Reaction #80587

Reaction equation

HBr

1-(4-chlorophenoxy)-2-chloro-2-propene

N-bromosuccinimide

acetonitrile water

→

1-bromo-3-[(4-chlorophenoxy)phenyl]-2-propanone

Yield 54.0%

Solvents

ether

Conditions

Workup

1. 1
   Washwashed with 5% w/v of sodium thiosulfate
2. 2
   OtherThe organic layer was separated
3. 3
   Washwashed with saturated sodium bicarbonate and brine
4. 4
   OtherAfter drying
5. 5
   Filtration(MgSO4), filtration and concentration in vacuo
6. 6
   Otherthe crude liquid (4.8 g) was chromatographed (silica gel, hexane/ethyl acetate, 80/20)

Procedure

To a turbid solution of 1-(4-chlorophenoxy)-2-chloro-2-propene from Step 1 (3 g, 15.7 mmol) in acetonitrile/water (4/1, 100 mL), N-bromosuccinimide (4.84 g, 31.4 mmol) was added in one lot. A catalytic amount of 48% HBr (40 μl) was added to the reaction and the yellowish orange mixture was stirred at room temperature. After 24 hours, the reaction mixture was diluted with ether and washed with 5% w/v of sodium thiosulfate. The organic layer was separated and washed with saturated sodium bicarbonate and brine. After drying (MgSO4), filtration and concentration in vacuo, the crude liquid (4.8 g) was chromatographed (silica gel, hexane/ethyl acetate, 80/20) to give crude 1-bromo-3-[(4-chlorophenoxy)phenyl]-2-propanone (2.3 g, 54%) which was used in the next step without further purification.

Source