Cis-and trans-glycidic esters may be synthesized in high enantiomeric purities by cyclisation with potassium carbonate in DMF of the corresponding syn-or anti-2-chloro-3-hydroxyesters, prepared by microbial reduction of 2-chloro-3-oxoesters. In contrast, more basic media such as sodium ethylate afford exclusively the trans-isomer, whatever the stereochemistry of the starting 2-chloro-3-hydroxyester is. Cyclisation of deuterated compounds showed that this ...