The general procedure for the synthesis of bromomethylcyclopentane from cyclopentanemethanol was as follows: a mixed solution of cyclopentanemethanol (48.5 g, 484 mmol), triethylamine (88.0 mL, 631 mmol) and anhydrous tetrahydrofuran (1 L) was cooled to 4 °C and stirred under nitrogen protection. Methylsulfonyl chloride (45.0 mL, 581 mmol) was added slowly, keeping the reaction temperature below 10 °C. After addition, the reaction mixture was continued to stir at 10 °C for 1 hour. Subsequently, lithium bromide (300.0 g, 3454 mmol) was added slowly, taking care to control the exotherm. After addition, the reaction mixture was stirred at room temperature for 16 hours. Upon completion of the reaction, water was added to dissolve the salts and the mixture was extracted with ether. The ether layers were combined, dried with anhydrous sodium sulfate and carefully concentrated at 25 °C at 100 Torr. The crude product was purified by vacuum distillation (35 °C, 1 Torr, collecting the first fraction) to give bromomethylcyclopentane (31.4 g, 40% yield) as a colorless oil.
