with high yields under mild conditions, owing to the electron-accepting and redox ability of Phen-based dications and radical cations. Moreover, the extended sample Phen˙+-PHP-2Br prepared by post-treatment of Phen˙+-PHP-2 with aqueous HBr was also employed as a metal-free efficient heterogeneous catalyst in the conversion of CO2with epoxides into cyclic carbonates under atmospheric pressure and low temperatures. The remarkable catalytic performance in CO2conversion should be assigned to the synergistic catalysis of POSS-derived Si-OH groups and nucleophilic Br?anions and N active atom-involved Phen cationic radical moieties within Phen˙+-PHP-2Br. These two catalysts can be facilely recovered and reused, also with stable recyclability in the above catalytic reaction systems, achieving the heterogeneous catalytic demands for multipurpose reactions.
- Chen, Guojian,Zhang, Yadong,Liu, Ke,Liu, Xiaoqing,Wu, Lei,Zhong, Hu,Dang, Xuejing,Tong, Minman,Long, Zhouyang
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supporting information
p. 7556 - 7565
(2021/04/06)
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- Selective Photocatalytic Oxidation of Sulfides in Lanthanide Metal -Organic Frameworks Incorporating Ru(2,2′-bpy)3 photosensitizer
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Three isostructural lanthanide metal-organic frameworks (Ln-MOFs) were synthesized with uncoordinated N^N site, and the Ru(N^N)3 photosensitizer was introduced via coordination link. These functionalized frameworks showed excellent performance
- Zhang, Xiaobang,Wei, Xiaomei,Huang, Sheng-Li,Yang, Guo-Yu
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supporting information
p. 2031 - 2034
(2021/07/06)
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- Two enantiocomplementary Baeyer-Villiger monooxygenases newly identified for asymmetric oxyfunctionalization of thioether
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Two enantiocomplementary Baeyer-Villiger monooxygenases RaBVMO and AmBVMO were identified by genome mining for the asymmetric sulfoxidation. Both recombinant BVMOs have optimal pH of 9.0 and temperature of 35 °C. The half-lives of RaBVMO and AmBVMO at 30 °C were 24.4 and 24.6 h. RaBVMO and AmBVMO exhibited broad substrate spectrum and could catalyze the oxidization of various compounds including fatty ketones, cyclic ketones, and thioethers. Kinetic parameters analysis revealed that both RaBVMO and AmBVMO displayed higher catalytic efficiency toward thioanisole than cyclohexanone. As much as 50 mM thioanisole could be completely oxidized by AmBVMO and RaBVMO with 99% (R) and 95% (S), respectively. Molecular docking analysis further provides evidence for the complementary enantioselectivity of RaBVMO and AmBVMO. Our results demonstrate the potential application of the two novel BVMOs in asymmetric synthesis of sulfoxides.
- Liu, Yafei,Ni, Ye,Wei, Shiyu,Xu, Guochao,Zhou, Jieyu
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- A mild and chemoselective CALB biocatalysed synthesis of sulfoxides exploiting the dual role of AcOEt as solvent and reagent
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A mild, chemoselective and sustainable biocatalysed synthesis of sulfoxides has been developed exploiting CALB and using AcOEt with a dual role of more environmentally friendly reaction solvent and enzyme substrate. A series of sulfoxides, including the drug omeprazole, have been synthesised in high yields and with excellent E-factors.
- Anselmi, Silvia,Liu, Siyu,Kim, Seong-Heun,Barry, Sarah M.,Moody, Thomas S.,Castagnolo, Daniele
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supporting information
p. 156 - 161
(2021/01/14)
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- Electrochemical oxygenation of sulfides with molecular oxygen or water: Switchable preparation of sulfoxides and sulfones
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A practical and eco-friendly method for the controllable aerobic oxygenation of sulfides by electrochemical catalysis was developed. The switchable preparation of sulfoxides and sulfones was effectively controlled by reaction time, in which both molecular oxygen and water can be used as the oxygen source under catalyst and external oxidant-free conditions. The electrochemical protocol features a broad substrate scope and excellent site selectivity and is successfully applied to the modification of some sulfide-containing pharmaceuticals and their derivatives. This journal is
- Li, Jin-Heng,Li, Yang,Sun, Qing,Xue, Qi,Zhang, Ting-Ting
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supporting information
p. 10314 - 10318
(2021/12/17)
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- Hydrazone-Based Ligand with Pyrrolidine Donor and Its Molybdenum(VI) Complex: Synthesis, Structure, and Reactivity
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The Schiff-base condensation of salicylaldehyde and 4-aminobutanehydrazide hydrochloride leads to the hydrazone-based ligand H2salhyab containing an amino side chain. The reaction of H2salhyab ? HCl with bis(acetylacetonato)dioxidomo
- Nica, Simona,Buchholz, Axel,G?rls, Helmar,Plass, Winfried
