General procedure for the synthesis of 5-(bromomethyl)undecane from 2-butyl-octanol: Bromine (100 mmol, 5.11 mL) and triphenylphosphine (26.18 g, 100 mmol) were dissolved in 250 mL of dichloromethane (DCM) and bubbled with argon (Ar) for 10 min. The reaction system was cooled to 0 °C, followed by the addition of 2-butyl-1-octanol (18.635 g, 100 mmol) and stirred at this temperature for 30 min, then at room temperature overnight. After completion of the reaction, a small amount of sodium carbonate (Na2CO3) was added to the reaction mixture. The solvent was removed by distillation under reduced pressure and the residue was filtered and washed with hexane. The crude product was purified by silica gel column chromatography using petroleum ether (PE) as eluent to give a colorless oily product (22.0 g, 88.1% yield). The structure of the product was confirmed by nuclear magnetic resonance hydrogen (1H NMR, 400 MHz, CDCl3) and carbon (13C NMR, 125 MHz, CDCl3) spectra: 1H NMR (400 MHz, CDCl3) δ 3.45 (d, J = 4.8 Hz, 2H), 1.59 (dd, J = 11.1, 5.3 Hz, 1H), 1.40- 1.21 (m, 16H), 0.90 (q, J = 6.9 Hz, 6H); 13C NMR (125 MHz, CDCl3) δ 39.88, 39.62, 32.71, 32.40, 31.95, 29.61, 28.92, 26.68, 22.99, 22.80, 14.25, 14.21.
