Regioselectivity in the Reductive Bond Cleavage of Diarylalkylsulfonium Salts: Variation with Driving Force and Structure of Sulfuranyl Radical Intermediates.
This investigation was stimulated by reports that one-electron reductions of monoaryldialkylsul- fonium salts never give aryl bond cleavage whereas reductions of diarylmonoalkylsulfonium salts preferentially give aryl bond cleavage. We studied the product ratios from the reductive cleavage of di-4-t...
| Publicado en: | Journal of the American Chemical Society Vol. 131; no. 29; pp. 10015 - 10023 |
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| Autores principales: | , , , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
7/29/2009
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=43797139&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 43797139 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 7/29/2009 vid: 131 iid: 29 pid: 997 pub: American Chemical Society artinfo: ui: 43797139 10.1021/ja809918k ppf: 10015 ppct: 8 formats: tig: atl: Regioselectivity in the Reductive Bond Cleavage of Diarylalkylsulfonium Salts: Variation with Driving Force and Structure of Sulfuranyl Radical Intermediates. aug: au: Kampmeier, Jack A. Hoque, Mansurul Saeva, Frankhn D. Wedegaertner, Donald K. Thomsen, Pia UlIah, Salt Krake, Jacob Lund, Torben affil: Department of Chemistry, University of Rochester, Rochester, New York 14627 Department of Science, Systems and Models, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark su: Chemical reduction Density functionals Chemical structure Electrolysis Radicals (Chemistry) Intermediates (Chemistry) Arylation sug: subj: Chemical reduction Density functionals Chemical structure Electrolysis Radicals (Chemistry) Intermediates (Chemistry) Arylation ab: This investigation was stimulated by reports that one-electron reductions of monoaryldialkylsul- fonium salts never give aryl bond cleavage whereas reductions of diarylmonoalkylsulfonium salts preferentially give aryl bond cleavage. We studied the product ratios from the reductive cleavage of di-4-tolylethylsulfonium and di-4-tolyl-2-phenylethylsulfonium salts by a variety of one-electron reducing agents ranging in potential from -0.77 to +2.5 eV (vs SCE) and including thermal reductants, indirect electrolyses mediated by a series of cyanoaromatics, and excited singlet states. We report that the cleavage products vary from regiospecific alkyl cleavage to predominant aryl cleavage as a function of the potential of the reducing agent. We conclude that differences between the reductive cleavages of mono- and diarylsulfonium salts are direct consequences of the structures of the sulfuranyl radical intermediates and the bond dissociation energies of the alkyl and aryl bonds. Competitions between the rates of cleavage and oxidation of the intermediate sulfuranyl radicals and between concerted and stepwise mechanisms are discussed to explain the variations in bond cleavage products as a function of the driving forces for the reductions. Density functional theory investigations of the nature of the antibonding S-alkyl and S-aryl orbitals of the starting sulfonium salts provide additional insight. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2009 holdings: @attributes: islocal: N |
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