反应详情

To an ice cold solution of 4.76 g (18 mmoles) of CBZ hydroxyproline (Sigma Chemical Co.) in 20 mL of dry THF was added 45 mL of a 1M solution borane-THF complex in THF (Aldrich). After stirring under argon for 15 minutes at 0°-5° C., and 4.5 h at room temperature, the mixture was quenched with 50 mL of methanol. After 30 min, the solution was concentrated. The residual colorless syrup was purified by flash chromatography (3.5×23 cm silica) using a gradient of methanol in methylene chloride. The product eluted with 10% methanol. The fractions containing pure product were stripped of solvent to give 2.18 g (46% yield) of (1) as a colorless syrup.

1. custom4.5 h at room temperature, the mixture was quenched with 50 mL of methanol
2. waitAfter 30 min
3. concentrationthe solution was concentrated
4. customThe residual colorless syrup was purified by flash chromatography (3.5×23 cm silica)
5. washThe product eluted with 10% methanol
6. additionThe fractions containing pure product