[CH3:1][O:2][C:3](=[O:20])[CH:4]([C:12]1[CH:17]=[CH:16][C:15]([Cl:18])=[C:14]([Cl:19])[CH:13]=1)[CH2:5][CH:6]1[CH2:10][CH2:9][CH:8](O)[CH2:7]1.C(N(S(F)(F)[F:27])CC)C>C(Cl)Cl.O>[CH3:1][O:2][C:3](=[O:20])[CH:4]([C:12]1[CH:17]=[CH:16][C:15]([Cl:18])=[C:14]([Cl:19])[CH:13]=1)[CH2:5][CH:6]1[CH2:10][CH2:9][CH:8]([F:27])[CH2:7]1A solution of 2-(3,4-dichloro-phenyl)-3-(3-hydroxy-cyclopentyl)-propionic acid methyl ester (prepared as in Example 36, 180 mg, 0.56 mmol) in methylene chloride (0.28 mL) was treated with diethylaminosulfur trifluoride (0.11 mL, 0.85 mmol). The resulting mixture was stirred at 25° C. for 18 h. At this time, the reaction was diluted with water (50 mL). This solution was extracted with methylene chloride (3×30 mL). The organics were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230–400 mesh, 50/50 hexanes/ethyl acetate) afforded 2-(3,4-dichloro-phenyl)-3-(3-fluoro-cyclopentyl)-propionic acid methyl ester (71.2 mg, 39.3%) as a light yellow oil.
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