- Alkylation of Nitropyridines via Vicarious Nucleophilic Substitution
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Electrophilic nitropyridines react with sulfonyl-stabilized carbanions to give products of C-H alkylation via vicarious nucleophilic substitution. The process consists of formation of the Meisenheimer-type adduct followed by base-induced β-elimination of the sulfinic acid (e.g., PhSO2H). Mechanistic studies reveal that in the latter step alkyl substituent and adjacent nitro group tend to planarize for effective stabilization of benzyl anion, and thus, adduct of hindered isopropyl carbanion remains stable toward elimination for steric reasons.
- Antoniak, Damian,Barbasiewicz, Micha?
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p. 516 - 519
(2022/01/20)
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- Synthesis of Sulfones and Sulfonyl Derivatives using Sodium (tert-butyldimethylsilyl)oxymethanesulfinate
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The present invention relates to a method for manufacturing a sulfone and sulfonyl derivative compound using sodium (tert-butyldimethylsilyl)oxymethanesulfinate, which is a novel organic sulfin salt, wherein the novel organic sulfin salt has good stability, environmental friendliness and economy, and is easy to handle, and thus significantly reduces the amount of transition metal catalysts and the amount of organic sulfin salts used when introducing aryl or alkenyl. Also, alkylation, arylation, amination, and fluorination are all possible during secondary functionalization. Therefore, the present invention can be usefully used in preparation and mass production of various kinds of sulfones and derivatives thereof including asymmetric sulfone derivatives.
- -
-
Paragraph 0836-0841; 0843; 0845-0846; 0848-0851; 0873-08765
(2021/04/29)
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- Silyloxymethanesulfinate as a sulfoxylate equivalent for the modular synthesis of sulfones and sulfonyl derivatives
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An efficient protocol for the modular synthesis of sulfones and sulfonyl derivatives has been developed utilizing sodium tert-butyldimethylsilyloxymethanesulfinate (TBSOMS-Na) as a sulfoxylate (SO22-) equivalent. TBSOMS-Na, easily prepared from the commercial reagents Rongalite and TBSCl, serves as a potent nucleophile in S-alkylation and Cu-catalyzed S-arylation reactions with alkyl and aryl electrophiles. The sulfone products thus obtained can undergo the second bond formation at the sulfur center with various electrophiles without a separate unmasking step to afford sulfones and sulfonyl derivatives such as sulfonamides and sulfonyl fluorides.
- Kim, Dae-Kwon,Um, Hyun-Suk,Park, Hoyoon,Kim, Seonwoo,Choi, Jin,Lee, Chulbom
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p. 13071 - 13078
(2021/01/09)
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- Cyanide-Mediated Synthesis of Sulfones and Sulfonamides from Vinyl Sulfones
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We report a facile synthesis of sulfones, β-keto sulfones, and sulfonamides from vinyl sulfones via an addition-elimination sequence where in situ generation of nucleophilic sulfinate ion is mediated by cyanide. The use vinyl sulfones renders high selectivity for S -alkylation to produce sulfones in high yields. In the presence of N -bromosuccinimide, primary and secondary amines underwent sulfonamide formation. A preliminary mechanistic study showed the formation of acrylonitrile as an innocent byproduct, without interfering with the desired reaction pathway while generating a sulfinate nucleophile.
- Lee, Ji-Woong,Roy, Tamal
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p. 455 - 458
(2020/03/13)
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- Calcium tungstate: A convenient recoverable catalyst for hydrogen peroxide oxidation
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Calcium tungstate was found to be an excellent catalyst for large scale "green" oxidations of organic substrates (amines, alkenes, alcohols, sulfides) with hydrogen peroxide. It displays the unusual dual characteristics of producing a soluble pertungstate species, allowing for homogeneous reaction conditions, but then precipitating, unchanged, at the end of the oxidation. These qualities allow for easy catalyst recovery and minimal waste stream generation for large scale application.
- Tressler, Caitlin M.,Stonehouse, Peter,Kyler, Keith S.
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supporting information
p. 4875 - 4878
(2016/10/06)
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- A chemoselective oxidation of sulfides to sulfoxides and sulfones using urea-2,2-dihydroperoxypropane as a novel oxidant
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Background: Sulfoxides and sulfones have been in the center of attention due to their wide range of promises in various approaches. The functional groups presented in these compounds serve as important building blocks in numerous natural, pharmeceutical and agricultural compounds. These deriatives have been prepared through a multitude of routes which were accompanied by several drawbacks. Therefore, there has been an ever-increasing interest to find a new methodology that leads to the production of these compounds via an environmentally benign path bringing about high yields. Recently, gem-dihydroperoxides have attracted much attention due to their oxidizing power and they have been utilized in several oxidation processes. Methods: We carried out a chemoselective oxidation of sulfides to sulfoxides and sulfones on treatment with urea-2,2-dihydroperoxypropane, a solid oxidant composed of equal amounts of 2,2-dihydroperoxypropane and urea, using THF as the solvent under catalyst-free conditions at room temprature. Results: Sulfides possessing a variety of substitutions namely dialkyl, diaryl, ally l and alkyl-aryl were subjected to the optimized reaction conditions and they could successfully afford different amounts of sulfoxides and sulfones depending on the amount of the oxidant utilized. Based on the results, electron-donating groups accelerated the reaction while electron-withdrawing substituents lowered the reactivity. Conclusion: Urea-2,2-dihydroperoxypropane as a solid oxidant which can be stored for several months without any loss in its activity has proved its capability to oxidize sulfides to sulfoxides and sulfones under catalyst-free and mild conditions. This approach is a cost-effective and environmentally benign methodology via which the products have been synthesized in high yields and short reaction times.
