反应详情

Triphenylphosphine (12.54 g, 47.8 mmol) was dissolved in 100 ml of anhydrous THF and at 0° C. tetrabromomethane (15.85 g, 47.8 mmol) in 100 mL of anhydrous THF was added dropwise. This was followed by the dropwise addition, after 15 min, of benzyl ((S)-2-hydroxy-1-methylethyl)carbamate (5.0 g, 23.9 mmol), dissolved in 150 ml of THF. After 10 min at 0° C. the cooling bath was removed and the mixture was stirred at room temperature overnight. The precipitate which had formed was separated off and washed with ethyl acetate and the combined organic phases were concentrated. The residue obtained was purified over silica gel (ethyl acetate-n-heptane=20:80). Yield: 3.41 g (52%).

1. additionwas added dropwise
2. customAfter 10 min at 0° C. the cooling bath was removed
3. customThe precipitate which had formed
4. customwas separated off
5. washwashed with ethyl acetate
6. concentrationthe combined organic phases were concentrated
7. customThe residue obtained
8. customwas purified over silica gel (ethyl acetate-n-heptane=20:80)