- Radical Ion Probes. 7. Behavior of a "Hypersensitive" Probe for Single Electron Transfer in Reactions Not Involving Electron Transfer
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1-Methyl-5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one (8) and 1,1-dimethyl-5,7-di-tert-butylspiro-[2.5]octa-4,7-dien-6-one (1) react with thiophenoxide ion to produce cyclopropane ring-opened products. Thermodynamic considerations effectively rule out any possibility that single electron transfer is involved in theses reactions; the process PhS- + substrate → PhS. + substrate.- is endothermic by over 50 kcal/moll Nucleophilic attack occurs both at the least- and most-hindered carbons of the cyclopropyl group, and the product ratio (R(1°/2°) from 8 and A(1°/3°) from 1, where 1°, 2°, and 3° refer to the regioisomeric phenyl sulfides formed from these substrates) is found to vary with solvent. In dipolar, aprotic solvents, nucleophilic attack occurs preferentially at the least-hindered carbon of the cyclopropyl group (A(1°/2°) and A(1°/3°) ≈ 4-5), consistent with an SN2 mechanism. In protic solvents, products arising from nucleophilic attack at the more-substituted carbon of the cyclopropyl group become increasingly important, consistent with the onset of a carbocationic (SN2(C+)) pathway. The strengths and weaknesses of 1 and 8 as probes for single electron transfer are discussed in the context of these results.
- Tanko, James M.,Brammer Jr., Larry E.
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Read Online
- Production of Alkyl Aryl Sulfides from Aromatic Disulfides and Alkyl Carboxylates via a Disilathiane–Disulfide Interchange Reaction
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The results of this study show that disilathiane is an effective mediator in the synthesis of alkyl aryl sulfides with disulfides and alkyl carboxylates. Mechanistic studies suggest that disilathiane promotes cleavage of the sulfur–sulfur bond of disulfides to generate thiosilane as a key intermediate. Diselenides were also applicable to this transformation to produce the corresponding selenides.
- Nakajima, Takumi,Takano, Ken,Maeda, Hiromu,Ogiwara, Yohei,Sakai, Norio
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supporting information
p. 4103 - 4107
(2021/11/10)
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- Nickel-catalyzed carbonylation of thioacetates with aryl iodides via CO insertion and C–S bond cleavage
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Aryl thioesters are synthesized via nickel-catalyzed carbonylation of thioacetates with aryl iodides. Alkyl thioacetates undergo coupling with carbon monoxide and aryl iodides to produce the desired aryl thioesters in moderate yields. This catalytic carbonylative coupling process provides a cost-effective and direct approach for the preparation of useful thioesters.
- Lu, Kui,Lv, Ming-Xiu,Mai, Wen-Peng,Sui, Hong-Da
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p. 890 - 895
(2021/07/02)
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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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- Palladium complex containing meta-position carborane triazole ligand and preparation method and application of palladium complex
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The invention relates to a palladium complex containing a meta-position carborane triazole ligand and a preparation method and application of the palladium complex. The palladium complex is prepared by the following steps: (1) dropwise adding an n-BuLi solution into a meta-position carborane m-C2B10H12 solution, carrying out stirring and reacting, then adding 3-propargyl bromide for a reaction again, and after the reaction is finished, carrying out separating to obtain 1,3-dipropargyl meta-carborane; and (2) under the catalytic condition of a catalyst CuI, carrying out a reaction on 1,3-dipropargyl meta-carborane and aryl azide, then adding PdCl2 into a reaction system, continuing the reaction, and after the reaction is finished, carrying out separation to obtain the palladium complex containing the meta-carborane triazole ligand. Compared with the prior art, the preparation method provided by the invention is simple and green; the complex can efficiently catalyze a coupling reaction of mercaptan and halogenated hydrocarbon to synthesize thioether compounds; reaction conditions are mild, substrate universality is good, catalytic efficiency is high, and few byproducts are produced;and the catalyst has high stability and is not sensitive to air and water.
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Paragraph 0041-0043
(2020/08/07)
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- Sulfoxide-Promoted Chlorination of Indoles and Electron-Rich Arenes with Chlorine as Nucleophile
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An efficient chlorination of indoles and electron-rich arenes with chlorine anion as nucleophile is described. With the use of ethyl phenyl sulfoxide as the promoter, the reaction went smoothly under metal-free and mild conditions. Various indoles and electron-rich arenes are converted into the corresponding chlorinated compounds in moderate to excellent yields. A plausible interrupted Pummerer reaction mechanism was proposed without the oxidation of chloride anion. In addition, the byproduct thioether could be easily converted to the starting material sulfoxide just by a simple oxidation reaction. (Figure presented.).
- Ji, Yuan-Zhao,Li, Hui-Jing,Wang, Yi-Ruo,Wu, Yan-Chao,Zhang, Zheng-Yan
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supporting information
(2020/02/05)
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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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- Generation of Aryl Radicals from Aryl Halides: Rongalite-Promoted Transition-Metal-Free Arylation
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A new and practical method for the generation of aryl radicals from aryl halides is reported. Rongalite as a novel precursor of super electron donors was used to initiate a series of electron-catalyzed reactions under mild conditions. These transition-metal-free radical chain reactions enable the efficient formation of C-C, C-S, and C-P bonds through homolytic aromatic substitution or SRN1 reactions. Moreover, the synthesis of antipsychotic drug Quetiapine was performed on gram scale through the described method. This protocol demonstrated its potential as a promising arylation method in organic synthesis.
