(Diethylamino)sulfur trifluoride → HCID 14612530, compound

(3R,4R)-3-Azidomethyl-1-benzyl-4-hydroxypyrrolidine (566 mg) was dissolved in dichloromethane (9 mL). While this solution was chilled in an ice water bath, diethylaminosulfur trifluoride (0.39 mL) was added dropwise and the mixture was stirred at room temperature for 2 hours. While the reaction vessel was chilled in an ice water bath, a saturated aqueous solution of sodium bicarbonate (9 mL) was added and the mixture was diluted with dichloromethane (15 mL). The dichloromethane layer was separated, washed sequentially with a saturated aqueous solution of sodium bicarbonate (10 mL) and water (10 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluant: hexane: ethyl acetate=4:1). The first half fraction yielded (3R,4R)-3-azidomethyl-1-benzyl-4-fluoropyrrolidine as a pale brown oil (76.7 mg).