- Iron(III) chloride (FeCl3)-catalyzed electrophilic aromatic substitution of chlorobenzene with thionyl chloride (SOCl2) and the accompanying auto-redox in sulfur to give diaryl sulfides (Ar2S): Comparison to catalysis by aluminum chloride (AlCl3)
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The Lewis acids MCl3(M = Fe and Al)-catalyzed electrophilic aromatic (ArH) substitution reactions with thionyl chloride (SOCl2) have been shown to give diaryl sulfoxide (Ar2SO) and the reduced diaryl sulfide (Ar2S). Under various selected conditions, the FeCl3-catalyzed reactions of chlorobenzene gave substantially much higher percent yields of Ar2S (Ar = p-ClC6H4) than the reactions catalyzed by AlCl3, showing that FeCl3facilitates the reduction in the sulfur center of SOCl2. A dπ?>pπ*back bond between Fe(III) and the O?S group is thought to be responsible for enhancement of the reduction.
- Sun, Xiaoping,Haas, David,Lockhart, Chyress
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Read Online
- Selective synthesis of sulfoxides and sulfonesviacontrollable oxidation of sulfides withN-fluorobenzenesulfonimide
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A practical and mild method for the switchable synthesis of sulfoxides or sulfonesviaselective oxidation of sulfides using cheapN-fluorobenzenesulfonimide (NFSI) as the oxidant has been developed. These highly chemoselective transformations were simply achieved by varying the NFSI loading with H2O as the green solvent and oxygen source without any additives. The good functional group tolerance makes the strategy valuable.
- Cao, Zhong-Yan,Li, Xiaolong,Lu, Hao,Wang, Panpan,Wang, Shengqiang,Xu, Xiaobo,Yan, Leyu,Yang, A-Xiu
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supporting information
p. 8691 - 8695
(2021/10/22)
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- Photocatalytic Activity of Ruthenium(II) Complex with 1,10-Phenanthroline-3,8-dicarboxylic Acid in Aerobic Oxidation Reactions
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Abstract: Mixed-ligand ruthenium(II) complex with 2,2′-bipyridine and 1,10-phenanthroline-3,8-dicarboxylic acid with the composition [Ru(phen-C)(bpy)2]Cl2·5H2O (bpy = 2,2′-bipyridine, phen-C = 1,10-phenantroline-3,8-dicarboxylic acid) has been synthesized and characterized by spectral data. The complex has been tested as photocatalyst in aerobic oxidation reactions, including transformation of arylboronic acids to phenols, primary amines to imines, and sulfides to sulfoxides in aqueous medium. The possibility of regeneration of the catalyst in the oxidation of sulfides has been demonstrated.
- Abel, A. S.,Averin, A. D.,Beletskaya, I. P.,Bessmertnykh-Lemeune, A. G.,Yakushev, A. A.,Zenkov, I. S.
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p. 1398 - 1404
(2021/10/26)
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- Ni-Catalyzed Borylation of Aryl Sulfoxides
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A nickel/N-heterocyclic carbene (NHC) catalytic system has been developed for the borylation of aryl sulfoxides with B2(neop)2 (neop=neopentyl glycolato). A wide range of aryl sulfoxides with different electronic and steric properties were converted into the corresponding arylboronic esters in good yields. The regioselective borylation of unsymmetric diaryl sulfoxides was also feasible leading to borylation of the sterically less encumbered aryl substituent. Competition experiments demonstrated that an electron-deficient aryl moiety reacts preferentially. The origin of the selectivity in the Ni-catalyzed borylation of electronically biased unsymmetrical diaryl sulfoxide lies in the oxidative addition step of the catalytic cycle, as oxidative addition of methoxyphenyl 4-(trifluoromethyl)phenyl sulfoxide to the Ni(0) complex occurs selectively to give the structurally characterized complex trans-[Ni(ICy)2(4-CF3-C6H4){(SO)-4-MeO-C6H4}] 4. For complex 5, the isomer trans-[Ni(ICy)2(C6H5)(OSC6H5)] 5-I was structurally characterized in which the phenyl sulfinyl ligand is bound via the oxygen atom to nickel. In solution, the complex trans-[Ni(ICy)2(C6H5)(OSC6H5)] 5-I is in equilibrium with the S-bonded isomer trans-[Ni(ICy)2(C6H5)(SOC6H5)] 5, as shown by NMR spectroscopy. DFT calculations reveal that these isomers are separated by a mere 0.3 kJ/mol (M06/def2-TZVP-level of theory) and connected via a transition state trans-[Ni(ICy)2(C6H5)(η2-{SO}-C6H5)], which lies only 10.8 kcal/mol above 5.
