Heptane → 7-bromo-3,4-dihydro-2H-1-benzopyran-4-one

HRID 1751402Notes

Reaction equation

HRID 1751402 reaction equation
[H-].C([Al+]CC(C)C)C(C)C.CCCCCCC.[Br:18][C:19]1[CH:28]=[C:27]2[C:22]([C:23](=[O:29])[CH:24]=[CH:25][O:26]2)=[CH:21][CH:20]=1>O1CCCC1>[Br:18][C:19]1[CH:28]=[C:27]2[C:22]([C:23](=[O:29])[CH2:24][CH2:25][O:26]2)=[CH:21][CH:20]=1

Participants

5

Reactant 3

HCID 8900HeptaneHCID 186867527-Bromo-4H-1-benzopyran-4-oneHCID 21225700Diisobutylaluminumhydride

Product 1

HCID 223357367-bromo-3,4-dihydro-2H-1-benzopyran-4-oneYield 78.5%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A solution of diisobutylaluminum hydride in heptane (1.0 M, 60 mL, 60.0 mmol) was added dropwise to a solution of 7-bromo-4H-chromen-4-one (4.5 g, 20.0 mmol) in tetrahydrofuran at −78° C. under an atmosphere of argon over a period of 30 minutes. After 30 minutes the reaction was quenched with a mixture of silica gel (10 g), and water (10 mL). The mixture was allowed to warm to room temperature and was filter through celite and the tetrahydrofuran was removed under reduced pressure. The residue was taken up in chloroform (100 mL) and washed with sodium hydroxide (1N, 25 mL) and dried over sodium sulfate. The mixture was filtered and the solvent was removed under reduced pressure. The residue was subjected to flash chromatography with eluant of dichloromethane. The product containing fractions were combined and the solvent was removed under reduced pressure to provide 7-bromochroman-4-one (3.57 g, 15.7 mmol, 78%).

Workup

  1. customAfter 30 minutes the reaction was quenched with a mixture of silica gel (10 g), and water (10 mL)
  2. filtrationwas filter through celite
  3. customthe tetrahydrofuran was removed under reduced pressure
  4. washwashed with sodium hydroxide (1N, 25 mL)
  5. dry with materialdried over sodium sulfate
  6. filtrationThe mixture was filtered
  7. customthe solvent was removed under reduced pressure
  8. additionThe product containing fractions
  9. customthe solvent was removed under reduced pressure

Sources & evidence

ORD record
ord-2e62a9abe9414b9baf9a2f74f020e7b8
Source dataset
uspto-grants-2015_10
Patent number
US09156823B2

Reaction notes

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