- A protic ionic liquid, when entrapped in cationic reverse micelles, can be used as a suitable solvent for a bimolecular nucleophilic substitution reaction
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In this work, we have explored how the confinement of the protic ionic liquid (IL) ethylammonium nitrate (EAN) inside toluene/benzyl-n-hexadecyldimethylammonium chloride (BHDC) reverse micelles (RMs) affects the Cl- nucleophilicity on the bimolecular nucleophilic substitution (SN2) reaction between this anion and dimethyl-4-nitrophenylsulfonium trifluoromethanesulfonate. To the best of our knowledge this is the first report where toluene/BHDC RMs use EAN as a polar component and it is used as a nanoreactor for carrying out kinetic experiments. Dynamic light scattering results reveal the formation of RMs containing the protic IL. The kinetic results show that upon confinement, EAN becomes a suitable solvent for the SN2 reaction while in homogeneous media it is a bad option. Entrapped in BHDC RMs, due to the strong hydrogen bond interactions, EAN behaves as an aprotic-like IL which cannot deactivate the nucleophilic power of Cl- and yet increases the substrate solubility. These facts show the versatility of this kind of organized system to alter the polar solvent entrapped and its influence on the reaction rate when it is used as a nanoreactor.
- Crosio, Matías A.,Correa, N. Mariano,Silber, Juana J.,Falcone, R. Darío
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Read Online
- Evidence for the importance of polarizability in biomimetic catalysis involving cyclophane receptors
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Cyclophanes 1-6 catalyze the nucleophilic dealkylation of a simple sulfonium compound by potassium iodide. The cation-π interaction is important in substrate binding, but the primarily electrostatic nature of this effect does not explain all observations concerning catalysis. As a series of substituents are placed on the cyclophane framework, a systematic variation in catalyst effectiveness is seen, such that more polarizable substituents produce more potent catalysts. This provides support for the notion that transition states are especially polarizable, and catalysis can be enhanced by maximizing London dispersion forces. The reactions studied here are very similar to the broad class of biological methylations mediated by S-adenosylmethionine, and the biological catalysts may use forces similar to those described here.
- Ngola, Sarah M.,Dougherty, Dennis A.
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Read Online
- N-bromosuccinimide/HCl mediated reduction of sulfoxides to sulfides
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An efficient reduction of sulfoxides to sulfides mediated by N-bromosuccinimide (NBS)/HCl system has been developed. This protocol shows good functional group compatibility as well as broad substrates scope with operational simplicity.
- Wang, Jianqiang,Shi, Fangmin,Dai, Dongyan,Xiong, Liping,Yang, Yongpo
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supporting information
p. 439 - 443
(2021/02/03)
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- Synthesis of Aryl Methyl Sulfides from Arysulfonyl Chlorides with Dimethyl Carbonate as the Solvent and C1 Source
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A new procedure for the synthesis of aryl methyl sulfides from dimethyl carbonate (DMC) and arylsulfonyl chlorides has been achieved. In this strategy, DMC plays a dual role as both, C1 building block and green solvent. Arylsulfonyl chlorides served as the sulfur precursors, and a variety of aryl methyl sulfides were obtained in moderate to excellent yields with good functional group tolerance. Additionally, alkylsulfonyl chloride and dibenzyl carbonate are proven to be suitable substrates as well.
- Miao, Ren-Guan,Qi, Xinxin,Wu, Xiao-Feng
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supporting information
p. 5219 - 5221
(2021/10/19)
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- Photoinduced Iron-Catalyzed ipso-Nitration of Aryl Halides via Single-Electron Transfer
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A photoinduced iron-catalyzed ipso-nitration of aryl halides with KNO2 has been developed, in which aryl iodides, bromides, and some of aryl chlorides are feasible. The mechanism investigations show that the in situ formed iron complex by FeSO4, KNO2, and 1,10-phenanthroline acts as the light-harvesting photocatalyst with a longer lifetime of the excited state, and the reaction undergoes a photoinduced single-electron transfer (SET) process. This work represents an example for the photoinduced iron-catalyzed Ullmann-type couplings.