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p. 937 - 942
(2021/03/29)
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- Chiral separation materials based on derivatives of 6-amino-6-deoxyamylose
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In order to develop new type of chiral separation materials, in this study, 6-amino-6-deoxyamylose was used as chiral starting material with which 10 derivatives were synthesized. The amino group in 6-amino-6-deoxyamylose was selectively acylated and then the hydroxyl groups were carbamoylated yielding amylose 6-amido-6-deoxy-2,3-bis(phenylcarbamate)s, which were employed as chiral selectors (CSs) for chiral stationary phases of high-performance liquid chromatography. The resulted 6-amido-6-deoxyamyloses and amylose 6-amido-6-deoxy-2,3-bis(phenylcarbamate)s were characterized by IR, 1H NMR, and elemental analysis. Enantioseparation evaluations indicated that most of the CSs demonstrated a moderate chiral recognition capability. The 6-nonphenyl (6-nonPh) CS of amylose 6-cyclohexylformamido-6-deoxy-2,3-bis(3,5-dimethylphenylcarbamate) showed the highest enantioselectivity towards the tested chiral analytes; the phenyl-heterogeneous (Ph-hetero) CS of amylose 6-(4-methylbenzamido)-6-deoxy-2,3-bis(3,5-dimethylphenylcarbamate) baseline separated the most chiral analytes; the phenyl-homogeneous (Ph-homo) CS of amylose 6-(3,5-dimethylbenzamido)-6-deoxy-2,3-bis(3,5-dimethylphenylcarbamate) also exhibited a good enantioseparation capability among the developed CSs. Regarding Ph-hetero CSs, the enantioselectivity depended on the combination of the substituent at 6-position and that at 2- and 3-positions; as for Ph-homo CSs, the enantioselectivity was related to the substituent at 2-, 3-, and 6-positions; with respect to 6-nonPh CSs, the retention factor of most analytes on the corresponding CSPs was lower than that on Ph-hetero and Ph-homo CSPs in the same mobile phases, indicating π–π interactions did occur during enantioseparation. Although the substituent at 6-position could not provide π–π interactions, the 6-nonPh CSs demonstrated an equivalent or even higher enantioselectivity compared with the Ph-homo and Ph-hetero CSs.
- Gao, Ya-Ya,Zhang, Yu-Hang,Zhang, Shan,Chen, Wei,Bai, Zheng-Wu
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supporting information
p. 899 - 914
(2021/10/07)
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- CO2-activated NaClO-5H2O enabled smooth oxygen transfer to iodoarene: A highly practical synthesis of iodosylarene
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A safe, rapid, and environmentally friendly synthesis of iodosylarene (ArIO) has been developed using NaClO under a carbon dioxide (CO2) atmosphere. Exposure of iodoarene to NaClO-5H2O in acetonitrile under CO2 (1 atm) resulted in the clean formation of ArIO within 10 minutes in high yield. The absence of a base in this method enables the direct use of in-situ-generated iodosylarene not only for a variety of oxidative transformations (synthesis of sulfilimine, pentavalent bismuth, benzyne adduct, etc.), but also for the synthesis of iodonium ylide and imino-λ3-iodane in one pot.
- Miyamoto, Kazunori,Watanabe, Yuichiro,Takagi, Taisei,Okada, Tomohide,Toyama, Takashi,Imamura, Shinji,Uchiyama, Masanobu
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- Trisaminomethane–cobalt complex supported on Fe3O4 magnetic nanoparticles as an efficient recoverable nanocatalyst for oxidation of sulfides and C–S coupling reactions
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In this work, trisaminomethane–cobalt complex immobilized onto the surface of Fe3O4 magnetic nanoparticles was successfully prepared via a simple and inexpensive procedure. The prepared nanocatalyst was considered a robust and clean nanoreactor catalyst for the oxidation and synthesis of sulfides under green conditions. This ecofriendly heterogeneous catalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, energy-dispersive X-ray spectroscopy, inductively coupled plasma-atomic emission spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, X-ray mapping, scanning electron microscopy, and transmission electron microscopy techniques. Use of green medium, easy separation and workup, excellent reusability of the nanocatalyst, and short reaction time are some outstanding advantages of this method.
- Ashraf, Muhammad Aqeel,Liu, Zhenling,Peng, Wan-Xi
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- Alloxan-catalyzed biomimetic oxidations with hydrogen peroxide or molecular oxygen
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Inspired by biological flavin catalysis, the nonionic alloxan derivatives were applied as the biomimetic catalysts for various oxidations, catalyzing oxidations of sulfides and amines with hydrogen peroxide or molecular oxygen under mild conditions with high yields in a short time. The whole catalytic cycle has been verified to be a biomimetic approach through the formation of the alloxan hydroperoxide reactive intermediate. Additionally, encouraging asymmetric catalytic results have been obtained with an easily prepared chiral alloxan in a sulfoxidation reaction.
