Enzyme-Catalyzed Asymmetric Synthesis; 10.<sup>1</sup>
<i>Pseudomonas cepacia</i>Lipase Mediated Synthesis of Enantiomerically Pure (2<i>R</i>,3<i>S</i>)- and (2<i>S</i>,3<i>R</i>)-2,3-<i>O</i>-Cyclohexylideneerythritol Monoacetate from 2,3-<i>O</i>-Cyclohexylideneerythritol
作者:Hans-Joachim Gais、Horst Hemmerle、Sebastian Kossek
DOI:10.1055/s-1992-34187
日期:——
Pseudomonas cepacia lipase catalyzed hydrolysis of 2, 3-O-cyclohexylideneerythritol diacetate in an emulsion of water and diisopropyl ether gives (2S,3R)-2, 3-O-cyclohexylideneerythritol monoacetate [(2S, 3R)-1-acetoxy-2,3-cyclohexylidenedioxy-4-hydroxybutane] with ≥ 99% ee in 91% yield by a preferential attack at the R-center CH2OAc group. The enantiomeric (2R, 3S)-2,3-O-cyclohexylideneerythritol monoacetate is obtained by acetylation of 2,3-O-cyclohexylideneerythritol with vinyl acetate catalyzed by the same enzyme with ≥ 99% ee in 78% yield by a combined enantiotopos and enantiomer differentiation through a preferential attack at the R-center CH2OH groups.
在水和二异丙基醚乳液中,假单胞菌脂肪酶催化 2,3-O-环己亚基季戊四醇二乙酸酯水解,得到 (2S,3R)-2.O-环己亚基季戊四醇单乙酸酯[(2S,3R)-1-乙酰氧基-2,3-环己亚基二氧-4-羟基双酚]、 (2S,3R)-2,3-O-环己亚基季戊四醇单乙酸酯[(2S,3R)-1-乙酰氧基-2,3-环己亚基二氧-4-羟基丁烷],通过优先攻击 R 中心 CH2OAc 基团,ee ≥ 99%,收率 91%。在同一酶的催化下,用乙酸乙烯酯对 2,3-O-环己基亚赤藓醇进行乙酰化,可得到对映体(2R, 3S)-2,3-O-环己基亚赤藓醇单乙酸酯,通过在 R 中心 CH2OH 基团上的优先反应进行对映体和对映体分化,ee 值≥ 99%,收率为 78%。