反应详情

(1,1-dimethyl-3-oxobutyl)carbamic acid tert-butylester (2.5 g; 11.6 mmol) was dissolved in tetrahydrofuran (15 mL) and added dropwise to the reaction mixture which was heated to reflux for 12 h. Ethyl acetate (100 mL) and hydrochloric acid (1 N; 100 mL) were added and the phases were separated. The aqueous phase was extracted with ethyl acetate (3×50 mL). The combined organic phases were washed with an aqueous solution of sodium hydrogen carbonate (saturated; 100 mL), dried (magnesium sulfate) and evaporated in vacuo. The residue was chromatographed on silica (3×40 cm) using ethyl acetate/heptane (1:2) as eluent to afford 2.0 g of (E)-5-tert-Butoxycarbonylamino-3,5-dimethylhex-2-enoic acid ethylester.

1. additionadded dropwise to the reaction mixture which
2. temperaturewas heated
3. temperatureto reflux for 12 h
4. customthe phases were separated
5. extractionThe aqueous phase was extracted with ethyl acetate (3×50 mL)
6. washThe combined organic phases were washed with an aqueous solution of sodium hydrogen carbonate (saturated; 100 mL)
7. dry with materialdried (magnesium sulfate)
8. customevaporated in vacuo
9. customThe residue was chromatographed on silica (3×40 cm)