- Khosravi, Kaveh,Naserifar, Shirin,Asgari, Atefeh
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p. 749 - 756
(2017/02/05)
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- One-pot synthesis of aryl sulfones from organometallic reagents and iodonium salts
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A transition-metal-free arylation of lithium, magnesium, and zinc sulfinates with diaryliodonium salts is described. The sulfinic acid salts were prepared from the reaction of the corresponding organometallic reagents and sulfur dioxide. Combination of the three single steps (preparation of the organometallic compound, sulfinate formation, and arylation) leads to a one-pot sequence for the synthesis of aryl sulfones from simple starting materials. The chemoselectivity of unsymmetrical diaryliodonium salts has been investigated. Potential and limitations of this method will be discussed.
- Margraf, Natalie,Manolikakes, Georg
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p. 2582 - 2600
(2015/03/18)
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- Lithium-titanium exchange of tertiary α-sulfonyl carbanions: Synthesis, structure, dynamics and reactivity of bis(1-sulfonylalkyl) titaniums
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Lithium-titanium exchange of tertiary α-sulfonyl carbanions with ClTi(OiPr)3 and Cl2Ti(OiPr)2 in diethyl ether gave bis(1-sulfonylalkyl) titaniums and not the corresponding (1-sulfon-ylalkyl) titaniums. X-ray crystal structure analysis of di(iso-propoxy) bis[1-(phenylsulfonyl) cyclobutyl]titanium and di-(isopropoxy) bis[1-(phenylsulfonyl) isopropyl]titanium showed asymmetric distorted octahedral complexes, having hexaco-ordinate Ti atoms, two C-Ti bonds, four Ti-O bonds, and two four-membered Ti-O-S-Cα rings. According to 1H NMR spectroscopy bis(1-sulfonylcycloalkyl) titaniums are non-flux-ional at room temperature. This suggests that chiral bis(1-sulfonylalkyl) titaniums should be configurationally stable. The bis(1-sulfonylalkyl) titaniums are stable at room temperature towards β-H elimination. They selectively add to benzaldehyde in the presence of acetophenone but do not react with methyl iodide. The reaction of tertiary acyclic α-sulfonyl carbanions with ClTi(OiPr)3 in tetrahydrofuran (THF) gives different titanium derivatives with unspecified structures, which not only selectively react with benzaldehyde in the presence of acetophenone but are also alkylated by methyl iodide.
- Hess, Thomas,Raabe, Gerhard,Gais, Hans-Joachim
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p. 7134 - 7147
(2015/03/04)
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- Engineering chiral Fe(salen)-based metal-organic frameworks for asymmetric sulfide oxidation
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Two chiral porous Fe(salen)-based metal-organic frameworks are constructed and are shown to be efficient and recyclable heterogeneous catalysts for asymmetric oxidation of sulfides to sulfoxides with an enantioselectivity of up to 96%.
- Yang, Zhiwei,Zhu, Chengfeng,Li, Zijian,Liu, Yan,Liu, Guohua,Cui, Yong
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p. 8775 - 8778
(2014/07/22)
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- Divergent reactivity of alkyl aryl sulfones with bases: Selective functionalization of ortho-aryl and α-alkyl units enabled by a unique carbanion transmetalation
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The electron-accepting sulfonyl group exhibits a strong acidifying influence on neighboring α-H atoms. The Julia and related olefinations are based on this effect. Here a surprising reversal in the metalation selectivity of branched alkyl aryl sulfones is described. Such sulfones were found to initially undergo directed ortho-metalation with good regioselectivity, despite having a more acidic α-H atom. The structure of the alkyl unit profoundly, but predictably, influences the regioselectivity of the attack of the base. In β- and γ-branched ortho-(alkylsulfonyl)aryllithiums a transmetalation to the α-carbanion proceeds only upon warming. Correspondingly generated ortho- or α-carbanions were then selectively applied thus permitting access to synthetically interesting compound classes. An unusual lithiation selectivity and subsequent transfer of the metal upon warming was observed for various branched alkyl phenyl sulfones. This divergent reactivity was used to prepare substituted aryl sulfones as well as olefins by application of the Julia reaction. Copyright
- Rehova, Lucie,Cisarova, Ivana,Jahn, Ullrich
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supporting information
p. 1461 - 1476
(2014/03/21)
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- Divergent Reactivity of Alkyl Aryl Sulfones with Bases: Selective Functionalization of ortho-Aryl and α-Alkyl Units Enabled by a Unique Carbanion Transmetalation
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The electron-accepting sulfonyl group exhibits a strong acidifying influence on neighboring α-H atoms. The Julia and related olefinations are based on this effect. Here a surprising reversal in the metalation selectivity of branched alkyl aryl sulfones is described. Such sulfones were found to initially undergo directed ortho-metalation with good regioselectivity, despite having a more acidic α-H atom. The structure of the alkyl unit profoundly, but predictably, influences the regioselectivity of the attack of the base. In β- and γ-branched ortho-(alkylsulfonyl)aryllithiums a transmetalation to the α-carbanion proceeds only upon warming. Correspondingly generated ortho- or α-carbanions were then selectively applied thus permitting access to synthetically interesting compound classes.
