Boron tribromide → 4,4-dimethyl-3,4-dihydro-2H-1-benzopyran-7-ol

HRID 1350877Notes

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]1

Participants

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.

Workup

customThe reaction mixture was then quenched with methanol
customthe solvent was removed under reduced pressure
customto give a residue, which
washeluted with ethyl acetate/hexane=¼

Sources & evidence

ORD record: ord-433f15aaf7e7459a8815c7923acecc1c
Source dataset: uspto-grants-2007_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07214824B2

Reaction notes

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