反应详情

To a solution of triphenylphosphine (1.47 g, 5.6 mmol) in acetonitrile (35 ml) at 0° C. was added dropwise over 5 minutes a solution of bromine (0.88 g, 5.6 mmol) in acetonitrile (5 ml) at a rate such that the temperature was kept between 5° C. and 10° C. The mixture was then allowed to warm to room temperature, then to this was added dropwise a solution of (E)-3-(3-nitrophenyl)-2-propen-1-ol (Preparation 21, 1 g, 5.6 mmol) in acetonitrile (5 ml). The mixture was warmed to 65° C. for 40 min, cooled to room temperature, and poured onto diethyl ether (150 ml). The mixture was concentrated in vacuo. The residue was purified by silica (10 g) column chromatography eluting with hexane then dichloromethane. Product-containing fractions were combined and concentrated in vacuo, and the residue recrystallised from cyclohexane to give the title compound as a very pale yellow solid (0.82 g, 61%).

1. customwas kept between 5° C. and 10° C
2. temperatureThe mixture was warmed to 65° C. for 40 min
3. temperaturecooled to room temperature
4. additionpoured onto diethyl ether (150 ml)
5. concentrationThe mixture was concentrated in vacuo
6. customThe residue was purified by silica (10 g) column chromatography
7. washeluting with hexane
8. concentrationconcentrated in vacuo
9. customthe residue recrystallised from cyclohexane