C([O:3][C:4]([C@H:6]1[CH2:10][CH2:9][C@@H:8]([C:11](=[O:24])[NH:12][C:13]2[CH:18]=[CH:17][CH:16]=[C:15]([O:19][C:20]([F:23])([F:22])[F:21])[CH:14]=2)[N:7]1[CH2:25][C:26]1[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=1)=O)C.[Li+].[Cl-].[BH4-].[Na+]>C1COCC1.CCO>[F:22][C:20]([F:21])([F:23])[O:19][C:15]1[CH:14]=[C:13]([NH:12][C:11]([C@@H:8]2[CH2:9][CH2:10][C@H:6]([CH2:4][OH:3])[N:7]2[CH2:25][C:26]2[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=2)=[O:24])[CH:18]=[CH:17][CH:16]=1To a solution of (2R,5S)-1-benzyl-5-(3-trifluoromethoxy-phenylcarbamoyl)-pyrrolidine-2-carboxylic acid ethyl ester (2.5 g, 5.73 mmol) in a mixture of THF (40 mL) and EtOH (20 mL) was added LiCl (486 mg, 11.5 mmol) followed by NaBH4 (451 mg, 11.5 mmol) and the mixture was stirred at RT overnight. The crude reaction mixture was concentrated, EtOAc and 1N HCl were added, the layers were separated and the aqueous one back-extracted with EtOAc. The combined organic extracts were washed with brine, dried over Na2SO4, filtered and concentrated. The crude residue was used without further purification in the next step. MS (LC/MS): 395 [M+H]+; tR (HPLC conditions b): 3.66 min.
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