Chemoenzymatic synthesis of the chiral side-chain of statins: application of an alcohol dehydrogenase catalysed ketone reduction on a large scale

Abstract

The chemoenzymatic synthesis of the tert-butyl (S)-6-chloro-5-hydroxy-3-ketohexanoate is described. Our approach relies on a highly regio- and enantioselective reduction of a beta,delta-diketohexanoate ester catalysed by NADP(H)-dependent alcohol dehydrogenase of Lactobacillus brevis (LBADH). A detailed description of the scale-up of the enzymatic synthesis of the hydroxyketo ester is given which includes a scale-up of the substrate synthesis as well, i.e. the preparation of diketo ester on a 100 g scale. Furthermore, studies directed towards improving the co-catalyst [NADP(H)] consumption of the enzymatic key step by kinetic studies and application of a biphasic reaction medium were performed.

Alcohol dehydrogenase in non‐aqueous media using high‐pressure technologies: reaction set‐up and deactivation determination

“…Many biphasic systems have been developed for LBADH: TONs higher than 10 4 were found for the biphasic system water-tert-buthyl methyl ether (MTBE) with LBADH after optimization. 16 The partition coefficient between the two phases of the substrates and products is an important issue. Indeed it was demonstrated that an ionic liquid, [BMIM][(CF 3 SO 2 ) 2 N], is more favourable to the conversion than MTBE.…”

“…Processes with ADHs in non-aqueous solvents are rare due to their instability in these media, 14 consequently, biphasic systems are often chosen instead of a non-aqueous media when water immiscible products are involved. Processes with LBADH were run in several biphasic systems with organic solvents 15,16 and patented several times.…”

Highly efficient enzymatic synthesis of tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate with a mutant alcohol dehydrogenase of Lactobacillus kefir

“…oxohexanoate ((S)-CHOH) is a highly valuable chiral building block, because it can be further converted to chiral building block 1 for the synthesis of atorvastatin, as well as the key hydroxyl-substituted chiral intermediate 2, which is used for the synthesis of rosuvastatin (Scheme 1). The enzymatic asymmetric reduction of tert-butyl 6-chloro-3,5-dioxohexanoate (CDOH), which can be effectively synthesized from the corresponding Meldrum's acid intermediate (Jackson et al 2012), represents a promising strategy for the synthesis of (S)-CHOH (Wolberg et al 2001(Wolberg et al , 2008 (Scheme 1). To date, a few of alcohol dehydrogenases (ADHs) have been reported to exhibit highly regioselectivity and enantioselectivity toward the reduction of CDOH, some with (R)-selectivity (Wolberg et al 2004), only two with the desired (S)-selectivity to produce (S)-CHOH (Wolberg et al 2001;Weckbecker and Hummel 2006).…”

Coexpression of Lactobacillus brevis ADH with GDH or G6PDH in Arxula adeninivorans for the synthesis of 1-(R)-phenylethanol

“…ADH from L. brevis is a versatile enzyme, which catalyzes the reduction of carbonyl compounds stereoselectively by oxidising the cofactor NADPH. It is currently used for the synthesis of methyl (R)-3-hydroxybutanoate, tert-butyl (S)-6-chloro-5-hydroxy-3-ketohexanoate and fluorinated hydrins (Wolberg et al 2001(Wolberg et al , 2008Borzęcka et al 2013). It has a broad substrate spectrum which includes aromatic ketones and keto-esters and is the reason for the growing interest in the ADH of L. brevis as a catalyst for other redox reactions (Leuchs and Greiner 2011).…”