- Yu, Fazhi,Mao, Runyu,Yu, Mingcheng,Gu, Xianfeng,Wang, Yonghui
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p. 9946 - 9956
(2019/09/04)
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- Corey-Chaykovsky Cyclopropanation of Nitronaphthalenes: Access to Benzonorcaradienes and Related Systems
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Nitronaphthalene derivatives react as Michael acceptors in the Corey-Chaykovsky reaction with alkyl phenyl selenones and alkyl diphenyl sulfonium salts. Mechanistic studies reveal that sterically demanding substituents at the carbanionic center favor formation of cyclopropanes and suppress competitive β-elimination to the alkylated products. The transformation, demonstrated also on heterocyclic nitroquinoline and nitroindazolines, is an example of transition metal-free dearomatization method.
- Antoniak, Damian,Barbasiewicz, Micha?
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supporting information
p. 9320 - 9325
(2019/11/19)
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- Copper-Catalyzed Three-Component Coupling Reaction of Aryl Iodides, a Disilathiane, and Alkyl Benzoates Leading to a One-Pot Synthesis of Alkyl Aryl Sulfides
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A copper-catalyzed three-component coupling reaction of aryl iodides, hexamethyldisilathiane and alkyl benzoates leading to alkyl aryl sulfides has been demonstrated. A disilathiane acted as both a sulfur source and a promoter of the sulfidation, and the alkyl moiety of the alkyl benzoate was effectively introduced on one side of the sulfide. Moreover, we found that the protocol can be expanded to the preparation of ethyl phenyl selenide with diphenyl diselenide.
- Sakai, Norio,Maeda, Hiromu,Ogiwara, Yohei
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p. 2323 - 2330
(2019/05/24)
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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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- Visible light-promoted formation of C-B and C-S bonds under metal- A nd photocatalyst-free conditions
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A green, efficient, photoinduced synthesis of arylboronic esters and aryl sulfides has been developed. Bench stable arylazo sulfones were used as radical precursors for a photocatalyst- A nd additive-free carbon-heteroatom bond formation under visible light. The protocols are applicable to a wide range of substrates, providing products in good yields.
- Blank, Lena,Fagnoni, Maurizio,Protti, Stefano,Rueping, Magnus
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p. 1243 - 1252
(2019/02/26)
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- 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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- 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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- Nano CoCuFe2O4-catalyzed coupling reaction of arylboronic acid with amines and thiols: An atom-economic and ligand-free route to access unsymmetrical amines and sulfides
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An efficient protocol was developed for the nano CoCuFe2O4-catalyzed C-N and C-S bond formation. By this catalytic system, both amine and sulfide-based structural motifs were formed efficiently in aryl halide-free route. The amination reaction of phenyl boronic acid with various types of amines was conducted under ligand-free conditions, in ethanol as a green solvent at 60°C. Unsymmetrical diaryl/aryl alkyl sulfide synthesis via the coupling reaction of arylboronic acids with thiols was also conducted. The nano cobalt-copper ferrite was used as a heterogenous efficient, inexpensive, magnetically separable and recyclable catalyst that can be used for several cycles.
- Moghaddam, Firouz Matloubi,Pourkaveh, Raheleh,Gholamtajari, Milad
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- Transalkylation of alkyl aryl sulfides with alkylating agents
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The reaction of methyl iodide with tert-butylphenylsulfide in DMF leads to a transalkylation that produces methylphenylsulfide. This transalkylation reaction was further studied by 1H NMR spectroscopy. The polarity of the solvent, the electron density on the sulfur atom, and the strength of the alkylating agent (MeI, EtI, BuI, dimethyl sulfate, or dimethyl carbonate) played important roles in the reaction. The suggested mechanism of the reaction involves the formation of a dialkyl aryl sulfonium salt that subsequently eliminates the radical. This mechanism was supported by the observation of higher conversion rates for compounds with more branched alkyl groups on the sulfur atom, which may lead to the formation of more stable radicals.
- Nawrot, Daria,Koleni?, Marek,Kune?, Ji?í,Kostelansky, Filip,Miletin, Miroslav,Novakova, Veronika,Zimcik, Petr
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p. 594 - 599
(2018/01/01)
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- One-pot synthesis of α-phenylsulfinyl ketones by reaction of phenyl benzenethiosulfinate with enolate anions, and synthesis of sulfoxides and sulfides by its reaction with Grignard reagents
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Phenyl benzenethiosulfinate reacts with enolate anions derived from ketones to give α-phenylsulfinyl ketones directly, together with minor amounts of α-phenylsulfanyl ketones. These are easily separated by forming the water-soluble sodium salts of the sulfinyl compounds. Grignard reagents also react with phenyl benzenethiosulfinate, to give mixtures of sulfoxides and sulfides.