- ?ehová, Lucie,Císa?ová, Ivana,Jahn, Ullrich
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supporting information
p. 1461 - 1476
(2015/10/05)
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- Cellulose as an efficient support for Mn(salen)Cl: Application for catalytic oxidation of sulfides to sulfoxides
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Supported Mn(salen)Cl was prepared by immobilization of a homogeneous Mn(salen)Cl complex onto cellulose and characterized by FT-IR, TGA and atomic absorption spectroscopy. This heterogeneous catalyst is able to effectively catalyze the oxidation of aromatic sulfides in good yield under mild conditions. The catalytic activity of Mn(salen)Cl and [Mn(salen)Cl-cellulose] in this reaction was investigated. The heterogeneous catalyst showed higher catalytic activity with respect to the neat Mn(salen)Cl complex. The key advantages of this process are cost effectiveness of the catalyst, reusability of the catalyst and easy work-up. This journal is
- Mohammadinezhad, Arezou,Nasseri, Mohammad Ali,Salimi, Mehri
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p. 39870 - 39874
(2014/12/11)
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- Highly efficient selective oxidation of sulfides to sulfoxides by montmorillonite-immobilized metalloporphyrins in the presence of molecular oxygen
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Highly efficient and selective oxidation of sulfides to sulfoxides with dioxygen catalyzed by cationic meso-tetrakis (1-methyl-4-pyridyl) (TM4PyP) metalloporphyrins immobilized into montmorillonite (MT) interlayer was achieved. Manganese (II) porphyrin (MnTM4PyP-MT) presented excellent activity for the oxidation of sulfides under ambient conditions. In the model oxidation, thioanisole was converted completely and the selectivity towards sulfoxide was up to 95%. This catalyst also showed high activity and selectivity for the most sulfides. The catalyst could be reused consecutively five times without significant loss of activity.
- Zhou, Xian-Tai,Ji, Hong-Bing
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- A novel organic electron donor derived from N-methylisatin
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We report the reactivity of an electron donor derived from N-methylisatin on reduction by sodium amalgam. Transfer of a clear supernatant solution to iodoarenes affords the products of two-electron reduction. Reductions of sulfones, activated arenesulfonamides, and Weinreb amides are also reported.
- Sword, Ryan,O'Sullivan, Steven,Murphy, John A.
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p. 314 - 322
(2013/05/08)
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- A chiral porous metallosalan-organic framework containing titanium-oxo clusters for enantioselective catalytic sulfoxidation
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A chiral porous zeolite-like metal-organic framework is constructed by using mixed ligands of dipyridyl-functionalized chiral Ti(salan) and biphenyl-4,4′-dicarboxylate. The framework containing salan-bound Ti 4O6 clusters consists of both hydrophobic and amphiphilic mesocages and is shown to be an efficient and recyclable heterogeneous catalyst for the oxidation of thioethers to sulfoxides by aqueous H2O 2 (up to 82% ee), displaying markedly enhanced enantioselectivity over the homogeneous catalyst by providing a cavity confinement effect. This work highlights the potential of significantly improving enantioselectivity of homogeneous catalysts by using MOFs as support structures.
- Xuan, Weimin,Ye, Chengcheng,Zhang, Mengni,Chen, Zhijie,Cui, Yong
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p. 3154 - 3159
(2013/07/26)
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- Titanium-salan-catalyzed asymmetric sulfoxidations with H2O 2: Design of more versatile catalysts
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Titanium-salan complexes with 3,3'-diphenyl substituents in the salicylidene rings of the salan ligand are efficient sulfoxidation catalysts, capable of catalyzing the asymmetric oxidation of bulky aryl benzyl sulfides with H2O2 with good to high enantioselectivities. In this paper, substituent effects on titanium-salan-catalyzed enantioselective oxidation of sulfides to sulfoxides have been systematically investigated. Titanium-salan catalysts with halogen substituents at the 5,5'-positions (3,3'-H2dihydrogen substituted) have been found to catalyze the oxidation of both bulky aryl benzyl sulfides and small alkyl phenyl sulfides with good to high enantioselectivities. Kinetic data witness a direct attack of the sulfide to the electrophilic active oxygen species; a consistent reaction mechanism is proposed. Copyright 2013 John Wiley & Sons, Ltd. Titanium-salan complexes with halogen substituents at the 5,5'-positions are versatile catalysts for the oxidation of both bulky aryl benzyl sulfides and small alkyl phenyl sulfides, demonstrating good to high chemoselectivity (up to 92 %) and enantioselectivity (up to 93 % ee). Copyright
- Talsi, Evgenii P.,Bryliakov, Konstantin P.
