反应详情

Methyltriphenylphosphonium bromide (12.4 g, 0.0347 mol) and 18-crown-6 (90 mg, 0.41 mmol) were added to THF (100 mL). The mixture was cooled in a ice-water bath. Potassium tert-butoxide (34.7 mL of 1.0M in THF, 0.0347 mol) was added via cannula to the stirred solution. 5-(Benzyloxy)-2-bromobenzaldehyde (9.2 g, 0.0316 mol) was added in one portion which resulted in a slight exotherm. After 30 minutes the cooling bath was removed and stirring was continued at 22° C. for 5 hours. The mixture was concentrated and the residue was purified by flash column chromatography on SiO2 (75 g) with hexanes/ethyl acetate (95:5) to provide 4-(benzyloxy)-1-bromo-2-vinylbenzene as a clear oil (7.9 g, 86% yield). 1H NMR (300 MHz, CDCl3) δ 5.03 (s, 2H), 5.32 (d, J=10.98 Hz, 2H,) 5.63 (d, J=17.20 Hz, 2H), 6.74 (dd, J=8.78, 2.93 Hz, 2H), 6.98 (dd, J=17.57, 10.98 Hz, 2H), 7.13 (d, J=2.93 Hz, 2H), 7.33 (m, 6H).

1. temperatureThe mixture was cooled in a ice-water bath
2. customresulted in a slight exotherm
3. customAfter 30 minutes the cooling bath was removed
4. concentrationThe mixture was concentrated
5. customthe residue was purified by flash column chromatography on SiO2 (75 g) with hexanes/ethyl acetate (95:5)