[CH3:1][N:2]([C:9](=[O:18])[C:10]#[C:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)[CH2:3][C:4]([O:6][CH2:7][CH3:8])=[O:5].O>C1COCC1.C(Cl)Cl>[CH3:1][N:2]1[C:9](=[O:18])[CH:10]=[C:11]([C:12]2[CH:13]=[CH:14][CH:15]=[CH:16][CH:17]=2)[CH:3]1[C:4]([O:6][CH2:7][CH3:8])=[O:5]To a 0° C. solution of ethyl 2-(N-methyl-3-phenylprop-2-ynoylamino)acetate (prepared according to the procedure described for Intermediate A, 20 g, 82 mmol) in THF (100 mL) was added a solution of Li(SiMe3)2 (1M in THF, 82 mL, 82 mmol). The resulting mixture was stirred for 2 h, then was slowly treated with water (20 mL) and diluted with CH2Cl2 (200 mL). The organic layer was washed with water (150 mL), a 1N HCl solution (150 mL) and water (150 mL), dried (Na2SO4) and concentrated under reduced pressure. The crude product was purified by flash chromatography (gradient from 0% to 50% EtOAc/hex) to give racemic ethyl 1-methyl-5-oxo-3-phenyl-3-pyrroline-2-carboxylate (14 g, 70%) as a brown oil: TLC (40% EtOAc/hex) Rf 0.13; 1H NMR (CDCl3) δ 1.10 (t, J=7.4 Hz, 3H), 3.03 (s, 3H), 4.12 (m, 2H), 5.13 (s, 1H), 6.46 (s, 1H), 7.39-7.41 (m, 3H), 7.53-7.60 (m, 2H); HPLC ES-MS m/z (rel abundance) 246 (MH+, 100%).
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