反应详情

To a solution of compound 27a (687 mg, 2.09 mmol) in anhydrous dichloromethane (10 mL) at 0° C. under argon were added potassium carbonate (1.16 g, 8.39 mmol), triphenylphosphine (1.1 g, 4.19 mmol) and carbon tetrabromide (1.39 g, 4.19 mmol). The solution was allowed to return to room temperature and stirred for 1 hr. The resulting solution was diluted with dichloromethane (50 mL) and filtered on a cotton plug. Purification of the resulting crude product by flash chromatography using ethyl acetate/hexane (2:8) gave the desired compound 28a (470 mg, 57%). 1H NMR (400 MHz, MeOD) δ: 1.72 (m, 4H), 2.11 (m, 2H), 3.37 (m, 2H), 3.54 (m, 2H), 3.77 (m, 2H), 7.18 (dd, 1H, J1=6.26 Hz, J2=2.62 Hz), 7.27 (d, 1H, J=2.07 Hz), 7.69 (d, 1H, J=8.83 Hz).

1. customto return to room temperature
2. filtrationfiltered on a cotton plug
3. customPurification of the resulting crude product by flash chromatography