Various β-keto esters have been reduced by one of β-keto ester reductases isolated frombakers’ yeast. The corresponding β-hydroxy esters have been obtained in excellent enantiomeric and diastereomeric excesses, respectively. It has also been elucidated that the reductase recognizes the stereochemistry not only at the β-carbon but also at the α-carbon affording one of the four possible diastereoisomers
Reduction of acyl enolates of .ALPHA.-substituted .BETA.-keto esters by bakers' yeast.
作者:Hiromichi OHTA、Naoki KOBAYASHI、Takeshi SUGAI
DOI:10.1271/bbb1961.54.489
日期:——
Enol esters of 2-substituted-3-oxoalkanoates of (Z)-configuration were reduced by bakers' yeast to chiral 2-substituted-3-hydroxyalkanoates. The syn-selectivities of this reaction increased compared with those of the reduction of the corresponding racemic keto esters. The reaction may proceed via an asymmetric hydrolysis of the enol esters, followed by the reduction of the resulting carbonyl group.
Stereochemical control in microbial reduction. 19. Effect of heat-treatment on the diastereoselectivity in the reduction with baker's yeast
作者:Kaoru Nakamura、Yasushi Kawai、Atsuyoshi Ohno
DOI:10.1016/0040-4039(91)80651-l
日期:1991.6
Diastereoselectivity in the reduction of 2-alkyl-3-oxobutanoates is controlled by the heat-treatment of bakers' yeast. The heat-treated yeast exerts higher syn-selectivities than the untreated one.
diastereoselectivity in a bakers’ yeastreduction of various alkyl 2-alkyl-3-oxoalkanoates can be controlled by a thermal treatment of the yeast in the presence of methyl vinyl ketone. Pretreated bakers’ yeast gives the corresponding (2R,3S)-hydroxy esters selectively. Two β-keto ester reductases, named L-enzyme-1 and L-enzyme-2, are actual reductants of intact bakers’ yeastreduction. The thermal stability
Reduction of ethyl 2-aikyl-3-oxobutanontes with bakers' yeast treated with methyl vinyl ketone gave the corresponding (2R,3S)-syn-2-alkyl-3-hydroxybutanoates in excellent anantio- and diastercoselectivities.