- Fakhry, Jerome,Grayson, David H.
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p. 556 - 563
(2017/12/28)
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- CYCLOPROPYL DERIVATIVES AS ROR-GAMMA MODULATORS
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The present invention provides compounds which are modulators of RORγ and their use for the treatment of diseases or conditions mediated by RORγ. Further, the present invention relates to processes of preparing such compounds, their tautomeric forms, novel intermediates involved in their synthesis, their pharmaceutically acceptable salts, methods for using such compounds and pharmaceutical compositions containing them (Formula I).
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Page/Page column 39
(2018/03/02)
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- C-H Alkenylation of Heteroarenes: Mechanism, Rate, and Selectivity Changes Enabled by Thioether Ligands
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Thioether ancillary ligands have been identified that can greatly accelerate the C-H alkenylation of O-, S-, and N-heteroarenes. Kinetic data suggest thioether-Pd-catalyzed reactions can be as much as 800× faster than classic ligandless systems. Furthermore, mechanistic studies revealed C-H bond cleavage as the turnover-limiting step, and that rate acceleration upon thioether coordination is correlated to a change from a neutral to a cationic pathway for this key step. The formation of a cationic, low-coordinate catalytic intermediate in these reactions may also account for unusual catalyst-controlled site selectivity wherein C-H alkenylation of five-atom heteroarenes can occur under electronic control with thioether ligands even when this necessarily involves reaction at a more hindered C-H bond. The thioether effect also enables short reaction times under mild conditions for many O-, S-, and N-heteroarenes (55 examples), including examples of late-stage drug derivatization.
- Gorsline, Bradley J.,Wang, Long,Ren, Peng,Carrow, Brad P.
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supporting information
p. 9605 - 9614
(2017/07/24)
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- Copper nanoparticles supported on polyaniline-functionalized multiwall carbon nanotubes: An efficient and recyclable catalyst for synthesis of unsymmetric sulfides using potassium ethyl xanthogenate in water
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A new and powerful polyaniline-functionalized carbon nanotube-supported copper(II) nanoparticle catalyst was successfully prepared and evaluated as a heterogeneous catalyst for the one-pot synthesis of unsymmetric thioethers by coupling of aryl, alkyl and benzyl halides using potassium ethyl xanthogenate as source of sulfur in water. All of these reactions gave the desired products in good to excellent yields. The catalyst is available, air-stable and can be reused several times without significant loss in its catalytic activity.
- Hajipour, Abdol R.,Jajarmi, Saeideh,Khorsandi, Zahra
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- B(C6F5)3-Catalyzed Deoxygenation of Sulfoxides and Amine N-Oxides with Hydrosilanes
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An efficient strategy for the deoxygenation of sulfoxides and amine N-oxides by using B(C6F5)3 and hydrosilanes was developed. This method provided the corresponding aromatic and aliphatic products in good to high yields and showed good functional-group tolerance under mild conditions.
- Ding, Fangwei,Jiang, Yanqiu,Gan, Shaoyan,Bao, Robert Li-Yuan,Lin, Kaifeng,Shi, Lei
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p. 3427 - 3430
(2017/07/04)
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- Exploring Regioselective Bond Cleavage and Cross-Coupling Reactions using a Low-Valent Nickel Complex
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Recently, esters have received much attention as transmetalation partners for cross-coupling reactions. Herein, we report a systematic study of the reactivity of a series of esters and thioesters with [{(dtbpe)Ni}2(μ-η2:η2-C6H6)] (dtbpe=1,2-bis(di-tert-butyl)phosphinoethane), which is a source of (dtbpe)nickel(0). Trifluoromethylthioesters were found to form η2-carbonyl complexes. In contrast, acetylthioesters underwent rapid Cacyl-S bond cleavage followed by decarbonylation to generate methylnickel complexes. This decarbonylation could be pushed backwards by the addition of CO, allowing for regeneration of the thioester. Most of the thioester complexes were found to undergo stoichiometric cross-coupling with phenylboronic acid to yield sulfides. While ethyl trifluoroacetate was also found to form an η2-carbonyl complex, phenyl esters were found to predominantly undergo Caryl-O bond cleavage to yield arylnickel complexes. These could also undergo transmetalation to yield biaryls. Attempts to render the reactions catalytic were hindered by ligand scrambling to yield nickel bis(acetate) complexes, the formation of which was supported by independent syntheses. Finally, 2-naphthyl acetate was also found to undergo clean Caryl-O bond cleavage, and although stoichiometric cross-coupling with phenylboronic acid proceeded with good yield, catalytic turnover has so far proven elusive. The reactivity of a low-valent nickel complex with esters and thioesters is reported. Trifluoromethylthioesters were found to form η2-carbonyl complexes, while acetylthioesters were found to undergo further Cacyl-S oxidative addition and decarbonylation to generate methylnickel complexes. In contrast, the same nickel precursor was found to induce Caryl-O bond cleavage in aryl esters to generate arylnickel acetate complexes (see scheme).