- Wu, Cunluo,Bian, Qilong,Ding, Tao,Tang, Mingming,Zhang, Wenkai,Xu, Yuanqing,Liu, Baoying,Xu, Hao,Li, Hai-Bei,Fu, Hua
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p. 9561 - 9568
(2021/08/06)
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- t-BuOK-promoted methylthiolation of aryl fluorides with dimethyldisulfide under transition-metal-free and mild conditions
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In the presence of potassium tert-butoxide (t-BuOK), the cross-coupling reaction between aryl fluorides and dimethyldisulfide was developed. A series of aryl methyl sulfides were obtained in moderate to good yields under transition-metal-free and mild conditions.
- Huang, Dayun,Wu, Xiangmei
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- Copper-Catalyzed Methylthiolation of Aryl Iodides and Bromides with Dimethyl Disulfide in Water
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An efficient route to aryl methyl sulfides through the copper-catalyzed coupling reaction of aryl iodides or bromides with dimethyl disulfide in water is described. Electron-donating and electron-withdrawing functional groups in the substrates were tolerated, and the corresponding products were obtained in moderate to good yields.
- Wang, Ying-Yu,Wu, Xiang-Mei,Yang, Ming-Hua
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supporting information
(2020/07/20)
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- Enhancement of Benzothiazoles as Pteridine Reductase-1 Inhibitors for the Treatment of Trypanosomatidic Infections
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2-Amino-benzo[d]thiazole was identified as a new scaffold for the development of improved pteridine reductase-1 (PTR1) inhibitors and anti-trypanosomatidic agents. Molecular docking and crystallography guided the design and synthesis of 42 new benzothiazoles. The compounds were assessed for Trypanosoma brucei and Leishmania major PTR1 inhibition and in vitro activity against T. brucei and amastigote Leishmania infantum. We identified several 2-amino-benzo[d]thiazoles with improved enzymatic activity (TbPTR1 IC50 = 0.35 μM; LmPTR1 IC50 = 1.9 μM) and low μM antiparasitic activity against T. brucei. The ten most active compounds against TbPTR1 were able to potentiate the antiparasitic activity of methotrexate when evaluated in combination against T. brucei, with a potentiating index between 1.2 and 2.7. The compound library was profiled for early ADME toxicity, and 2-amino-N-benzylbenzo[d]thiazole-6-carboxamide (4c) was finally identified as a novel potent, safe, and selective anti-trypanocydal agent (EC50 = 7.0 μM). Formulation of 4c with hydroxypropyl-β-cyclodextrin yielded good oral bioavailability, encouraging progression to in vivo studies.
- Linciano, Pasquale,Pozzi, Cecilia,Iacono, Lucia Dello,Di Pisa, Flavio,Landi, Giacomo,Bonucci, Alessio,Gul, Sheraz,Kuzikov, Maria,Ellinger, Bernhard,Witt, Gesa,Santarem, Nuno,Baptista, Catarina,Franco, Caio,Moraes, Carolina B.,Müller, Wolfgang,Wittig, Ulrike,Luciani, Rosaria,Sesenna, Antony,Quotadamo, Antonio,Ferrari, Stefania,P?hner, Ina,Cordeiro-Da-Silva, Anabela,Mangani, Stefano,Costantino, Luca,Costi, Maria Paola
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p. 3989 - 4012
(2019/05/06)
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- Transition-Metal-Free Aryl-Heteroatom Bond Formation via C-S Bond Cleavage
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Aryl-heteroatom bonds (C-Het) are almost ubiquitously present in chemical molecules. However, methods for diverse C-Het bond formations from a simple substrate are limited. Herein, we report a convenient and efficient C-S bond transformation of aryl sulfoniums to various C-Het bonds (C-O, C-S, C-Sn, C-Si, C-Se) in the absence of any transition-metal catalyst. These reactions proceeded in mild conditions with a wide substrate scope.
- Zhao, Jian-Nan,Kayumov, Muzaffar,Wang, Dong-Yu,Zhang, Ao
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supporting information
p. 7303 - 7306
(2019/10/02)
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- A Manganese N-Heterocyclic Carbene Catalyst for Reduction of Sulfoxides with Silanes
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The first reduction of sulfoxides catalysed by a well-defined manganese complex is described. A variety of sulfoxides are reduced to the corresponding sulfides in high yields using phenylsilane, diphenylsilane, and the economically feasible 1,1,3,3-tetramethyldisiloxane (TMDS) as reducing agents in the presence of a Mn-NHC complex. The reaction is performed under air and without the need of any additive. The involvement of radicals in the catalytic reaction is probed by spin-trap experiments.