- Huang, Mingming,Wu, Zhu,Krebs, Johannes,Friedrich, Alexandra,Luo, Xiaoling,Westcott, Stephen A.,Radius, Udo,Marder, Todd B.
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supporting information
p. 8149 - 8158
(2021/05/10)
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- PROCESS FOR PRODUCING 4,4'-DICHLORODIPHENYL SULFONE
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The invention relates to a process for producing 4,4'-dichlorodiphenyl sulfone, comprising: (I) reacting thionyl chloride, chlorobenzene and aluminum chloride forming an intermediate reaction product and hydrogen chloride; (II) mixing aqueous hydrochloric acid and the intermediate reaction product to obtain an organic phase comprising 4,4'-dichlorodiphenyl sulfoxide and an aqueous phase; (III) cooling the organic phase to a temperature below the saturation point of 4,4'- dichlorodiphenyl sulfoxide to obtain a suspension; (IV) solid-liquid-separation of the suspension to obtain crystallized 4,4'-dichlorodiphenyl sulfoxide, and mother liquor; (V) washing the crystallized 4,4'-dichlorodiphenyl sulfoxide with a carboxylic acid to obtain carboxylic acid-wet 4,4'-dichlorodiphenyl sulfoxide; (VI) reacting the washed 4,4'-dichlorodiphenyl sulfoxide and an oxidizing agent in a carboxylic acid as solvent to obtain a reaction mixture comprising 4,4'-dichlorodiphenyl sulfone and carboxylic acid; (VII) separating the reaction mixture comprising 4,4'-dichlorodiphenyl sulfone and carboxylic acid into a residual moisture comprising 4,4'-dichlorodiphenyl sulfone as crude product and a liquid phase comprising carboxylic acid.
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Page/Page column 31-32
(2021/03/05)
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- (C)CRYSTAL COMPOSITION (CC) COMPRISING 4,4'-DICHLORODIPHENYLSULFONE CRYSTALS (C)
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The invention relates to crystals (C) consisting of at least 98 % by weight of 4,4'- dichlorodiphenylsulfone, 0 to 2 % by weight of impurities and 0 to 2 % by weight of at least one solvent (c). Moreover, the present invention relates to a crystal composition (CC) comprising crystals (C) and a process for the production of the crystal composition (CC) and the crystals (C).
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Page/Page column 11-12
(2021/03/05)
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- Selective oxidation of (hetero)sulfides with molecular oxygen under clean conditions
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The development of eco-friendly and switchable catalytic systems for the conversion of a sole raw-material into distinct high-value products is a particularly attractive concept and a daunting synthetic challenge. In the present work, the first example of efficient and selective oxidation of sulfides to sulfones and sulfoxides using molecular oxygen under clean conditions was established.
- Liu, Kai-Jian,Deng, Ji-Hui,Yang, Jie,Gong, Shao-Feng,Lin, Ying-Wu,He, Jun-Yi,Cao, Zhong,He, Wei-Min
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supporting information
p. 433 - 438
(2020/02/13)
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- PROCESS FOR PRODUCING 4,4`-DICHLORODIPHENYL SULFOXIDE
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The invention relates to a process for producing 4,4'-dichlorodiphenyl sulfoxide comprising: (I) reacting thionyl chloride, chlorobenzene and aluminum chloride in a molar ratio of thionyl chloride : chlorobenzene : aluminum chloride of 1 : (6 to 9) : (1 to 1.5) at a temperature in the range from 0 to below 20°C, forming an intermediate reaction product and hydrogen chloride; (II) mixing aqueous hydrochloric acid and the intermediate reaction product at a temperature in the range from 70 to 110°C to obtain an organic phase comprising 4,4'-dichlorodiphenyl sulfoxide and an aqueous phase; (III) cooling the organic phase comprising the 4,4'-dichlorodiphenyl sulfoxide to a temperature below the saturation point of 4,4'-dichlorodiphenyl sulfoxide to obtain a suspension comprising crystallized 4,4'-dichlorodiphenyl sulfoxide; (IV) solid-liquid-separation of the suspension to obtain a residual moisture containing solid 4,4'-dichlorodiphenyl sulfoxide comprising crystallized 4,4'-dichlorodiphenyl sulfoxide and mother liquor.