- Desnoyer, Addison N.,Friese, Florian W.,Chiu, Weiling,Drover, Marcus W.,Patrick, Brian O.,Love, Jennifer A.
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supporting information
p. 4070 - 4077
(2016/03/16)
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- Hydrogenative Kinetic Resolution of Vinyl Sulfoxides
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Enantiopure sulfoxides are valuable precursors of organosulfur compounds with broad application in organic and pharmaceutical chemistry. An unprecedented strategy for obtaining highly enantioenriched sulfoxides based on a hydrogenative kinetic resolution using Rh-complexes of phosphine-phosphite ligands as catalysts is reported. After optimization, highly efficient conditions for the kinetic resolution of racemic sulfoxides have been identified. This methodology has been applied to a set of racemic aralkyl or aryl vinyl sulfoxides and allowed the isolation of both recovered and reduced products in excellent yields and enantioselectivities (up to 99% and 97% ee, respectively; 16 examples).
- Lao, Joan R.,Fernndez-Prez, Hctor,Vidal-Ferran, Anton
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supporting information
p. 4114 - 4117
(2015/09/01)
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- Boron-Catalyzed N-Alkylation of Amines using Carboxylic Acids
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A boron-based catalyst was found to catalyze the straightforward alkylation of amines with readily available carboxylic acids in the presence of silane as the reducing agent. Various types of primary and secondary amines can be smoothly alkylated with good selectivity and good functional-group compatibility. This metal-free amine alkylation was successfully applied to the synthesis of three commercial medicinal compounds, Butenafine, Cinacalcet. and Piribedil, in a one-pot manner without using any metal catalysts.
- Fu, Ming-Chen,Shang, Rui,Cheng, Wan-Min,Fu, Yao
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supporting information
p. 9042 - 9046
(2015/08/03)
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- 1,2,3-Triazolylidene ruthenium(ii)-cyclometalated complexes and olefin selective hydrogenation catalysis
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Silver(i) 1,2,3-triazol-5-ylidenes [(RCH2C2N2(NMe)Ph)2Ag][AgCl2] (R = Ph 3a, C6H2iPr33b, C6H2Me33c) and [(PhCH2C2N2(NMe)R)2Ag][AgCl2] (R = C6H4Me 3d, C6H4CF33e) were synthesized and subsequently treated with RuHCl(PPh3)3 and RuHCl(H2)(PCy3)2. The reaction of 3a with RuHCl(PPh3)3 gave RuHCl(PPh3)2(PhCH2C2N2(NMe)Ph) (4a1) as the minor product and the cyclometalated complex RuCl(PPh3)2(PhCH2C2N2(NMe)C6H4) (4a2) as the major product. However, similar reaction with 3b selectively formed the cyclometalated complex RuCl(PPh3)2((C6H2iPr3)CH2C2N2(NMe)C6H4) (4b2). Similarly the silver(i) triazolylidenes 3a and 3b were reacted with RuHCl(H2)(PCy3)2; gave RuHCl(PCy3)2(PhCH2C2N2(NMe)Ph) (5a1), RuCl(PCy3)2(PhCH2C2N2(NMe)C6H4) (5a2) and RuCl(PCy3)2((C6H2iPr3)CH2C2N2(NMe)C6H4) (5b2), respectively. Species 3c, 3d and 3e resulted in the cyclometalated complexes (5c2, 5d2 and 5e2) as the major products as well as the ruthenium-hydride complexes (5c1, 5d1 and 5e1) as the minor products. The cyclometalated species are derived from the ruthenium-hydride complexes via C(sp2)-H activation. These Ru-complexes were shown to act as hydrogenation catalyst precursors for olefinic substrates including those containing a variety of functional groups. This journal is
- Bagh, Bidraha,McKinty, Adam M.,Lough, Alan J.,Stephan, Douglas W.
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p. 2712 - 2723
(2015/02/19)
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- Efficient Oxidation of Sulfides to Sulfoxides and Deoxygenation of Sulfoxides over Carbonaceous Solid Acid
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Carbonaceous Solid Acid (CSA) was found to be a highly efficient, environmentally friendly, recyclable heterogeneous solid acid for the oxidation of sulfides and deoxygenation of sulfoxides, in good to excellent yields under mild reaction conditions.
