Diethyl Malonate → Diethyl 2-(2-(4-bromophenoxy)ethyl)malonate

To a solution of NaH (0.160 g, 6.68 mmol) in anhydrous tetrahydrofuran (20 mL) was added diethyl malonate (1.07 g, 6.68 mmol) dropwise at 0° C. The resulting colorless solution was stirred at 0° C. for 15 minutes, then at room temperature for 30 minutes before cooling again to 0° C. A solution of 1-bromo-4-(2-bromoethoxy)benzene (1.70 g, 6.07 mmol) in anhydrous tetrahydrofuran (10 mL) was added over 5 minutes. The resulting mixture was heated at reflux until complete as judged by TLC. The mixture was cooled to room temperature and carefully quenched with water and then extracted with ethyl acetate (4×50 mL). The combined organic phases were dried over sodium sulfate filtered and concentrated under reduced pressure to give the title compound (2.5 g) as a colorless oil which was used in the next step without purification.