Triethylamine → (+/-)-1-Methoxy-2-butanol Methanesulfonate

A solution of 1-methoxy-2-butanol (52.08 g, 57.23 mL, 0.5 mol) and Et3N (108.2 mL, 0.75 mol, 1.5 equiv) in CH2Cl2 (500 mL) was treated dropwise with methanesulfonyl chloride (68.73 g, 46.44 mL, 0.6 mol, 1.2 equiv) at 0° C. under N2. The reaction mixture was warmed to 25° C. and stirred at 25° C. for an additional 4 h before being quenched with H2O (300 mL). The two layers were separated, and the aqueuos was extracted with CH2Cl2 (3×100 mL). The combined CH2Cl2 extracts were washed with H2O (2×200 mL) and saturated aqueuos NaCl (200 mL), dried (MgSO4), and concentrated in vacuo. The residue was dried enough in vacuo to afforded the desired mesylate 1 (85-90.0 g, 91 g theoretical, 93-98%) as a pale-yellow oil, which was pure enough and directly used in the next reaction without further purification.