- Atabaki, Fariborz,Abedini, Ebrahim,Shokrolahi, Arash
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p. 1169 - 1176
(2015/08/04)
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- Half sandwich ruthenium(ii) hydrides: Hydrogenation of terminal, internal, cyclic and functionalized olefins
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Bis(1,2,3-triazolylidene) silver(i) complex 1a was reacted with [RuCl2(p-cymene)]2 to give the ruthenium complex [PhCH2N2(NMe)C2(C6H4CF3)]RuCl2(p-cymene) (2a) as major product in addition to the minor C(sp2)-H activated product [PhCH2N2(NMe)C2(C6H3CF3)]RuCl(p-cymene) (2a′). Similar ruthenium complexes 2b, 2c, 2d and 2e with general formula RuCl2(p-cymene)(NHC) (NHC = MesCH2N2(NMe)C2Ph 2b, PhCH2N2(NMe)C2Ph 2c, TripCH2N2(NMe)C2Ph 2d, IMes 2e) were also synthesized. Subsequent reaction of Me3SiOSO2CF3 with 2a and 2b resulted in cationic ruthenium species [(PhCH2N2(NMe)C2(C6H4CF3))RuCl(p-cymene)][OSO2CF3] (3a) and [(MesCH2N2(NMe)C2Ph)RuCl(p-cymene)][OSO2CF3] (3b), respectively. Complexes 3a and 3b dissolved in CD3CN to give [(PhCH2N2(NMe)C2(C6H4CF3))RuCl(CD3CN)(p-cymene)][OSO2CF3] (4a) and [(MesCH2N2(NMe)C2Ph)RuCl(CD3CN)(p-cymene)][OSO2CF3] (4b), respectively. Cationic ruthenium species 4a and 4b failed to show catalytic activity towards hydrogenation of olefins. Ruthenium(ii) complexes 2b-e with the general formula RuCl2(p-cymene)(NHC) were reacted with Et3SiH to generate a series of ruthenium(ii) hydrides 5b-e. These compounds 5b-e are effective catalysts for the hydrogenation of terminal, internal and cyclic and functionalized olefins.
- Bagh, Bidraha,Stephan, Douglas W.
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p. 15638 - 15645
(2015/01/08)
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- Reduction of alkenes catalyzed by copper nanoparticles supported on diamond nanoparticles
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Copper nanoparticles (Cu NPs) supported on diamond nanoparticles (D NPs) previously purified by Fenton treatment (Cu/D) followed by annealing with hydrogen (Cu/DH) are highly efficient and reusable heterogeneous catalysts for hydrogenation of styrene to ethylbenzene with the minimum productivity value of 30617 cycles. The Royal Society of Chemistry.
- Dhakshinamoorthy, Amarajothi,Navalon, Sergio,Sempere, David,Alvaro, Mercedes,Garcia, Hermenegildo
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supporting information
p. 2359 - 2361
(2013/07/05)
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- Gas-phase S-alkylation of benzenethiol with aliphatic alcohols, ethers, esters, alkyl halides and olefins over halide cluster catalysts of Groups 5 and 6 transition metals
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Benzenethiol was reacted with methanol under a hydrogen stream over [(Nb6Cl12)Cl2(H2O) 4]·6H2O supported on silica gel. Catalytic activity of the cluster commenced above 250 °C, yielding methyl phenyl sulfide. The selectivity was 98% at 400 °C. Molybdenum, tantalum and tungsten halide clusters with the same octahedral metal framework also catalyzed the reaction. Primary alcohols with shorter alkyl chains were effective reagents for the S-alkylation. Aliphatic ethers, dialkyl carbonates, orthoesters and alkyl halides were effective reagents for the S-alkylation. When 1-hexene was applied to the reaction, spontaneous and catalytic S-alkylation proceeded simultaneously above 200 °C, yielding n-hexyl phenyl sulfide. When alkyl acetates were subjected to this reaction, the niobium cluster afforded S-phenyl thioacetate, and the other clusters afforded alkyl phenyl sulfides selectively. A Br?nsted acid site attributable to a hydroxo ligand, which is formed on the cluster complex by thermal activation, is proposed as the active site of the catalysts.
- Nagashima, Sayoko,Kudo, Kentaro,Yamazaki, Hitomi,Kamiguchi, Satoshi,Chihara, Teiji
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- Sulfoxide-to-sulfilimine conversions: Use of modified Burgess-type reagents
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Sulfoxides can directly be converted into N-cyanosulfilimines using a new Burgess-type reagent. By applying this strategy with a related reagent variant, synthetically valuable NH-sulfoximines have been prepared from sulfoxides via N-protected sulfilimines. The practical three-step reaction sequence is generally high yielding and applicable to a wide range of substrates. The sulfoxide-to-sulfilimine conversion can also be performed under solvent-reduced conditions in a ball mill. Copyright
- Hendriks, Christine M. M.,Lamers, Philip,Engel, Julien,Bolm, Carsten
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supporting information
p. 3363 - 3368
(2013/12/04)
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- Enantioselective nitrene transfer to sulfides catalyzed by a chiral iron complex
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Iron works: Enantioselective nitrene transfer to sulfide was accomplished by a chiral iron(III)/PyBOX catalyst (see scheme). Various sulfimides were thus obtained in high enantioselectivities and yields. Applications of this protocol to the syntheses of enantioenriched sulfoximines and an epoxide were also demonstrated. Copyright
- Wang, Jun,Frings, Marcus,Bolm, Carsten
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supporting information
p. 8661 - 8665
(2013/09/12)
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- S-Acylation of aliphatic and aromatic thiols with carboxylic acids and their esters over solid acid catalysts in the gas phase at temperatures above 200 °c
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Benzenethiol is reacted with acetic acid in a hydrogen stream over [(Mo6Cl8)Cl4(H2O) 2]·6H2O. Catalytic activity of the clusters appears above 200 °C, yielding S-phenyl thioacetate. The selectivity is 98% at 300 °C. Niobium, tantalum, and tungsten halide clusters with the same octahedral metal framework also catalyze the reaction. Benzoic acid and aliphatic carboxylic acids afford the corresponding S-phenyl carbothioates by reaction with benzenethiol. Aliphatic thiols are also S-acylated to yield the corresponding S-alkyl carbothioates. When carboxylic esters are applied to the reaction with benzenethiol over [(Nb6Cl12)Cl 2(H2O)4]·4H2O at 450 °C, the sterically unhindered moiety of the ester is incorporated into the products: S-phenyl thioacetate or methyl phenyl sulfide is obtained selectively. A Br?nsted acid site developed on the cluster complex by thermal activation is the active site of the catalyst. Hence, solid acids such as silica-alumina, zeolites, and heteropoly acids that are stable above 200 °C also catalyze these reactions.
