To a suspension of 60% sodium hydride in mineral oil (0.840 g, 21.0 mmol) in DMF (100 mL) was added a solution of 2-(diethoxyphosphoryl)acetic acid 4-methoxybenzyl ester (6.04 g, 19.1 mmol) from Step A in DMF (10 mL). The reaction mixture was stirred for 30 min at room temperature. Bromomethylcyclopropane (2.4 mL, 24.8 mmol) was added and the reaction mixture was stirred at room temperature for 12 h. The reaction mixture was diluted with diethyl ether, poured into saturated sodium bicarbonate, and extracted three times with diethyl ether. The organic layers were combined, washed with saturated sodium chloride, dried over sodium sulfate, and filtered. The volatiles were removed in vacuo and the residue was purified by FC (40% ethyl acetate in hexanes) to afford 4.31 g of the title compound.
