ENZYMES IN ORGANIC-SYNTHESIS - SYNTHESIS OF HIGHLY ENANTIOMERICALLY PURE 1,2-EPOXY ALDEHYDES, EPOXY ALCOHOLS, THIIRANE, AZIRIDINE, AND GLYCERALDEHYDE-3-PHOSPHATE

This paper describes a chemoenzymatic procedure for the synthesis of (R)- and (S)-glycidaldehyde diethyl acetal [2-(diethoxymethyl)oxirane] (4 and 5). 2-Acetoxy-3-chloropropanal diethyl acetal (1c) was enantioselectively hydrolyzed by LP-80 lipase to give (S)-3-chloro-2-hydroxypropanal diethyl acetal (2c) and the unreacted acetate (3c), both in >95% calculated yield and >98% ee. Both products were subsequently converted to epoxides 4 and 5, respectively. Resolutions of 2-acetoxy-l-(benzyloxy)-3-chloropropane (11a) and 3-(allyloxy)-2-acetoxypropyl p-toluenesulfonate (14b) were similarly carried out to give the corresponding optically active 2-hydroxy and 2-acetoxy derivatives in 90% and >95% ee. These products were subsequently converted to the corresponding 1,2-epoxides. Nucleophilic opening of epoxide 4 was exemplified by the syntheses of (R)-3-azido-2-hydroxypropanal and D-glyceraldehyde 3-phosphate. Conversion of the chiral epoxides to thiirane and aziridine was also described. © 1990, American Chemical Society. All rights reserved.