Reacción #1772829

Ecuación de reacción

3-benzoyloxy-4-fluorotoluene

NBS

→

3-benzoyloxy-4-fluorobenzyl bromide

Rendimiento 58.2%

Disolventes

Et2O

water

carbon tetrachloride

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroCommercial N-bromosuccinimide (NBS) was recrystallised from water
2. 2
   Otrothoroughly dried in vacuo (24 h)
3. 3
   Otro(mp. 180-182° C., lit. 180-183° C.)
4. 4
   TemperaturaThe mixture heated
5. 5
   Temperaturaat reflux for 2 h
6. 6
   Temperaturacooled
7. 7
   LavadoThe ethereal layer was washed with brine (20 mL)
8. 8
   Secadodried (Na2SO4)
9. 9
   OtroConcetration in vacuo and subsequent purification by flash column chromatography [SiO2, EtOAc/n-hexane (1:25)]

Procedimiento

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%.

Fuente