Dichloromethane → 8-Acetoxy-6-bromo-2,2,4,4-tetramethyl chroman

HRID 2377331Notes

Reaction equation

HRID 2377331 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.ClCCl.ClC1C=[C:25](C=CC=1)[C:26]([O:28]O)=[O:27].C(OCC)(=O)C>CCCCCC>[C:26]([O:28][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:27])[CH3:25]

Participants

6

Reactant 4

HCID 6344DichloromethaneHCID 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 92%

Reagents, catalysts & solvents 1

HCID 8058HexaneSolvent

Procedure

A solution of 8-acetyl-6-bromo-2,2,4,4-tetramethyl chroman (Intermediate 15A, 1.3 g, 4.18 mol) in anhydrous dichloromethane (30 mol) 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-9f21925dd17e44a9acc40f1194f99d1a
Source dataset
uspto-grants-2008_12
Patent number
US07468391B2

Reaction notes

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