Enzymes in Organic Synthesis: Synthesis of Highly Enantiomerically Pure 1,2-Epoxy Aldehydes, Epoxy Alcohols, Thiirane, Aziridine, and Glyceraldehyde 3-Phosphate

Article abstract of DOI:10.1021/jo00303a026

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 >95percent calculated yield and >98percent ee.Both products were subsequently converted to epoxides 4 and 5, respectively.Resolutions of 2-acetoxy-1-(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 90percent and >95percent 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.