反应详情

温度

-70 °C

(S)-tert-Butyl 4-(tert-butoxycarbonylamino)-5-(methoxy(methyl)amino)-5-oxopentanoate (4.12 g, 12.2 mmol) was dissolved in anhydrous tetrahydrofuran (100 mL) and cooled to −70° C. under nitrogen. Vinylmagnesium bromide (37 mL, 1.0 M soln in THF, 3.0 eq) was added dropwise. The reaction stirred for 30 min at −70° C. and was then the cooling bath was removed and the reaction stirred at room temperature overnight. The mixture was colled on in an ice bath and acetic anhydride (20 mL) was added, followed by methanol (27 mL). The mixture was concentrated under pressure to a small volume and then diluted with ethyl acetate. The reaction mixture was washed successively with water and brine and dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by flash column chromatography, on silica gel, eluting with 1:4 ethyl acetate:hexanes to yield (S)-tert-butyl 4-(tert-butoxycarbonylamino)-5-oxohept-6-enoate (0.94 g) as a yellow oil. 1H NMR (CDCl3): 6.48-6.45 (m, 2H), 5.94 (m, 1H), 5.29 (m, 1H), 4.70 (m, 1H), 2.38-2.05 (m, 2H), 2.02 (m, 1H), 1.70 (m, 1H), 1.45 ppm (s, 18H).

1. customthe cooling bath was removed
2. stirringthe reaction stirred at room temperature overnight
3. customThe mixture was colled on in an ice bath
4. additionacetic anhydride (20 mL) was added
5. concentrationThe mixture was concentrated under pressure to a small volume
6. additiondiluted with ethyl acetate
7. washThe reaction mixture was washed successively with water and brine
8. dry with materialdried over anhydrous sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated under reduced pressure
11. customThe resulting residue was purified by flash column chromatography, on silica gel
12. washeluting with 1:4 ethyl acetate