[C:1]1([S:7]([CH:10]([C:17]2[O:18][C:19]([CH3:22])=[N:20][N:21]=2)[CH:11]2[CH2:15][CH2:14][C:13](=[O:16])[CH2:12]2)(=[O:9])=[O:8])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[H-].[Na+].[CH3:25]I>CN(C=O)C.[NH4+].[Cl-]>[C:1]1([S:7]([C:10]([CH:11]2[CH2:15][CH2:14][C:13](=[O:16])[CH2:12]2)([C:17]2[O:18][C:19]([CH3:22])=[N:20][N:21]=2)[CH3:25])(=[O:9])=[O:8])[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1
375 mg (1.17 mmol) of 3-[benzenesulfonyl-(5-methyl-[1,3,4]oxadiazol-2-yl)-methyl]-cyclopentanone in 10 mL of DMF, were treated with 52 mg (1.29 mmol, 1.1 eq) of NaH (55% in oil) over 30 min. 300 mg (2.32 mmol, 1.8 eq) of methyliodide were added, and after 2 hours, the reaction mixture was diluted with saturated aqueous NH4Cl and extracted with EtOAc. The combined organic phases were dried over Na2SO4, filtered and evaporated. The resulting two diastereomers were separated by column chromatography on silica gel with EtOAc/heptane 1:2, yielding 95 mg (24%) of (RS,SR)-3-[1-benzenesulfonyl-1-(5-methyl-[1,3,4]oxadiazol-2-yl)-ethyl]-cyclopentanone as a white solid, MS: 335 (MH+) and 90 mg (23%) of (RR,SS)-3-[1-benzenesulfonyl-1-(5-methyl-[1,3,4]oxadiazol-2-yl)-ethyl]-cyclopentanone as a white solid, MS: 335 (MH+).
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