[F:1][C:2]1[CH:7]=[CH:6][C:5]([S:8]([N:11]2[CH2:15][CH2:14][CH2:13][C@H:12]2[C:16]([O:18]CC2C=CC=CC=2)=[O:17])(=[O:10])=[O:9])=[CH:4][CH:3]=1>C(O)C.[Pd]>[F:1][C:2]1[CH:7]=[CH:6][C:5]([S:8]([N:11]2[CH2:15][CH2:14][CH2:13][C@H:12]2[C:16]([OH:18])=[O:17])(=[O:10])=[O:9])=[CH:4][CH:3]=1Benzyl (2S)-1-[(4-fluorophenyl)sulfonyl]-2-pyrrolidinecarboxylate (10.03 g) [see Preparation 48] was dissolved in ethanol (200 ml) and hydrogenated over 10% w/w palladium-on-charcoal (2.0 g) at 60 psi (414 kPa) for 18 hours. The reaction mixture was then filtered through a plug of ARBOCEL (trade mark) filter aid and the filtrate evaporated under reduced pressure. The residue was azeotroped with dichloromethane to afford (2S)-1-[(4-fluorophenyl)sulfonyl]-2-pyrrolidinecarboxylic acid (5.50 g) as a white solid.
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