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Asymmetric oxidatio...
Asymmetric oxidation of sulfides catalyzed by vanadium(IV) complexes of dibromo- and diiodo-functionalized chiral Schiff bases
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Gao, Aiping (författare)
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Wang, Mei (författare)
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Wang, Dongping (författare)
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Zhang, Lu (författare)
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Liu, Haibin (författare)
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Tian, Wei (författare)
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- Sun, Licheng (författare)
- KTH,Organisk kemi
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(creator_code:org_t)
- 2006
- 2006
- Kinesiska.
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Ingår i: Cuihuà xuébào. - 0253-9837 .- 1872-2067. ; 27:8, s. 743-748
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- The catalyst system of VO(acac)(2) and Schiff base ligands derived from 3,5-dibromo- or 3,5-diiodosalicylaldehyde and inexpensive chiral amino alcohols was prepared. This catalyst displayed good yields and moderate to high enantioselectivity for the asymmetric oxidation of aryl methyl sulfides at room temperature when 1% catalyst (VO(acac)(2)/ligand molar ratio of 1: 2) and H2O2 Oxidant were used. The ligands derived from ( S)valinol exhibited considerably higher enantioselectivity than those ligands derived from ( S)-phenylalaninol and (R)-leucinol. The enantiomeric excess values were improved up to 88% for methyl phenyl sulfoxide and 92% for methyl p-bromophenyl sulfoxide by slow dropwise addition of H2O2 with the ligand prepared from 3 15-diiodosalicylaldehyde and (s)-valinol. The present study showed that the catalytic efficiency of VO(acac)(2) /Schiff base systems could not be improved by the addition of carboxylic acids or carboxylate salts.
Nyckelord
- bromine
- iodine
- Schiff base
- chiral sulfoxide
- vanadium
- thioether
- asymmetric oxidation
- aqueous hydrogen-peroxide
- tert-butyl disulfide
- enantioselective oxidation
- sulfoxides
- h2o2
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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