[CH2:1]([O:8][C:9]([C:11]1([N:16]([CH2:34][CH2:35][CH2:36][O:37][Si](C(C)(C)C)(C)C)[S:17]([C:20]2[CH:25]=[CH:24][C:23]([O:26][C:27]3[CH:32]=[CH:31][C:30]([F:33])=[CH:29][CH:28]=3)=[CH:22][CH:21]=2)(=[O:19])=[O:18])[CH2:15][CH2:14][CH2:13][CH2:12]1)=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.B(F)(F)F.CCOCC>C(Cl)Cl>[CH2:1]([O:8][C:9]([C:11]1([N:16]([S:17]([C:20]2[CH:21]=[CH:22][C:23]([O:26][C:27]3[CH:32]=[CH:31][C:30]([F:33])=[CH:29][CH:28]=3)=[CH:24][CH:25]=2)(=[O:19])=[O:18])[CH2:34][CH2:35][CH2:36][OH:37])[CH2:12][CH2:13][CH2:14][CH2:15]1)=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1To a solution of the crude 1{[3-(tert-butyl-dimethylsilanyloxy)-propyl]-[4-(4-fluorophenoxy)benzenesulfonyl]-amino}cyclopentanecarboxylic acid benzyl ester (279 grams) in methylene chloride (1 L) at room temperature was added boron trifluoride etherate (103 mL, 0.84 mole). After 1 hour, the reaction was quenched by sequential addition of saturated ammonium chloride solution and water. The organic phase was separated, washed with water and brine and dried over magnesium sulfate. Evaporation of the solvent under vacuum provided crude 1-[[4-(4-fluorophenoxy)benzenesulfonyl]-(3-hydroxypropyl)amino]cyclopentanecarboxylic acid benzyl ester as an amber oil (235 grams).
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