反应详情

Triethylborane (1.0 M in THF, 149.5 ml, 149.5 mmol) was added to oxazole (10.33 g, 149.5 mmol) and stirred for 45 minutes at room temperature. The mixture was then cooled to −78° C. and n-BuLi (2.5 M in hexane, 59.8 ml, 149.5 mmol) was added dropwise and allowed to stir for one hour under nitrogen. Compound (1) (8.0 g, 42.7 mmol) was dissolved in 25 ml of THF and added to the reaction mixture. The reaction was stirred for 5 hours at −78° C. then it was allowed to warm to 0° C. for one hour. The reaction was then cooled back to −78° C. and quenched with 7% acetic acid in ethanol (700 ml) which was allowed to stir overnight at room temperature. The mixture was concentrated in vacuum and the residue was dissolved in ether and filtered. The filtrate was concentrated in vacuum and the residue was dissolved in ethyl acetate washed twice with 0.005 N HCl, twice with saturated sodium bicarbonate and brine. The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified on silica using 10–40% ethyl acetate/heptane to give [(S)-1-(Hydroxy-oxazol-2-yl-methyl)-propyl]-carbamic acid tert-butyl ester ((2), 3.85 g).

1. temperatureThe mixture was then cooled to −78° C.
2. stirringto stir for one hour under nitrogen
3. additionadded to the reaction mixture
4. stirringThe reaction was stirred for 5 hours at −78° C.
5. temperatureto warm to 0° C. for one hour
6. temperatureThe reaction was then cooled back to −78° C.
7. customquenched with 7% acetic acid in ethanol (700 ml) which
8. stirringto stir overnight at room temperature
9. concentrationThe mixture was concentrated in vacuum
10. dissolutionthe residue was dissolved in ether
11. filtrationfiltered
12. concentrationThe filtrate was concentrated in vacuum
13. dissolutionthe residue was dissolved in ethyl acetate
14. washwashed twice with 0.005 N HCl, twice with saturated sodium bicarbonate and brine
15. dry with materialThe organic layer was dried over magnesium sulfate
16. filtrationfiltered
17. concentrationconcentrated in vacuum
18. customThe residue was purified on silica using 10–40% ethyl acetate/heptane