Asymmetric reduction of α-thiocyanatoketones by Saccharomyces cerevisiae and Mortierella isabellina—a new route to optically active thiiranes

A simple method for the preparation of optically active 1-aryloxy- and 1-arylsulphanyl-3-thiocyanatopropan-2-oles from racemic 1-chloro-3-aryloxy- and 1-chloro-3-arylsulphanyl-2-propanols via 1-aryloxy- and 1-arylsulphanyl-3-thiocyanatopropan-2-ones has been developed. The enantiomerically enriched β-hydroxythiocyanates were obtained by a microbiological reduction of the thiocyanatoketones with Saccharomyces cerevisiae or Mortierella isabellina and subsequently converted into optically active thiiranes on treatment with a lithium hydroxide solution.

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(R)-(+)-2-(Phenoxymethyl)thiiraneC9H10SOEe = 93%[α]D20.5=+16.5 (c 2, CHCl3)Source of chirality: chemo-enzymatic preparationAbsolute configuration: (R)

(R)-(+)-2-((4-Chlorophenoxy)methyl)thiiraneC9H9ClSOEe = 95%[α]D24=+11.4 (c 2.89, CHCl3)Source of chirality: chemo-enzymatic preparationAbsolute configuration: (R)

(R)-(+)-2-(p-Tolyloxymethyl)thiiraneC10H12SOEe = 96%[α]D25=+11.7 (c 3.16, CHCl3)Source of chirality: chemo-enzymatic preparationAbsolute configuration: (R)

(R)-(+)-2-((2-Chlorophenoxy)methyl)thiiraneC9H9ClSOEe = 99%[α]D25=+3 (c 2, CHCl3)Source of chirality: chemo-enzymatic preparationAbsolute configuration: (R)

(R)-(+)-2(o-Tolyloxymethyl)thiiraneC10H12SOEe = 92%[α]D31.5=+13.6 (c 2.5, CHCl3)Source of chirality: chemo-enzymatic preparationAbsolute configuration: (R)

(R)-(−)-2-(Phenylsulphanylmethyl)thiiraneC9H10S2Ee = 55%[α]D29=-32.8 (c 5, CHCl3)Source of chirality: chemo-enzymatic preparationAbsolute configuration: (R)

(R)-(−)-2-((4-Chlorophenylsulphanyl)methyl)thiiraneC9H9ClS2Ee = 80%[α]D25=-44.95 (c 5, CHCl3)Source of chirality: chemo-enzymatic preparationAbsolute configuration: (R)

(R)-(−)-2-(p-Tolylsulphanylmethyl)thiiraneC10H12S2Ee = 56%[α]D25=-37.9 (c 5.38, CHCl3)Source of chirality: chemo-enzymatic preparationAbsolute configuration: (R)