- Tellurium(II)/Tellurium(III)-Catalyzed Cross-Dehydrogenative C?N Bond Formation
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The TeII/TeIII-catalyzed dehydrogenative C?H phenothiazination of challenging phenols featuring electron-withdrawing substituents under mild aerobic conditions and with high yields is described. These unexpected TeII/Tesu
- Cremer, Christopher,Goswami, Monalisa,Rank, Christian K.,de Bruin, Bas,Patureau, Frederic W.
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supporting information
p. 6451 - 6456
(2021/02/12)
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- Nickel(II) Tetraphenylporphyrin as an Efficient Photocatalyst Featuring Visible Light Promoted Dual Redox Activities
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Nickel(II) tetraphenylporphyrin (NiTPP) is presented as a robust, cost-effective and efficient visible light induced photoredox catalyst. The ground state electrochemical data (CV) and electronic absorption (UV-Vis) spectra reveal the excited state redox potentials for [NiTPP]*/[NiTPP].? and NiTPP].+/[NiTPP]* couples as +1.17 V and ?1.57 V vs SCE respectively. The potential values represent NiTPP as a more potent photocatalyst compare to the well-explored [Ru(bpy)3]2+. The non-precious photocatalyst exhibits excited state redox reactions in dual fashions, i. e., it is capable of undergoing both oxidative as well as reductive quenching pathways. Such versatility of a photocatalyst based on first-row transition metals is very scarce. This unique phenomenon allows one to perform diverse types of redox reactions by employing a single catalyst. Two different sets of chemical reactions have been performed to represent the synthetic utility. The catalyst showed superior efficiency in both carbon-carbon and carbon-heteroatom bond-forming reactions. Thus, we believe that NiTPP is a valuable addition to the photocatalyst library and this study will lead to more practical synthetic applications of earth-abundant-metal-based photoredox catalysts. (Figure presented.).
- Mandal, Tanumoy,Das, Sanju,De Sarkar, Suman
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supporting information
p. 3200 - 3209
(2019/05/16)
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- Copper-catalyzed: Ipso -selenation of aromatic carboxylic acids
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The copper-catalyzed decarboxylative selenation of aromatic carboxylic acids with diselenide is reported. This transformation tolerated a diverse set of functional groups on the substrates, including pentafluorobenzoic acid and heteroaromatic acids, delivering diaryl and methyl aryl selenides in good to excellent yields. Mechanistic studies indicated that the copper catalyst is essential in the activation of the Se-Se bond and the decarboxylation of aromatic acids. The utility of the products has been demonstrated in the facile synthesis of 10H-phenoselenazine and 11-methyldibenzo-(b,f)-1,4-selenazepine.
- Wang, Jing,Li, Hongchen,Leng, Tao,Liu, Miaochang,Ding, Jinchang,Huang, Xiaobo,Wu, Huayue,Gao, Wenxia,Wu, Ge
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p. 9718 - 9726
(2017/11/30)
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- Visible light photocatalyzed direct conversion of aryl-/heteroarylamines to selenides at room temperature
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A novel strategy for the direct conversion of aryl- and heteroarylamines to selenides has been developed via diazotization of amines with tert-butyl nitrite in neutral medium followed by reaction with diaryl/diheteroaryl/dialkyl diselenides in one pot under photocatalysis at room temperature in the absence of any metal. This reaction is also applied for the synthesis of tellurides. The selenylation of heteroarylamine by this protocol is of much significance because of the difficulty in diazotization of these molecules by a standard diazotization method in acid medium.
- Kundu, Debasish,Ahammed, Sabir,Ranu, Brindaban C.
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supporting information
p. 1814 - 1817
(2014/04/17)
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- Potassium tert-butoxide-mediated synthesis of unsymmetrical diaryl ethers, sulfides and selenides from aryl bromides
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Potassium tert-butoxide mediated carbon-chalcogen C-E (E=O, S and Se) coupling reaction has been studied from aryl bromide and phenol/aryl disulfide/diselenide substrates. A series of unsymmetrical diaryl chalcogenides were accessed from aryl bromide and diaryl dichalcogenide precursors by using 2.5 equiv of potassium tert-butoxide in DMSO at 80 C. Unsymmetrical diaryl ethers were also obtained by using phenol precursors at 40-45 C. Aryl bromides with methyl, trifluoromethyl, methoxy and nitro substituents showed compatibility in the carbon-chalcogen bond forming reaction. 4-Methoxy, methyl, trifluoromethyl substituted bromobenzene substrates gave two regioisomers: 3-substituted and 4-substituted diaryl chalcogenides when reacted with phenols/diaryl disulfides/diselenides. Formation of two regioisomeric diaryl chalcogenides in the reaction mixture suggests that potassium tert-butoxide reacts with bromobenzene to produce benzyne intermediate, which subsequently reacts with diaryl dichalcogenides and finally give a regioisomeric mixture of 4-substituted and 3-substituted diaryl chalcogenides.
