反应详情

To a solution of 4-[1-(5-bromo-2-trifluoromethoxyphenyl)-methylidene]-2,2,5,5-tetramethyldihydrofuran-3-one (7.06 g, 18.00 mmol) in methanol (300 ml) at 35° C. is added 50% aqueous hydrogen peroxide (1.80 ml, 27.00 mmol), immediately followed by 2M aqueous lithium hydroxide (1.80 ml, 3.60 mmol). After stirring at this temperature for 1 hour the reaction mixture is allowed to cool, then quenched with 10% sodium metabisulfite solution (negative KI-starch indicator test). The reaction mixture is extracted with diethyl ether (×3), then the organic phase is further washed with saturated aqueous sodium bicarbonate (×2) then brine. All organics are combined, dried over magnesium sulfate, filtered and the filtrate concentrated in vacuo to afford 2-(5-bromo-2-trifluoromethoxyphenyl)-4,4,6,6-tetramethyl-1,5-dioxaspiro[2.4]heptan-7-one (6.34 g, 86%) as a yellow oil.

1. temperatureto cool
2. customquenched with 10% sodium metabisulfite solution (negative KI-starch indicator test)
3. extractionThe reaction mixture is extracted with diethyl ether (×3)
4. washthe organic phase is further washed with saturated aqueous sodium bicarbonate (×2)
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationthe filtrate concentrated in vacuo