Chemoenzymatic synthesis of (2S)- and (2R)-2-(1,3-dithian-2-ylmethyl)oxirane

Lipase-catalyzed transesterifications and biological reductions were used to obtain the (S)-enantiomers of 3-chloro-1-(1,3-dithian-2-yl)-2-propanol and 1-(1,3-dithian-2-yl)-3-fluoro-2-propanol and their (R)-acetates. (S)-3-Chloro-1-(1,3-dithian-2-yl)-2-propanol and (R)-3-chloro-1-(1,3-dithian-2-yl)-2-propyl acetate were converted into the respective enantiomers of 2-(1,3-dithian-2-ylmethyl)oxirane. During this work we also isolated a new gem-disubstituted epoxide, 2-(chloromethyl)-2-(1,3-dithian-2-yl)oxirane.