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Page/Page column 23-24
(2020/08/22)
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- Preparation method for catalytic synthesis 4 and 4 ’ -dichlorophenylsulfone (by machine translation)
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A catalyst, chlorobenzene and thionyl chloride 4 are 4 ’ - subjected to a Fourier reaction under the action of catalyst, chlorobenzene and thionyl chloride are subjected to a Fourier reaction under the action of a catalyst pH value is poured into reaction liquid to obtain '- dichlorodiphenyl sulfoxide, then the reaction solution is cooled down to devitrification and filtered to obtain' - dichlorodiphenyl sulfone 4,4 . 0 - 5 °C 4,4The product has the advantages of simple process, low cost, less impurities, high purity of the obtained product, less than 99.2percent, 2 and 4 ’ isomer content, more than 0.1percent, good economic benefit and suitability for industrial production 90percent. (by machine translation)
- -
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Paragraph 0021-0038
(2020/07/13)
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- Synthesis and nano-Pd catalyzed chemoselective oxidation of symmetrical and unsymmetrical sulfides
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A highly chemoselective, efficient and nano-Pd catalyzed protocol for the rapid construction of sulfoxides and sulfones via the oxidation of symmetrical and unsymmetrical sulfides using H2O2 as an oxidant has been developed, respectively. The ready availability of starting materials, easy recovery and reutilization of the catalyst, wide substrate scope, and high yields make this protocol an attractive alternative. The process also involves the metal-free and microwave-promoted synthesis of symmetrical diarylsulfides, and FeCl3-mediated preparation of symmetrical diaryldisulfides through the reaction of arenediazonium tetrafluoroborates with Na2S·9H2O as a sulfur source. In addition, unsymmetrical sulfides were generated via the K2CO3-mediated reaction of arenediazonium tetrafluoroborates with symmetrical disulfides.
- Li, Xing,Du, Jia,Zhang, Yongli,Chang, Honghong,Gao, Wenchao,Wei, Wenlong
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p. 3048 - 3055
(2019/03/21)
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- Method used for preparing 4, 4'-dichlorophenyl sulfone through sulfoxide oxidation
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The invention relates to a method used for preparing 4, 4'-dichlorophenyl sulfone, and more specifically relates to a method used for preparing 4, 4'-dichlorophenyl sulfone through sulfoxide oxidation. The method comprises following steps: chlorobenzene and thionyl chloride are subjected to Friedel-Crafts reaction in the presence of a catalyst so as to obtain 4, 4'-dichlorodiphenyl sulfoxide; theobtained 4, 4'-dichlorodiphenyl sulfoxide is dissolved with a solvent, hydrogen peroxide is added for oxidation reaction so as to obtain a 4, 4'-dichlorophenyl sulfone crude product; and the 4, 4'-dichlorophenyl sulfone crude product is subjected to secondary oxidation refining so as to obtain 4, 4'-dichlorophenyl sulfone at last. The catalyst is a mixture of aluminium chloride anhydrous and tetrabutylammonium bromide. According to the method, the composite catalyst and secondary oxidation refining method are adopted, the purity of the prepared 4, 4'-dichlorophenyl sulfone is larger than 99.5%, and the refining yield is larger than 99.0%.
