Triphenylphosphine → (Z)-1-Bromo-4-decene

To a solution of cis-dec-4-en-1-ol (1.00 g, 6.41 mmol) in DMF (15 mL) was added triphenylphosphine (1.87 g, 7.13 mmol). The solution was cooled to 0° C. and NBS (1.23 g, 6.91 mmol) was added in portions. After stirring for 30 min at room temperature, the reaction was quenched with methanol (0.6 mL). The solution was diluted with ether (60 mL), washed with water, saturated aqueous NaHCO3 and brine successively. The organic layer was dried and concentrated. The residue was purified by flash chromatography on silica gel, eluting with hexane to afford cis-1-bromo-dec-4-ene (1.23 g, 96%) as a colorless oil: 1H NMR (300 MHz, CDCl3) δ 5.38 (1H, m), 5.29 (1H, m), 3.39 (2H, t, J=6.9 Hz), 2.17 (2H, m), 2.03 (2H, m), 1.88 (2H, m), 1.28 (6H, m), 0.87 (3H, t, J=6.6 Hz); 13C NMR (75 MHz, CDCl3) δ 131.87, 127.39, 33.65, 32.90, 31.76, 29.63, 27.51, 25.87, 22.83, 14.35.