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p. 239 - 244
(2013/06/04)
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- Chiral microporous Ti(salan)-based metal-organic frameworks for asymmetric sulfoxidation
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Chiral porous metal-metallosalan frameworks are constructed from an unsymmetrical chiral pyridinecarboxylate ligand derived from Ti(salan) and are shown to be heterogeneous catalysts for asymmetric oxidation of thioethers to sulfoxides.
- Zhu, Chengfeng,Chen, Xu,Yang, Zhiwei,Du, Xia,Liu, Yan,Cui, Yong
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p. 7120 - 7122
(2013/08/23)
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- Imidazolium perrhenate ionic liquids as efficient catalysts for the selective oxidation of sulfides to sulfones
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A series of imidazolium perrhenate ionic liquids (IPILs) have been synthesized and used as efficient catalysts for the oxidation of sulfides to sulfones with aqueous hydrogen peroxide under mild conditions. Various sulfones are obtained in good to excellent yields. IPILs are stable and can be reused at least ten times without detectable activity loss. Furthermore, this system provides a reasonably environmentally benign chemical process in terms of potential industrial application.
- Zhang, Bo,Li, Su,Yue, Shuang,Cokoja, Mirza,Zhou, Ming-Dong,Zang, Shu-Liang,Kühn, Fritz E.
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p. 108 - 112
(2013/10/01)
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- ELECTROLYTE SOLUTION FOR DYE SENSITIZED SOLAR CELL, AND DYE SENSITIZED SOLAR CELL USING SAME
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It is to provide an electrolyte solution for a dye sensitized solar cell that does not generate a gas, can be used in a wide temperature range, and is excellent in durability. The electrolyte solution contains a chain sulfone compound represented by formula (1) as a solvent. (In the formula, R1 and R2 each independently represent an alkyl group having from 1 to 12 carbon atoms, which may be partially substituted by a halogen, an alkoxy group or an aromatic ring, an alkoxy group, or a phenyl group.)
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- Application of a novel 1,3-diol with a benzyl backbone as chiral ligand for asymmetric oxidation of sulfides to sulfoxides
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A chiral 1,3-diol with a benzyl backbone has been used for the asymmetric oxidation of sulfides to sulfoxides. Moderate to good yields and enantioselectivity (upto 87% ee) have been observed.
- Gogoi, Paramartha,Kotipalli, Trimurthulu,Indukuri, Kiran,Bondalapati, Somasekhar,Saha, Pipas,Saikia, Anil K.
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supporting information; experimental part
p. 2726 - 2729
(2012/07/17)
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- Activation of H2O2 by chiral confined Bronsted acids: A highly enantioselective catalytic sulfoxidation
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Confined chiral Bronsted acids are shown to catalyze asymmetric oxidations of sulfides to sulfoxides with hydrogen peroxide. The wide generality and high enantioselectivity of the developed method compare even to the best metal-based systems and suggest utility in other asymmetric oxidations.
- Liao, Saihu,Coric, Ilija,Wang, Qinggang,List, Benjamin
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supporting information; experimental part
p. 10765 - 10768
(2012/08/28)
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- Asymmetric counteranion-directed iron catalysis: A highly enantioselective sulfoxidation
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A highly active and enantioselective ion-pair sulfoxidation catalyst, consisting of an achiral iron(III)-salen cation and a chiral phosphate counteranion, mediates the oxidization of various sulfides with high yields and enantioselectivities. The enantioselectivities observed, especially for electron-poor substrates, represent the best results so far in manganese and iron-salen systems. This work represents the first application of our concept of asymmetric counteranion-directed catalysis (ACDC) to iron catalysis. Copyright
- Liao, Saihu,List, Benjamin
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supporting information
p. 2363 - 2367
(2012/10/30)
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- Highly atom-economic, catalyst- and solvent-free oxidation of sulfides into sulfones using 30% aqueous H2O2
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Highly atom-efficient oxidation of sulfides into sulfones under solvent- and catalyst-free reaction conditions using a 30% aqueous solution of H 2O2 at 75 °C is reported. A structurally diverse set of phenyl alkyl-, phenyl benzyl-, benzyl alkyl-, dialkyl-, heteroaryl alkyl- and cyclic sulfides were transformed into sulfones regardless of the aggregate state and electronic nature of the substituents. In spite of the heterogeneous reaction mixtures throughout the work, no difficulties with stirring and reaction progress were noted. In numerous cases, only 10 mol% excess of H 2O2 was used, thus contributing considerably to the high atom economy of the process. Some solid substrates required a variable excess of hydrogen peroxide; however, the reactions were performed strictly without organic solvents. The transformation was demonstrated to be amenable for scale-up with both liquid and solid sulfides. In addition, isolation and purification of the crude products can be simply done with only filtration and crystallization.