- Zhang, Shiqi,Li, Guangxun,Li, Ling,Deng, Xiongfei,Zhao, Gang,Cui, Xin,Tang, Zhuo
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p. 245 - 252
(2019/12/24)
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- Selective and solventless oxidation of organic sulfides and alcohols using new supported molybdenum (VI) complex in microwave and conventional methods
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A new dioxo-molybdenum (VI) complex supported on functionalized Merrifield resin (MR-Mo) has been synthesized and characterized by elemental, scanning electron mcroscopy, energy-dispersive X-ray analysis, TGA, Brunauer–Emmett–Teller method, powder-X-ray d
- Das, Siva Prasad,Boruah, Jeena Jyoti
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- Emodinas a novel organic photocatalyst for selective oxidation of sulfides under mild conditions
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Herein, we have developed naturally-occurringEmodin, which is commercially available at low-cost, as a novel organic photocatalyst for the first time.Emodinwas successfully employed in the selective oxidation of sulfides promoted by visible-light, deliver
- Li, Min,Lou, Jiangli,Rao, Yijian,Yuan, Zhenbo,Zhang, Yan
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p. 19747 - 19750
(2020/06/04)
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- Chiral: N, N ′-dioxide-iron(iii)-catalyzed asymmetric sulfoxidation with hydrogen peroxide
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A highly enantioselective sulfoxidation of various sulfides has been achieved by a N,N′-dioxide-iron(iii) complex with 35% aq. H2O2 as the oxidant. The utility of the current method was demonstrated by asymmetric gram-scale synthesis of drug molecule (R)-modafinil. Moreover, a possible working mode was provided to elucidate the chiral induction.
- Dong, Shunxi,Feng, Lili,Feng, Xiaoming,Liu, Xiaohua,Wang, Fang
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supporting information
p. 3233 - 3236
(2020/03/23)
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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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- Accessing Enantiopure Epoxides and Sulfoxides: Related Flavin-Dependent Monooxygenases Provide Reversed Enantioselectivity
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Enantiopure organic compounds are of major importance for the chemical and pharmaceutical industry. Flavin-dependent group E monooxygenases, composed of monooxygenase and reductase, are known to perform epoxidation of substituted alkenes as well as sulfoxidation in a regio- and enantioselective fashion. Group E is divided into styrene monooxygenases (SMO) and indole monooxygenases (IMO). Hitherto mainly SMOs have been characterized. In this study, we assayed 31 monooxygenases from both types, while 23 of which showed activity. They almost exclusively produced (S)-styrene oxide at high enantiomeric excess with maximum activities of 0.73 μmol min?1 mg?1 (kcat=0.54 s?1). In case of sulfoxidation, we found that the enantioselectivity is contrary between both types. IMOs preferably produce the (S)-enantiomer while SMOs have a tendency to produce the (R)-enantiomer. Sequence analysis and molecular docking of substrates allowed identifying fingerprint motives: SMO N46-V48-H50-Y73-H76-S96 and IMO S46-Q48-M50-V/I73-I76-A96. These form an essential part of the active site while the loop (AS44-51) interacts with the co-substrate and other amino acids direct the substrate. The motives clearly distinguish group E monooxygenases and define the enantioselectivity and thus direct biotechnological applications. Two-hour biotransformations with several sulfides in conjunction with upscale experiments (10 and 100 mg scale) resulted in the identification of promising candidates for the realization of biocatalytic processes.
- Heine, Thomas,Scholtissek, Anika,Hofmann, Sarah,Koch, Rainhard,Tischler, Dirk
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p. 199 - 209
(2019/11/13)
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- Highly Efficient Access to (S)-Sulfoxides Utilizing a Promiscuous Flavoprotein Monooxygenase in a Whole-Cell Biocatalyst Format
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Chiral sulfoxides have gained attention as synthons and precursors for API synthesis. Flavoproteins such as Baeyer-Villiger or styrene monooxygenases mainly provide access to (R)-sulfoxides and often suffer from low selectivity, activity, and/or limited substrate scope. The flavoprotein monooxygenase AbIMO from Acinetobacter baylyi ADP1 initiates indole degradation. Here, AbIMO was expressed recombinantly in E. coli and characterized for its sulfoxidation activity and substrate spectrum. Next to indole and styrene, AbIMO was found to accept numerous alkyl aryl sulfides as substrates, transforming them to (S)-sulfoxides with high enantioselectivity (95 percent to '99 percent for most sulfides). The formulation as a whole-cell biocatalyst allowed specific production rates of up to 370 U gcdw?1 – the highest specific oxygenase activity achieved in whole cells so far – and the preparative synthesis of enantiopure (S)-aryl alkyl sulfoxides. With its extraordinarily high specific activity, high specificity, ease of handling, and high stability (catalyst is stable for '16 days at 4 °C), the designed whole-cell biocatalyst adds enormous value to the portfolio of chemical and biological catalysts for asymmetric sulfoxide synthesis.
- Willrodt, Christian,Gr?ning, Janosch A. D.,Nerke, Philipp,Koch, Rainhard,Scholtissek, Anika,Heine, Thomas,Schmid, Andreas,Bühler, Bruno,Tischler, Dirk
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p. 4664 - 4671
(2020/01/22)
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- The mutagenesis of a single site for enhancing or reversing the enantio- or regiopreference of cyclohexanone monooxygenases
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The mutagenesis of a "second sphere"switch residue of CHMOAcineto could control its enantio- and regiopreference. Replacing phenylalanine (F) at position 277 of CHMOAcineto into larger tryptophan (W) enabled a significant enhancement of enantio- or regioselectivity toward structurally diverse substrates, moreover, a complete reversal of enantio- or regiopreference was realized by mutating F277 into a range of smaller amino acids (A/C/D/E/G/H/I/K/L/M/N/P/Q/R/S/T/V).
