反应详情

Anhydrous lithium bromide (25 g, 287.3 mmol) was added to a stirring mixture of 2 (15.84 g, 57.4 mmol) in acetone (150 mL) under argon, and the mixture was refluxed for 2 hours. After cooling, the acetone was evaporated under reduced pressure, and the residue was taken up in ether (100 mL), washed with water (100 mL), brine, dried (MgSO4), and the solvent was evaporated under reduced pressure to give the dibromide 3 (13.5 g, 55.8 mmol, 97%) as an orange liquid; δH (400 MHz; CDCl3): 3.5 (4H, m), 2.45 (2H, m), 2.05 (2H, m), 1.6 (2H, m).

1. temperaturethe mixture was refluxed for 2 hours
2. temperatureAfter cooling
3. customthe acetone was evaporated under reduced pressure
4. washwashed with water (100 mL), brine
5. dry with materialdried (MgSO4)
6. customthe solvent was evaporated under reduced pressure