- -
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Paragraph 0022-0024; 0028-0030
(2019/07/04)
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- Preparation 4, 4' - two chlorine benzoin sulphone process (by machine translation)
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The invention belongs to the field of organic synthesis, in particular to a process for preparing 4, 4' - two chlorine benzoin sulphone process. The thionyl chloride and chlorobenzene in the catalyst under the action of the Friedel-crafts reaction, reaction reducing the temperature after hydrolysis, further heating up to dissolve, then cooling, crystals, filtering to obtain 4, 4 '- two chlorine benzoin asia sulphone, then dissolved in glacial acetic acid, hydrogen peroxide oxidation reaction, after the reaction cooling, filtering, to obtain the 4, 4' - two chlorine benzoin sulphone; for the catalyst is anhydrous aluminum trichloride and benzyl triethyl ammonium chloride mixture. The process of the invention is simple, low cost, little impurity, using composite catalyst, and does not additionally adding solvent, the product purity is high, the content of 99.4% or more, the yield of 92% or more, good economic benefit, to industrial production. (by machine translation)
- -
-
Paragraph 0017-0019; 0022-0024
(2019/07/04)
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- Enantioselective Synthesis of Chiral-at-Sulfur 1,2-Benzothiazines by CpxRhIII-Catalyzed C?H Functionalization of Sulfoximines
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Sulfoximines with stereogenic sulfur atoms are attractive structural motifs in drug discovery. A direct catalytic enantioselective method for the synthesis of sulfur-chiral 1,2-benzothiazines from readily accessible diaryl sulfoximines is presented. Rhodium(III) complexes equipped with chiral cyclopentadienyl ligands and paired with suitable carboxylic acid additives engage in an enantiodetermining C?H activation directed by the sulfoximine group. Subsequent trapping of the rhodacycle with a broad range of diazoketones gives access to S-chiral 1,2-benzothiazines with synthetically highly attractive substitution patterns in good yields and enantioselectivities.
- Sun, Yang,Cramer, Nicolai
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supporting information
p. 15539 - 15543
(2018/11/02)
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- Selective synthesis of sulfoxides and sulfones from sulfides using silica bromide as the heterogeneous promoter and hydrogen peroxide as the terminal oxidant
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Silica bromide as a heterogeneous promoter and reagent is prepared from the reaction of silica gel with PBr3as a non-hydroscopic, filterable, cheap, and stable yellowish powder that can be stored for months. The results show that silica bromide is a suitable and efficient promoter for the chemoselective oxidation of sulfides to the corresponding sulfoxides or sulfones in the presence of 30% H2O2in acetonitrile. The excellent yields, heterogeneous conditions, simplicity, compatibility with a variety of functionalities, and ease of isolation of the products make our procedure a practical alternative.
- Maleki, Behrooz,Hemmati, Saba,Sedrpoushan, Alireza,Ashrafi, Samaneh Sedigh,Veisi, Hojat
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p. 40505 - 40510
(2015/02/03)
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- Hydrogenation of sulfoxides to sulfides under mild conditions using ruthenium nanoparticle catalysts
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The first demonstration of the hydrogenation of sulfoxides under atmospheric H2 pressure is reported. The highly efficient reaction is facilitated by a heterogeneous Ru nanoparticle catalyst. The mild reaction conditions enable the selective hydrogenation of a wide range of functionalized sulfoxides to the corresponding sulfides. The high redox ability of RuO x nanoparticles plays a key role in the hydrogenation.
- Mitsudome, Takato,Takahashi, Yusuke,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 8348 - 8351
(2014/08/18)
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- Investigations on the Lewis-acids-catalysed electrophilic aromatic substitution reactions of thionyl chloride and selenyl chloride, the substituent effects, and the reaction mechanisms
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The previously established aluminium-chloride-(AlCl3)-catalysed electrophilic aromatic substitution (EAS) of benzene (PhH) with thionyl chloride (SOCl2) has been extended to toluene (PhCH3), chlorobenzene (PhCl), and phenol (PhOH). -CH3 was found to be mainly a para-director with a minor ortho-directing effect on the EAS reactions giving diaryl sulfoxides (Ar2SO). -Cl was found to be exclusively a para-director for formation of Ar2SO. All the -CH3, -Cl, and -OH groups were shown to be exclusive para-directors for formation of diaryl sulfides (Ar2S) from the EAS reactions. Although the reactions of PhH and PhCH3 with SOCl2 in the presence of AlCl 3 gave the major Ar2SO and minor Ar2S at ambient temperature, the phenol (PhOH) reaction was shown to give only the reduced sulfide (p-HOC6H4)2S with no sulfoxide (p-HOC6H4)2SO formed. The mixed diaryl sulfoxides ArSOAr′ (Ar, Ar′=C6H5, p-CH 3C6H4; C6H5, o-CH 3C6H4; and C6H5, p-ClC6H4) were produced in the AlCl3-catalysed reactions of SOCl2 with molar 1:1 PhH-PhX mixtures (X=CH3 and Cl). Efforts to enhance the yield of S-aryl arenesulfonothioates ArSO 2SAr (Ar=Ph, p-CH3C6H4, and p-ClC6H4) from the AlCl3-catalysed EAS reactions of SOCl2 were made, showing that decreasing the molar ratios of ArH/SOCl2 or lowering the temperature resulted in an increase in the product yield. A detailed mechanism has been proposed to account for the formation of ArSO2SAr. The Lewis-acid-MCl3-(M=Al and Fe)-catalysed EAS reactions of PhH with selenyl chloride (SeOCl2) were demonstrated to give the reduced diphenyl selenide (Ph2Se) and diphenyl diselenide (PhSeSePh) via novel auto-redox processes in selenium of the key EAS intermediates.