- Hu, Yujing,Xu, Weihua,Hui, Chenggong,Xu, Jian,Huang, Meilan,Lin, Xianfu,Wu, Qi
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supporting information
p. 9356 - 9359
(2020/11/02)
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- Selectivity switch in the aerobic oxygenation of sulfides photocatalysed by visible-light-responsive decavanadate
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Nanometre-sized metal oxides are promising species for the development of visible-light-responsive photocatalysts for the selective transformation of organic functional groups. In this article, we report that decavanadate ([V10O28]6-, V10) behaved as an efficient visible-light-responsive photocatalyst in the product-selective oxygenation of sulfides achieved using O2 (1 atm) as the green oxidant. In particular, we revealed that visible-light-responsive photocatalysis of V10 showed remarkable activity for the oxygenation of structurally diverse sulfides to form the corresponding sulfones using O2 in methyl ethyl ketone (MEK). Furthermore, by simply adding water to the reaction mixture, the product selectivity of sulfide oxygenation can be significantly switched toward the production of sulfoxides, without concomitant loss of photocatalytic activity. Based on experimental evidence, we inferred the following mechanistic steps for this photocatalytic system: the aerobic oxygenation of sulfides to form the corresponding sulfoxides initiated by a visible-light-induced photoredox reaction of V10. As for the formation of sulfones, MEK-derived peroxide species as the co-catalysts are probably involved in the oxygenation of sulfoxides to sulfones. The selectivity switch of the V10-photocatalysed reaction brought about by water addition is most likely achieved by suppressing the formation of MEK-derived peroxide species. This journal is
- Li, Chifeng,Mizuno, Noritaka,Murata, Kei,Ishii, Kazuyuki,Suenobu, Tomoyoshi,Yamaguchi, Kazuya,Suzuki, Kosuke
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supporting information
p. 3896 - 3905
(2020/07/09)
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- Effect of Ligand Fields on the Reactivity of O2-Activating Iron(II)-Benzilate Complexes of Neutral N5 Donor Ligands
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Three new iron(II)-benzilate complexes [(N4Py)FeII(benzilate)]ClO4 (1), [(N4PyMe2)FeII(benzilate)]ClO4 (2) and [(N4PyMe4)FeII(benzilate)]ClO4 (3) of neutral pentadentate nitrogen donor ligands have been isolated and characterized to study their dioxygen reactivity. Single-crystal X-ray structures reveal a mononuclear six-coordinate iron(II) center in each case, where benzilate binds to the iron center in monodentate mode via one carboxylate oxygen. Introduction of methyl groups in the 6-positions of the pyridine rings makes the N4PyMe2 and N4PyMe4 ligand fields weaker compared to that of the parent N4Py ligand. All the complexes (1–3) react with dioxygen to decarboxylate the coordinated benzilate to benzophenone quantitatively. The decarboxylation is faster for the complex of the more sterically hindered ligand and follows the order 3>2>1. The complexes display oxygen atom transfer reactivity to thioanisole and also exhibit hydrogen atom transfer reactions with substrates containing weak C?H bonds. Based on interception studies with external substrates, labelling experiments and Hammett analysis, a nucleophilic iron(II)-hydroperoxo species is proposed to form upon two-electron reductive activation of dioxygen by each iron(II)-benzilate complex. The nucleophilic oxidants are converted to the corresponding electrophilic iron(IV)-oxo oxidant upon treatment with a protic acid. The high-spin iron(II)-benzilate complex with the weakest ligand field results in the formation of a more reactive iron-oxygen oxidant.
- Bhattacharya, Shrabanti,Paine, Tapan Kanti,Singh, Reena
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- Improved catalytic performance of Co-MOF-74 by nanostructure construction
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Herein, we demonstrate for the first time the construction of hollow structural Co-MOF-74, whose shell is as thin as ~50 nm and assembled by nanoparticles ranging from 8 to 18 nm. It exhibits high performance for the photocatalytic oxidation of thioanisole and thermocatalytic cyanosilylation of aldehydes.
- Cheng, Xiuyan,Han, Buxing,Wan, Qiang,Zhang, Bingxing,Zhang, Fanyu,Zhang, Jianling,Zhang, Jing,Zheng, Lirong
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supporting information
p. 5995 - 6000
(2020/10/18)
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- Copper Nanoparticles Immobilized on Nanocellulose: A Novel and Efficient Heterogeneous Catalyst for Controlled and Selective Oxidation of Sulfides and Alcohols
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In this work, we have described the versatility of low metal loading copper nanoparticles immobilized on nanocellulose for the controlled and selective oxidation of sulfides to sulfoxides and primary alcohols to aldehydes using green oxidant at room temperature. Aromatic, aliphatic and heterocyclic sulfides were oxidized to their corresponding sulfoxides with high yields without formation of over oxidized sulfones. Similarly, benzylic, allylic and aliphatic alcohols were selectively oxidized to aldehydes without traces of carboxylic acids in good to excellent yields.