- Nagashima, Sayoko,Yamazaki, Hitomi,Kudo, Kentaro,Kamiguchi, Satoshi,Chihara, Teiji
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p. 332 - 338
(2013/07/26)
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- RUTHENIUM-BASED COMPLEX CATALYSTS
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The present invention provides novel Ruthenium-based transition metal complex catalysts comprising specific ligands, their preparation and their use in hydrogenation processes. Such complex catalysts are inexpensive, thermally robust, and olefin selective.
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Page/Page column 54; 67
(2013/03/26)
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- NaI/silica sulfuric acid as an efficient reducing system for deoxygenation of sulfoxides in poly ethylene glycol (PEG-200)
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Deoxygenation of structurally diverse sulfoxides including dialkyl, diaryl, aryl alkyl and allyl sulfoxides to the corresponding sulfides were carried out using a NaI/silica sulfuric acid reducing system at room temperature in poly ethylene glycol (PEG-200) in excellent yields.
- Zarei, Morteza,Ameri, Mohammad Aghil,Jamaleddini, Azar
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p. 259 - 263
(2013/08/26)
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- A cis-bis-mixed-carbene ruthenium hydride complex: An olefin-selective hydrogenation catalyst
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The N-heterocyclic carbene C3H2N2(CH 2CH2OMe)2 (1; IOMe) reacts with RuHCl(PPh 3)3 to give RuClH(IOMe)(PPh3)2 (2), which reacts further with SIMes to give the cis-bis-mixed-carbene complex RuClH(IOMe)(SIMes)(PPh3) (3). This species has been shown to be a highly effective hydrogenation catalyst that tolerates the presence of a wide range of functional and donor groups.
- Lund, Clinton L.,Sgro, Michael J.,Cariou, Renan,Stephan, Douglas W.
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scheme or table
p. 802 - 805
(2012/04/17)
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- I 2 as a mild and efficient catalyst in deoxygenation of sulfoxides with thioacetic acid
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An effective procedure for deoxygenation of sulfoxides to sulfides using thioacetic acid as a reducing agent and a catalytic amount of I2 in MeCN at ambient temperature has been developed. Using this protocol, a variety of sulfoxides including benzyl, allyl, alkyl and aryl sulfoxides have been successfully reduced to the corresponding sulfides in excellent yields.
- Jabbari, Arida,Zarei, Morteza,Jamaleddini, Azar
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p. 413 - 418
(2012/10/29)
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- Zn in ionic liquid: An efficient reaction media for the synthesis of diorganyl chalcogenides and chalcogenoesters
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A straightforward and efficient methodology is described to synthesize structurally diverse diorganyl selenides, sulfides, seleno- and thioesters by using commercially available Zn dust in ionic liquid. Excellent yields were achieved under neutral conditions at room temperature in a short time. The solvent/ionic liquid is reusable and exhibited higher performance as compared with organic solvents.
- Narayanaperumal, Senthil,Alberto, Eduardo E.,Gul, Kashif,Kawasoko, Cristiane Yuriko,Dornelles, Luciano,Rodrigues, Oscar E.D.,Braga, Antonio Luiz
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experimental part
p. 4723 - 4730
(2011/06/27)
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- Bimetallic system for the synthesis of diorganyl selenides and sulfides, chiral β-seleno amines, and seleno- and thioesters
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The bimetallic reagent Sn(II)/Cu(II) in [bmim]BF4 was efficiently used for the cleavage of diaryl diselenides and disulfides and reacts with a variety of organic substrates, such as organic halides, acid chlorides, and β-amino mesylates affording the diorganyl selenides and sulfides within very short reaction times, under mild conditions and with excellent yields, using BMIM-BF4 as a reusable solvent.
