- Stereoselective reduction of 2-butenolides to chiral butanolides by reductases from cultured cells of Glycine max
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The stereoselective reduction of 2-butenolides by two reductases, p51 and p83, from cultured plant cells of Glycine max was investigated. The reduction of 2-methyl-2-butenolide by p51 reductase produced (R)-2-methylbutanolide, whereas the reduction by p83 reductase gave (S)-2-methylbutanolide. Both reductases reduced 3-methyl-2-butenolide to (R)-3-methylbutanolide. The reduction of 2,3-dimethyl-2-butenolide by p51 reductase gave (2R,3R)-2,3-dimethylbutanolide, whereas the reduction by p83 reductase produced (2S,3R)-2,3-dimethylbutanolide. The reduction of 4-alkyl-2-butenolides with these reductases was accompanied by resolution of chiral centers affording (R)-4-alkylbutanolides.
- Shimoda, Kei,Kubota, Naoji,Hirata, Toshifumi,Kondo, Yoko,Hamada, Hiroki
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- Biocatalytic oxidation of 1,4-diols and γ-lactols into γ-lactones: Application to chemoenzymatic synthesis of drospirenone
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Oxidation of 1-alkyl-1,4-butanediols with Acetobacter aceti MIM 2000/28 gave the corresponding γ-lactones in good yields. The biotransformation occurred with intermediate formation of γ-lactols, which are also substrates for oxidation with Acetobacter aceti MIM 2000/28, as validated by selective biotransformation of 6β,7β;15β,16β-dimethylene-3- oxo-17α-pregn-4-en-21,17-carbolactol to drospirenone.
- Romano, Diego,Contente, Martina,Granato, Tiziana,Remelli, William,Zambelli, Paolo,Molinari, Francesco
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p. 735 - 737
(2013/07/26)
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- Lactone synthesis via biotransformations of γ-hydroxyamides
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An enzyme was expressed in E. coli from a cloned amidase gene. When characterized, it was more enantioselective than commercial amidases. Three pheromones were made. An enzyme was expressed in Escherichia coli from a cloned amidase gene. When characterized, it was more enantioselective than commercial amidases. Three pheromones were made using this biotransformation chemistry.
- Taylor, Stephen K.,Arnold, Carrie R.,Gerds, Aaron T.,Ide, Nathan D.,Law, Keri M.,Kling, Dale L.,Pridgeon, Matthew G.,Simons, Lloyd J.,Vyvyan, James R.,Yamaoka, Jennifer S.,Liao, Min-Ken,Goyne, Thomas E.
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p. 3819 - 3821
(2007/10/03)
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- Convenient enantioselective synthesis of new 1,4-sulfanylalcohols from γ-lactones
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A synthetic strategy based upon three basic reactions - enzymatic resolution, oxygen-sulfur exchange, reduction - allowed us to carry out an easy and useful synthesis of a series of new 1,4-sulfanylalcohols from aliphatic γ-lactones. Final products have been obtained in good yields with enantiomeric excesses in a 66-91% range.
- Filippi, Jean-Jacques,Fernandez, Xavier,Lizzani-Cuvelier, Louisette,Loiseau, André-Michel
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p. 6267 - 6270
(2007/10/03)
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- A facile synthesis of chiral ω-allyl- and ω-n-propyllactones via asymmetric allylboration of formyl esters with B- allyldiisopinocampheylborane
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Asymmetric allylboration of aldehydes containing an adjacent ester group with B-allyldiisopinocampheylborane, followed by hydrolysis and cyclization, provides the corresponding allyl substituted lactones in high yields and ≥92% enantiomeric excess. Hydrogenation of these lactones provides the corresponding propyl substituted lactones without any loss of optical purity.
- Ramachandran, P. Veeraraghavan,Krzeminski, Marek P.,Reddy, M. Venkat Ram,Brown, Herbert C.
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- Chiral synthesis via organoboranes. 39. A facile synthesis of γ- substituted-γ-butyrolactones in exceptionally high enantiomeric purity
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Optically active homoallylic alcohols of exceptionally high enantiomeric purity (98-≥99% ee) readily available via asymmetric allylboration were converted into p-nitrobenzoate esters and subjected to hydroboration followed by oxidation with CrO3 in aqueous acetic acid (10% H2O) to obtain the corresponding carboxylic acids with the same number of carbon atoms. The protecting ester group was hydrolyzed and the product lactonized in situ to the γ-substituted γ-butyrolactones 5 (R = Me, Pr, i-Pr, t-Bu, Ph, (E)- CH=CHCH3) usually without racemization and in good yields. The method is convenient and potentially valuable for the synthesis of highly functionalized γ-butyrolactones in high optical purity.
- Brown,Kulkarni,Racherla
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p. 365 - 369
(2007/10/02)
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- Baker's yeast reduction of arylalkyl and arylalkenil γ- and δ-keto acids
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γ- and δ-Lactones 5, 6, 13, 14, 15 and 16 were synthesized via baker's yeast reduction of the corresponding keto acids 3, 4 and 9-12. The enantioselectivity of the reduction is strongly dependent on the nature of the keto acid; the δ-lactones ware always obtained in an ee% higher than the γ-lactones and ranging from 70% to 100%.
- Aquino, Mario,Cardani, Silvia,Fronza, Giovanni,Fuganti, Claudio,Fernandez, Rosalino Pulido,Tagliani, Auro
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p. 7887 - 7896
(2007/10/02)
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- ENZYMATIC RESOLUTION OF RACEMIC LACTONES
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PPL, HLE or PLE enzymatic resolution of racemic γ, δ and ε-lactones gives optically active lactones (ee: 60 to 90percent).
- Blanco, L.,Guibe-Jampel, E.,Rousseau, G.
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p. 1915 - 1918
(2007/10/02)
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- Synthesis of the optical antipodes of 4-alkyl-γ-lactones
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Optical antipodes of 4-alkyl-γ-lactones 3 have been prepared by photochemical rearrangement of optically active α,β-epoxy diazomethyl ketones 1 in ethanol to give 4-hydroxy-alkenoates 2, followed by reduction of the alkene bond and subsequent lactonization.The required epoxy diazomethyl ketones 1 were obtained via the following sequence of reactions: alkylation of 2-propyn-1-ol, subsequent reduction to the alkenols 6, Sharpless epoxidation to 2,3-epoxy alcohols 7, oxidation to glycidic esters 8 and finally conversion to diazo ketones 1.The enantiomeric purities range from 84 to 100percent.
- Thijs, Lambertus,Waanders, Peter P.,Stokkingreef, Edwin H. M.,Zwanenburg, Binne
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p. 332 - 337
(2007/10/02)
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