GENERAL STEPS: 4-Bromobutanoyl chloride (10.27 g, 55.4 mmol) was dissolved in 100 mL of dichloromethane, followed by the addition of benzyl alcohol (6.29 g, 58.1 mmol). Potassium carbonate (8.3 g, 60 mmol) was added to the reaction mixture in four batches. After 2 hours of reaction, water was added for layering. The organic layer was washed sequentially with water and brine and dried with anhydrous magnesium sulfate. The solvent was removed by evaporation under reduced pressure to give benzyl 4-bromo n-butyrate (11.87 g, 83% yield) as a colorless oil. Its 1H NMR (400 MHz, CDCl3) data were as follows: δ 7.36 (m, 5H), 5.14 (s, 2H), 3.46 (t, J = 6.4 Hz, 2H), 2.56 (t, J = 7.2 Hz, 2H), 2.20 (quin, J = 6.6 Hz, 2H).