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

HRID 2272212Notes

Reaction equation

HRID 2272212 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, 1.2q) 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-0580feeed563403b8be776a14b40532a
Source dataset
uspto-grants-2015_09
Patent number
US09120751B2

Reaction notes

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