To a solution of 454 mg (1.175 mmol) of (5R,6S)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-1-(cyclopent-2-enyl)piperidin-2-one (Example 104, Step A) in THF (6 mL) was added water dropwise (3.5 mL) and tBuOH (0.2 mL). 4-methylmorpholine 4-oxide (207 mg, 1.763 mmol) was added followed by 4% aq. osmium(VIII) oxide (37.3 μL, 5.88 μmol). The reaction mixture was stirred at room temperature for 18 h. Sodium periodate (704 mg, 3.29 mmol) was added and the cloudy reaction mixture was stirred at room temperature for 90 min. Water (4 mL) was added and the mixture was filtered and washed with EtOAc. The filtrate was diluted with EtOAc and the layers were separated. The combined organic layers were washed with sat. Na2S2O3, sat. aq. NaCl solution, dried over Na2SO4 and concentrated in vacuo to provide the title compound.
