反应详情

To a solution of (1R,2S)-1,2-dihydroxy-1-(4,5-diphenyloxazol-2-yl)cyclohexane (18 g) in methylene chloride (200 ml) were added orthoacetic acid trimethyl ester (9.7 ml) and p-toluenesulfonic acid (20 mg) at room temperature under N2. After stirring the mixture for 30 minutes, the solvent was evaporated in vacuo. The residue was diluted with methylene chloride (200 ml) and acetyl bromide (5.8 ml) was added to the solution at 0° C. under N2. After stirring the mixture for 2 hours at room temperature, the solvent was evaporated in vacuo, the residue was diluted with MeOH (200 ml), and potassium carbonate (12 g) was added to the solution at room temperature. The mixture was stirred for 2 hours at the same temperature and partitioned between EtOAc and water. The organic layer was washed with 1N-hydrochloric acid, water, saturated sodium hydrogencarbonate and brine. The dried solvent was evaporated in vacuo and the residue was purified by chromatography on silica gel to give (1R,2S)-1-(4,5-diphenyloxazol-2-yl)-1,2-epoxycyclohexane (14.1 g).

1. customthe solvent was evaporated in vacuo
2. additionThe residue was diluted with methylene chloride (200 ml) and acetyl bromide (5.8 ml)
3. additionwas added to the solution at 0° C. under N2
4. stirringAfter stirring the mixture for 2 hours at room temperature
5. customthe solvent was evaporated in vacuo
6. additionthe residue was diluted with MeOH (200 ml), and potassium carbonate (12 g)
7. additionwas added to the solution at room temperature
8. stirringThe mixture was stirred for 2 hours at the same temperature
9. custompartitioned between EtOAc and water
10. washThe organic layer was washed with 1N-hydrochloric acid, water, saturated sodium hydrogencarbonate and brine
11. customThe dried solvent was evaporated in vacuo
12. customthe residue was purified by chromatography on silica gel