- Transition-metal-free synthesis of unsymmetrical diaryl chalcogenides from arenes and diaryl dichalcogenides
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A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical diaryl chalcogenides (S, Se, and Te) from diaryl dichalcogenides and arenes under oxidative conditions by using potassium persulfate at room temperature. Variously substituted arenes such as anisole, thioanisole, diphenyl ether, phenol, naphthol, di- and trimethoxy benzenes, xylene, mesitylene, N,N-dimethylaniline, bromine-substituted arenes, naphthalene, and diaryl dichalcogenides underwent carbon-chalcogen bond-forming reaction to give unsymmetrical diaryl chalcogenides in trifluoroacetic acid. To understand the mechanistic part of the reaction, a detailed in situ characterization of the intermediates has been carried out by 77Se NMR spectroscopy by using diphenyl diselenide as the substrate. 77Se NMR study suggests that electrophilic species ArE+ is generated by the reaction of diaryl dichalcogenide with persulfate in trifluoroacetic acid. The electrophilic attack of arylchalcogenium ion on the arene may be responsible for the formation of the aryl-chalcogen bond.
- Prasad, Ch Durga,Balkrishna, Shah Jaimin,Kumar, Amit,Bhakuni, Bhagat Singh,Shrimali, Kaustubh,Biswas, Soumava,Kumar, Sangit
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p. 1434 - 1443
(2013/03/29)
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- Convenient synthesis of unsymmetrical organochalcogenides using organoboronic acids with dichalcogenides via cleavage of the S-S, Se-Se, or Te-Te bond by a copper catalyst
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(Chemical Equation Presented) This article describes the methodology for a copper-catalyzed preparation of numerous monochalcogenides from dichalcogenides with organoboronic acids. Unsymmetrical diorgano-monosulfides, selenides, and tellurides can be synthesized by the coupling of dichalcogenides with aryl- or alkylboronic acids using a copper catalyst in air. The present reaction can take advantage of both organochalcogenide groups on dichalcogenide.
- Taniguchi, Nobukazu
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p. 1241 - 1245
(2007/10/03)
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- Microwave-assisted copper-catalyzed preparation of diaryl chalcogenides
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Diaryl chalcogenide synthesis employing diaryl dichalcogenides and aryl halides as starting materials in the presence of excess magnesium and a catalytic amount of CuI/bipyridyl is significantly improved by microwave heating. Reaction times can be reduced from 2 to 3 days to 6-8 h. Both aryl bromides and aryl chlorides can be used as substrates in the substitution reaction. The procedure is useful not only for diaryl sulfide and diaryl selenide synthesis but also for the preparation of unsymmetrical diaryl tellurides. Starting from suitable aryl halides, the novel microwave-assisted procedure was used for the facile preparation of novel chalcogen analogues (PhS-, PhSe-, and PhTe-) of various antioxidants (ethoxyquin and 3-pyridinol). Attempts to use dialkyl dichalcogenides for the coupling of alkylchalcogeno moieties to aryl halides were only successful in the case of long-chain (such as n-octyl) disulfides and diselenides.
- Kumar, Sangit,Engman, Lars
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p. 5400 - 5403
(2007/10/03)
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- Thiol Peroxidase Activity of Diorganyl Tellurides
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A number of diorganyl tellurides, including diaryl tellurides, diheteroaryl tellurides, and alkyl aryl and dialkyl tellurides, were found to catalyze the reaction of hydrogen peroxide with thiols.The thiol peroxidase activity of the compounds was assessed
- Engman, Lars,Stern, David,Pelcman, Mikael,Andersson, Carl M.
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p. 1973 - 1979
(2007/10/02)
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- Application of the Hammett Equation to the Electrochemical Oxidation of Diaryl Chalcogenides and Aryl Methyl Chalcogenides
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The electrochemical oxidation of symmetrical 4,4'-disubstituted diaryl selenides and tellurides and 4-substituted aryl methyl sulfides, selenides and tellurides has been studied.Peak oxidation potentials show good correlation with Hammett ?+-va
- Engman, Lars,Persson, Joachim,Andersson, Carl M.,Berglund, Mats
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p. 1309 - 1313
(2007/10/02)
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