- Deracemization of 1,2-diol monotosylate derivatives by a combination of enzymatic hydrolysis with the Mitsunobu inversion using polymer-bound triphenylphosphine
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The deracemization of 1,2-diol monotosylate derivatives is achieved by the sequential combination of enzymatic hydrolysis and Mitsunobu inversion using a polymer-bound triphenylphosphine. After the lipase-catalysed hydrolysis of the racemic 2-acetoxyhexyl tosylate, the subsequent Mitsunobu reaction without separation causes an inversion of the resulting (R)-alcohol to give the (S)-enantiomer of the acetate as a single product. In particular, the reaction using the polymer-bound triphenylphosphine also proceeds smoothly, and the product is easily separated by filtration from the polymer-bound reagent and its by-products. This deracemization process is applicable to the preparation of several optically active 1,2-diol monotosylates.
- Shimada, Yasutaka,Usuda, Kazumasa,Okabe, Hirokazu,Suzuki, Tsuguru,Matsumoto, Kazutsugu
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experimental part
p. 2802 - 2808
(2010/03/30)
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- Montmorillonite clay catalyzed tosylation of alcohols and selective monotosylation of diols with p-toluenesulfonic acid: An enviro-economic route
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An enviro-economic route for tosylation of alcohols and selective monotosylation of diols in good yield directly using p-toluenesulfonic acid together with metal-exchanged montmorillonite instead of p-toluenesulfonyl chloride or p-toluenesulfonic anhydrid
- Choudary, Boyapati M.,Chowdari, Naidu S.,Kantam, Mannepalli L.
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p. 7291 - 7298
(2007/10/03)
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- Efficient routes to isotopically labelled epichlorohydrins ((chloromethyl) oxiranes)
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Efficient routes are developed for the synthesis of variously labelled 2H- and 13C- labelled epichlorohydrins prepared from appropriately labelled acetic acids and sodium borodeuteride. The route is versatile and can be used for strategic location of isotopes at C-I, C-2 and C-3 of epichlorohydrin. By way of demonstration [2-13C]-, [2-2H]-, [3-2H2] and [2-2H, 3-2H2]-epithlorohydrins have been prepared. In addition the syntheses can be adapted for the preparation of enantiomerically pure and isotopically labelled epichlorohydrins.
- O'Hagan,White,Jones
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p. 871 - 880
(2007/10/02)
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- A Convenient Chemoenzymatic Synthesis of (R)- and (S)-(Chloromethyl)oxirane
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(R)- and (S)-1-Chloro-3-tosyloxypropan-2-ol have been prepared by biocatalysed enantioselective esterification in hexane, and in turn could be readily converted into optically active (chloromethyl)oxirane in high yield.
- Chen, Ching-Shih,Liu, Yeuk-Chuen,Marsella, Michael
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p. 2559 - 2561
(2007/10/02)
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- A CHEMOENZYMATIC ACCESS TO OPTICALLY ACTIVE 1,2-EPOXIDES
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Lipase-catalyzed transacylation in organic media was employed to produce optically active α-hydroxy tosylate which could be readily converted to the corresponding 1,2-epoxides with high optical purity.
- Chen, Ching-Shih,Liu, Yeuk-Chuen
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p. 7165 - 7168
(2007/10/02)
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- Lipase-catalyzed Stereoselective Hydrolysis of 2-Acyloxy-3-chloropropyl p-toluenesulfonate
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Lipase-catalyzed stereoselective hydrolysis of 2-acyloxy-3-chloropropyl p-toluenesulfonate (1) was investigated.From the screening tests, lipases from Pseudomonas aeruginosa, Aspergillus niger, Mucor species, Rhizopus delemar and Rhizopus japonicus were f
- Hamaguchi, Shigeki,Ohashi, Takehisa,Watanabe, Kiyoshi
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p. 375 - 380
(2007/10/02)
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