- Sousa, Sara C. A.,Carrasco, Carlos J.,Pinto, Mara F.,Royo, Beatriz
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p. 3839 - 3843
(2019/06/24)
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- Visible light-promoted 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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- Merging visible-light photoredox and micellar catalysis: Arylation reactions with anilines nitrosated in situ
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An aqueous photocatalytic system was designed by merging visible-light photoredox catalysis with micellar catalysis. Eosin B, an organic dye, was utilized as the photocatalyst, and Triton X-100 was employed as the surfactant; both are inexpensive and commercially available. This clean and energy-saving catalytic system enables photocatalytic reactions of the diazonium ion generated in situ to proceed smoothly in water without any co-solvents or additives at room temperature.
- Bu, Mei-Jie,Lu, Guo-Ping,Jiang, Jianzhong,Cai, Chun
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p. 3728 - 3732
(2018/08/12)
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- Cesium carbonate-promoted synthesis of aryl methyl sulfides using: S -methylisothiourea sulfate under transition-metal-free conditions
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In the presence of cesium carbonate, an efficient synthesis of aryl methyl sulfides by the reactions of aryl halides with commercially available S-methylisothiourea sulfate is developed. This odourless and highly crystalline solid can be used as the subst
- Zhang, Caiyang,Zhou, You,Huang, Jintao,Tu, Canhui,Zhou, Xiaoai,Yin, Guodong
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p. 6316 - 6321
(2018/09/10)
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- Metal-free S-methylation of diaryl disulfides with di-tert-butyl peroxide
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An efficient approach for S-methylation of diaryl disulfides with di-tert-butyl peroxide under metal-free and neutral conditions was established. The present protocol shows good functional group tolerance to afford aryl methyl sulfides in moderate to good
- Wu, Xiangmei,Wang, Yan
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supporting information
p. 1240 - 1243
(2018/03/08)
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- Rapid and efficient deoxygenation of sulfoxides to sulfides with tantalum(V) chloride/sodium iodide system
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TaCl5/NaI system converts a wide range of sulfoxides to the corresponding sulfides in high yields with short reaction times, under mild conditions. It is worth mentioning that this protocol is chemoselective and tolerates various functional groups (such as –Br, –Cl, –OCH3, –CHO, and –NO2) and double bond.
- Yoo, Byung Woo,Park, Jeeyeon,Shin, Hyo Jong,Yoon, Cheol Min
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p. 597 - 603
(2017/10/06)
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- 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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- Pummerer rearrangement using bis(p-nitrophenyl) phosphorazidate as an azidation reagent: A novel synthesis of azidomethyl sulfides
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A novel method for the synthesis of azidomethyl sulfides by Pummerer rearrangement using bis(p-nitrophenyl) phosphorazidate (p-NO2DPPA) as an azidation reagent was developed. Various methyl sulfoxides were converted into the corresponding azidomethyl sulfides. Importantly, this reaction enables the preparation of azidomethyl sulfides without the use of toxic or explosive azide sources.
- Ishihara, Kotaro,Shioiri, Takayuki,Matsugi, Masato
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supporting information
p. 3932 - 3935
(2017/09/20)
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- Transition-Metal-Free and Oxidant-Free Cross-Coupling of Arylhydrazines with Disulfides: Base-Promoted Synthesis of Unsymmetrical Aryl Sulfides
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A novel synthesis of unsymmetrical aryl sulfides, which requires no transition metal catalyst and no oxidant, was developed. This base-promoted cross-coupling reaction proceeded using arylhydrazines and 1 equiv amount of disulfides under inert gas conditions to afford the unsymmetrical aryl sulfides in good yields.
