[H-].[Na+].[Cl:3][C:4]1[CH:9]=[CH:8][C:7]([CH2:10][CH2:11][C:12](=[O:14])[CH3:13])=[CH:6][CH:5]=1.[CH2:15]([O:17][C:18](=[O:24])[C:19](OCC)=[O:20])[CH3:16].CC[O-].[Na+]>CCO>[CH2:15]([O:17][C:18](=[O:24])[C:19](=[O:20])[CH2:13][C:12](=[O:14])[CH2:11][CH2:10][C:7]1[CH:6]=[CH:5][C:4]([Cl:3])=[CH:9][CH:8]=1)[CH3:16]
Sodium hydride (0.4163 g, 17.35 mmol) was added slowly to a NaCl ice bath containing EtOH (5.3 mL, 2.5 M) stirring under N2. 66 (2.4253 g, 13.28 mmol) and diethyloxalate (1.803 g, 13.28 mmol) were mixed together, and then added to the chilled NaOEt solution. After stirring for 5 minutes, the reaction was warmed to room temperature. After 10 minutes, the reaction solidified and an additional 10 mL EtOH was added. After stirring for ˜5 h, the reaction was quenched at 0° C. with 1N HCl and extracted 2× with CH2Cl2. The combined organics were washed with H2O, dried with Na2SO4, filtered, concentrated, and purified by silica gel chromatography (Combiflash column, 1:1 Hexanes:CH2Cl2): Only pure fractions were combined and concentrated to obtain 67 (1.7561 g, 46.8%): 1H (CDCl3, 400 MHz): δ 14.27 (1H, broad s), 7.22 (2H, d, J=8.3 Hz), 7.10 (2H, d, J=8.3 Hz), 6.32 (1H, s), 4.31 (2H, q, J=7.2 Hz), 2.92 (2H, t, J=7.8 Hz), 2.78 (2H, t, J=7.8 Hz), 1.34 (3H, t, J=7.2 Hz) ppm. 13C (CDCl3, 100 MHz): δ 201.59, 166.07, 161.79, 138.51, 132.00, 128.53, 128.54, 101.72, 62.38, 42.08, 29.60, 13.88 ppm. DEPT (CDCl3, 100 MHz): CH3 carbons: 13.88; CH2 carbons: 62.38, 42.08, 29.60; CH carbons: 129.53, 128.54, 101.72 ppm. HPLC: 11.103 min.
Wird geladen…
