Stereoselective carbonyl reductases and their roles in asymmetric synthesis of bulky chiral hydroxyl compounds

Abstract

Chiral hydroxyl compounds have been widely used in pharmaceutical, agrochemical, fine chemicals, and functional materials industries, due to their unique physical and chemical properties. Stereoselective carbonyl reductases can be efficiently applied to catalyze asymmetric synthesis of chiral hydroxyl compounds with high optical purity from directed reduction of prochiral carbonyl group of the corresponding keto substrates. Based on the diversity of substrates, single enantiomers of various chiral hydroxyl compounds, including chiral alcohols, hydroxyl esters, and hydroxyl amino acids, can be prepared through carbonyl reductase-catalyzed asymmetric reduction in a high efficiency. However, most of the available carbonyl reductases only exhibit low activity towards the substrates involving bulky groups. This review summarizes the basic traits and principles of biocatalytic asymmetric oxidoreductions, and the key characteristics and structure-function relationship of stereoselective carbonyl reductases. In addition, the carbonyl reductases and their systems for asymmetric synthesis of bulky chiral hydroxyl compounds are also addressed, and the potential strategies targeting the critical issue are further discussed.