Lipase-catalyzed kinetic resolution of 4-aryl- and 4-heteroarylbut-3-en-2-ols

Abstract

Several 4-aryl-and 4-heteroarylbut-3-en-2-ones [2a-c, bearing 4-phenyl-, 4-(furan-2-yl)-and 4-(1-benzyl-1H-indol-3yl)-substituents, respectively] were prepared by condensation reaction of acetone with the corresponding aldehydes (1a-c). Reduction of the ketones (2a,b) with NaBH 4 resulted in the formation of the corresponding racemic secondary alcohols (rac-3a,b). On the other hand, reduction of the ketone bearing indole moiety (2c) gave an unstable product. The lipase-catalyzed enantiomer selective acetylation of the alcohols (rac-3a,b) by vinyl acetate has been investigated with a crude lipase from submerged fermentation (SmF) of a thermophilic fungus, with several crude enzyme preparations from solid state fermentation (SSF) of selected mesophilic fungi and with several commercially available lipases. The commercial and SmF lipases and the majority of SSF preparations exhibited high but usual enantiomer selectivities and resulted in the formation of (R)-acetates [(R)-4a,b] according to the Kazlauskas' rule. Several SSF preparations, however, behaved as selective anti-Kazlauskas catalysts.

One-pot two-step chemoenzymatic deracemization of allylic alcohols using laccases and alcohol dehydrogenases

“…Alternatively, biocatalytic tools have become very relevant along the last decades as enzymes can promote extremely selective transformations under very mild reaction conditions. For instance, enantioenriched allylic alcohols have been obtained through lipasemediated kinetic [20,21] and dynamic kinetic resolutions [22][23][24][25] of the corresponding racemates. Also, oxidoreductases have been successfully applied to obtain these chiral compounds through the oxidative kinetic resolution catalyzed by alcohol dehydrogenases (ADHs) [26] or alcohol oxidases [27] starting from the racemic alcohols, or the bioreduction of the corresponding α,β-unsaturated ketones [28,29].…”

From Synthetic Chemistry and Stereoselective Biotransformations to Enzyme Biochemistry – The Bioorganic Chemistry Group at the Budapest University of Technology and Economics

“…8A) [51]. The majority of lipases catalyzed the formation of (R)-acetates [(R)-2m,n] according to the Kazlauskas' rule [52].…”