反应详情

温度

0 °C

n-Butyl lithium (139 mL of a 2M solution in hexanes, 277 mmol) was added via canula to a stirred solution 1,4-diiodobenzene (89.0 g, 277 mmol) in THF (500 mL) at −78° C. such that the internal temperature was maintained below −65° C. during the addition process. After 0.5 h, 3-methyl-2 butanone (24.0 g, 280 mmole) was added via syringe, again maintaining the internal temperature below −65° C. After 0.5 h, the reaction mixture was warmed to 0° C. and quenched with saturated aqueous ammonium chloride. The resulting mixture was dried (MgSO4), concentrated in vacuo, and the crude residue purified by flash chromatography on silica gel (gradient elution; 10-25% EtOAc/hexanes) to afford the title compound 5a. 1H NMR (500 MHz, CDCl3) δ 7.67 (d, 2H, J=7.5 Hz), 7.20 (d, 2H, J=7.5 Hz), 3.79 (s, 1H), 2.00 (m, 1H, J=7.0 Hz), 1.52 (s, 3H), 0.92 (d, 3H, J=7.0 Hz), 0.81 (d, 3H, J=7.0 Hz).

1. temperaturewas maintained below −65° C. during the addition process
2. temperatureagain maintaining the internal temperature below −65° C
3. waitAfter 0.5 h
4. customquenched with saturated aqueous ammonium chloride
5. dry with materialThe resulting mixture was dried (MgSO4)
6. concentrationconcentrated in vacuo
7. customthe crude residue purified by flash chromatography on silica gel (gradient elution; 10-25% EtOAc/hexanes)