Drastic enhancement of the enantioselectivity of lipase-catalysed esterification in organic solvents by the addition of metal ions
作者:Takashi Okamoto、Shinichi Ueji
DOI:10.1039/a902255d
日期:——
By the addition of metal ion-containing water, a marked enhancement of the enantioselectivity for the lipase-catalysed esterification of 2-(4-substituted-phenoxy)propionic acids in Pri2O was observed, the mechanism of which will be discussed briefly on the basis of the initial rate obtained for each enantiomer of the substrate.
Metal ions dramatically enhance the enantioselectivity for lipase-catalysed reactions in organic solvents
作者:Takashi Okamoto、Ebara Yasuhito、Shin-ichi Ueji
DOI:10.1039/b514885e
日期:——
simple and a powerful method to enhance the enantioselectivity for lipase-catalysed transformations in organicsolvents by an addition of metal ion-containing water to the reaction mixture. In this paper, various metal ions such as LiCl or MgCl2 are tested to improve the enantioselectivity for the model reactions. The enantioselectivities obtained are dramaticallyenhanced, the E values of which are about
of the enantioselectivity of Candida rugosa lipase was investigated in the esterification of 2-(4-substitutedphenoxy)propionicacids with 1-butanol in aliphatic, aromatic, and ethereal solvents. The observed enantioselectivity (E value) was greatly affected by the solvent nature. Two key solvent characteristics, dielectric constant (e) and hydrophobicity (log P), failed to explain the solvent effects
2-(4-取代苯氧基)丙酸与 1-丁醇在脂肪族、芳香族和醚类溶剂中的酯化反应中研究了假丝酵母脂肪酶的对映选择性行为。观察到的对映选择性(E 值)受溶剂性质的影响很大。两个关键的溶剂特性,介电常数 (e) 和疏水性 (log P),未能解释溶剂对 E 值的影响。另一方面,发现 E 值的变化与溶剂效应带来的脂肪酶灵活性成功相关,其灵活性是通过自旋标记脂肪酶的 ESR 测量来估计的。尽管有机化学家通常应该在生物催化不对称拆分中进行溶剂筛选步骤,