- Taniguchi, Toshihide,Naka, Takuya,Imoto, Mitsutaka,Takeda, Motonori,Nakai, Takeo,Mihara, Masatoshi,Mizuno, Takumi,Nomoto, Akihiro,Ogawa, Akiya
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p. 6647 - 6655
(2017/07/15)
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- A concise and convenient synthesis of 4-(trifluoromethylthio)aniline
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4-(Trifluoromethylthio)aniline, a key agricultural intermediate, can be synthesized from 4-nitrobromobenzene. First 4-nitrothioanisole was obtained by the methylthiotriazine of 4-nitrobromobenzene with sodium salt of methyl mercaptan in the presence of phase-transfer catalyst in a 91.4 % yield; then 4-(trifuroromethylthio)nitrobenzene was produced through chlorination in a 83.7 % yield and fluorination in a 86.3 % yield; finally the hydrogenation in the presence of Pd/C can afford 4-(trifluoromethylthio)aniline with a 98 % yield.
- Gong, Shunze,Cai, Xinhong,Fu, Hao,Xu, Defeng
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- Metal-free radical thiolations mediated by very weak bases
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Aromatic thioethers and analogous heavier chalcogenides were prepared by reaction of arene-diazonium salts with disulfides in the presence of the cheap and weak base NaOAc. The mild and practical reaction conditions (equimolar reagents, DMSO, r.t., 8 h) tolerate various functional groups (e.g. Br, Cl, NO2, CO2R, OH, SCF3, furans). Mechanistic studies indicate the operation of a radical aromatic substitution mechanism via aryl, acetyloxyl, thiyl, and dimsyl radicals.
- Koziakov, Denis,Majek, Michal,Jacobi Von Wangelin, Axel
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supporting information
p. 11347 - 11352
(2016/12/16)
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- A practical and chemoselective Mo-catalysed sulfoxide reduction protocol using a 3-mercaptopropyl-functionalized silica gel (MPS)
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A convenient sulfoxide deoxygenation procedure using a mercaptopropyl-functionalized silica gel as the reducing agent is described. This new protocol based on a heterogeneous reagent displays broad scope and tolerance to reducible functional groups and, from an experimental point of view, enhances previous methods by simplifying the isolation of the sulfide to a simple filtration.
- García, Nuria,Fernández-Rodríguez, Manuel A.,García-García, Patricia,Pedrosa, María R.,Arnáiz, Francisco J.,Sanz, Roberto
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p. 27083 - 27086
(2016/03/25)
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- Metal-Free, DTBP-Mediated Methylthiolation of Arylboronic Acids with Dimethyldisulfide
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An efficient method for the C-S bond formation via the coupling reaction of arylboronic acids with dimethyldisulfide has been developed under the metal-free conditions. This novel protocol provides an attractive route for the synthesis of aryl methyl sulf
- Wu, Xiang-Mei,Lou, Jia-Ming,Yan, Guo-Bing
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supporting information
p. 2269 - 2273
(2016/10/30)
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- Ascorbic Acid Promoted Metal-Free Synthesis of Aryl Sulfides with Anilines Nitrosated in Situ by tert -Butyl Nitrite
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A mild, metal-free synthesis of aryl sulfides has been disclosed. Aryl diazonium ion was generated by the in situ nitrosation of aniline, and it was reduced by ascorbic acid (vitamin C) to form aryl radical, which underwent a thiolation with disulfide to yield aryl sulfide. The reaction proceeded smoothly without heating or irradiation. This strategy was also expanded to the synthesis of aryl selenides.
- Bu, Mei-Jie,Lu, Guo-Ping,Cai, Chun
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supporting information
p. 1841 - 1846
(2015/08/06)
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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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- A convenient method for the synthesis of aryl methyl sulfides via Cu(I)-mediated methylthiolation of haloarenes with DMSO
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An efficient process for the Cu(I)-mediated methylthiolation of haloarenes using simple and readily available DMSO as a convenient and environment friendly source of SMe moiety has been developed. In the presence of CuI and DABCO, a variety of aryl/heteroaryl halides reacted with DMSO to afford corresponding aryl methyl sulfides in good to excellent yields.
- Ghosh, Ketaki,Ranjit, Sadananda,Mal, Dipakranjan
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supporting information
p. 5199 - 5202
(2015/08/19)
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- Aryl methyl sulfides via SNAr using DMSO as the source of the thiomethyl moiety
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A unique synthesis of aryl methyl sulfides is reported proceeding via reduction of dimethylsulfoxide to dimethylsulfide at elevated temperature in the presence of Hunig's base followed by nucleophilic aromatic substitution and demethylation. Activated aryl fluorides, chlorides, and nitrobenzenes are suitable substrates with 13 examples provided. Dimethylsulfoxide serves as a simple and inexpensive formal source of the thiomethyl moiety.
