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

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Reaction Steps

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).

Provenance & Evidence