1,4-Dibromo-2-(2-bromoethoxy)benzene → 6-Bromo-2,3-dihydro-1-benzofuran

HRID 1036115Notes

Reaction equation

HRID 1036115 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][C:3]=1[O:9][CH2:10][CH2:11]Br.[Li]CCCC>C1COCC1.CCCCCC>[Br:8][C:5]1[CH:6]=[CH:7][C:2]2[CH2:11][CH2:10][O:9][C:3]=2[CH:4]=1

Participants

5

Reactant 2

HCID 114738351,4-Dibromo-2-(2-bromoethoxy)benzeneHCID 178418339Butyllithium

Product 1

HCID 112526166-Bromo-2,3-dihydro-1-benzofuranYield 98.5%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8058HexaneSolvent

Conditions

Temperature
-78 °C

Procedure

1,4-dibromo-2-(2-bromoethoxy)benzene (136) (922 mg, 2.57 mmol) was dissolved in 25 ml dry THF. After cooled down to −78° C., a solution of 2.5M n-BuLi (1.23 ml, 1.2 q) in hexane was added dropwise. The reaction mixture was stirred at −78° C. for 4 h before poured into ice-water. After extracted twice with ethyl acetate, the org. phase was washed with brine, dried over sodium sulfate and then concentrated to give 504 mg (purity ca 80%) 6-bromo-2,3-dihydrobenzo[b]furan (137) as dark brow oil which was used directly for further reaction.

Workup

  1. extractionAfter extracted twice with ethyl acetate
  2. washphase was washed with brine
  3. dry with materialdried over sodium sulfate
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-f76f6ebd679740baa486b91732a5048e
Source dataset
uspto-grants-2013_10
Patent number
US08546403B2

Reaction notes

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