- Sun, Xiaoping,Haas, David,McWilliams, Samantha,Smith, Benjamin,Leaptrot, Katrina
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p. 736 - 744
(2014/01/23)
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- Desymmetrization of prochiral diaryl sulfoxides by an asymmetric sulfoxide-magnesium exchange
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The first desymmetrizations of prochiral diaryl sulfoxides 1 by an asymmetric sulfoxide-magnesium exchange reaction are reported. The respective substrate (1), iPr2Mg, and the dilithium salt of (S)-BINOL (which was prepared in situ) provided (S)-configured aryl isopropyl sulfoxides 2 in up to 91 % yield and with up to 91 % ee. (S)-BINOL was re-isolable in 98 % yield. Copyright
- Hampel, Thomas,Ruppenthal, Simon,Saelinger, Daniel,Brueckner, Reinhard
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supporting information; body text
p. 3136 - 3140
(2012/05/20)
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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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body text
p. 2993 - 2996
(2011/09/14)
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- Kinetics and mechanism of (saJen)Mnlll-catalysed hydrogen peroxide oxidation of diphenyl sulphides
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The kinetics of (salen)MIII complexes-catalysed oxidation of a few diphenyl sulphides by hydrogen peroxide have been investigated at 25°C in acetonitrile (80%) - water (20%) spectrophotometrically. The reaction follows first-order kinetics in (salen)Mn111 complex and zero-order kinetics in hydrogen peroxide. The order of the reaction with respect to .sulphide is fractional. The effects of nitrogenous bases, free radical inhibitor and changes in solvent composition have also been studied. A suitable mechanism involving a manganese(III)-hydroperoxide complex as reactive species has been proposed.
- Chellamani,Alhaji
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experimental part
p. 346 - 351
(2010/01/16)
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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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- Oxidation kinetics of some sulfoxides with N,N-dibromobenzene sulfonamide
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The kinetics of oxidation of some sulfoxides with dibromamine-B yielding sulfones was investigated in presence of HgII, and the rate equation, kobs = k3K2K′h[S]/[RNH 2] + K′h was found to be valid. The reaction involves two distinct pathways namely initial fast step and a subsequent slow step. The chloride ions have no effect on the reactivity of sulfoxides. Sulfoxides containing electron-attracting substituents retard the reactivity while those containing electron-releasing constituents accelerate the rate of oxidation. Exner plot confirms the operation of same mechanism in all the sulfoxides studied. Electrophilic addition of Br+ to sulfur atom results in an electron-deficient sulfonium centre which decomposes in a slow rate-limiting step. The rate coefficients are treated in terms of multiparametric extensions of the Hammett equation to have more insight into the mechanistic aspects.
- Meenakshisundaram, Subbiah,Amutha
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p. 679 - 682
(2008/09/18)
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- Lithium/Sodium Perchlorate Catalyzed Synthesis of Symmetrical Diaryl Sulfoxides
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Synthesis of diaryl sulfoxides from aromatics and thionyl chloride catalyzed by LiClO4/NaClO4 at room temperature is described. Mild reaction conditions, simple work-up, inexpensive and easily available catalysts are important and attractive features of this method.
