The asymmetric reduction of unsaturated carbonyl functionalities is one of the most important chemical transformations to generate optically active stereocenters. Optically active secondary alcohols are a class of compounds which displays significant importance as various intermediates, chiral building blocks and biologically active compounds. Various methods have been utilized for the synthesis of these secondary alcohols to achieve high activity and enantioselectivity for reduction reactions of prochiral ketones. Organocatalysis plays a pivotal role in the area of asymmetric synthesis. Recently, several types of organocatalysts have been investigated for asymmetric reduction of prochiral ketones to obtain chiral alcohols with excellent enantioselectivity. This review is focused on selected studies on the development of organocatalysts which are classified into six major categories: i) oxazaborolidine, ii) hydroxyamide, iii) BINOL, iv) ionic liquid, v) phosphoric acid and vi) thiourea-amine based catalysts for asymmetric reduction of prochiral ketones. Mechanistic studies performed in this area are also briefly summarised herein. This review specifically focuses on the most recent applications of organocatalysts used for reduction of ketones for the past seven years.

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有机催化前手性酮不对称还原的最新趋势

不饱和羰基官能团的不对称还原是产生光学活性立体中心的最重要的化学转化之一。旋光仲醇是一类化合物，其作为各种中间体，手性结构单元和生物活性化合物显示出重要的意义。已经采用了各种方法来合成这些仲醇，以实现高活性和对映选择性，用于手性酮的还原反应。有机催化在不对称合成领域中起着关键作用。近来，已经研究了几种类型的有机催化剂，用于不对称还原前手性酮，从而获得具有优异对映选择性的手性醇。这篇综述的重点是针对有机催化剂开发的精选研究，这些研究分为六大类：i）恶唑硼烷，ii）羟酰胺，iii）BINOL，iv）离子液体，v）磷酸和vi）基于硫脲胺的催化剂前手性酮的不对称还原。本文还简要概述了在该领域进行的机械研究。这篇综述专门针对过去七年来用于还原酮的有机催化剂的最新应用。