反应详情

温度

5 °C

Under a nitrogen atmosphere, 273 mg (1.0 mmol) of 3-propionyl-spiro[2,3-dihydro-4H-1,3-benzoxazine-2,1′-cyclohexan]-4-one was charged in a 30-ml three-necked flask to dissolve it in 2 ml of tetrahydrofuran. To the resulting solution, 2.44 ml (2.2 mmol) of a tetrahydrofuran solution (0.9M) of n-butylmagnesium chloride was slowly added dropwise at room temperature. The resulting mixture was reacted for 25 minutes under the same conditions. After cooling to 5° C., 2 ml of a tetrahydrofuran solution of 287 mg (1.0 mmol) of (3R,4R)-4-acetoxy-3-[(R)-1-tert-butyldimethylsilyloxyethyl]azetidin-2-one was added at the same temperature. The resulting mixture was stirred for 15 minutes, added with 10 ml of ethyl acetate and then added dropwise with 2 ml of a 10% aqueous solution of citric acid. After separation, the organic layer was washed with 2 ml of a saturated aqueous solution of sodium bicarbonate and 2 ml of a saturated aqueous solution of sodium chloride, dried over anhydrous magnesium sulfate and distilled to remove the solvent. The residue was purified by column chromatography, whereby 263 mg (0.53 mmol) of a condensation product was obtained (yield: 53%, β:α=92:8).

1. customThe resulting mixture was reacted for 25 minutes under the same conditions
2. customAfter separation
3. washthe organic layer was washed with 2 ml of a saturated aqueous solution of sodium bicarbonate and 2 ml of a saturated aqueous solution of sodium chloride
4. dry with materialdried over anhydrous magnesium sulfate
5. distillationdistilled
6. customto remove the solvent
7. customThe residue was purified by column chromatography