- Bandgar,Makone
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p. 743 - 750
(2007/10/03)
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- Highly Rapid and Direct Synthesis of Diaryl Sulfoxides
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Aromatic compounds react smoothly with thionyl chloride in the presence of 10 mol% of water at ambient temperature to afford the corresponding symmetrical diaryl sulfoxides in good to excellent yields with high regioselectivity.
- Bandgar,Kinkar,Kamble,Bettigeri
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p. 2029 - 2032
(2007/10/03)
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- A selective and convenient oxidation of sulfides to sulfoxides with trichloroisocyanuric acid
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Sulfides are readily oxidized to sulfoxides by a solution of pyridine, water, and trichloroisocyanuric acid in acetonitrile and methylene chloride.
- Xiong,Huang,Zhong
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p. 245 - 248
(2007/10/03)
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- Electrophilic oxidant produced in the photodeoxygenation of 1,2-benzodiphenylene sulfoxide
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We report that the photodeoxygenation of 1,2-benzodiphenylene sulfoxide, 1, generates an intermediate capable of oxidizing the solvent benzene to phenol. The reactivity of the intermediate was probed with various substrates (2-methylbutane, chloride ion,
- Lucien,Greer
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p. 4576 - 4579
(2007/10/03)
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- Trifluoromethanesulfonic acid catalyzed preparation of symmetrical diaryl sulfoxides from arenes and thionyl chloride
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The preparation of symmetrical diaryl sulfoxides from thionyl chloride and arenes catalyzed by trifluoromethanesulfonic acid is described. The reaction is characterized by its mildness, high yields, selectivity, and ease of workup.
- Olah, George A.,Marinez, Eric R.,Prakash, G. K. Surya
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p. 1397 - 1398
(2007/10/03)
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- Oxidation of Sulfides to Sulfoxides with Hypervalent (tert-Butylperoxy)iodanes
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Oxidation of sulfides with the crystalline (alkylperoxy)iodanes, 1-(tert-butylperoxy)-1,2-benziodoxol-3(1H)-ones 2a and 2b, in acetonitrile-water or in dichloromethane, affords sulfoxides in high yields. Measurement of the relative rates of oxidation for a series of ring-substituted thioanisoles 3b (p-MeO), 3c (p-Me), and 3d (p-Cl) in acetonitrile-water indicates that electron-releasing groups such as p-MeO and p-Me groups increase the rate of oxidation, and Hammett correlation of the relative rate factors with the substituent constants affords the reaction constants ρ+ = -2.23 (σ+, r = 0.98) for BF3-catalyzed oxidation and ρ = -3.32 (σ, r = 0.98) for uncatalyzed oxidation. The effects of a free-radical scavenger, galvinoxyl, were examined. A mechanism involving the intermediary formation of the sulfonium species 11 by nucleophilic attack of sulfide toward the iodine(III) atom of 2 is proposed for the oxidation in acetonitrile-water in the presence and the absence of BF3· Et2O. On the other hand, the oxidation of sulfoxides in dichloromethane probably proceeds by a radical process, which involves the decomposition at room temperature of 2 via homolytic bond cleavage of the weak iodine(III)-peroxy bond, generating tert-butylperoxy radical and the [9-1-2] iodanyl radical 12.
- Ochiai, Masahito,Nakanishi, Akinobu,Ito, Takao
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p. 4253 - 4259
(2007/10/03)
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- Interaction of diphenyl sulfide with sulfuryl chloride
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The reaction of diphenyl sulfide with sulfuryl chloride was studied. Depending on the reaction conditions, it occurs either as chlorination of the aromatic ring or as oxidation to give sulfoxide.
