Reaction #1833247

Reaction equation

N,N-dimethylformamide

4-bromo-5-fluorobenzene-1,2-diol

cesium carbonate

bromochloromethane

→

5-bromo-6-fluorobenzo[d][1,3]dioxole

Yield 85.0%

Solvents

Et2O

Conditions

Workup

1. 1
   Temperaturewas then heated to an external temperature of 80° C. for 3 h
2. 2
   TemperatureUpon cooling
3. 3
   Washwashed with water (50 mL)
4. 4
   Washa wash with saturated NaCl solution (50 mL)
5. 5
   DryingThe organic layer was dried over MgSO4
6. 6
   Filtrationfiltered

Procedure

To N,N-dimethylformamide (25 mL) in a 50 mL flask was added 4-bromo-5-fluorobenzene-1,2-diol (2 g, 9.66 mmol), cesium carbonate (4.72 g, 14.49 mmol) and bromochloromethane (1.875 g, 14.49 mmol). The reaction mixture was allowed to stir at room temperature for 1 h and was then heated to an external temperature of 80° C. for 3 h. Upon cooling, the reaction mixture was diluted with Et2O (75 mL) and washed with water (50 mL) followed by a wash with saturated NaCl solution (50 mL). The organic layer was dried over MgSO4 and filtered. Concentration of the organic solution gave 5-bromo-6-fluorobenzo[d][1,3]dioxole as a light orange solid (1.8 g, 85%): 1H NMR (400 MHz, CDCl3) δ 6.94 (d, J=5.9 Hz, 1H), 6.67 (d, J=7.9 Hz, 1H), 6.00 (s, 2H); 19F NMR (376 MHz, CDCl3) δ −113.82 (s); ESIMS m/z 220 ([M+H]+), 218 ([M−H]−).

Source