Abstract

Biocatalytic asymmetric reduction of ketone is an efficient method for the production of chiral carbinols. The study indicates selective bioreduction of different ketones (1–8) to their respective (R)-alcohols (1a–8a) in low to high selectivity (0- >99%) with good yields (11–96%). In this work, whole-cell of Lactobacillus kefiri P2 catalysed enantioselective reduction of various prochiral ketones was investigated. (R)-4-Phenyl-2-butanol 2a, which is used as a precursor to antihypertensive agents and spasmolytics (anti-epileptic agents), was obtained using L kefiri P2 in 99% conversion and 91% enantiomeric excess (ee). Moreover, bioreduction of 2-methyl-1-phenylpropan-1-one substrate 8, containing a branched alkyl chain and difficult to asymmetric reduction with chemical catalysts as an enantioselective, to (R)-2-methyl-1-phenylpropan-1-ol (8a) in enantiomerically pure form was carried out in excellent yield (96%). The gram-scale production was carried out, and 9.70 g of (R)-2-methyl-1-phenylpropan-1-ol (8a) in enantiomerically pure form was obtained in 96% yield. Also especially, the yield and gram scale of (R)-2-methyl-1-phenylpropan-1-ol (8a) synthesised through catalytic asymmetric reduction using the biocatalyst was the highest report so far. The efficiency of L kefiri P2 for the conversion of the substrates and ee of products were markedly influenced by the steric factors of the substrates. This is a cheap, clean and eco-friendly process for production of chiral carbinols compared to chemical processes.

摘要

酮的生物催化不对称还原是生产手性甲醇的有效方法。该研究表明，不同酮类 ( 1-8 ) 以低至高选择性 (0->99%)选择性生物还原为它们各自的 ( R )-醇 ( 1a-8a )，产率良好 (11-96%)。在这项工作中，研究了开菲尔乳杆菌P2的全细胞催化的各种前手性酮的对映选择性还原。( R )-4-Phenyl-2-butanol 2a，用作抗高血压药和解痉药（抗癫痫药）的前体，使用L kefiri获得P2 转化率为 99%，对映体过量 (ee) 为 91%。此外，2-methyl-1-phenylpropan-1-one 底物8（含有支链烷基链且难以用化学催化剂作为对映选择性的不对称还原）生物还原为 ( R )-2-methyl-1-phenylpropan-1-对映体纯形式的ol (8a)以优异的产率(96％)进行。进行克级生产，以96％的收率获得9.70g对映体纯形式的( R )-2-甲基-1-苯基丙-1-醇(8a) 。还特别是 ( R )-2-甲基-1-苯基丙-1-醇(8a)的产率和克级使用生物催化剂通过催化不对称还原合成是迄今为止最高的报道。L kefiri P2 转化底物和产物ee的效率明显受底物空间因子的影响。与化学工艺相比，这是一种廉价、清洁和环保的手性甲醇生产工艺。