- Dutta, Apurba,Chetia, Mitali,Ali, Abdul A.,Bordoloi, Ankur,Gehlot, Praveen S.,Kumar, Arvind,Sarma, Diganta
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p. 141 - 150
(2018/12/13)
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- Synthesis and nano-Pd catalyzed chemoselective oxidation of symmetrical and unsymmetrical sulfides
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A highly chemoselective, efficient and nano-Pd catalyzed protocol for the rapid construction of sulfoxides and sulfones via the oxidation of symmetrical and unsymmetrical sulfides using H2O2 as an oxidant has been developed, respectively. The ready availability of starting materials, easy recovery and reutilization of the catalyst, wide substrate scope, and high yields make this protocol an attractive alternative. The process also involves the metal-free and microwave-promoted synthesis of symmetrical diarylsulfides, and FeCl3-mediated preparation of symmetrical diaryldisulfides through the reaction of arenediazonium tetrafluoroborates with Na2S·9H2O as a sulfur source. In addition, unsymmetrical sulfides were generated via the K2CO3-mediated reaction of arenediazonium tetrafluoroborates with symmetrical disulfides.
- Li, Xing,Du, Jia,Zhang, Yongli,Chang, Honghong,Gao, Wenchao,Wei, Wenlong
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p. 3048 - 3055
(2019/03/21)
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- Versatile catalysis of “natural extract”: oxidation of sulfides and alcohols and ipso-hydroxylation of arylboronic acids
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Abstract: In the present work, we have described the versatile applications of naturally available inexpensive citrous lemon juice as biocatalyst for controlled oxidation of sulfides and alcohols and ipso-hydroxylation of arylboronic acids using 30% H2O2 as a green oxidant. A series of structurally divergent sulfides and benzyl alcohols were oxidized to their corresponding sulfoxides and aldehydes, respectively, with good-to-excellent yields. Similarly, aryl and heteroaryl boronic acids were rapidly, often within minutes, transformed to their corresponding phenols at room temperature. Graphic abstract: [Figure not available: see fulltext.]
- Dutta, Apurba,Ali, Abdul Aziz,Sarma, Diganta
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p. 2379 - 2388
(2019/06/28)
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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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p. 3381 - 3388
(2019/04/01)
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- Asymmetric sulfoxidation by C1-symmetric V(IV)O(ONO) (S)-NOBIN Schiff-base vanadyl complexes
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C1-symmetric vanadyl Schiff-base complexes were synthesized by reacting vanadium(IV) acetylacetonate with (S)-3-[(1-(2-hydroxynaphthalen-1-yl)naphthalen-2-ylimino]methyl]-phenanthrene-4-ol and (S)-2-{[1-(2-hydroxynaphthalen-1-yl)naphthalen-2-ylimino]methyl}tetraphene-1-ol. The complexes were characterized by MALDI-TOF-MS, UV-vis, and circular dichroism (CD) spectroscopy. The catalysts showed moderate activity for the oxidation of thioanisole to methyphenylsulfoxide with hydrogen peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide as the oxidants.
- Barman, Sanmitra,Levy, Christopher J.
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supporting information
p. 637 - 641
(2019/09/06)
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- Enhanced Activity and Substrate Specificity by Site-Directed Mutagenesis for the P450 119 Peroxygenase Catalyzed Sulfoxidation of Thioanisole
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P450 119 peroxygenase was found to catalyze the sulfoxidation of thioanisole and the sulfonation of sulfoxide in the presence of tert-butyl hydroperoxide (TBHP) for the first time with turnover rates of 1549 min?1 and 196 min?1 respectively. Several mutants were designed to improve the peroxygenation activity and thioanisole specificity by site-directed mutagenesis. The F153G/T213G mutant gave an increase of sulfoxide yield and a decrease of sulfone yield. Moreover the S148P/I161T/K199E/T214V mutant and the K199E mutant with acidic Glu residue contributed to improving the product ratio of sulfoxide to sulfone. Addition of short-alkyl-chain organic acids to the P450 119 peroxygenase-catalyzed sulfur oxidation of thioanisole was investigated. Octanoic acid was found to induce a preferred sulfoxidation of thioanisole catalyzed by the F153G/T213G mutant to give approximately 2.4-fold increase in turnover rate with a kcat value of 3687 min?1 relative to that of the wild-type, and by the F153G mutant to give the R-sulfoxide up to 30 % ee. The experimental control and the proposed mechanism for the P450 119 peroxygenase-catalyzed sulfoxidation of thioanisole in the presence of octanoic acid suggested that octanoic acid could partially occupy the substrate pocket; meanwhile the F153G mutation could enhance the substrate specificity, which could lead to efficiently regulate the spatial orientation of thioanisole and facilitate the formation of Compound I. This is the most effective catalytic system for the P450 119 peroxygenase-catalyzed sulfoxidation of thioanisole.
