Practical synthesis of optically pure methyl (2R,3S)-2,3-epoxybutanoate via microbial asymmetric reduction of α-chloroacetoacetate

Article abstract of DOI:10.1055/s-1993-25895

Asymmetric reduction of ethyl α-chloroacetoacetate (3) with Baker's yeast followed by treatment with sodium ethoxide afforded a mixture of ethyl (2R,3S)-(8) and (2S,3S)-2,3-epoxybutanoate (9) (8/9, 85:15), which could be converted into the optically pure methyl (2R,3S)-2,3-epoxybutanoate (25) via one recrystallization of the brucine salt of the diastereomeric mixture of the corresponding epoxy acid.