反应详情

79.6 mg of lithium chloride was suspended in 5 ml of dry tetrahydrofuran under an argon atmosphere. Then, a solution prepared by dissolving 670 mg of ethyl 2-diethylphosphono-4-(2-tetrahydropyranyloxy)butanoate in 0.6 ml of dry tetrahydrofuran, was added thereto under stirring. The mixture was stirred for 5 minutes at room temperature, and then 1.75 ml of a 20% dry tetrahydrofuran solution of diazabicycloundecene was added thereto. The mixture was stirred for 10 minutes at room temperature. Then, a solution prepared by dissolving 506 mg of (4S,5R)-3-benzyloxycarbonyl-2,2-dimethyl-5-formyl-4-isobutyloxazolidine in 1.0 ml of dry tetrahydrofuran, was added thereto, and the mixture was stirred overnight at room temperature. The reaction mixture was cooled to 0° C. and neutralized with 1N hydrochloric acid. Then, the mixture was extracted three times with ethyl acetate, and the ethyl acetate layer was washed sequentially with water and a saturated sodium chloride aqueous solution and then dried over anhydrous sodium sulfate. The solvent is distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (20 g of Kieselgel 60) by using a mixture of hexane/ethyl acetate (10/1) to obtain 550 mg of ethyl 3-[(4S,5S)-3-benzyloxycarbonyl-2,2-dimethyl-4-isobutyloxazolidin-5-yl]-2-[2-(2-tetrahydropyranyloxy)ethyl]- 2-propenoate (E/Z (50/50)) as a colorless oily substance.

1. customThen, a solution prepared
2. additionwas added
3. stirringThe mixture was stirred for 5 minutes at room temperature
4. stirringThe mixture was stirred for 10 minutes at room temperature
5. customThen, a solution prepared
6. additionwas added
7. stirringthe mixture was stirred overnight at room temperature
8. extractionThen, the mixture was extracted three times with ethyl acetate
9. washthe ethyl acetate layer was washed sequentially with water
10. dry with materiala saturated sodium chloride aqueous solution and then dried over anhydrous sodium sulfate
11. distillationThe solvent is distilled off under reduced pressure
12. customthe residue was purified by silica gel column chromatography (20 g of Kieselgel 60)
13. additiona mixture of hexane/ethyl acetate (10/1)