Water → (2,2-Dimethyl-4-oxo-chroman-6-yl)boronic acid

HRID 1718517Notes

Reaction equation

HRID 1718517 reaction equation
Br[C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7]([CH3:13])([CH3:12])[CH2:6][C:5]2=[O:14].[B:15]1(B2OC(C)(C)C(C)(C)O2)[O:19]C(C)(C)C(C)(C)[O:16]1.C([O-])(=O)C.[K+].O>CN(C)C=O.C([O-])(=O)C.[Pd+2].C([O-])(=O)C>[CH3:12][C:7]1([CH3:13])[CH2:6][C:5](=[O:14])[C:4]2[C:9](=[CH:10][CH:11]=[C:2]([B:15]([OH:19])[OH:16])[CH:3]=2)[O:8]1

Participants

7

Reactant 4

HCID 962WaterHCID 517044Potassium AcetateHCID 2733548Bis(pinacolato)diboraneHCID 147553646-bromo-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

Product 1

HCID 57460405(2,2-Dimethyl-4-oxo-chroman-6-yl)boronic acidYield 84%

Reagents, catalysts & solvents 2

HCID 167845palladium(II) acetateCatalystHCID 6228DimethylformamideSolvent

Procedure

A solution of 6-bromo-2,2-dimethyl-2,3-dihydro-4H-chromen-4-one (21 g), pinacol diborane (25 g), palladium acetate (0.92 g) and potassium acetate (2.4 g) in N,N-dimethylformamide (250 mL) was stirred at 90° C. for 2 hr under an argon atmosphere. Water was added to the reaction mixture, and the mixture was extracted with diethyl ether. The organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure. The residue was dissolved in tetrahydrofuran (80 mL), and 0.5 M hydrochloric acid (40 mL) and sodium periodate (7.0 g) were added at 0° C. The reaction mixture was stirred at room temperature for 2 hr and extracted with ethyl acetate. The organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure. The residue was crystallized from ethyl acetate and hexane to give the title compound (15 g, 84%) as a colorless solid.

Workup

  1. extractionthe mixture was extracted with diethyl ether
  2. washThe organic layer was washed with saturated brine
  3. dry with materialdried over anhydrous magnesium sulfate
  4. customThe solvent was evaporated under reduced pressure
  5. dissolutionThe residue was dissolved in tetrahydrofuran (80 mL)
  6. addition0.5 M hydrochloric acid (40 mL) and sodium periodate (7.0 g) were added at 0° C
  7. extractionextracted with ethyl acetate
  8. washThe organic layer was washed with saturated brine
  9. dry with materialdried over anhydrous magnesium sulfate
  10. customThe solvent was evaporated under reduced pressure
  11. customThe residue was crystallized from ethyl acetate and hexane

Sources & evidence

ORD record
ord-735b3f62146545328722353549a5b4a6
Source dataset
uspto-grants-2010_09
Patent number
US07803940B2

Reaction notes

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