- Jereb, Marjan
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supporting information
p. 3047 - 3052,6
(2020/09/16)
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- Catalytic enantioselective oxidation of bulky alkyl aryl thioethers with H2O2 over titanium-salan catalysts
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A simple and efficient catalytic procedure for the oxidation of bulky (preferably aryl benzyl substituted) thioethers with hydrogen peroxide in good to high yields and enantioselectivities (up to 98.5%ee) is reported. The high optical yields are achieved in a tandem stereoconvergent enantioselective oxidation and kinetic resolution process. A reasonable balance between the sulfoxide yield and enantioselectivity could be found by varying the concentration and temperature. An improved synthesis of the titanium-salan catalysts for the preparation of a more stereoselective catalyst is reported.
- Bryliakov, Konstantin P.,Talsi, Evgenii P.
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experimental part
p. 4693 - 4698
(2011/10/03)
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- TiO2 nanoparticles and Preyssler-type heteropoly acid modified nano-sized TiO2: A facile and efficient catalyst for the selective oxidation of sulfides to sulfones and sulfoxides
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A new and efficient synthetic method has been developed for the selective conversion of sulfides into their corresponding sulfones and sulfoxides using H2O2 in the presence of neat or Preyssler-type heteropoly acid modified nano-sized TiO2 as catalyst, respectively. The reaction was performed at room temperature with quantitative yields. The catalyst is reusable without significant loss of activity for the next oxidation reaction.
- Rahimizadeh, Mohammad,Rajabzadeh, Ghadir,Khatami, Seyed-Mola,Eshghi, Hossein,Shiri, Ali
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scheme or table
p. 59 - 64
(2010/09/04)
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- Selective oxidation of sulfides to sulfones using H2O 2 and anderson-type hexamolybdochromate(III) as catalyst
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An Anderson-type hexamolybdochromate(III) is found to be an effective catalyst for the selective oxidation of sulfides to their corresponding sulfones. The reaction was carried out in 60% aq. acetonitrile (v/v) using 30% H2O2 at 60C. Various dialkyl, alkyl-aryl, and diaryl sulfides were selectively oxidized, giving high yields of sulfones after a simple workup procedure.
- Supale, Amit R.,Gokavi, Gavisiddappa S.
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experimental part
p. 725 - 731
(2010/07/05)
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- Transformation of alkynyl sulfones into alkynylphosphonates with trialkyl phosphites
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1-Alkynylphosphonates were obtained in good to high yields by simple heating of 1-alkynyl sulfones with trialkyl phosphites.
- Yatsumonji, Yasutaka,Ogata, Akitoshi,Tsubouchi, Akira,Takeda, Takeshi
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p. 2265 - 2267
(2008/09/18)
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- Super-electron donors: Bis-pyridinylidene formation by base treatment of pyridinium salts
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Deprotonation of bispyridinium salt 7b affords bispyridinylidene 10, a very powerful neutral organic two-electron donor [E1/2 (DMF) = -1.13 V vs Ag/AgCI/KCI (sat)], presumably via the pyridinylidene 8. Donor 10 reduces aryl iodides and bromides to aryl anions in excellent yield and also reductively cleaves selected phenylalkylsulfones very efficiently.
- Murphy, John A.,Gamier, Jean,Park, Stuart R.,Schoenebeck, Franziska,Zhou, Sheng-Ze,Turner, Andrew T.
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supporting information; experimental part
p. 1227 - 1230
(2009/04/06)
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- Titanium-salan-catalyzed asymmetric oxidation of sulfides and kinetic resolution of sulfoxides with H2O2 as the oxidant
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Asymmetric oxidation of sufides to sulfoxides by aqueous hydrogen peroxide with catalysis by titanium-salan complexes is presented. Optically active sulfoxides have been obtained with good to high enantioselectivities (up to 97% ee) by a tandem enantioselective oxidation and kinetic resolution procedure, the catalyst performing over 500 turnovers with no loss of enantioselectivity. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Bryliakov, Konstantin P.,Talsi, Evgenii P.