- Kumar, Amit,Bhakuni, Bhagat Singh,Prasad, Ch. Durga,Kumar, Shailesh,Kumar, Sangit
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p. 5383 - 5392
(2013/07/04)
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- Synthesis of arylseleno-1,2,3-triazoles via copper-catalyzed 1,3-dipolar cycloaddition of azido arylselenides with alkynes
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The use of organoselenium compounds in the copper-catalyzed Huisgen 1,3-dipolar cycloaddition of azido arylselenides with various alkynes is described. Arylseleno-1,2,3-triazoles are prepared in excellent yields via reaction of amino arylselenides with is
- Deobald, Anna M.,Camargo, Leandro R.S.,Hoerner, Manfredo,Rodrigues, Oscar E.D.,Alves, Diego,Braga, Antonio L.
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scheme or table
p. 2397 - 2406
(2011/09/15)
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- Synthesis of azido arylselenides and azido aryldiselenides: a new class of selenium-nitrogen compounds
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We present here our results of the efficient synthesis of azido arylselenides and azido aryldiselenides under mild conditions. Starting from nitrogen-substituted benzenes, we incorporated selenium atom at aromatic ring and obtained amino arylselenides and diselenides in satisfactory yields. Treatment of these compounds with iso-pentyl nitrite (i-C5H11ONO) and azido trimethylsilane (Me3SiN3) in THF affords a variety of azido arylselenides and diselenides in good to excellent yields.
- Deobald, Anna Maria,Simon de Camargo, Leandro R.,Tabarelli, Greice,H?rner, Manfredo,Rodrigues, Oscar E.D.,Alves, Diego,Braga, Ant?nio L.
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experimental part
p. 3364 - 3367
(2010/08/19)
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- Methods for formation of aryl-sulfur and aryl-selenium compounds using copper(I) catalysts
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A mild, palladium-free synthetic protocol for the cross-coupling reaction of vinyl or aryl iodides and thiols or selenols using, in certain embodiments, 10 mol % CuI and 10 mol % neocuproine, with NaOt-Bu as the base, in toluene at 110 ° C. A variety of vinyl/aryl sulfides and vinyl/aryl selenides can be synthesized in excellent yields from readily available iodides and thiols or selenols.
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Page/Page column 17-18; 42
(2008/06/13)
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- Magnesium-Induced Copper-Catalyzed Synthesis of Unsymmetrical Diaryl Chalcogenide Compounds from Aryl Iodide via Cleavage of the Se-Se or S-S Bond
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The methodology for a copper-catalyzed preparation of diaryl chalcogenide compounds from aryl iodides and diphenyl dichalcogenide molecules is reported. Unsymmetrical diaryl sulfide or diaryl selenide can be synthesized from aryl iodide and PhYYPh (Y = S, Se) with a copper catalyst (CuI or Cu2O) and magnesium metal in one pot. This reaction can be carried out under neutral conditions according to an addition of magnesium metal as the reductive reagent. Furthermore, it is efficiently available for two monophenylchalcogenide groups generated from diphenyl dichalcogenide.
- Taniguchi, Nobukazu,Onami, Tetsuo
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p. 915 - 920
(2007/10/03)
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- A general method for the formation of diaryl selenides using copper(I) catalysts
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We report a mild, palladium-free synthetic protocol for the cross coupling reaction of aryl iodides and phenyl selenol using 10 mol% CuI/neocuproine, NaOt-Bu or K2CO3 as base, in toluene, at 110°C. Using this protocol, we show that a variety of diaryl selenides can be synthesized in good yields from commercially available aryl iodides.
- Gujadhur, Rattan K.,Venkataraman
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- Copper-catalyzed synthesis of diaryl selenide from aryl iodide and diphenyl diselenide using magnesium metal
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Various unsymmetrical diaryl selenides can be synthesized from aryl iodides and diphenyl diselenide by an addition of magnesium metal in the presence of a copper catalyst. This method can exploit efficiently two phenylselenide-molecules generated from diphenyl diselenide under neutral conditions.
