6-Bromo-2',4',5',6'-tetrahydrospiro[chroman-2,3'-pyran]-4-one → 6-Bromo-3-fluoro-2',4',5',6'-tetrahydrospiro[chroman-2,3'-pyran]-4-one

HRID 2096538Notes

Reaction equation

HRID 2096538 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[C:14](=[CH:15][CH:16]=1)[O:13][C:7]1([CH2:12][CH2:11][CH2:10][O:9][CH2:8]1)[CH2:6][C:5]2=[O:17].CO.[B-](F)(F)(F)[F:21].[B-](F)(F)(F)F.C1[N+]2(CCl)CC[N+](F)(CC2)C1>>[Br:1][C:2]1[CH:3]=[C:4]2[C:14](=[CH:15][CH:16]=1)[O:13][C:7]1([CH2:12][CH2:11][CH2:10][O:9][CH2:8]1)[CH:6]([F:21])[C:5]2=[O:17]

Participants

3

Reactant 2

HCID 584238236-Bromo-2',4',5',6'-tetrahydrospiro[chroman-2,3'-pyran]-4-oneHCID 131730597MeOH Selectfluor

Product 1

HCID 584237746-Bromo-3-fluoro-2',4',5',6'-tetrahydrospiro[chroman-2,3'-pyran]-4-oneYield 10%

Procedure

To a solution of 6-bromo-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-one (2 g, 6.8 mmol) in MeOH Selectfluor™ (2.5 g, 7.1 mmol) was added. The suspension was refluxed overnight. Then the solvent was removed in vacuo. CH2Cl2 was added to the resulting residue and insoluble material filtered off. The filtrate was washed with H2O, dried and concentrate in vacuo. The crude product was purified by column chromatography to give 6-bromo-3-fluoro-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-one (220 mg, 10%). 1H-NMR (CDCl3): 1.72-2.21 (m, 4H), 3.44 (m, 1H), 3.63 (m, 1H), 3.73 (m, 1H), 3.92 (m, 1H), 4.91 (m, 1H), 6.94 (m, 1H), 7.56 (m, 1H), 7.90 (m, 1H).

Workup

  1. temperatureThe suspension was refluxed overnight
  2. customThen the solvent was removed in vacuo
  3. additionCH2Cl2 was added to the resulting residue and insoluble material
  4. filtrationfiltered off
  5. washThe filtrate was washed with H2O
  6. customdried
  7. concentrationconcentrate in vacuo
  8. customThe crude product was purified by column chromatography

Sources & evidence

ORD record
ord-f2583d4de459427bbc1a87375d8ac730
Source dataset
uspto-grants-2013_05
Patent number
US08450308B2

Reaction notes

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