反应详情

Oxalyl chloride (0.42 mL, 5.0 mmol) was added dropwise to a solution of 2a (0.582 g, 3.28 mmol) in toluene (10 mL) at −78° C. The reaction mixture was stirred for 2 h at room temperature. After evaporation of all the volatiles by vacuum, CH2Cl2 (10 mL) was added. 3a (0.778 g, 3.50 mmol) was added to the reaction solution at −78° C., and the reaction mixture was slowly warmed to room temperature for 30 min. After stirring for 3 h at room temperature, the reaction solution was concentrated to 2 mL. The solution was dropped to a rapidly stirred hexanes (10 mL). The precipitated solid was collected and was washed with hexane (10 mL×2) to give 4a (1.028 g, 90.8%) as a white solid. 1H NMR (300 MHz, CDCl3) δ 8.90 (s, 1H), 7.11-6.78 (m, 10H), 1.56 (s, 18H); 13C NMR (75 MHz, CDCl3) δ 153.8, 136.1, 130.3, 128.9, 66.2, 29.7. HRMS-ESI (m/z): [M]+ calcd for C21H29ClN2, 309.2325. found, 309.2322.

1. customAfter evaporation of all the volatiles by vacuum, CH2Cl2 (10 mL)
2. additionwas added
3. temperaturethe reaction mixture was slowly warmed to room temperature for 30 min
4. stirringAfter stirring for 3 h at room temperature
5. concentrationthe reaction solution was concentrated to 2 mL
6. additionThe solution was dropped to a rapidly stirred hexanes (10 mL)
7. customThe precipitated solid was collected
8. washwas washed with hexane (10 mL×2)