To a stirred solution of (R)-1-(5-bromo-7-methylquinolin-6-yl)ethane-1,2-diol (197 mg, 0.70 mmol) in CH2Cl2 (97 mL), dibutyltinoxide (3.3 mg, 0.01 mmol), TsCl (150 mg, 0.79 mmol), and Et3N (0.12 mL, 0.83 mmol) were added at 0° C. The reaction mixture was allowed to warm to room temperature overnight. The reaction mixture was quenched with saturated aqueous NH4Cl, and then diluted with CH2Cl2. The organic phase was washed with brine, dried over Na2SO4, filtered and concentrated and purified by flash column chromatography (silica gel, 5 to 100% ethyl acetate/hexanes) to give (R)-2-(5-bromo-7-methylquinolin-6-yl)-2-hydroxyethyl 4-methylbenzenesulfonate. LCMS-ESI+ (m/z): [M+H]+ calc'd for C19H19BrNO4S: 436.02; Found: 436.1.