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scheme or table
p. 3369 - 3376
(2009/04/07)
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- Reductive cleavage of sulfones and sulfonamides by a neutral organic super-electron-donor (S.E.D.) reagent
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Sulfones and sulfonamides are reductively cleaved using the neutral and easily prepared organic electron-donor, bis-imidazolylidene 3. Copyright
- Schoenebeck, Franziska,Murphy, John A.,Zhou, Sheng-Ze,Uenoyama, Yoshitaka,Miclo, Yves,Tuttle, Tell
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p. 13368 - 13369
(2008/04/04)
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- Iron-catalyzed oxidation of thioethers by iodosylarenes: Stereoselectivity and reaction mechanism
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Catalytic properties of a series of iron(III)-salen (salen = N,N′-bis(salicylidene)ethylenediamine dianion) and related complexes in asymmetric sulfoxidation reactions, with iodosylarenes as terminal oxidants, have been explored. These catalysts have been found to efficiently catalyze oxidation of alkyl aryl sulfides to sulfoxides with high chemoselectivity (up to 100%) and moderate-to-high enantioselectivity (up to 84% with isopropylthiobenzene and iodosylmesitylene), the TON (TON = turnover number) approaching 500. The influence of the ligand (electronic and steric effects of the substituents). oxidant, and substrate structures on the oxidation stereoselectivity has been investigated systematically. The structure of the reactive intermediates (complexes of the type [FeIII(ArIO)(salen)] and the reaction mechanism have been revealed by both mechanistic studies with different iodosylarenes and direct in situ 1H NMR observation of the formation of the reactive species and its reaction with the substrate.
- Bryliakov, Konstantin P.,Talsi, Evgenii P.
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p. 8045 - 8050
(2008/04/01)
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- Selective oxidation of sulfides to sulfoxides catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride in the presence of molecular oxygen
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Highly efficient selective oxidation of sulfides to sulfoxides by molecular oxygen catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride (Ru(TPP)Cl) with isobutyraldehyde as oxygen acceptor has been reported. In large-scale experiment of thioanisole oxidation, the isolated yield of sulfoxide of 92% was obtained and the turnover number reached up to 92,000.
- Zhou, Xian-Tai,Ji, Hong-Bing,Cheng, Zhao,Xu, Jian-Chang,Pei, Li-Xia,Wang, Le-Fu
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p. 4650 - 4653
(2008/02/09)
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- Selective oxidation of sulfides to sulfoxides and sulfones using n-butyltriphenylphosphonium dichromate (BunPPh3) 2Cr2O7 in the presence of aluminium chloride in solution and under microwave irradiation
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A wide variety of sulfides are efficiently oxidized to their corresponding sulfoxides and sulfones in excellent yields using n-butyltriphenylphosphonium dichromate (BTPPDC) in the presence of aluminium chloride in acetonitrile solution and under microwave irradiation. In addition, selective oxidation of sulfides in the presence of functional groups such as a carbon-carbon double bond, ketone, oxime, aldehyde, ether, and acetal can be considered as a noteworthy advantage of this method. Copyright Taylor & Francis Inc.
- Mohammadpoor-Baltork, Iraj,Memarian, Hamid Reza,Bahrami, Kiumars,Esmayilpour, Karim
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p. 2751 - 2766
(2007/10/03)
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- 3-Carboxypyridinium chlorochromate - aluminium chloride - An efficient and inexpensive reagent system for the selective oxidation of sulfides to sulfoxides and sulfones in solution and under microwave irradiation
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3-Carboxypyridinium chlorochromate (CPCC) in the presence of aluminium chloride is a very efficient reagent for the selective oxidation of sulfides to sulfoxide and sulfones in solution and under microwave irradiation. It is noteworthy that different functional groups including carbon-carbon double bonds, ketones, oximes, aldehydes, ethers, and acetals were tolerated under these reaction conditions.
- Mohammadpoor-Baltork, Iraj,Memarian, Hamid R.,Bahrami, Kiumars
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p. 115 - 121
(2007/10/03)
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- Total synthesis of (-)-spirotryprostatin B: Synthesis and related studies
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The total synthesis of spirotryprostatin B, a cytostatic spiro[pyrrolidine-3,3′-oxindole] alkaloid, is described. The key step of the synthetic approach consists of the application of the Mgl 2-mediated ring-expansion reaction of a spiro[cyclopropane-1, 3′-oxindole] with an aldimine, leading to rapid assembly of the spirotryprostatin core. The route documents the installation of the prenyl side chain by Julia-Kocienski olefination of a key aldehyde precursor, a transformation that ultimately allows for facile synthesis of analogues and facilitates structure-activity relationships studies.
- Marti, Christiane,Carreira, Erick M.
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p. 11505 - 11515
(2007/10/03)
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- 24-Sulfur-substituted analogs of 1 alpha, 25-dihydroxy vitamin D3
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The present invention provides novel C24-sulfone analogs of 1α,25-dihydroxy vitamin D3, compositions comprising these compounds and methods of using these compounds as selective inhibitors of CYP24. In particular, the compounds of the invention are useful for treating diseases which benefit from a modulation of the levels of 1α,25-dihydroxy vitamin D3, for example, cell-proliferative disorders.
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- Rapid and highly chemoselective biomimetic oxidation of organosulfur compounds with tetrabutylammonium peroxymonosulfate in the presence of manganese meso-tetraphenylporphyrin and imidazole
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A novel and efficient method is described for the immediate oxidation of different organosulfur compounds using tetrabutylammonium peroxymonosulfate in the presence of manganese meso-tetraphenylporphyrin and imidazole. The method is highly chemoselective and the yields are excellent.
