Kinetic Resolution of Cyclic Sulfoxides by Enzyme Promoted Hydrolysis of 2-Alkoxycarbonyl-3,6-Dihydro-2H-Thiapyran-1-Oxides

Among many methods of preparation of optically active sulfoxides, those applying enzymes are becoming more and more popular1. In continuation of our recent investigations on the enzyme promoted hydrolysis of sulfinyldicarboxylates2 we turned our attention to cyclic six-membered sulfoxides 1. These compounds are easily available by the cycloaddition reaction of butadienes with appropriate sulfines obtained in situ from the corresponding esters (or their O-silyl enolethers) with thionyl chloride in the presence of a base3. Three compounds shown in the scheme were chosen for our investigations. It should be noted that compounds lb and lc are obtained as single diastereoisomers.