Dimethyl Sulfoxide → 6-bromo-2,2-dimethyl-4H-spiro[chromene-3,1'-cyclopropan]-4-one

A 3-necked-flask was charged with dimethylsulfoxide (17 ml) and potassium hydroxide (0.84 g, 15 mmol). Then trimethylsulfoxonium iodide (3.3 g, 15 mmol) was added and the mixture was stirred at room temperature for 30 minutes. To this mixture, 6-bromo-2,2-dimethyl-3-methylene-2,3-dihydro-4H-chromen-4-one (2.0 g, 7.5 mmol) and dimethylsulfoxide (3 ml) were added. The mixture was stirred at room temperature for 15 hours and then water (30 ml) was added. The mixture was extracted with a mixture of hexane (70 ml) and ethyl acetate (70 ml). The organic layer was washed with water (50 ml) twice and then with brine (30 ml), dried over anhydrous magnesium sulfate, and concentrated in vacuo. The residue was purified by silica gel column chromatography (NH-silica gel, hexane/ethyl acetate=100:1-20:1) to afford 6-bromo-2,2-dimethyl-4H-spiro[chromene-3,1′-cyclopropan]-4-one (1.2 g).

1. stirringThe mixture was stirred at room temperature for 15 hours
2. extractionThe mixture was extracted with a mixture of hexane (70 ml) and ethyl acetate (70 ml)
3. washThe organic layer was washed with water (50 ml) twice
4. dry with materialwith brine (30 ml), dried over anhydrous magnesium sulfate
5. concentrationconcentrated in vacuo
6. customThe residue was purified by silica gel column chromatography (NH-silica gel, hexane/ethyl acetate=100:1-20:1)

ORD record

ord-345d9e60c8bc4df2b8f1c0f755c7211d

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08975415B2