Triethylamine → (R)-(-)-3-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]-2-methyl-1-propyl methanesulfonate

To a mixture of (R)-(-)-3-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]-2-methyl-1-propanol (7.26 g, 24.8 mmol), triethylamine (3 ml, 30 mmol) in methylene chloride (DCM, 120 ml), methanesulfonyl chloride (3.13g, 27.3 mmol) was added dropwise at 0° C. The mixture was stirred at room temperature for 1 hour, then concentrated down to a crude mixture. Triethylamine hydrochloride salt was removed by filtration with DCM/ether as solvent. The crude oily mixture was purified with a flash chromatography column (SiO2, 90 g; eluted with DCM). The colorless oil, which is the methanesulfonate ester, weighed 6.48 g (70%), and was used directly in the following step.