- Savin,Nedel'kin
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p. 2668 - 2669
(2007/10/03)
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- Extremely Facile Ligand-Exchange and Disproportionation Reactions of Diaryl Sulfoxides, Selenoxides, and Triarylphosphine Oxides with Organolithium and Grignard Reagents
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Diaryl sulfoxides undergo unusually rapid ligand-exchange reaction upon treatment with organolithium reagents at -95 deg C.Optically pure phenyl p-tolyl sulfoxide (4b) reacted with organolithium reagents at the range from -20 to -95 deg C to give facile ligand-exchange and disproportionation products, i.e., diphenyl sulfoxide (7), recovered 4b, and di-p-tolyl sulfoxide (8) in a statistical ratio of 1:2:1 in quantitative yields, and the recovered 4b was completely racemized.This facile ligand exchange was observed in the similar reactions using only diaryl selenoxides and triarylphosphine oxides.The reactions of 18O-labeled phenyl p-tolyl sulfoxide (4c) with organolithium reagents gave products in a statistical ration without 18O scrambling, indicating that only the C-S bond cleavage took place under low temperature.It is suggested that the ligand exchange reactions occur by the nucleophilic attack by organolithium reagent at the sulfinyl sulfur atom, giving ?-sulfurane as an intermediate that collapses rapidly.These results suggest that the treatment of arylic sulfoxides, selenoxides, and phosphine oxides with strong bases should be effected with caution.
- Furukawa, Naomichi,Ogawa, Satoshi,Matsumura, Kazunori,Fujihara, Hisashi
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p. 6341 - 6348
(2007/10/02)
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- An Organic Tridentate Ligand Stabilizing a 10-I-4 Iodinane Oxide and Related Species
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The tridentate ligand of iodinane 7, with electronegative apical oxygens joined by five-membered rings to an electropositive equatorial carbon, strongly stabilizes pseudo-trigonal-bipyramidal (Ψ-TBP) 10-I-3 species 7, as well as 10-I-4 species such as iodinane oxide 5.Fluorination of 7 forms a pseudooctahedral (Ψ-Oc) 12-I-5 periodinane, 4, which is easily hydrolyzed to 5, or reacts with Lewis acids to form 10-I-4 fluoroperiodonium cation 8.The equatorial I+-O- bond of 5 reacts with electrophiles at the oxygen .Small amounts of tetrabutylammonium hydroxide give nucleophilic addition to the iodine of 5 to form 12-I-5 intermediates (18) leading to rapid inversion of geometry at the 10-I-4 center of the iodinane oxide.Excess KOH cleaves the C-I bond of 5, forming the reduced arenediol 17.Diphenyldialkoxysulfurane 14 converts 5 to dialkoxyperiodinane 13, forming diphenyl sulfoxide.Iodine oxide 5 is a strong oxidizing agent, rapidly oxidizing HCl to Cl2, or pinacol to acetone.Oxidation of a diaryl sulfide to the sulfoxide and the sulfones occurs unselectively, but slowly, at 160 deg C with pure 5.With a catalytic amount of TFAA, selective oxidation of the diaryl sulfide to the sulfoxide by 5 is rapid at room temperature.
- Weclas-Henderson, L.,Nguyen, T. T.,Hayes, R. A.,Martin, J. C.
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p. 6565 - 6573
(2007/10/02)
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- Selectivity in the TiO2-mediated photocatalytic oxidation of thioethers
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The relative rates of photooxygenation of substituted diphenyl sulfides on irradiated TiO2 powders suspended in oxygenated acetonitrile correlate linearly with σ+, as is consistent with formation of a surface bound cation radical in the primary photoprocess. Substituted dibenzyl sulfides, in contrast, suffer C-S cleavage upon photocatalyzed oxidation. Factors disposing these reactions toward preferential sulfoxide formation or bond cleavage are discussed.
- Fox,Abdel-Wahab
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p. 4533 - 4536
(2007/10/02)
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- TURNING THE REACTIVITY OF CARBONYL OXIDES FROM NUCLEOPHILIC TO ELECTROPHILIC. A NOVEL DEOXYGENATION OF SULFOXIDES BY ELECTROPHILIC α,α,α-TRIFLUOROACETOPHENONE O-OXIDE
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The well-known nucleophilic reactivity of carbonyl oxides could be turned into electrophilic by a potent electron-attracting group.Thus α,α,α-trifluoroacetophenone O-oxide oxidizes both sulfides and sulfoxides electrophilically, and the most characteristic reaction is the deoxyganation of sulfoxides.
- Ishiguro, Katsuya,Hirano, Yukimichi,Sawaki, Yasuhiko
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p. 6201 - 6204
(2007/10/02)
-
