Synthesis of erythro- and threo-α-bromo-α′-fluorosuccinic acids

$\text{erythro}$- and $\text{threo}$-α-Bromo-α′-fluorosuccinic acids have been prepared from their corresponding dimethyl esters. Because of the extreme readiness of elimination of hydrogen fluoride in basic medium, a special method of acid hydrolysis had to be applied. Hydrogen and fluorine NMR spectra are reported.