[CH2:1]([O:3][C:4]([C@H:6]1[C@H:10]([C:11]([OH:13])=[O:12])[CH2:9][N:8](CC2C=CC=CC=2)[CH2:7]1)=[O:5])[CH3:2].C(O[C:26](=[O:32])[O:27][C:28]([CH3:31])([CH3:30])[CH3:29])(C)(C)C.CCOC(C)=O>CCO.[OH-].[OH-].[Pd+2]>[CH2:1]([O:3][C:4]([C@H:6]1[C@H:10]([C:11]([OH:13])=[O:12])[CH2:9][N:8]([C:26]([O:27][C:28]([CH3:29])([CH3:30])[CH3:31])=[O:32])[CH2:7]1)=[O:5])[CH3:2]A mixture of (3S*,4S*)-1-benzyl-pyrrolidine-3,4-dicarboxylic acid monoethyl ester (10 g, 36.1 mmol), di-tert-butylcarbonate (7.9 g, 39.6 mmol) and Pd(OH)2/C 20% (1 g, 50% wet) in EtOH (200 mL) is stirred under hydrogen atmosphere for 5 h. The crude material is filtered over a pad of Celite and concentrated. 1H-NMR indicates that the title compound is obtained cleanly. TLC, Rf (AcOEt)=0.17. MS (LC-MS): 286.1 [M−H]−.
Loading…