- A preparation of trifluorolactic aldehyde
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A five-step preparation of 2-benzoyloxy-333-trifluoropropanal from 1,2- epoxy-3,3,3-trifluoropropane via Pummerer rearrangement is described. The total yield of the aldehyde from the epoxide was 90%. The aldehyde kept its optical purity when it was in hydrate form, but it was found to readily racemize in its formyl form. The utilization of selenium instead of sulfur in these procedures offered advantages in controlled oxidation of the heteroatom for Pummerer rearrangement and the subsequent hydrolysis of Pummerer product, an aldehyde equivalent.
- Katagiri, Toshimasa,Kutose, Koichi,Shimokawa, Naoya,Kusunoki, Norihiko,Uneyama, Kenji
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p. 9163 - 9170
(2007/10/03)
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- Asymmetric reduction of trifluoromethyl ketones containing a sulfur functionality by the alcohol dehydrogenase from Geotrichum
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The reduction of trifluoromethyl ketones containing a sulfur functionality by the crude alcohol dehydrogenase from Geotrichum proceeded successfully, and the corresponding optically active alcohols were synthesized with high yields and excellent enantiose
- Nakamura, Kaoru,Matsuda, Tomoko,Shimizu, Makoto,Fujisawa, Tamotsu
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p. 8393 - 8402
(2007/10/03)
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- Preparation of Sulfur-Containing Optically Active Secondary Alcohols Based on Pichia farinosa-Catalyzed anti-Prelog-Rule Reduction as the Key Step
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A Pichia farinosa IAM 4682 mediated reduction of sulfur containing ketones afforded secondary alcohols with (R)-absolute configuration. For example, 4-(phenylthio)-2-butanone and 4-(phenylsulfonyl)-2-butanone afforded (R)-4-(phenylthio)-2-butanol (91%ee) in 90% yield and (R)-4-(phenylsulfonyl)-2-butanol (97%ee) in 94% yield, respectively. In the case that the ee of the product was not satisfactory, any contaminating (S)-enantiomer was selectively oxidized by Rhodococcus rhodochrous IFO 15564 to leave pure (R)-enantiomer. The substrate specificity of Pichia farinosa-mediated reduction and Rhodococcus rhodochrous-mediated oxidation was further examined.
- Ohtsuka, Yoshikazu,Katoh, Osamu,Sugai, Takeshi,Ohta, Hiromichi
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p. 483 - 491
(2007/10/03)
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- Catalytic asymmetric synthesis of new halogenated chiral synthons
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Two-step and practical asymmetric syntheses of enantiomerically pure 4-trifluoromethyl-2.2-dioxo-1,3,2-dioxathiolane and 4-trichloromethyl-2,2-dioxo-1,3,2-dioxathiolane (>98% ee) have been achieved. Catalytic asymmetric dihydroxylation (AD) of 3,3,3-trifl
- Vanhessche, Koen P. M.,Sharpless, K. Barry
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p. 517 - 522
(2007/10/03)
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- Highly stereocontrolled access to 1,1,1-trifluoro-2,3-epoxypropane via lipase-mediated kinetic resolution of 1,1,1-trifluoro-3-(phenylthio)propan-2-ol and its application
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1,1,1-Trifluoro-3-(phenylthio)propan-2-ol was prepared in high enantiomeric purity by lipase-mediated kinetic resolution of the corresponding esters. The resolved alcohol was successfully converted into 1,1,1 -trifluoro-2,3-epoxypropane and/or used in the
- Shimizu, Makoto,Sugiyama, Kouki,Fujisawa, Tamotsu
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p. 2655 - 2659
(2007/10/03)
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