Reaction #43602

Reaction equation

1,2-dibromoethane

3-bromo-4,5-dihydroxybenzaldehyde

cesium carbonate

→

desired compound

Yield 75.0%

8-Bromo-2,3-dihydro-1,4-benzodioxin-6-carbaldehyde

Yield 75.0%

Solvents

dimethylformamide

Conditions

Workup

1. 1
   TemperatureAfter heating at 80° for 4 h
2. 2
   Otherthe dimethylformamide was removed under reduced pressure
3. 3
   OtherThe residue was partitioned between water and ethyl acetate
4. 4
   Washthe organic layer was washed with brine
5. 5
   Otherdried
6. 6
   OtherThe crude product was purified by flash column chromatography (silica gel, 4:1 hexane:ethyl acetate)

Procedure

To a solution of 3-bromo-4,5-dihydroxybenzaldehyde (11.5 g, 0.52 mol) in dimethylformamide (220 ml) was added cesium carbonate (50.7 g, 1.56 mol). The mixture was stirred at ambient temperature for 30 min, then 1,2-dibromoethane (12.76 g, 0.68 mol) were added. After heating at 80° for 4 h, the dimethylformamide was removed under reduced pressure. The residue was partitioned between water and ethyl acetate, and the organic layer was washed with brine and dried. The crude product was purified by flash column chromatography (silica gel, 4:1 hexane:ethyl acetate) to give the desired compound as an off-white solid (9.57 g, 75%).

Source