- Wei, Xiaoyao,Zhang, Chun,Gao, Xiaowei,Gao, Yanping,Yang, Ya,Guo, Kai,Du, Xi,Pu, Lin,Wang, Qin
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p. 1076 - 1083
(2019/07/15)
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- Incorporation of Ti as a Pyramidal Framework Site in the Mono-Layered MCM-56 Zeolite and its Oxidation Activity
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MWW zeolite MCM-56 with Al atoms on the surface was functionalized with Ti to produce pyramidal TiOH groups. This was carried out by removal of Al with nitric acid, calcination and treatment with titanium diisopropoxide bis(acetylacetonate) (Ti(acac)
- Korzeniowska, Aleksandra,Grzybek, Justyna,Roth, Wieslaw J.,Kowalczyk, Andrzej,Michorczyk, Piotr,?ejka, Ji?i,P?ech, Jan,Gil, Barbara
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p. 520 - 527
(2018/09/10)
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- METHOD FOR PRODUCING SULFOXIDE DERIVATIVE
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[Problem] To provide an industrially preferred method for producing a sulfoxide derivative. [Solution] A method for producing a sulfoxide derivative represented by general formula (1), the method being characterized in that a sulfide derivative represente
- -
-
Paragraph 0315-0317
(2019/03/08)
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- A novel homochiral metal-organic framework with an expanded open cage based on (: R)-3,3′-bis(6-carboxy-2-naphthyl)-2,2′-dihydroxy-1,1′-binaphthyl: synthesis, X-ray structure and efficient HPLC enantiomer separation
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A new homochiral metal-organic framework (MOF) with an expanded open cage based on the (R)-3,3′-bis(6-carboxy-2-naphthyl)-2,2′-dihydroxy-1,1′-binaphthyl ligand was synthesized and utilized as a novel chiral stationary phase for high-performance liquid chromatography. Twelve racemates including sec-alcohols, sulfoxides, epoxides, lactone, 1,3-dioxolan-2-one, and oxazolidinone were used as analytes for evaluating the separation properties of the chiral-MOF-packed column. Experimentally, the homochiral MOF offered good molecular recognition ability, which suggests good prospects for the application of chiral MOFs as stationary phases for enantioseparation.
- Tanaka, Koichi,Kawakita, Tomohiro,Morawiak, Maja,Urbanczyk-Lipkowska, Zofia
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p. 487 - 493
(2019/01/21)
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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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- Steric Tuning of Sulfinamide/Sulfoxides as Chiral Ligands with C1, Pseudo-meso, and Pseudo-C2 Symmetries: Application in Rhodium(I)-Mediated Arylation
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A new family of sulfinamide/sulfoxide derivatives was synthesized as chiral bidentate ligands by stereoselective additions of methylsulfinyl carbanions to N-tert-butylsulfinylimines. The new ligands, with C1, pseudo-meso, and pseudo-C2 symmetries, were successfully assayed in Rh-catalyzed additions of arylboronic acids to activated ketones. The sterically dissymmetric C1 ligand (RS,SC,RS)-N-[1-(phenylsulfinyl)-3-methylbut-2-yl] tert-butylsulfinamide turned out to be the optimal one, allowing the 1,4-additions of diverse arylboronic acids, on different α,β-unsaturated cyclic ketones with high chemical yields and enantioselectivities up to >99% ee.
- Borrego, Lorenzo G.,Recio, Rocío,álvarez, Eleuterio,Sánchez-Coronilla, Antonio,Khiar, Noureddine,Fernández, Inmaculada
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supporting information
p. 6513 - 6518
(2019/08/20)
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- Photocatalytic Properties and Mechanistic Insights into Visible Light-Promoted Aerobic Oxidation of Sulfides to Sulfoxides via Tin Porphyrin-Based Porous Aromatic Frameworks
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Using concepts of biomimetic catalysis, a kind of tin porphyrin-based porous aromatic framework (SnPor@ PAF) with broad and strong optical absorption in the visible light region was successfully synthesized and subsequently used in the aerobic oxidation of sulfides to sulfoxides under ambient conditions and visible light irradiation, in which exhibited enzyme-like features of high efficiency and high selectivity. More interestingly, heterogeneous SnPor@PAF was naturally regarded as an intriguing and versatile photosensitizer for photocatalytic transformation and could be reused several times because of its robust and rigid porphyrin framework. As expected, their π-conjugated structure characteristic in the molecular skeleton might facilitate the activation of molecular oxygen under mild reaction conditions and promoted the production of reactive oxygen species (singlet oxygen (1O2) and superoxide radical anion (O2.?)), which would involve energy transfer and/or electron transfer process. Experimental investigations including emission quenching experiment, oxygen-isotope labelling, typical inhibition experiments, classical fluorescence probe study, photo-oxidation of α-terpinene and in situ electron spin resonance, could provide a mechanistic insight into the photocatalytic reactions. (Figure presented.).
- Jiang, Jun,Luo, Rongchang,Zhou, Xiantai,Chen, Yaju,Ji, Hongbing
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supporting information
p. 4402 - 4411
(2018/10/15)
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- One-Pot Unsymmetrical {[4 + 2] and [4 + 2]} Double Annulations of o/ o′-C-H Bonds of Arenes: Access to Unusual Pyranoisoquinolines
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With the aid of a transformable sulfoximine directing group, unprecedented one-pot unsymmetrical double annulations {[4 + 2] and [4 + 2]} of hetero(arenes) with alkynes are revealed under Ru(II) catalysis. Functionalization of both ortho-C-H bonds of (hetero)arene is reflected in the building of unusual 6,6-fused pyranoisoquinoline skeletons. Construction of four [(C-C)-(C-N) and (C-C)-(C-O)] bonds occurs in one step under single catalytic conditions. The challenging unsymmetrical double annulations of both o-C-H bonds of arenes with two distinct alkynes is effectively demonstrated. Control experiments and deuterium scrambling findings are shown.
- Shankar, Majji,Ghosh, Koushik,Mukherjee, Kallol,Rit, Raja K.,Sahoo, Akhila K.
