Cyclopentyl chloroformate

32315-10-9

96-41-3

50715-28-1

A mixed solution of cyclopentanol (10.9 mL, 120 mmol) and pyridine (10.7 mL, 132 mmol) was added slowly and dropwise to a solution of triphosgene (11.87 g, 40.0 mmol) in anhydrous ether (100 mL) at -70 °C. The reaction mixture was stirred continuously for 1 h at this temperature and then removed from the low temperature bath. Stirring was continued at room temperature for 1.5 h. Subsequently, 1.0 N HCl aqueous solution (110 mL) was added for acidification. The organic phase was separated, washed with brine (60 mL) and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure to afford cyclopentyl chloroformate (14.395 g, boiling point 80 °C/75 mmHg, 80.7% yield). The resulting cyclopentyl chloroformate could be used directly in the subsequent reaction without further purification.