A 100 mL round-bottom flask, was charged with 4-bromo-2-phenoxybenzaldehyde (1.00 g, 3.61 mmol, 1.00 equiv), tert-butyl piperazine-1-carboxylate (0.674 g, 3.62 mmol, 1.00 equiv), and dichloromethane (30 mL). The resulting solution was stirred for 30 min at room temperature. Sodium triacetoxyborohydride (2.30 g, 10.8 mmol, 3.01 equiv) was added. The resulting solution was stirred for overnight at room temperature and then diluted with H2O (10 mL). The resulting mixture was extracted with dichloromethane (2×10 mL) and the organic layers were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was chromatographed on a silica gel column with ethyl acetate/petroleum ether (8/92) to provide 1.20 g (74% yield) of tert-butyl 4-[(4-bromo-2-phenoxyphenyl)methyl]piperazine-1-carboxylate as yellow oil. LCMS (ESI, m/z): 447 [M+H]+.