- Gul, Kashif,Narayanaperumal, Senthil,Dornelles, Luciano,Rodrigues, Oscar E.D.,Braga, Antonio Luiz
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supporting information; experimental part
p. 3592 - 3596
(2011/07/31)
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- Mild and efficient deoxygenation of sulfoxides to sulfides with Cp 2TiCl2/gallium system
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The Cp2TiCl2/Ga system was found to be a new reagent for reducing a variety of sulfoxides to the corresponding sulfides in good to excellent yields under mild conditions. Copyright
- Yoo, Byung Woo,Min, Sang Ki
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experimental part
p. 2993 - 2996
(2011/09/14)
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- Efficient organic transformations mediated by ZrOCl28H 2O in Water
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Operationally simple and environmentally benign methods for some organic transformations comprising reductive coupling of sulfonyl chlorides, chemoselective deoxygenation of sulfoxides, and halogenation of alcohols mediated by ZrOCl28H2O/MX in water have been developed.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Heidari, Mahdieh
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experimental part
p. 1470 - 1482
(2011/10/05)
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- One-pot reduction of sulfoxides with NaBH4, CoCl2. 6H2O catalyst, and moist alumina
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Sulfoxides are reduced by a combination of sodium borohydride, a catalytic amount of cobalt(II) chloride hexahydrate, and chromatographic neutral alumina preloaded with a small amount of water (moist alumina) in hexane to produce the corresponding sulfides in good to excellent yields under mild conditions. An interesting structural influence of sulfoxides on their reactivity is observed. Copyright
- Yakabe, Shigetaka,Hirano, Masao,Morimoto, Takashi
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experimental part
p. 2251 - 2255
(2011/06/27)
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- Exploring chromium(III)-alkyl bond homolysis with CpCr[(ArNCMe) 2CH](R) complexes
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A range of paramagnetic Cr(III) monohydrocarbyl complexes CpCr[(ArNCMe)2CH](R) (Ar = ortho-disubstituted aryl; R = primary alkyl, trimethylsilylmethyl, benzyl, phenyl, alkenyl, or alkynyl) were synthesized to investigate how varying the steric and electronic properties of the R group affected their propensity for Cr-R bond homolysis. Most complexes were prepared by salt metathesis of known CpCr[(ArNCMe)2CH](Cl) compounds in Et2O with commercial RMgCl solutions, although more sterically demanding combinations of Ar and R groups necessitated the use of halide-free MgR2 reagents and the Cr(III) tosylate or triflate derivatives. Alternative synthetic routes to Cr(III)-R species using the previously reported Cr(II) compounds CpCr[(ArNCMe)2CH] and sources of R? radicals (e.g., BEt3 and air) were also explored. The UV-vis spectra of the CpCr[(ArNCMe)2CH](R) complexes possessed two strong bands with maximum absorbances in the ranges 395-436 nm and 535-582 nm, with the band in the latter range being particularly characteristic of the Cr(III)-R compounds. The Cr-CH2R bond lengths as determined by single-crystal X-ray diffraction were longer than those in the corresponding Cr-CH3 complexes, typically falling in the range 2.10 to 2.13 A. The Cr(III) benzyl compounds displayed longer Cr-CH2Ph distances, while the bond lengths for the alkenyl and alkynyl species were substantially shorter. The rate of Cr-R bond homolysis at room temperature was determined by monitoring the reaction of Cr(III) neopentyl, benzyl, and isobutyl complexes with excess PhSSPh using UV-vis spectroscopy. Although the other primary alkyl, phenyl, and alkenyl compounds did not undergo appreciable homolysis under these conditions, they were cleanly converted to CpCr[(ArNCMe)2CH](SPh) by photolysis.
- MacLeod, K. Cory,Conway, Julia L.,Patrick, Brian O.,Smith, Kevin M.
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scheme or table
p. 17325 - 17334
(2011/03/01)
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- Lewis acid-promoted electron transfer deoxygenation of epoxides, sulfoxides, and amine N-oxides: the role of low-valent niobium complexes from NbCl5 and Zn
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A mild and operationally simple deoxygenation of epoxides, sulfoxides, and amine N-oxides is described using a sub-stoichiometric amount of low-valent niobium complexes generated in situ from commercially available NbCl5 and zinc dust. The deoxygenation proceeds by a reductive cleavage of polarized O-C/O-N/O-S bonds through a single electron transfer from zinc metal to the niobium-substrate complex due to the high oxophilic nature of the niobium species. The presence of adjacent radical-stabilizing groups is beneficial to epoxide substrates; however the similar prerequisite does not apply to sulfoxides and amine N-oxides, where a broad range of substrates are efficiently deoxygenated in excellent yields.
- Oh, Kyungsoo,Knabe, William Eric
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experimental part
p. 2966 - 2974
(2009/05/30)
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- Sulfite-promoted one-pot synthesis of sulfides by reaction of aryl disulfides with alkyl halides
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A sodium dithionite, sodium thiosulfate and rongalite promoted one-pot synthesis of aryl alkyl sulfides at room temperature has been developed. The reactions of a range of disulfides with alkyl halides proceeded smoothly in the presence of rongalite. Possible reaction pathways are discussed and the effects of these sulfites on disulfides are investigated. The important features of this protocol are metal-free, strong-base-free, and mild reaction conditions, operational simplicity, short reaction times and high yields of products. Georg Thieme Verlag Stuttgart.
