[C:1]([O:5][C:6](=[O:18])[CH:7]=[CH:8][C:9]1[CH:10]=[C:11]([C:14]([O:16][CH3:17])=[O:15])[NH:12][CH:13]=1)([CH3:4])([CH3:3])[CH3:2]>CCOC(C)=O.[Pd]>[C:1]([O:5][C:6](=[O:18])[CH2:7][CH2:8][C:9]1[CH:10]=[C:11]([C:14]([O:16][CH3:17])=[O:15])[NH:12][CH:13]=1)([CH3:4])([CH3:3])[CH3:2]To a solution of methyl 4-(3-tert-butoxy-3-oxoprop-1-enyl)-1H-pyrrole-2-carboxylate (2.0 g, 7.96 mmol) in EtOAc (20 mL) under nitrogen was added 10% Pd/C. The flask was evacuated and refilled with hydrogen three times. The reaction mixture was stirred for 2 h. The catalyst was removed by filtration through Celite and the filtrate was concentrated to give methyl 4-(3-tert-butoxy-3-oxopropyl)-1H-pyrrole-2-carboxylate as a white solid (2.02 g, 100%). 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.43 (s, 9H), 2.48 (t, J=7.59 Hz, 2H), 2.77 (t, J=7.54 Hz, 2H), 3.84 (s, 3H), 6.77 (dd, J=2.37, 1.93 Hz, 2H), 930 (br s, 1H); LCMS-MS (ESI+) 198.2 (M-isobutylene).
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