- Iranpoor, Nasser,Mohajer, Daryoush,Rezaeifard, Abdol-Reza
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p. 3811 - 3815
(2007/10/03)
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- 24-sulfur-substituted analogs of 1alpha, 25-dihydroxy vitamin D3
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The present invention provides novel C24-aryl sulfone analogs of 1α,25-dihydroxy vitamin D3, compositions comprising these compounds and methods of using these compounds as selective inhibitors of CYP24. In particular, the compounds of the invention are useful for treating diseases which benefit from a modulation of the levels of 1α,25-dihydroxy vitamin D3, for example, cell-proliferative disorders.
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- WO3-30% H2O2-cinchona alkaloids: A new heterogeneous catalytic system for the asymmetric oxidation of sulfides and the kinetic resolution of racemic sulfoxides
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WO3-catalyzed asymmetric oxidation of thioethers and kinetic resolution of sulfoxides with 30% aq. H2O2 in the presence of cinchona alkaloids under heterogeneous conditions affords chiral sulfoxides in high yields with moderate to good enantioselectivities.
- Thakur, Vinay V.,Sudalai
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p. 407 - 410
(2007/10/03)
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- Mechanistic organic chemistry in a microreactor. Zeolite-controlled photooxidations of organic sulfides
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The intrazeolite and solution photooxygenations of a series of sulfides have been compared. The unusual zeolite environment enhances the rates of reaction, it suppresses the Pummerer rearrangements, and it has a dramatic effect on the sulfoxide/sulfone ratio. A detailed kinetic study utilizing trapping experiments and intramolecular competition provides evidence for cation complexation to a persulfoxide intermediate as the underlying phenomenon for the unique intrazeolite behavior. For example, the enhanced rate of reaction is traced to the cation stabilization of the persulfoxide toward unproductive decomposition to substrate and triplet oxygen.
- Clennan, Edward L.,Zhou, Wenhui,Chan, Jacqueline
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p. 9368 - 9378
(2007/10/03)
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- A novel method for the synthesis of aryl sulfones
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New sulfones were produced from aryl trifluoromethyl sulfones and Grignard reagents in good to high yields. The advantage of this transformation over a previous method by which sulfones were prepared from sulfonyl fluorides and organometallic reagents is discussed.
- Steensma, Ruo W.,Galabi, Sharen,Tagat, Jayaram R.,McCombie, Stuart W.
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p. 2281 - 2283
(2007/10/03)
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- Reactions of 1,2-thiazetidine 1,1-dioxides with organometallics: β- elimination and N-S bond cleavage
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Reactions of 4-nonsubstituted β-sultams 1 with methyllithium gave only (E)-vinylsulfonamides 2, whereas 2-aminoethyl sulfones 3 were obtained as minor products by use of methylmagnesium bromide. Reactions of 4- monosubstituted β-sultams 6 with organolithiums gave (E)-vinylsulfonamides 7 stereoselectively regardless of the configuration of 3- and 4-substituents. Treatment of 4,4-dimethyl-β-sultam 8a with methylmagnesium bromide and methyllithium provided 2-aminoethyl sulfone 9 and bis-sulfone 10, respectively, and isopropyl phenyl sulfone 11 was obtained by use of phenyllithium or phenylmagnesium bromide.
- Iwama, Tetsuo,Kataoka, Tadashi,Muraoka, Osamu,Tanabe, Genzoh
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p. 5507 - 5522
(2007/10/03)
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- α-Fluorination of methyl phenyl sulfoxide and related compounds by molecular fluorine: A novel method for the introduction of fluorine into sulfoxides bearing α-H atoms
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Direct formation of α-fluorosulfones from sulfoxides bearing α-H atoms merely by reaction with molecular fluorine (5% F2/N2) is reported, and a novel non-Pummerer-type mechanism is proposed for this α-fluorination reaction.
- Toyota, Akemi,Ono, Yoshinori,Chiba, Jun,Sugihara, Takumichi,Kaneko, Chikara
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p. 703 - 708
(2007/10/03)
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- Scope and limitations in the use of α-silyl and α-stannyl sulfones as latent α-sulfonyl anions
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Three methods for the regeneration of α-sulfonyl anions from α-silyl sulfones and α-stannyl sulfones are investigated. These methods include: (1) treatment of α-silyl sulfones with electrophiles (aldehydes and acid halides) in the presence of fluoride ion; (2) reaction of α-silyl sulfones with n-butyllithium which produces an α-silyl anion via a migration of the -SiMe3 group from the α-position to the ortho-position of the phenyl sulfones; and (3) direct transmetalation of α-stannyl sulfone by treatment with n-butyllithium. The addition of cerium [III] chloride is shown to substantially decrease enolization problems associated with addition of α-sulfonyl anions to carbonyl compounds bearing enolizable protons.
