反应详情

To a cooled (0°-5° C.), magnetically stirred solution of 0.445 g (1.13 mmol) of the product of step D and 0.446 g (1.70 mmol) of triphenylphosphine dissolved in 5 mL of dichloromethane was added 0.564 g (1.70 mmol) of carbon tetrabromide in several portions. After the addition was complete, the reaction was allowed to warm to room temperature and was stirred an additional 30 minutes. The methylene chloride was then removed in vacuo, and the residue was applied to a silica gel flash chromatography column and eluted with 10% EtOAc-hexane. Evaporation of the purified fractions and drying in vacuo afforded the title compound which was used directly in the next step without further characterization.

1. additionAfter the addition
2. customThe methylene chloride was then removed in vacuo
3. washeluted with 10% EtOAc-hexane
4. customEvaporation of the purified fractions
5. customdrying in vacuo