- Chemo-biological preparation of the chiral building block (R)-4-acetoxy-2-methyl-1-butanol using Pseudomonas putida
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In order to develop new methyl substituted chiral building blocks which are useful for the synthesis of methyl branched natural products, the enantioselective bioreduction of an exo-methylene to a methyl group was investigated. 4-Acetoxy-2-methylene-1-butanol 3 was prepared from itaconic acid over four steps and converted to the chiral alcohol (R)-4-acetoxy-2-methyl-1- butanol 4, by growing cells of Pseudomonas putida. The bioconversion achieved a high enantioselectivity (92% ee) and a high chemical yield (65%) within a relatively short reaction time (18-20 h). Copyright
- Kim, Youngju,Watanabe, Hidenori,Kim, Bieong-Kil,Seu, Young-Bae
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experimental part
p. 1658 - 1661
(2012/01/13)
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- New C 2-symmetric optically active salen ligands and their cobalt(II) complexes. Hydridoborate reduction of prochiral C=O and C=C bonds
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Novel optically active salen ligands and their cobalt(II) complexes were synthesized on the basis of 1,3-dioxolane. Spectral parameters of the complexes and their catalytic activity in enantioselective reduction of carbonyl and unsaturated compounds with sodium tetrahydridoborate were studied. The catalytic reduction of acetophenone is characterized by quantitative yield, the optical yields ranging from 0 to 42%. Benzil and ethyl benzoylformate undergo noncatalytic reduction. The catalytic activity and enantioselectivity in the reduction prochiral C=C bond strongly depend on the solvent and change from low to moderate values in the reduction of methyl 2-acetylamino-3-phenylprop-2- enoate. Dimethyl 2-methylidenebutane-1,4-dioate is reduced in DMF and its mixtures with ethanol and toluene in quantitative yield; in chloroform, the optical yield reaches 89%, but the chemical yield sharply decreases.
- Nindakova,Lebed',Zamazei,Shainyan
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p. 1322 - 1329
(2008/03/27)
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- Synthesis and Radical Polymerization of Itaconates Containing an Adamantyl Ester Group
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Itaconates containing a 1-adamantyl or a 3,5-dimethyl-1-adamantyl ester group were prepared and polymerized in the presence of a radical initiator.The polymerization reactivity has been investigated in relation to the structure of ester alkyl groups of the monomer.It has been clarified that the adamantyl-containing polyitaconates show high thermal stability, i.e., high glass transition temperatures and decomposition temperatures.The relationship between polymer structures and thermal properties of polymers from some α- and β-substituted acrylic esters, i.e., acrylates, methacrylates, crotonates, fumarates, and itaconates was discussed .
- Matsumoto, Akikazu,Watanabe, Hiroyuki,Otsu, Takayuki
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p. 846 - 852
(2007/10/02)
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