Triethylsilane → 6-bromo-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran

TO a solution of 6-bromo-2,2-dimethyl-2,3-dihydro-4H-1-benzopyran-4-one (7.57 g) in trifluoroacetic acid (21.4 ml) was added at room temperature triethylsilane (10.4 ml), and the mixture was stirred for 4 days. To the mixture was added triethylsilane (7.1 ml), and the mixture was stirred at 50° C. for 24 hours. To the mixture was added at 0° C. 12N sodium hydroxide solution to make the solution alkaline, and the mixture was extracted with diethylether. The organic layer was washed with saturated brine, dried with magnesium sulfate and concentrated under reduced pressure. The residue was purified with silica gel column chromatography (hexane) to give colorless oil of 6-bromo-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran (10.77 g).

1. stirringthe mixture was stirred at 50° C. for 24 hours
2. additionTo the mixture was added at 0° C
3. extractionthe mixture was extracted with diethylether
4. washThe organic layer was washed with saturated brine
5. dry with materialdried with magnesium sulfate
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified with silica gel column chromatography (hexane)

ORD record

ord-f720480f9e6b4f629a9321a3a5635523

Source dataset

uspto-grants-2001_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06235771B1