- Tang, Ri-Yuan,Zhong, Ping,Lin, Qiu-Lian
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- Efficient CuO-nanoparticle-catalyzed C-S cross-coupling of thiols with iodobenzene
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Cheap but good: Readily available CuO nanoparticles are not only less expensive than other catalysts used for the C-S cross-coupling of thiols with aryl halides, but they are also effective at a moderate temperature and low concentration. The title reaction proceeds with a variety of alkyl and aryl thiols to give the corresponding sulfides in high yields (see scheme).
- Rout, Laxmidhar,Sen, Tamal K.,Punniyamurthy, Tharmalingam
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p. 5583 - 5586
(2008/03/18)
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- Mild and efficient deoxygenation of sulfoxides with MoCl5/indium system
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It has been demonstrated that dialkyl, diaryl, and aryl alkyl sulfoxides can be efficiently converted into the corresponding sulfides by the reaction with a MoCl5/In system in good to excellent yields under mild conditions. Copyright Taylor & Francis Group, LLC.
- Yoo, Byung Woo,Song, Min Suk,Park, Min Chol
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p. 3089 - 3093
(2008/02/12)
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- Mild and efficient deoxygenation of sulfoxides with a WCl6/indium system
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Dialkyl, diaryl, and aryl alkyl sulfoxides can be rapidly converted to the corresponding sulfides with a WCl6/In system in excellent yields under mild conditions. Copyright Taylor & Francis Group, LLC.
- Yoo, Byung Woo,Park, Min Chol,Song, Min Suk
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p. 4079 - 4083
(2008/03/13)
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- Reaction of thiometon and disulfoton with reduced sulfur species in simulated natural environment
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The reactions of thiometon and its ethyl analogue, disulfoton, with reduced sulfur species [e.g., bisulfide (HS-), polysulfide (S n2-), thiophenolate (PhS-), and thiosulfate (S2O32-)] were examined in well-defined aqueous solutions under anoxic conditions. The role of reduced sulfur species was investigated in the abiotic degradation of thiometon and disulfoton. Experiments at 25°C demonstrated that HS-, Sn2-, PhS-, and S2O32- promoted the degradation of thiometon to a great extent while only Sn2- and PhS- showed a small accelerating effect in the degradation of disulfoton. Reactions were monitored at varying concentrations of reduced sulfur species to obtain the second-order rate constants. The reactivity of the reduced sulfur species decreased in the following order: Sn 2- > PhS- > HS- ≈ S2O 32-. Transformation products were confirmed by standards or characterized by gas chromatography mass spectrometry. The results illustrate that multiple pathways occur in the reactions with reduced sulfur species, among which the nucleophilic attack at the α-carbon of the alkoxy group was the predominant pathway. Activation parameters of the reaction of thiometon and disulfoton with HS- were also determined from the measured second-order rate constants over a temperature range. ΔH≠ values indicated that the reactivity of thiometon toward HS- was much greater than for disulfoton. Nucleophilic attack at the alkoxy group was more important for thiometon than disulfoton. When the measured second-order rate constants at 25°C are multiplied by [HS-] and ∑[S n2-] reported in saltmarsh porewaters, predicted half-lives show that reduced sulfur species present at environmentally relevant concentrations may present an important sink for thiometon in coastal marine environments.
- Gan, Qui,Jans, Urs
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p. 7753 - 7760
(2007/10/03)
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- Dibromoborane-dimethyl sulfide: A new, mild, chemoselective reagent for the rapid deoxygenation of sulfoxides to sulfides
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Dibromoborane-dimethyl sulfide chemoselectively deoxygenates aliphatic and aromatic sulfoxides to the corresponding sulfides in excellent chemical yields in CH2Cl2 solvent in 15 minutes at both 0°C and room temperature, in the presence of reducible functional groups, such as alkene, ketone, ester, lactone, nitrile, amide, azide, sulfone, and N-oxide.
- Roy, Chandra D.,Brown, Herbert C.
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p. 642 - 644
(2007/10/03)
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- Anionic ring-opening polymerization of alkyl 1- cyanocyclopropanecarboxylates
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Poly(alkyl 1-cyanotrimethylene-1-carboxylate)s (CH2CH 2C(CN)(COOR))n are the next higher chain homologues of poly(α-cyanoacrylate)s. They were synthesized via the anionic ring-opening polymerization of the corresponding alkyl 1-cyanocyclopropanecarboxylate monomers initiated with thiophenolate salts (PhSM, with M = Li, Na, K, and NBu4) and at temperatures above 50°C. Precipitation of the growing polymer chains at an early stage during the polymerization did not prevent further propagation, probably via polymerization in the solid or at the solid surface. The propagating cyanoacetate carbanion is very stable in a normal air atmosphere, surviving for long periods of time in the absence of strong acids. Although monodisperse polymers were obtained in most experiments (M w/Mn + and NBu 4+ counterions were used. Nonquantitative initiations characterized polymerizations initiated by PhSLi and PhSNa. Attempted polymerizations of ethyl 1-cyanocyclobutanecarboxylate failed under similar or slightly more energetic experimental conditions, with the thiophenolate initiator attacking the pendant ester rather than the cyclic methylene group.
- Kagumba, Lawino C.,Penelle, Jacques
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p. 4588 - 4594
(2007/10/03)
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