- Lamothe,Anderson,Fuchs
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p. 1675 - 1693
(2007/10/02)
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- Unusual Two-Bond 13C,13C Coupling Constants in Sulphones
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A measurable coupling between carbon atoms through the SO2 group is observed in a series of structurally diverse sulphones.In open-chain (single coupling path) sulphones this 2J coupling ranges from 5.5 to 27.2 Hz, while in cyclic (multiple coupling path) sulphones values ranging from 4.3 to 21.6 Hz are observed.Sulphides and sulphoxides do not exhibit a corresponding coupling of comparable magnitude.A positive sign for this coupling is derived from the data of cyclic sulphones.Whereas substituents and branching at the coupling termini exert minor influences on the coupling, the most important factor determining the magnitude of the 2J(CSC) coupling is the hybridization of the coupling carbon atoms.A linear relationship between the 2J value and the s character product of the C-S bond forming C orbitals is established.KEY WORDS Sulphones 13C NMR Geminal 13C,13C coupling
- Ruecker, Christoph,Fritz, Hans
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p. 1103 - 1108
(2007/10/02)
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- CHEMICAL MODIFICATION OF POLY-VINYLBENZYLTRIPHENYLPHOSPHONIUM SALTS AND THEIR APPLICATIONS AS REAGENTS IN ORGANIC SYNTHESIS
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Insoluble polymer-bound reagents derived from poly(vinylbenzyltriphenylphosphonium salts) have been prepared and used as reagents in organic synthesis.The polymer-supported borohydride was used as reducing agent towards carbonyl compounds.The reaction of polymer-supported thiocyanate and nitrile anions with alkyl halides in hydrocarbon solvents gave good yields of the corresponding alkyl thiocyanates and nitroalkanes, respectively.In addition, polymer-bound carboxylate, phenoxide, and sulfinate anions were used for the synthesis of esters, ethers, and sulfones by reaction with alkyl halides in non-polar solvents.
- Akelah, Ahmed,Abdel Galil, Fathy M.
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- The Synthesis of Ketones via α-Silyl Sulphides
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α-Phenylthiosilanes (2) have been prepared by alkylation of the anion (4) derived from the 1-phenylthio-1-trimethylsilylalkane (1).These anions (4) have benn prepared by a variety of methods including, direct deprotonation of (1), displacement of a phenylthio group by lithium naphthalenide addition of an alkyl-lithium to 1-phenylthio-1-trimethylsilylethene (7), and transmetallation of a tributylstannyl moiety.The formation of an alkyl-lithium by reaction of lithium naphthalenide with a phenyl sulphide provided an additional route to (2) from bis(phenylthio)acetals (8).An alternative path to the α-phenylthiosilanes (2) was to reduce the corresponding α-phenylsulphonylsilane (15); these, in turn, being readily available from alkylation or silylation of α-sulphonyl anions.The α-phenylthiosilanes (2) were converted into the O-trimethylsilylphenylthioacetal (18) by the sila-Pummerer rearrangement, although this was complicated by vinyl sulphide (20) formation in certain cases.Subsequent hydrolysis of (18) and (20) gave the ketone (3).
- Ager, David J.
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p. 195 - 204
(2007/10/02)
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- Reactions of Carbanions with Electron Acceptors
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Second-order rate constants for reactions of families of 9-substituted fluorenide ions, 9-R-Fl(-), and related carbanions in Me2SO solution with the electron acceptors PhSO2CH2Br, PhSO2CH(Ph)Br, PhSO2C(Me)(Ph)Br, Me2CBr2, Me2C(NO2)X, PhS(O)CH2Cl, Me2C(SO2Ph)2, and Ph2I(+)Cl(-) have been measured.The carbanions used varied in basicity over a range of about 20pKHA units.For a given family, Broensted plots of log k vs. pKHA were linear, with slopes usually near unity.The relative order of rate constants correlated for the most part with the order of reduction potentials of the electron acceptors.The carbanions were converted by the electron acceptors to dimers, i.e., 9-R-Fl- -> (9-R-Fl)2, by way of a single electron transfer (e-T) mechanism.The Broensted lines for the e-T reactions of the GC6H4C(Me)CN- ion family (G = p-Cl, H, and p-Me) and the 9-t-BuFl- ion family were displaced below that of the 9-MeFl- ion family (slower rates); the kinetic points for PhC(Me)SO2Ph- and Ph2CSO2Ph- ions fell near the 9-t-BuFl- ion family line.It is demonstrated that carbanions too weakly basic to undergo thermal e-T with a given electron acceptor can be made to undergo comparable e-T reactions under photostimulation.
- Bordwell, Frederick G.,Clemens, Anthony H.,Smith, Donald E.,Begemann, John
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p. 1151 - 1156
(2007/10/02)
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- ZUR OXIDATION VON THIOETHERN MIT HYPOCHLORIT
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The oxidation of thioethers with hypochlorite using a two phase system is investigated.The following parameters are varied: (a) the pH-value, (b) the concentration of hypochlorite (c) the participation of phase transfer catalysts (d) the structure of the
- Horner, Leopold,Gerhard, Joachim
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