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p. 5144 - 5148
(2018/09/13)
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- Schiff base Mn(III) and Co(II) complexes coated on Co nanoparticles: An efficient and recyclable magnetic nanocatalyst for H2O2 oxidation of sulfides to sulfoxides
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In this paper, an effective and selective heterogeneous catalyst was produced by immobilization of manganese and cobalt Schiff base-complexes on Co magnetite nanoparticles (MNP). The catalysts Co@SiO2[(EtO)3Si-L3]/M (M = Mn(iii) and Co(ii)) were synthesized using Co@SiO2 core-shell nanoparticles and amino-functionalized Co@SiO2. The Schiff base ligand Co@SiO2[(EtO)3Si-L3] was synthesized by reacting Co@SiO2 core-shell nanoparticles with 2-hydroxy 1-naphthaldehyde for the synthesis of Co@SiO2[(EtO)3Si-L3]/M. The catalysts were characterized by several techniques, such as FT-IR, TEM, XRD, TGA and VSM. The catalytic activities of the prepared catalysts were studied by oxidation of sulfides to the sulfoxides under different conditions. These catalysts can be easily recovered and reused in at least seven sequential cycles without considerable leaching and loss of reactivity.
- Saremi, Shokoufeh Ghahri,Keypour, Hassan,Noroozi, Mohammad,Veisi, Hojat
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p. 3889 - 3898
(2018/02/07)
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- Aluminum(III) Chloride Promoted Oxygen Transfer: Selective Oxidation of Sulfides to Sulfoxides
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An efficient selective oxidation of sulfides to sulfoxides has been developed by means of AlCl 3 -promoted oxygen transfer from phenyliodine diacetate [PhI(OAc) 2 ]. AlCl 3 proved to be the optimalLewis acid for the activation of PhI(OAc) 2. Various substituted sulfides were selectively transformed into the corresponding sulfoxides in good to excellent yields (≤99%). The high efficiency, excellent functional-group compatibility, broad substrate scope, and mild conditions render the current transformation useful for the synthesis of sulfoxides.
- Xie, Yongtao,Li, Yuxin,Zhou, Sha,Zhou, Shaa,Zhang, Yan,Chen, Minggui,Li, Zhengming
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supporting information
p. 340 - 343
(2017/12/06)
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- Green synthesis of PbCrO4 nanostructures using gum of ferula assa-foetida for enhancement of visible-light photocatalytic activity
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Photocatalytic selective oxidation has attracted considerable attention as an environmentally friendly strategy for organic transformations. Some methods have been reported for the photocatalytic oxidation of sulfides into sulfoxides in recent years. Howe
- Zhiani, Rahele,Es-Haghi, Ali,Sadeghzadeh, Seyed Mohsen,Shamsa, Farzaneh
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p. 40934 - 40940
(2019/01/03)
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- Molybdenum-catalyzed enantioselective sulfoxidation controlled by a nonclassical hydrogen bond between coordinated chiral imidazolium-based dicarboxylate and peroxido ligands
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Chiral alkyl aryl sulfoxides were obtained by molybdenum-catalyzed oxidation of alkyl aryl sulfides with hydrogen peroxide as oxidant in mild conditions with high yields and moderate enantioselectivities. The asymmetry is generated by the use of imidazoli
- Carrasco, Carlos J,Montilla, Francisco,Galindo, Agustín
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- Biocatalytical Asymmetric Sulfoxidation by Identifying Cytochrome P450 from Parvibaculum Lavamentivorans DS-1
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Cytochrome P450 monooxygenases (P450s) catalyzed asymmetric sulfoxidation represents a green route for the synthesis of valuable enantiopure sulfoxides, which are potentially interesting synthons in synthetic and pharmaceutical chemistry. Here the potential P450 and redox partner genes from Parvibaculum lavamentivorans DS-1 are screened and co-expressed in Escherichia coli host to construct twenty recombinant P450 strains. By testing the whole-cell biooxidation of thioanisole, P450PL2 (CYP278A4) and P450PL7 (CYP108G3) are identified with excellent S enantioselectivity while P450PL1 (CYP111B1) and P450PL9 (CYP153A26) exhibit the complementary R enantioselectivity. Asymmetric sulfoxidation of sulfides 1 a–1 m is further investigated using the recombinant E. coli strain P450PL2-2 based on the optimal conditions, producing the corresponding enantioenriched sulfoxides with up to 82 % isolated yield and 99 % ee.
- Wu, Kailin,Tang, Linchao,Cui, Haibo,Wan, Nanwei,Liu, Ziyan,Wang, Zhongqiang,Zhang, Shimin,Cui, Baodong,Han, Wenyong,Chen, Yongzheng
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p. 5410 - 5413
(2018/11/23)
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- Panel of New Thermostable CYP116B Self-Sufficient Cytochrome P450 Monooxygenases that Catalyze C?H Activation with a Diverse Substrate Scope
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The ability of cytochrome P450 monooxygenases to catalyse a wide variety of synthetically challenging C?H activation reactions makes them highly desirable biocatalysts both for the synthesis of chiral intermediates and for late-stage functionalisations. However, P450s are plagued by issues associated with poor expression, solubility and stability. Catalytically self-sufficient P450s, in which the haem and reductase domains are fused in a single protein, obviate the need for additional redox partners and are attractive as biocatalysts. Here we present a panel of natural self-sufficient P450s from thermophilic organisms (CYP116B65 from A. thermoflava, CYP116B64 from A. xiamenense, CYP116B63 from J. thermophila, CYP116B29 from T. bispora and CYP116B46 from T. thermophilus). These P450s display enhanced expression and stability over their mesophilic homologues. Activity profiling of these enzymes revealed that each P450 displayed a different fingerprint in terms of substrate range and reactivity that cover reactions as diverse as hydroxylation, demethylation, epoxidation and sulfoxidation. The productivity of the bio-transformation of diclofenac to produce the 5-hydroxy metabolite increased 42-fold using the thermostable P450-AX (>0.5 g L?1 h?1) compared to the P450-RhF system reported previously. In conclusion, we have generated a toolkit of thermostable self-sufficient P450 biocatalysts with a broad substrate range and reactivity.
