反应详情

温度

0 °C

To a suspension of methyl(triphenyl)phosphonium bromide (20.8 g, 58.2 mmol) in tetrahydrofuran (168 ml) was added n-butyllithium (2.69 M solution in hexane, 21.6 ml, 58.2 mmol) under dry ice-acetone bath cooling and argon atmosphere. The mixture was stirred for 1 hour at 0° C. To the mixture was added 6-bromo-2,2-dimethyl-4H-spiro[chromene-3,1′-cyclopropan]-4-one (8.18 g, 29 mmol). The mixture was stirred for 1 hour at 0° C. The reaction was quenched by adding water and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo. The residue was purified by silicagel column chromatography (hexane/ethyl acetate=20:1-10:1) to afford 6-bromo-2,2-dimethyl-4-methylene-4H-spiro[chromene-3,1′-cyclopropane] (7.69 g).

1. temperaturecooling
2. stirringThe mixture was stirred for 1 hour at 0° C
3. customThe reaction was quenched
4. additionby adding water
5. extractionextracted with ethyl acetate
6. washThe organic layer was washed with brine
7. dry with materialdried over anhydrous magnesium sulfate
8. concentrationconcentrated in vacuo
9. customThe residue was purified by silicagel column chromatography (hexane/ethyl acetate=20:1-10:1)