Asymmetric reduction of 1-(benzoazol-2-ylsulfanyl)propan-2-ones using whole cells of Mortierella isabellina, Debaryomyces hansenii, Geotrichum candidum and Zygosaccharomyces rouxii

Abstract

Abstract Growing cells of four fungal strains were used in reduction of 1-(benzoazol-2-ylsulfanyl)propan-2-ones 3a – c to corresponding ( R )-(+)-1-(benzoazol-2-ylsulfanyl)propan-2-ols ( R )-(+)- 4a – c . All of the investigated yeast strains displayed a very high activity toward prochiral ketones 3a – c converting them to the desired alcohols after relatively short reaction time (1–3.5 h). The biotransformation products were isolated with moderate to good yields (45–89%) and in highly enantioenriched forms (94–99% ee). Stereoselective bioreduction of 1-(1 H -benzimidazol-2-ylsulfanyl)propan-2-one 3a by D. hansenii DSM 3428 growing cells provided the respective ( R )-alcohol with >99% yield, in reasonable 65% isolated yield and in a highly stereoselective manner (98% ee) after 3 h of cultivation. In the same culture, bioreduction of 1-(1,3-benzoxazol-2-ylsulfanyl)propan-2-one 3b led to a 76% yield, 65% isolated yield and very high 94% ee of the formed ( R )-alcohol. Similar 1.5 h incubation of 1-(1,3-benzothiazol-2-ylsulfanyl)propan-2-one 3c in G. candidum LOCK 105 culture resulted in the corresponding ( R )-alcohol preparation in moderate 45% isolated yield with excellent enantiomeric purity (99% ee).