- Jones-Mensah, Ebenezer,Magolan, Jakob
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supporting information
p. 5323 - 5326
(2015/01/16)
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- Catalyst free, base free microwave irradiated synthesis of aryl nitrites from potassium aryltrifluoroborates and bismuth nitrate
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A mixture of bismuth nitrate pentahydrate and potassium aryltrifluoroborate in toluene under microwave heating at 120 C for 20 min provides an interesting and mild reaction protocol for the synthesis of aryl nitrite. The conversion to aryl nitrites from aryltrifluoroborates without transition metal catalyst and base in high yields is remarkable.
- Al-Masum, Mohammad,Welch, Rebecca L.
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p. 1726 - 1728
(2014/03/21)
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- Organocatalytic visible light mediated synthesis of aryl sulfides
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Photo-sensitized synthesis of arylsulfides from arenediazonium salts in the presence of eosin Y has been developed. This protocol exhibits high functional group tolerance and a wide substrate scope and is an attractive alternative to the thermal reaction that involves explosive intermediates.
- Majek, Michal,Von Wangelin, Axel Jacobi
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supporting information
p. 5507 - 5509
(2013/06/27)
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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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- An unprecedented use for glycerol: Chemoselective reducing agent for sulfoxides
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A new application for glycerol that expands its possibilities beyond a green solvent and a precursor of value-added products has been demonstrated. Simple, easily available, and environmentally friendly dioxomolybdenum(vi) complexes are highly efficient catalysts for the chemoselective sulfoxide deoxygenation with this biomass-derived chemical feedstock. Both refined glycerol and crude glycerin can be used, thus expanding the potential application of this reaction. Subsequent transformation of glycerol during this reductive process has also been investigated.
- Garcia, Nuria,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Garcia, Daniel,Pedrosa, Maria R.,Arnaiz, Francisco J.,Sanz, Roberto
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supporting information
p. 999 - 1005
(2013/07/25)
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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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- Copper MOF: Scope and limitation in catalytic hydroxylation and nitration of aryl halides
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The potential catalytic application of MOFs like [Cu3(btc) 2] (btc=1,3,5-benzenetricarboxylate), [Cu(bdc)] (bdc=1,4- benzenedicarboxylate), [Cu(pymo)2] (pymo=2-hydroxypyrimidinalote) and [Cu(im)2] (im=imidazolate) was explored in the hydroxylation and nitration of aryl halides. Cu3(btc)2 was found to be superior for both the reactions furnishing good to excellent yields of the respective products. The studies demonstrated that MOFs are not recyclable, attributable to their instability in the highly polar and basic conditions demanded for these reactions. Complete transformation of MOFs to copper oxide nanoparticles occurred in hydroxylation, whereas significant alteration in frameworks was observed for the recovered catalyst in nitration.
- Priyadarshini,Amal Joseph,Kantam, M. Lakshmi,Sreedhar
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p. 6409 - 6414
(2013/07/26)
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- Investigation of the scope and mechanism of copper catalyzed regioselective methylthiolation of aryl halides Dedicated to Professor Dr. Irina Beletskaya
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Methylthiolation of structurally diverse aryl halides was accomplished under fluoride free conditions using catalytic amounts of CuI, and DMSO as the methylthiolation source. Optimization studies unveiled several varieties of promoters among which Zn(OAc)2 was found ideal. The analogous reaction with DMSO-d6 afforded corresponding deuterated aryl methyl thioether with 99% purity. Mechanistic studies revealed CuSMe as the active methylthiolation agent.
