Ethyl Acetate → 8-Acetoxy-6-bromo-2,2,4,4-tetramethyl chroman

HRID 1869851Notes

Reaction equation

HRID 1869851 reaction equation
C([C:4]1[CH:5]=[C:6]([Br:18])[CH:7]=[C:8]2[C:13]=1[O:12][C:11]([CH3:15])([CH3:14])[CH2:10][C:9]2([CH3:17])[CH3:16])(=O)C.ClC1C=[C:22](C=CC=1)[C:23]([O:25]O)=[O:24].C(OCC)(=O)C>ClCCl.CCCCCC>[C:23]([O:25][C:4]1[CH:5]=[C:6]([Br:18])[CH:7]=[C:8]2[C:13]=1[O:12][C:11]([CH3:14])([CH3:15])[CH2:10][C:9]2([CH3:16])[CH3:17])(=[O:24])[CH3:22]

Participants

6

Reactant 3

HCID 8857Ethyl AcetateHCID 70297m-Chloroperbenzoic acidHCID 211072398-Acetyl-6-bromo-2,2,4,4-tetramethyl chroman2×

Product 1

HCID 574242158-Acetoxy-6-bromo-2,2,4,4-tetramethyl chromanYield 95%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8058HexaneSolvent

Procedure

A solution of 8-acetyl-6-bromo-2,2,4,4-tetramethyl chroman (Intermediate 15A, 10.3 g, 4.18 mmol) in anhydrous dichloromethane (30 mL) was treated with a 77% aqueous solution of 3-chloroperoxybenzoic acid (5.75 g, 33.44 mmol) and the resulting reaction mixture was stirred at ambient temperature for 24 h. The reaction mixture was then cooled in an ice bath and cautiously quenched with saturated sodium thiosulfate solution. The phases were separated and the organic phase was washed with saturated, aqueous sodium bicarbonate solution, water and brine, dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to afford a residue that on flash column chromatography over silica gel (230-400 mesh) using 10% ethyl acetate in hexane as the eluent afforded the title compound as an oil (1.3 g, 92%).

Workup

  1. customthe resulting reaction mixture
  2. temperatureThe reaction mixture was then cooled in an ice bath
  3. customcautiously quenched with saturated sodium thiosulfate solution
  4. customThe phases were separated
  5. washthe organic phase was washed with saturated, aqueous sodium bicarbonate solution, water and brine
  6. dry with materialdried over anhydrous sodium sulfate
  7. filtrationfiltered
  8. customevaporated in vacuo
  9. customto afford a residue that on flash column chromatography over silica gel (230-400 mesh)

Sources & evidence

ORD record
ord-70e03cd572a44c889004dc3f55095bc0
Source dataset
uspto-grants-2009_12
Patent number
US07638648B2

Reaction notes

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