Enzyme-mediated catalytic asymmetric oxidations

Enantiomerically pure sulfoxides are excellent chiral auxiliares for asymmetric synthesis and in the preparation of several enantiopure biologically active compounds. We have explored biocatalytic approaches based on the use of heme peroxidalytic and flavin monooxygenases such as chloroperoxidase and cyclohexanone monooxygenase respectively. By using isolated enzymes or whole-cell biotransformations, we have prepared alkyl aryl sulfoxides, 1, 3-dithioacetal-1-oxides, dialkyl sulfoxides, and thiosulfinates in high enantiomeric excess. An active site model of cyclohexanone monooxygenase has been proposed in order to explain and to predict the absolute configuration of the product. (C) 2002 Wiley Periodicals, Inc.