- Joseph, P.J. Amal,Priyadarshini,Kantam, M. Lakshmi,Sreedhar
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supporting information
p. 8276 - 8283
(2013/09/02)
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- Pinacol as a new green reducing agent: Molybdenum-catalyzed chemoselective reduction of sulfoxides and nitroaromatics
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Pinacol is disclosed as a new chemoselective and environmentally benign reducing agent for sulfoxides and nitroaromatics assisted by readily available dichlorodioxomolybdenum(VI) complexes as catalysts. A wide range of substrates including those bearing challenging functional groups has been efficiently and selectively reduced with acetone and water being the only by-products of these reactions. Copyright
- Garcia, Nuria,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Rubio, Ruben,Pedrosa, Maria R.,Arnaiz, Francisco J.,Sanz, Roberto
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supporting information; experimental part
p. 321 - 327
(2012/04/11)
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- Copper catalyzed ipso-nitration of iodoarenes, bromoarenes and heterocyclic haloarenes under ligand-free conditions
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A catalytic protocol for the conversion of haloarenes into the corresponding nitroarenes is presented using copper salts under ligand-free conditions. The method was effectively utilized for the ipso-nitration of a broad variety of haloarenes that includes iodoarenes, bromoarenes, and heterocyclic haloarenes.
- Amal Joseph,Priyadarshini,Lakshmi Kantam,Maheswaran
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supporting information; experimental part
p. 1511 - 1513
(2012/03/27)
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- Reduction of sulfoxides to sulfides in the presence of copper catalysts
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Copper complexes catalyze the reduction of aliphatic and aromatic sulfoxides in the presence of silanes as reducing reagent. The influence of different reaction parameters on the catalytic activity is investigated in detail. The scope and limitations of the described catalyst is demonstrated in the reduction of various sulfoxides. In most cases, high conversion and excellent chemoselectivity are obtained. Graphical Abstract: [Figure not available: see fulltext.]
- Enthaler, Stephan,Weidauer, Maik
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experimental part
p. 833 - 838
(2012/02/14)
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- Copper-mediated methylthiolation of aryl halides with DMSO
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A copper-mediated methylthiolation of aryl halides with the widely available DMSO is described. The procedure tolerates a series of functional groups such as methoxy, nitro, chloro, fluoro, trifluoromethyl, formyl and methoxycarbonyl groups. Thus, it represents a simple and facile methylthiolation procedure.
- Luo, Fang,Pan, Changduo,Li, Liping,Chen, Fan,Cheng, Jiang
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scheme or table
p. 5304 - 5306
(2011/06/21)
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- Dimethyl sulfoxide/potassium hydroxide: A superbase for the transition metal-free preparation of cross-coupling products
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Potassium hydroxide (KOH) in dimethyl sulfoxide (DMSO) forms a superbasic medium that allows one to access cross-coupling products from reactions between aryl halides with various sulfur-, oxygen- and nitrogen-based nucleophiles under transition metal-free conditions. Copyright
- Yuan, Yu,Thome, Isabelle,Kim, Seok Hwan,Chen, Duanteng,Beyer, Astrid,Bonnamour, Julien,Zuidema, Erik,Chang, Sukbok,Bolm, Carsten
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experimental part
p. 2892 - 2898
(2011/01/05)
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- A mild and efficient method for nucleophilic aromatic fluorination using tetrabutylammonium fluoride as fluorinating reagent
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Anhydrous tetrabutylammonium fluoride (TBAFanh.) has been found to be a highly efficient fluorinating reagent for nucleophilic aromatic fluorinations such as fluorodenitration or halogen exchange (Halex) reaction. The products were formed in high to excellent yields under surprisingly mild reaction conditions and no phenol or ether side-products were detected in these reactions.
- Hu, Yu Feng,Luo, Jun,Lü, Chun Xu
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experimental part
p. 151 - 154
(2010/11/18)
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- Reduction of sulfoxides catalyzed by oxo-complexes
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This work reports the catalytic activity of the oxo-complexes HReO 4, MoO2(acac)2, WO2Cl2, and VO(acac)2 in the reduction of sulfoxides with PhSiH3 or HBcat. The results obtained showed that the catalyst systems PhSiH 3/HReO4 (5 mol %) and HBcat/HReO4 (5 mol %) are highly efficient for the deoxygenation of sulfoxides. The complex MoO 2(acac)2 was also efficient, but the reactions required more time and heating. Finally, the complexes WO2Cl2 and VO(acac)2 showed a moderate activity.
- Cabrita, Ivania,Sousa, Sara C.A.,Fernandes, Ana C.
