反应 #1772829

反应方程式

3-benzoyloxy-4-fluorotoluene

NBS

→

3-benzoyloxy-4-fluorobenzyl bromide

收率 58.2%

溶剂

Et2O

water

carbon tetrachloride

反应条件

后处理

1. 1
   其他Commercial N-bromosuccinimide (NBS) was recrystallised from water
2. 2
   其他thoroughly dried in vacuo (24 h)
3. 3
   其他(mp. 180-182° C., lit. 180-183° C.)
4. 4
   温度The mixture heated
5. 5
   温度at reflux for 2 h
6. 6
   温度cooled
7. 7
   洗涤The ethereal layer was washed with brine (20 mL)
8. 8
   干燥dried (Na2SO4)
9. 9
   其他Concetration in vacuo and subsequent purification by flash column chromatography [SiO2, EtOAc/n-hexane (1:25)]

实验过程

Commercial N-bromosuccinimide (NBS) was recrystallised from water and thoroughly dried in vacuo (24 h) prior to use (mp. 180-182° C., lit. 180-183° C.). To a solution of 3-benzoyloxy-4-fluorotoluene (2.47 g, 10 mmol) in anhydrous carbon tetrachloride (25 mL) was added finely powdered NBS (1.96 g, 11 mmol) and benzoylperoxide (0.01 g). The mixture heated at reflux for 2 h, cooled and diluted with Et2O (100 mL) and water (50 mL). The ethereal layer was washed with brine (20 mL) and dried (Na2SO4). Concetration in vacuo and subsequent purification by flash column chromatography [SiO2, EtOAc/n-hexane (1:25)] gave 3-benzoyloxy-4-fluorobenzyl bromide as a white solid (1.80 g, 58%); δH (400 MHz, CDCl3) 4.48 (s, 2H), 7.18 (dd, J=9.8, 8.6, 1H), 7.28 (ddd, J=8.6, 4.3, 2.3, 1H), 7.34 (dd, J=7.0, 2.3, 1H), 7.50-7.55 (m, 2H), 7.64-7.69 (m, 1H), 8.18-8.23 (m, 2H); LRMS (FAB+) m/z (rel. intensity) 229.1 (95), 309.0 (100, [M+H]+). Found: C, 54.1, H, 3.22; C14H10BrFO2 requires C, 54.39, H, 3.26%.

来源