- Facile optical resolution of tert-butanethiosulfinate by molecular complexation with (R)-BINOL and study of chiral discrimination of the diastereomeric complexes
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An important synthon, tert-butanethiosulfinate (2), has been effectively resolved by forming molecular complexes with (R)-2,2′-dihydroxy-1,1′-binaphthyl (BINOL, 3) in high enantioselectivity (> 99% ee). The present procedure represents the first example of the resolution of thiosulfinate. The mechanism of chiral discrimination is discussed in terms of molecular recognition based on IR and X-ray analyses of the diastereomeric complexes during the resolution. In the less-soluble complex, (R)-3 and (R)-2 self-assembled as a linear supramolecule; however, in the more-soluble complex, (R)-3 and (S)-2 formed a simple bimolecular complex by one stronger hydrogen bond. Hydrogen bonding is the major driving force for effective resolution.
- Liao, Jian,Sun, Xiaoxia,Cui, Xin,Yu, Kaibei,Zhu, Jin,Deng, Jingen
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- An Economic Approach to Chiral Thiosulfinates by Enantioselective Oxidation with Hydroperoxide
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Some novel chiral ligands and VO(acac)2 were utilized to catalytic asymmetric oxidation of disulfides. The optically active thiosulfinates were obtained.
- Ma, Yudao,Wang, Xiaomei,Wang, Yong,Feng, Yu,Zang, Yunfu
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- Enantioselective oxidation of di-tert-butyl disulfide with a vanadium catalyst: Progress toward mechanism elucidation
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The mechanism of the oxidation of di-tert-butyl disulfide (1) to the chiral thiosulfinate (2) by H2O2 catalyzed by bis(acetylacetonato)oxovanadium and a chiral Schiff-base ligand (3) has been investigated. Techniques included 51V NMR spectroscopy, solvent effects on reaction enantioselectivity, and the isolation and full characterization of a 2:1 ligand-to-vanadium catalyst precursor. A model for the dramatic solvent effect on the enantioselectivity of this reaction was developed, based on the identification of a competing nonselective oxidation pathway. From this model, strategies for limiting this competing pathway were developed.
- Blum, Suzanne A.,Bergman, Robert G.,Ellman, Jonathan A.
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- Process for synthesizing chiral tert-butanesulfinyl amide
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The invention discloses a process for synthesizing chiral tert-butanesulfinyl amide. The process includes carrying out reaction on tert-butyl mercaptan and iodine/hydrogen peroxide acetone to generate di-tert-butyl disulfide; oxidizing hydrogen peroxide under the catalytic effect of vanadium to generate chiral tert-butyl sulfenyl tert-butyl mercaptide; carrying out one-pot reaction on the chiral tert-butyl sulfenyl tert-butyl mercaptide and lithium reagents/liquid ammonia in the presence of alkyl chloride to obtain the tert-butanesulfinyl amide. Compared with existing processes, the process has the advantages that the smoothness of the process can be enhanced, the usage of the liquid ammonia can be reduced to a great extent, and the operational efficiency can be improved.
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Paragraph 0018; 0019
(2017/08/28)
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- Enantioselective organocatalytic oxidation of functionalized sterically hindered disulfides
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Figure presented The first study on enantioselective oxidation of functionalized sterically hindered disulfides is reported. This study shows that the Shi organocatalytic system using carbohydrate-derived ketone with oxone is superior to the Ellman-Bolm v
- Khiar, Noureddine,Mallouk, Siham,Valdivia, Victoria,Bougrin, Khalid,Soufiaoui, Mohammed,Fernandez, Inmaculada
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p. 1255 - 1258
(2007/10/03)
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- Catalytic enantioselective oxidation of sulfides and disulfides by a chiral complex of bis-hydroxamic acid and molybdenum
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A chiral bis-hydroxamic acid (BHA)-molybdenum complex was used for the catalytic asymmetric oxidation of sulfides and disulfides utilizing one equivalent of alkyl peroxide with yields up to 83% and ee up to 86%. An extension of our methodology combines the asymmetric oxidation with kinetic resolution providing excellent enantioselectivity (ee 92-99%).
- Basak, Arindrajit,Barlan, Allan U.,Yamamoto, Hisashi
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p. 508 - 511
(2007/10/03)
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- Contra-Friedel-Crafts tert-butylation of substituted aromatic rings via directed metallation and sulfinylation
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Directed metallation and sulfinylation yields sulfoxides which undergo ipso nucleophilic aromatic substitution with tertiary and secondary alkyllithiums, giving aromatic rings bearing alkyl groups generally incompatible with directed metallation methods and with regioselectivity complementary with classical Friedel-Crafts substitution. The Royal Society of Chemistry 2006.
- Clayden, Jonathan,Stimson, Christopher C.,Keenan, Martine
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p. 1393 - 1394
(2008/02/03)
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- Enantioselective synthesis of thiosulfinates and of acyclic alkylidenemethylene sulfide sulfoxides
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Enantioselectivities up to 75 % have been found in the catalytic mono-oxidation of di-tert-butyl disulfide and related compounds as well as of ketene-S,S-acetals with an in situ generated chiral dioxirane. The effect of solvents on the enantiomeric excess
- Colonna, Stefano,Pironti, Vincenza,Drabowicz, Jozef,Brebion, Franck,Fensterbank, Louis,Malacria, Max
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p. 1727 - 1730
(2007/10/03)
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- Improved synthesis of tert-butanesulfinamide suitable for large-scale production
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(Matrix presented) An improved synthesis of tert-butanesulfinamide that overcomes the scalability problems of the previous syntheses is described. The key step is the catalytic asymmetric oxidation of the inexpensive di-tert-butyl disulfide starting material. The new homogeneous reaction conditions utilize an inexpensive chiral ligand prepared in a single step from commercially available cis-1-amino-indan-2-ol. The reaction is performed at a 2.3 M concentration in the practical solvent acetone and can readily be run on a kilogram scale.
- Weix, Daniel J.,Ellman, Jonathan A.
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p. 1317 - 1320
(2007/10/03)
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- Chemistry of Oxaziridines. 3. Asymmetric Oxidation of Organosulfur Compounds Using Chiral 2-Sulfonyloxaziridines
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Chiral 2-sulfonyloxaziridines, 9-12, afford the best enantioselectivity of any chiral oxidizing reagent for the asymmetric oxidation of sulfides and disulfides to sulfoxides and thiosulfinates, respectively, 5-8 times better than chiral peracids.For asymmetric oxidations using 9-12, the configuration of the oxaziridine three-membered ring was shown to control the configuration of the product, which could be predicted using a chiral recognition mechanism (Figure 2).The increased asymmetric bias exhibited by chiral 2-sulfonyloxaziridines was attrbuted to the fact that the active-site oxygen was incorporated into a rigid chiral environment.The group size difference (GSD) effect in both the oxaziridine and substrate play important roles in determining the absolute configuration of the product and the magnitude of the asymmetric bias.As the GSD increases the enantioselectivity increases.
- Davis, Franklin A.,Jenkins, Robert H.,Awad, Sami B.,Stringer, Orum D.,Watson, William H.,Galloy, Jean
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p. 5412 - 5418
(2007/10/02)
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