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experimental part
p. 6132 - 6135
(2010/12/24)
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- Highly efficient reduction of sulfoxides with the system borane/oxo-rhenium complexes
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This work reports the reduction of sulfoxides with boranes, in excellent yields, catalyzed by oxo-rhenium complexes (1 mol %) at room temperature under air atmosphere. The best results were obtained with catecholborane (HBcat) in the catalytic systems HBcat/ReIO2(PPh3)2, HBcat/Re2O7, and HBcat/MTO. DFT calculations were performed for the system based on ReIO2(PPh3)2, which was studied in more detail. The reaction starts with the formation of ReIO2(R2SO)2, followed by addition of the first molecule of HBcat and loss of R2S. In a second step, a second HBcat molecule attacks the Re(VII) intermediate, reducing the metal back to Re(V), while H2 and catBOBcat are released and the Re catalyst is regenerated, reentering the reaction cycle. The computed reaction barriers are much lower than those for any alternative pathway that could be envisaged.
- Fernandes, Ana C.,Fernandes, Jose A.,Romao, Carlos C.,Veiros, Luis F.,Calhorda, Maria Jose
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experimental part
p. 5517 - 5525
(2011/01/07)
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- Efficient synthesis of aryl methyl sulfide derivatives using (methylthio)trimethylsilane as methylthiolation reagent
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The synthesis of various aryl methyl sulfides has been achieved by treatment of nitroarenes with a combination of (methylthio)trimethylsilane and cesium carbonate in dimethylsulfoxide. This reaction gives access to aryl methyl sulfide derivatives in high yields. Copyright
- Qiao, Qi,Dominique, Romyr,Sidduri, Achyutharao,Lou, Jianping,Goodnow, Robert A.
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scheme or table
p. 3691 - 3698
(2010/12/25)
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- Mild and efficient deoxygenation of sulfoxides to sulfides using HFCL 4/KBH4 system
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HfCl4/KBH4 was found to be a facile, efficient, convenient, and chemoselective system for the deoxygenation of dialkyl, diaryl, and aryl alkyl sulfoxides, especially for the reduction of dibenzyl sulfoxide to the corresponding sulfides under mild conditions. In addition, the HfCl 4/KBH4 system could be used in reduction of some other sulfur-bearing substrates to the corresponding sulfides, such as 2,2'-dibenzothiazolyl disulfide, but this reducing system could not reduce sulfolane, diphenyl sulfone, p-toluenesulfonic acid, and p-toluenesulfonyl chloride to their corresponding thiophenols. Copyright
- Zhang, Jianghua,Gao, Xinqin,Zhang, Chengyi,Zhang, Cheng,Luan, Jiming,Zhao, Defeng
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experimental part
p. 1794 - 1801
(2010/07/14)
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- Enzyme-catalyzed transfer of a ketone group from an S-adenosylmethionine analogue: A tool for the functional analysis of methyltransferases
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"Chemical equation presented" S-Adenosylmethionine (AdoMet or SAM)-dependent methyltransferases belong to a large and diverse family of group-transfer enzymes that perform vital biological functions on a host of substrates. Despite the progress in genomics, structural proteomics, and computational biology, functional annotation of methyltransferases remains a challenge. Herein, we report the synthesis and activity of a new AdoMet analogue functionalized with a ketone group. Using catechol O-methyltransferase (COMT, EC 2.1.1.6) and thiopurine S-methyltransferase (TPMT, EC 2.1.1.67) as model enzymes, this robust and readily accessible analogue displays kinetic parameters that are comparable to AdoMet and exhibits multiple turnovers with enzyme. More importantly, this AdoMet surrogate displays the same substrate specificity as the natural methyl donor. Incorporation of the ketone group allows for subsequent modification via bio-orthogonal labeling strategies and sensitive detection of the tagged ketone prod cts. Hence, this AdoMet analogue expands the toolbox available to interrogate the biochemical functions of methyltransferases.
- Lee, Bobby W. K.,Sun, He G.,Zang, Tianzhu,Ju-Kim, Byung,Alfaro, Joshua F.,Zhou, Zhaohui Sunny
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supporting information; experimental part
p. 3642 - 3643
(2010/05/15)
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- Highly efficient and chemoselective reduction of sulfoxides using the system silane/oxo-rhenium complexes
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This work reports a novel method for the reduction of sulfoxides with silanes catalyzed by high valent oxo-rhenium(V) and (VII) complexes. The catalytic system PhSiH3/ReIO2(PPh3)2 (1 mol %) proved to be highly efficient for the reduction of a wide range of sulfoxides in excellent yields under mild conditions. This novel methodology is also highly chemoselective, tolerating several functional groups such as -CHO, -CO2R, -Cl, -NO2, and double or triple bonds.