- Tavanti, Michele,Porter, Joanne L.,Sabatini, Selina,Turner, Nicholas J.,Flitsch, Sabine L.
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p. 1042 - 1051
(2018/03/21)
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- Diastereoselective Synthesis and Catalytic Activity of Two Chiral cis-Dioxidomolybdenum(VI) Complexes
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Two enantiomerically pure chiral dioxidomolybdenum(VI) complexes (1 and 2) of the type [MoO2L] (L = dianionic, tetradentate ONNO-ligand) were synthesized and investigated in enantioselective oxidation reactions. The solid-state structures of complex 1 and 2, determined via single-crystal X-ray diffraction analysis revealed two fundamentally different coordination geometries: a C1-symmetric cis-β isomer (Λ-1), and a C2-symmetric cis-α isomer (Δ-2). In both cases, only one of the two possible helical enantiomers (Λ- or Δ-helix) was formed. The complexes were examined as precatalysts in the epoxidation of the challenging prochiral substrate trans-stilbene, using either tert-butyl hydroperoxide (TBHP) or cumyl hydroperoxide (CHP) as oxidants. The asymmetric cis-β complex 1 was found to be significantly more active in the epoxidation than its cis-α counterpart 2, asymmetric induction was, however, negligible for both complexes. The complexes were also tested in catalytic enantioselective sulfoxidation reactions where chiral induction could be achieved, albeit small. The observed putative molybdenum oxido-peroxido intermediate 1-O2 could be identified as an important precomplex before formation of the active catalyst in sulfoxidation.
- Haghdoost, Mohammad Mehdi,Zwettler, Niklas,Golbaghi, Golara,Belaj, Ferdinand,Bagherzadeh, Mojtaba,Schachner, J?rg A.,M?sch-Zanetti, Nadia C.
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p. 2549 - 2556
(2018/06/04)
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- Bioinspired Olefin cis-Dihydroxylation and Aliphatic C-H Bond Hydroxylation with Dioxygen Catalyzed by a Nonheme Iron Complex
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A mononuclear iron(II)-α-hydroxy acid complex [(TpPh,Me)FeII(benzilate)] (TpPh,Me = hydrotris(3-phenyl-5-methylpyrazol-1-yl)borate) of a facial tridentate ligand has been isolated and characterized to explore its catalytic efficiency for aerial oxidation of organic substrates. In the reaction between the iron(II)-benzilate complex and O2, the metal-coordinated benzilate is stoichiometrically converted to benzophenone with concomitant reduction of dioxygen on the iron center. Based on the results from interception experiments and labeling studies, different iron-oxygen oxidants are proposed to generate in situ in the reaction pathway depending upon the absence or presence of an external additive (such as protic acid or Lewis acid). The five-coordinate iron(II) complex catalytically cis-dihydroxylates olefins and oxygenates the C-H bonds of aliphatic substrates using O2 as the terminal oxidant. The iron(II) complex exhibits better catalytic activity in the presence of a Lewis acid.
- Chatterjee, Sayanti,Bhattacharya, Shrabanti,Paine, Tapan Kanti
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p. 10160 - 10169
(2018/08/28)
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- Nanoarchitecturing of open metal site Cr-MOFs for oxodiperoxo molybdenum complexes [MoO(O2)2@En/MIL-100(Cr)] as promising and bifunctional catalyst for selective thioether oxidation
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In this work, open metal site metal-organic framework of MIL-100(Cr) was selected as a support for the multi-step grafting of molybdenum complexes. The oxodiperoxo molybdenum complexes were coordinated onto the ethylene diamine-decorated MIL-100(Cr) pore
- Rostamnia, Sadegh,Mohsenzad, Farahnaz
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- Zeolite nanoparticles (H-ZSM5) as a highly efficient, green, and reusable heterogeneous catalyst for selective oxidation of sulfides to sulfoxides under mild conditions
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H-ZSM5 is applied as an efficient, highly reusable, and heterogeneous catalyst for the oxidation of sulfides to sulfoxides using 30% H2O2 under solvent-free conditions at room temperature. A variety of aromatic and aliphatic sulfides with different functional groups were successfully oxidized with good to excellent yields in short reaction times. The catalyst can be easily recovered by simple filtration and recycled for several consecutive runs without any significant loss of its catalytic activity.
- Rostami, Amin,Saedmocheshi, Noosheen,Shirvandi, Zeinab
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p. 835 - 839
(2018/06/20)
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