Boron tribromide → 4,4-dimethyl-3,4-dihydro-2H-1-benzopyran-7-ol
Reaction equation
C[O:2][C:3]1[CH:12]=[C:11]2[C:6]([C:7]([CH3:14])([CH3:13])[CH2:8][CH2:9][O:10]2)=[CH:5][CH:4]=1.B(Br)(Br)Br>C(Cl)Cl>[CH3:13][C:7]1([CH3:14])[C:6]2[C:11](=[CH:12][C:3]([OH:2])=[CH:4][CH:5]=2)[O:10][CH2:9][CH2:8]1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
To a methylene chloride (3 ml) solution of 7-methoxy-4,4-dimethylchromane (1.9 g, 9.7 mmol) was added methylene chloride solution of boron tribromide (1M, 19.4 mL, 19.4 mmol) at 0° C. The mixture was stirred at 0° C. for 1 hour. The reaction mixture was then quenched with methanol and then the solvent was removed under reduced pressure to give a residue, which was applied to a silica gel chromatography column and eluted with ethyl acetate/hexane=¼ to furnish 1.3 g (75% yield) of the title compound as a yellow solid.