- Sousa, Sara C.A.,Fernandes, Ana C.
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experimental part
p. 6872 - 6876
(2010/05/03)
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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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- One-pot synthesis of sulfides by reaction of disulfides with alkyl halides in the presence of sodium dithionite
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Sodium dithionite-promoted synthesis of unsymmetrical diorganyl sulfides by a reaction of diaryl disulfides with alkyl halides at r.t. has been developed. The advantages offered by this method are operational simplicity, a faster reaction, neutral and mild reaction conditions, and moderate to good yields of products.
- Tang, Ri-Yuan,Zhong, Ping,Lin, Qiu-Lian
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p. 167 - 174
(2007/10/03)
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- Photoinduced nucleophilic substitution of aryl halides with potassium thioacetate - A one-pot approach to aryl methyl and diaryl sulfides
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Aryl methyl sulfides and diaryl sulfides were prepared by photoinduced reactions of potassium thioacetate with aryl halides under entrainment conditions. Without isolation, the arene thiolates obtained by the aromatic substitution were quenched with methyl iodide to afford the aryl methyl sulfides in 26-59% yields in a "one-pot" procedure together with the diaryl sulfides in variable yields (3-31 %). By optimization of the reaction conditions it was possible to improve the formation of the Ar2S, going from moderate to good yields (64-83%). Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Schmidt, Luciana C.,Rey, Valentina,Penenory, Alicia B.
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p. 2210 - 2214
(2007/10/03)
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- One-Pot Two-Step Synthesis of Aryl Sulfur Compounds by Photoinduced Reactions of Thiourea Anion with Aryl Halides
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(Equation presented) The photoinduced reactions of aryl halides with the thiourea anion afford arene thiolate ions in DMSO. These species without isolation, and by a subsequent aliphatic nucleophilic substitution, S RN1 reaction, oxidation, or protonation, yield aryl methyl sulfides, diaryl sulfides, diaryl disulfides, and aryl thiols with good yields (50-80%). This is a simple and convenient approach which involves the use of the commercially available and inexpensive thiourea in a one-pot two-step process for the synthesis of aromatic sulfur compounds.
- Argueello, Juan E.,Schmidt, Luciana C.,Penenory, Alicia B.
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p. 4133 - 4136
(2007/10/03)
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- Alkyl- and Arylthiodediazoniations of Dry Arenediazonium o-Benzenedisulfonimides. Efficient and Safe Modifications of the Stadler and Ziegler Reactions to Prepare Alkyl Aryl and Diaryl Sulfides
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The reaction between dry arenediazonium o-benzenedisulfonimides 1 and sodium thiolates in anhydrous methanol represents an efficient and safe procedure, of general validity, for the preparation of unfunctionalized or variously functionalized alkyl aryl and diaryl sulfides. As a rule, the reaction temperature was maintained at 0-5°C for the alkylthiodediazoniations and at room temperature (20-25°C) for the arylthiodediazoniations. The sulfide yields are generally high; of the 63 considered examples, 43 gave yields greater than 80% and 13 were between 70% and 80%. Lower yields were obtained only when sterically hindered diazonium salts or thiols were used. A good amount of the o-benzenedisulfonimide (8) was always recovered from the reactions and could be reused to prepare salts 1. The copious experimental data collected in homogeneous conditions have offered several starting points for the study of the mechanism of these reactions.
- Barbero, Margherita,Degani, Iacopo,Diulgheroff, Nicola,Dughera, Stefano,Fochi, Rita,Migliaccio, Mara
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p. 5600 - 5608
(2007/10/03)
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- The cathodic cleavage of the S-P bond. Synthesis and electrochemical behaviour of sulfonamide phosphorus analogues
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P-diphenylarylsulfophosphamides can be obtained by condensation of Ph2PLi on various arylsulfonyl chlorides. These sulfonamide phosphorus analogues exhibit facile cathodic cleavage reaction yielding, after quenching, diphenylphosphinic acid and arylsulfide.
- Pilard, Jean-Francois,Simonet, Jacques
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p. 3735 - 3738
(2007/10/03)
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