Preparation of enantiomerically pure (R)-(1-hydroxyethyl)dimethyl(phenyl)silane using resting cells of Saccharomyces cerevisiae (DHW-S-3) as biocatalyst.
The prochiral sila-ketone acetyldimethyl(phenyl)silane (1) was reduced enantioselectively into (R)-(1-hydroxyethyl)dimethyl(phenyl)silane [(R)-2] using resting cells of the commercially available yeast Saccharomyces cerevisiae (DHW S-3) as the biocatalyst. The bioconversion was performed on a 2.0-g scale in a 5-1 bioreactor. Starting with a substrate (1) concentration of 0.4 g.l-1, the highest production rate measured for this bioconversion was about 45-55 mumol (R)-2.l-1.min-1. After an incubation time of 1 h, all substrate in the medium had been converted, either biocatalytically reduced to (R)-2 or (probably chemically) converted into dimethyl(phenyl)silanol (Me2PhSiOH). After extraction of the cell-free medium with ethyl acetate/dichloromethane and subsequent purification of the extract by Kugelrohr distillation and chromatography on silica gel (medium-pressure liquid chromatography), 800 mg (yield 40%) of the bioconversion product (R)-2 was isolated. As shown by HPLC studies (cellulose triacetate as the chiral stationary phase) and 1H-nuclear magnetic resonance experiments (after derivatization of the bioconversion product with a chiral auxiliary agent), compound (R)-2 was almost enantiomerically pure (> 99% enantiomeric excess).
Fischer
L
L
Institut für Biochemie und Biotechnologie, Technische Universität Braunschweig, Germany.
Wagner
S A
SA
Tacke
R
R
D001709:Biotechnology; D002384:Catalysis; D007700:Kinetics; D015394:Molecular Structure; D010084:Oxidation-Reduction; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D012821:Silanes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013237:Stereoisomerism
C092718:(1-hydroxyethyl)dimethyl(phenyl)silane; D012821:Silanes