- Taniguchi, Nobukazu,Onami, Tetsuo
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p. 829 - 832
(2007/10/03)
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- Rapid and precise preparation of reactive benzeneselenolate solutions by reduction of diphenyl diselenide with hydrazine-sodium methanolate
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Solutions of sodium benzeneselenolate sufficiently reactive to effect 'aromatic substitution and ester dealkylation are prepared in DMSO or NMP from diphenyl diselenide and hydrazine hydrate by titration with methanolic sodium methanolate.
- Henriksen, Lars,Stuhr-Hansen, Nicolai
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p. 1915 - 1916
(2007/10/03)
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- Thiol/Diselenide Exchange for the Generation of Benzeneselenolate Ion. Catalytic Reductive Ring-Opening of α,β-Epoxy Ketones
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In the presence of N-acetylcysteine sodium salt, benzeneselenolate ion was generated in situ from diphenyl diselenide via thiol/diselenide and thiol/selenenyl sulfide exchange in aqueous methanol under mild conditions.Benzeneselenolate ion thus formed was efficiently alkylated and arylated to afford alkyl phenyl selenides and aryl phenyl selenides, respectively. α,β-Epoxy ketones were catalytically reduced by benzeneselenolate ion to afford β-hydroxy ketones (aldols) in good yields.The stereospecificity of the reaction was demonstrated in the preparation of optically active β-hydroxy ketones from chiral α,β-epoxy ketones.
- Engman, Lars,Stern, David
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p. 5179 - 5183
(2007/10/02)
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- The use of aminoiminomethanesulfinic acid (thiourea dioxide) under phase transfer conditions for generating organochalcogenate anions. Synthesis of sulfides, selenides and tellurides
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A procedure is described which allows for the in situ synthesis of arylalkyl, diaryl and dialkylchalcogenides under phase transfer conditions starting from the corresponding diorganodichalcogenides.The dichalcogenides are reduced by aminoiminomethanesulfinic acid (thiourea dioxide) in alkaline medium and catalyzed by a quaternary ammonium salt.The reduction proceeds easily for diaryl disulfides and diaryl diselenides at a sodium hydroxide concentration of 13percent; diaryl ditellurides require a 50percent sodium hydroxide solution to give the aryl tellurolate anion.The dialkyl diselenides and dialkyl ditellurides are more difficult to reduce.The intermediate arylthiolates and arylselenolates are quenched by alkyl and activated aryl halides to give the corresponding sulfides and selenides in high yield (77-97percent).The aryltellurolates react with alkyl halides giving the aryl alkyl tellurides in 81-96percent yield.The procedure could not be successfully used for the synthesis of dialkylselenides and dialkyl tellurides; low yields and mixture of products were formed.
- Comasseto, J. V.,Lang, E. S.,Ferreira, J. Tercio B.,Simonelli, F.,Correira, V. R.
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p. 329 - 340
(2007/10/02)
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- SYNTHESIS OF DIARYLSELENIDES AND DIARYLSULFIDES UNDER PHASE TRANSFER CONDITIONS
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Diarylselenides and diarylsulfides are synthesized from the corresponding diaryldiselenide and diaryldisulfide by reduction with aminoiminomehanesulfinic acid, and reaction with activated aryl halides under phase transfer conditions.The reactions yields vary from good to excellent.
- Ferreira, J. Tercio,Simonelli, F.,Comasseto, J. V.
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p. 1335 - 1342
(2007/10/02)
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- Aryl Arylazo Sulfones Chemistry. 2. Reactivity toward Alkaline Alkane- and Areneselenolate and Alkane- and Arenetellurolate Anions
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Tolyl arylazo sulfones react with various alkyl- and arylseleno reagents to produce substituted alkyl aryl and unsymmetrical diaryl selenides.The corresponding tellurides can also be obtained.Isolated yields in both cases are good.This procedure is an interesting alternative to the classical Sandmeyer reaction.
- Evers, Michel J.,Christiaens, Leon E.,Renson, Marcel J.
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p. 5196 - 5198
(2007/10/02)
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- COPPER(I) IODIDE-FACILITATED NUCLEOPHILIC SUBSTITUTIONS OF NONACTIVATED ARYL IODIDES WITH ARENESELENOLATES
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Nonactivated aryl iodides readily react with areneselenolates, in the presence of copper(I) iodide, in hexamethylphosphoric triamide to produce the corresponding diaryl selenides in good yields.
- Suzuki, Hitomi,Abe, Hisako,Osuka, Atsuhiro
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p. 151 - 152
(2007/10/02)
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