反应详情

In a 5 ml round-bottomed flask provided with a stirrer, MeOH (10 ml) was added to the (3S)-3-acetoxy-4-fluoro-1-phenyl-4,4-bis(phenylsulfonyl)-1-but ene (200 mg, 0.41 mmol, 94% ee) prepared in Reference Example 4, and the resultant mixture was cooled to −40° C. Then, samarium(II) iodide/tetrahydrofuran (0.1 M, 41 ml) was slowly added dropwise, and the mixture was stirred for 6 hours. Then, a saturated ammonium chloride aqueous solution was added. The aqueous layer was extracted with dichloromethane. A sodium thiosulfate aqueous solution was added to the organic layer, and the mixture was extracted. Then, the organic layer was dried over anhydrous magnesium sulfate. The solvent was removed by distillation using an evaporator, and then complete removal of the salt was carried out by silica gel column chromatography (ethyl acetate). Next, a magnesium ribbon (164 mg, 6.73 mmol) was activated by a heat gun in a nitrogen atmosphere, then left to cool at room temperature. Then, the magnesium ribbon was cooled to 0° C., and MeOH (0.5 ml) was added. Then, a solution of the crude product, which had been dried, in MeOH (2.0 ml) was added to the mixture, and then the mixture was stirred. After 1 hour, a saturated ammonium chloride aqueous solution was added. The aqueous layer was extracted with dichloromethane. The organic layer was dried over anhydrous magnesium sulfate. The solvent was removed by distillation using an evaporator, and then the product was purified by preparative thin-layer chromatography (dichloromethane:methanol=95:5) to obtain the target (3S)-(E)-4-fluoro-3-hydroxy-1-phenyl-1-butene. However, the isolated yield was low, at 30% (20.4 mg, 93% ee).

1. customIn a 5 ml round-bottomed flask provided with a stirrer
2. customprepared in Reference Example 4
3. extractionThe aqueous layer was extracted with dichloromethane
4. additionA sodium thiosulfate aqueous solution was added to the organic layer
5. extractionthe mixture was extracted
6. dry with materialThen, the organic layer was dried over anhydrous magnesium sulfate
7. customThe solvent was removed by distillation
8. customan evaporator
9. customcomplete removal of the salt
10. waitleft
11. dry with materialThen, a solution of the crude product, which had been dried, in MeOH (2.0 ml)
12. additionwas added to the mixture
13. stirringthe mixture was stirred
14. waitAfter 1 hour
15. additiona saturated ammonium chloride aqueous solution was added
16. extractionThe aqueous layer was extracted with dichloromethane
17. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
18. customThe solvent was removed by distillation
19. customan evaporator
20. customthe product was purified by preparative thin-layer chromatography (dichloromethane:methanol=95:5)