Combine 1-carbobenzyloxy-3-phenyl-3-(2-hydroxyethyl)pyrrolidine (9.6 g, 29.6 mmol) and triethylamine (8.2 mL, 59.2 mmol) in dichloromethane (150 mL). Cool in an ice-bath. Add methanesulfonyl chloride (2.5 mL, 32.6 mmol). After 16 hours, dilute the reaction mixture with dichloromethane and extract with brine. Dry the organic layer over MgSO4, filter, and evaporate in vacuo to give residue. Chromatograph the residue on silica gel eluting with methanol/dichloromethane 1/10 containing 1% concentrated aqueous ammonia to give 1-carbobenzyloxy-3-phenyl-3-(2-methanesulfonyloxyethyl)pyrrolidine.
