Stereochemisty of oxygenation of organic sulphides with pig liver microsomal FAD-containing mono-oxygenase: comparison with cytochrome P-450PB oxidations

Abstract

The enantiotopic differentiating ability of pig liver microsomal FAD-containing mono-oxygenase (EC 1.14.13.8) in the oxygenation of nine unsymmetrical sulphides has been investigated. By this enzymatic oxygenation, the sulphides are converted into the corresponding optically active sulphoxides with varying degrees of enantiomeric excess (96–12%).

Three cyclic sulphides have been studied in order to establish the diastereotopic differentiating ability of the enzyme. In the oxygenation of racemic 2-methyl-2,3-dihydrobenzo[b]thiophene both enantiomeric and diastereotopic differentiation appears to take place concurrently with high selectivity. The enantiotopic, diastereotopic, and enantiomeric differentiating abilities of the FAD-containing mono-oxygenase are all higher than those of the phenobarbital-induced rabbit liver microsomal cytochrome P-450.