- DABSO-based, three-component, one-pot sulfone synthesis
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The addition of Grignard reagents or organolithium reagents to the SO 2-surrogate DABSO generates a diverse set of metal sulfinates, suitable for direct conversion to sulfone products. The metal sulfinates can be trapped in situ with a wide range of C-electrophiles, including alkyl, allyl, and benzyl halides, epoxides, and (hetero)aryliodoniums.
- Deeming, Alex S.,Russell, Claire J.,Hennessy, Alan J.,Willis, Michael C.
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supporting information
p. 150 - 153
(2014/01/23)
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- Merrifield resin supported peroxomolybdenum(vi) compounds: Recoverable heterogeneous catalysts for the efficient, selective and mild oxidation of organic sulfides with H2O2
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We have generated new heterogeneous catalysts by immobilizing dioxomonoperoxomolybdenum(vi) on amino acid functionalized Merrifield resin, which exhibit excellent activity, stability and selectivity for the oxidation of thioethers and dibenzothiophene (DBT) to the corresponding sulfoxides or sulfones by H2O2 at ambient temperature. The synthetic protocols are high-yielding, halogen-free, environmentally clean and safe, and operationally simple. The catalysts, [MoO2(O2)(L) 2]2--MR [L = valine (MRVMo) or alanine (MRAMo) and MR = Merrifield resin] were prepared by reacting H2MoO4 with 30% H2O2 and the respective amino acid functionalized resin, at near neutral pH. The compounds were characterized by elemental analysis, spectral studies (FTIR, Raman, 13C NMR and 95Mo NMR, diffuse reflectance UV-Vis and XPS), SEM, EDX, XRD, Brunauer-Emmett-Teller (BET) and TGA-DTG analysis. The easy recyclability of the catalysts for several catalytic cycles without change in activity and selectivity, their complete chemoselectivity towards the sulfur group of substrates bearing other oxidation prone functional groups, are important "green" attributes of these catalysts.
- Boruah, Jeena Jyoti,Das, Siva Prasad,Ankireddy, Seshadri Reddy,Gogoi, Sandhya Rani,Islam, Nashreen S.
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p. 2944 - 2959
(2013/10/08)
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- Selective oxidation of organic sulfides by mononuclear and dinuclear peroxotungsten(VI) complexes
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Clean conversion of a variety of sulfides and dibenzothiophene (DBT) to the corresponding sulfoxide or sulfone could be achieved in high yields at room temperature using mononuclear as well as dinuclear diperoxo complexes of tungsten as oxidants, by a variation of reaction conditions. The compounds could also effectively catalyze oxidation of sulfides by H2O2 to selectively yield sulfone with reasonably good turnover frequency (TOF).
- Das, Siva Prasad,Boruah, Jeena Jyoti,Chetry, Hiran,Islam, Nashreen S.
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experimental part
p. 1163 - 1168
(2012/03/26)
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- New polymer-immobilized peroxotungsten compound as an efficient catalyst for selective and mild oxidation of sulfides by hydrogen peroxide
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A new polymer-bound peroxotungstate(VI) catalyst of the type [W(O) 2(O2)(CN)2]-PAN [PAN = poly(acrylonitrile)] (PANW) has been prepared by reacting H2WO4 with 30% H 2O2 and the macromolecular ligand, PAN at pH 5.0. The compound was characterized by elemental analysis, SEM, EDX, TGA and spectral studies (FTIR and 13C NMR). Clean conversion of a variety of sulfides and dibenzothiophene (DBT) to the corresponding sulfoxide or sulfone, using H2O2 as oxidant, could be achieved in the presence of the heterogeneous catalyst PANW, by a versatile variation of reaction conditions. The reactions proceed under mild conditions to afford the resulting products with impressive turn over frequency (TOF). The catalyst exhibit complete chemoselectivity toward sulfur group of substituted sulfides with other oxidation prone functional groups. Easy regeneration and reusability of the catalyst for at least up to seven catalytic cycles with consistent activity and selectivity is an important attribute of the catalyst.
- Das, Siva Prasad,Boruah, Jeena Jyoti,Sharma, Niharika,Islam, Nashreen S.
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experimental part
p. 36 - 45
(2012/04/17)
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