- Synthesis of [1]Benzothieno[3,2- b][1]benzothiophene Derivatives via Successive Iodocyclization/Photocyclization of Alkynes
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A new synthetic method for [1]benzothieno[3,2-b][1]benzothiophene derivatives (BTBTs) was developed. The present method consists of iodocyclization of 1,2-bis(2-methylthiophenyl)ethynes and photolysis of 3-iodo-(2-methylthiophenyl)benzo[b]thiophenes. With 1,2-bis(2-methylthiophenyl)ethynes treated with I2/PhI(OAc)2 in CH2Cl2 at room temperature, selective cyclization at sulfur took place to give 3-iodo-(2-methylthiophenyl)benzo[b]thiophenes in good yields. Irradiation of the iodinated benzo[b]thiophenes with a high-pressure Hg lamp (>290 nm) provided BTBTs in good yields. Furthermore, the present method was applied to the synthesis of bis[1]benzothieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene (BBTBDT).
- Kitamura, Tsugio,Morita, Kazuhiro,Nakamori, Haruka,Oyamada, Juzo
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- Facile syntheses of 3-trifluoromethylthio substituted thioflavones and benzothiophenes via the radical cyclization
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3-CF3S substituted thioflavones and benzothiophenes were achieved via the reactions of AgSCF3 with methylthiolated alkynones and alkynylthioanisoles, respectively, promoted by persulfate. This protocol possesses good functional group tolerance and high yields. Mechanistic studies suggested that a classic two-step radical process was involved, which includes addition of CF3S radical to triple bond and cyclization with SMe moiety.
- Wang, Lu,Wang, Huaiyu,Meng, Weidong,Xu, Xiu-Hua,Huang, Yangen
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supporting information
p. 389 - 392
(2020/03/04)
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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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- B(C6F5)3-Catalyzed cyclization of alkynes: direct synthesis of 3-silyl heterocyclic compounds
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An efficient one-pot strategy for easy access to 3-silyl heterocyclic compounds was developedviaa B(C6F5)3-catalyzed cycloaddition reaction ofo-(1-alkynyl)(thio)anisoles oro-(1-alkynyl)-N-methylaniline. In this reaction, benzenethiophene, benzofuran or indole skeletons could be constructed by an intermolecular cyclization with diphenylsilane. This protocol elicited moderate-to-good yields with metal-free reaction systems.
- Li, Mengxing,Wang, Ting,An, Zhenyu,Yan, Rulong
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supporting information
p. 11953 - 11956
(2020/10/15)
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- Copper-catalysed aromatic-Finkelstein reactions with amine-based ligand systems
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A new efficient and low-cost ligand, diethylenetriamine, has been utilised to promote the iodination of 16 different bromo-substrates via the copper catalysed Finkelstein halogen exchange reaction under mild conditions. In contrast to earlier methods, the use of inert atmosphere conditions was not required to obtain high yields and purity. Studies on the speciation of the catalyst in solution indicate rapid disproportionation of copper(i) in the presence of diethylenetriamine to give copper(0) and a bis-ligated copper(ii) complex which is characterised by X-ray diffraction. This copper(ii) complex was also shown to be catalytically active in the halogen exchange reaction. In contrast, no significant disproportionation was observed using dimethylethylenediamine as the ligand, and the solid-state structures of a copper(i) dimeric complex and a 2D polymeric network of copper(i) iodide tetramers are reported. The catalytic activity of diethylenetriamine and dimethylethylenediamine with both copper(i) and copper(ii) salts are compared, and possible mechanistic implications discussed.
- Jin, Xiaodong,Davies, Robert P.
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p. 2110 - 2117
(2017/07/22)
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- A new effective synthesis of arene mono- and disulfonyl chlorides
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Arene mono- and disulfonyl chlorides have been easily synthesized starting from the corresponding anilines via aqueous oxidative chlorination of S-aryl O-ethyl dithiocarbonates intermediates, aryl methyl sulfides, or from arenethiols. Georg Thieme Verlag Stuttgart.
- Barbero, Margherita,Bazzi, Stefano,Cadamuro, Silvano,Dughera, Stefano,Magistris, Claudio,Venturello, Paolo
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supporting information; experimental part
p. 1803 - 1806
(2010/10/20)
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- Electroreduction of Organic Compounds, 19. Formation of Benzoanellated Sulfur Heterocycles by Intramolecular Cathodic Cyclization of Dithiocarboxylic Esters
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Cathodic reduction of aryl (3) and benzyl (5) dithiopivaloates and related dithioesters with leaving groups at the benzene ring or a side chain yield the sulfur heterocycles 23, 30 - 32, and 34 depending on the nature of the starting material and the reaction conditions.In the case of the α-oxo-dithioester 22, thioindigo (44) is formed. - The corresponding thioamides 14, 16, and 18 show a strong tendency to reductive dehalogenation but the S,N-heterocycles 38 and 39 are also formed in minor amounts. - The formation of the rearranged products 29 - 32, and 34 isdiscussed in terms of C,S-splitting in the primarily formed radical anion and subsequent C,C-coupling of the fragments and follow-up reactions.Key Words: Dithiopivaloates, S-aryl, S-benzyl / Electroreduction
- Gade, Thomas,Streek, Michael,Voss, Juergen
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p. 127 - 142
(2007/10/02)
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- Mercury in Organic Chemistry. 26. Synthesis of Heterocycles via Intramolecular Solvomercuration of Aryl Acetylenes
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A number of ortho substituted aryl acetylenes, o-CH3XC6H4YCCR (X=O, S, CO2; Y=-, CO), have been observed to undergo facile intramolecular solvomercuration with mercuric acetate in acetic acid to afford the corresponding benzofuran, benzothiophene, isocoumarin, and chromone organomercuric chlorides, after aqueous sodium chloride workup.The aryl acetylenes m-XC6H4YCH2CCR (X=H, Y=O, R=CH3; X=CH3O, Y=CH2, R=n-C3H7) undergo similar cyclizations to yield mercurated 2H-1-benzopyrans and 1,2-dihydronaphthalenes.The mercuration and subsequent carbonylation of o-R1OC6H4CCR2 1=Si(t-Bu)Me2, R2=CH3; R1=CH3, R2=o-C6H4OCH3> has provided a new approach to the coumarin and coumestan ring systems.
- Larock, Richard C.,Harrison, L. Wayne
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p. 4218 - 4227
(2007/10/02)
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