- Highly selective sulfoxidation of allylic and vinylic sulfides by hydrogen peroxide using a flavin as catalyst
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A highly chemoselective oxidation of allylic and vinylic sulfides to the corresponding sulfoxides has been developed using flavin 1 as the oxidation catalyst and hydrogen peroxide as the terminal oxidant. The sulfoxides were formed in good to excellent yields in a highly selective manner even when an excess of the oxidant was used. Sulfone formation was completely suppressed to 0.5% (in one single case 1.5% sulfone was detected). No epoxidation of double bonds or interference with other functional groups was observed under the reaction conditions. The general applicability was demonstrated by the selective oxidation of various allylic and vinylic sulfides having different electronic properties. A number of functionalities including hydroxy, acetoxy, amino, silyloxy, and formyl groups are tolerated under these mild reaction conditions.
- Linden, Auri A.,Krueger, Lars,Baeckvall, Jan-E.
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p. 5890 - 5896
(2007/10/03)
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- Selective oxidation of allylic sulfides by hydrogen peroxide with the trirutile-type solid oxide catalyst LiNbMoO6
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Chemoselective sulfur oxidation of allylic sulfides containing double bonds of high electron density due to multiple alkyl substituents or extended conjugation was developed using the composite metal oxide catalyst, LiNbMoO6, without any epoxidation of the electron-rich double bond(s). Selective oxidation to either the corresponding sulfoxides or the sulfones was realized by controlling the stoichiometry of the quantitative oxidant, H202. This new oxidant system had general applicability for chemoselective oxidation of various allylic, benzylic, or propargylic sulfides containing unsaturated carbon-carbon bonds with different electron properties. Various functional groups including hydroxy, formyl, and ethers of THP or TBDMS are compatible under this mild oxidation reaction condition.
- Choi, Soojin,Yang, Jae-Deuk,Ji, Minkoo,Choi, Hojin,Kee, Minyong,Ahn, Kwang-Hyun,Byeon, Song-Ho,Baik, Woonphil,Koo, Sangho
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p. 8192 - 8198
(2007/10/03)
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- Surface-mediated reactions. 5. Oxidation of sulfides, sulfoxides, and alkenes with tert-butyl hydroperoxide
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Silica gel mediates the reactivity of (CH3)3COOH, affording a convenient, environmentally benign method for oxidizing sulfides, sulfoxides, and alkenes. Electrophilic oxidation of sulfides and alkenes (Scheme 1A) and nucleophilic oxidation of sulfoxides (Scheme 1B) are apparently involved. Basic alumina mediates the oxidation of sulfoxides.
- Breton, Gary W.
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p. 3825 - 3828
(2007/10/02)
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- The Formation of Allyl Sulphides by Phenylthio-migration: Control by Silicon
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When γ-silyl-β-phenylthio-alcohols are treated with acid, the strategically placed silyl group encourages the rearrangement of the phenylthio-group, both from a secondary migration origin to a secondary migration terminus, and from a secondary migration origin to a tertiary migration terminus (4)->(6).Geraniol/nerol (12) and linalool (14) have been synthesised from a common intermediate (11) using this type of reaction.Phenylthio-migration from a tertiary migration origin (17)->(3) can be controlled to a limited extent by a suitably placed silyl group, but it is easier to achieve direct β-elimination of the silyl and phenylthio-groups (17)->(18).
- Fleming, Ian,Paterson, Ian,Pearce, Andrew
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p. 256 - 262
(2007/10/02)
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