- Efficient large scale stereoinversion of (R)-ethyl 3-hydroxybutyrate
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A three step method for the large scale preparation of enantiomerically pure ethyl (S)-3-hydroxybutyrate is reported starting from the commercial biopolymer poly[(R)-hydroxybutyrate]. The key step depends on the ability to cleanly invert the stereochemistry of (R)-ethyl 3-hydroxybutyrate via its mesylate ester under neutral conditions, avoiding the competing elimination process. This has been achieved in good (75%) yield on >100g scale by controlled addition of the mesylate to a stirred slurry of calcium carbonate in water at 80°C.
- Carnell, Andrew J.,Head, Robert,Bassett, Derek,Schneider, Michael
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p. 821 - 825
(2007/10/03)
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- Preparation of optically active β-amino acids from microbial polyester polyhydroxyalkanoates
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An efficient method for the preparation of optically active ethyl β-aminobutyrate from the biopolymer, poly-(R)-(-)-3-hydroxybutyrate (PHB) obtained from bacterial cells has been established using chemical transforamtions: simple recovery of PHB from bacterial cells followed by acidic alcoholysis, tosylation, nucleophilic substitution by azide, and an indium mediated reduction.
- Park, Sang Hyun,Lee, Seung Hwan,Lee, Sang Yup
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p. 498 - 499
(2007/10/03)
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- Synthesis of (+)-Turmeronol A, an Inhibitor of Soybean Lipoxygenase, and (+)-ar-Turmerone
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Syntheses of optically pure turmeronol A and turmerone were achieved in a simple manner starting from ethyl (R)-3-hydroxybutanoate (4) of 100percent e.e.The key step was the displacement of the chiral tosylate (6) with an organocopper reagent.
- Kitahara, Takeshi,Furusho, Yoshio,Mori, Kenji
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p. 1137 - 1140
(2007/10/02)
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- THE USE OF METHYL SUBSTITUTED CHIRAL SYNTHONS IN THE SYNTHESIS OF PINE SAWFLIES PHEROMONES
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The preparation of methyl-substituted synthons of high enantiomerical purities by Claisen transposition, cuprate substitution of secondary optically active alcohols and microbial reduction of β-ketoesters was investigated and applied to the synthesis of (2S,3S,7S) and (2S,3R,7R)-3,7-dimethylpentadecan-2-ol, the pheromones of diprionid species of pine sawflies.
- Larcheveque, Marc,Sanner, Caroline,Azerad, Robert,Buisson, Didier
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p. 6407 - 6418
(2007/10/02)
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