反应详情

温度

-20 °C

A 1 M solution of BBr3 (9 ml, 9 mmol) in CH2Cl2 was added to a well-stirred solution of 5-benzyloxy-3-fluoro-4′-acetoxystilbene (1.09 g, 3 mmol) in dry CH2Cl2 (120 mL) at −78° C. The mixture was warmed to −20° C. and stirred for 10 minutes. Then MeOH was added at −78° C. The mixture was washed with saturated NaHCO3, and water, dried over Na2SO4, filtered and evaporated. The 4′-acetoxy-3-fluoro-5-hydroxystilbene (0.50 g, 61%) was obtained as white solid. To a solution of the crude 4′-acetoxy-3-fluoro-5-hydroxystilbene (0.50 g, 1.8 mmol) in MeOH (7.5 ml) was added 3.7 ml 4M HCl in 1,4-dioxane. The mixture was stirred for 20 minutes at ambient temperature. After purification by flash column, 3-fluoro-5,4′-dihydroxystilbene (0.33 g, 78%) was obtained. Data are: 1H NMR (Aceton-d6, 300 MHz) δ 8.624 (s, 2H), 7.46 (m, 2H), 7.06 (q, 2H), 6.84 (m, 4H), 6.66 (dt, 1H); 13C NMR (Aceton-d6, 75 MHz) δ 164.90 (d), 159.96 (d), 158.57, 142.02 (d), 130.84, 129.63, 129.10, 125.55 (d), 116.53, 110.28 (d), 104.44 (d), 102.00 (d); 19F NMR (Aceton-d6, 282 MHz) δ −32429.72 (t); HRMS (EI+) found 230.0738 M+, calcd 230.0743 for C14H11FO2.

1. washThe mixture was washed with saturated NaHCO3, and water
2. dry with materialdried over Na2SO4
3. filtrationfiltered
4. customevaporated