反应详情

A mixture of ethyl (methyl)phosphinate (3.2 g, 30 mmol) and 1, 1,1,3,3,3-hexamethyldisilazane (4.8 g, 30 mmol) was heated to reflux for 2 h under an argon atmosphere. The mixture was cooled to room temperature and a diastereomeric mixture of ethyl 2-fluorobut-2-enoate (4.0 g, 30 mmol) was added. The reagents were heated to 70° C. for three days and then at room temperature for 4 days under an argon atmosphere. The mixture was diluted with methylene chloride (200 mL). The solution was washed with 1 N HCl (200 mL) and the aqueous solution extracted with methylene chloride (200 mL). The combined organic solutions were washed with saturated sodium chloride, dried over MgSO4, filtered and evaporated. The residue was purified by chromatography on a wet-packed silica gel column eluting with methylene chloride/methanol (99:1-97:3). The appropriate fractions were combined and evaporated to give 2.9 g (40%) of ethyl 3-[ethoxy(methyl)phosphoryl]-2-fluorobutanoate as a clear oil. 1H NMR (400 MHz, CDCl3) δ4.8-5.6 (m, 1H), 4.2-4.4 (m, 2H), 4.0-4.2 (m, 2H), 2.4-2.6 (m, 1H), 1.1-1.5 (m, 12H).

1. temperaturewas heated
2. temperatureto reflux for 2 h under an argon atmosphere
3. additionwas added
4. temperatureThe reagents were heated to 70° C. for three days
5. washThe solution was washed with 1 N HCl (200 mL)
6. extractionthe aqueous solution extracted with methylene chloride (200 mL)
7. washThe combined organic solutions were washed with saturated sodium chloride
8. dry with materialdried over MgSO4
9. filtrationfiltered
10. customevaporated
11. customThe residue was purified by chromatography on a wet-packed silica gel column
12. washeluting with methylene chloride/methanol (99:1-97:3)
13. customevaporated