The key steps in the synthesis of MDL-72,974A were the conversion of (II) to (IV). Treatment of the malonate (II) with sodium tert-butoxide followed by ClCHF2 afforded the difluoromalonate (III), which was selectively deprotected with CF3CO2H, then reacted with base to stereoselectively yield (E)-(IV). Elaboration of (IV) to MDL-72,974A followed standard procedures; the final product was purified via the N-BOC derivative.