To a solution of 3-(R)-(4-fluoro-phenyl)-3-(3-trifluoromethyl-benzenesulfonylamino)-N-(6-vinyl-1,2,3,4-tetrahydro-naphthalen-2-(R)-yl)-propionamide (314 mg, 0.575 mmol) in 13 mL of a mixture solvent t-butanol/THF/water (10:2:1) was added NMO (135 mg, 1.15 mmol), followed by OsO4 (2.5% w/w in t-butanol, 175 mg, 0.017 mmol). After stirring overnight at RT, 4 mL of pH=7.2 phosphate buffer was added, followed by NaIO4 (615 mg, 2.875 mmol). After stirring for 5 h at RT, the solution was diluted with EtOAc and washed with brine. The organic phase was dried over Na2SO4 and evaporated to dryness in vacuo. Flash chromatography (SiO2, EtOAc/hexane=1:1) afforded the desired compound as a white solid.
