反应详情

A solution of carboxylic acid 1g (11.4 g, 40.7 mmol), triethylamine (5.67 mL, 40.7 mmol), and DPPA (8.86 mL, 40.7 mmol) in 180 mL 1,4-dioxane was heated at reflux for 2 h. Benzyl alcohol (4.67 mL, 45 mmol) was added and the mixture was heated at reflux for an additional 3 h. The mixture was concentrated in vacuo and the oil obtained was purified by flash chromatography (50 to 100% EtOAc/hexanes) to provide 11.13 g (73%) of the benzyl carbamate (1h) as a tan solid. 1H NMR (300 MHz, CDCl3) δ8.67 (br s, 1H), 7.39-7.34 (m, 5H), 5.21 (s, 2H), 4.98 (dd, J=9.6, 3.0, 1H), 3.23-2.98 (m, 2H), 2.63-2.49 (m, 1H), 2.37-2.23 (m, 1H), 1.48 (s, 9H).

1. temperatureat reflux for 2 h
2. temperaturethe mixture was heated
3. temperatureat reflux for an additional 3 h
4. concentrationThe mixture was concentrated in vacuo
5. customthe oil obtained
6. customwas purified by flash chromatography (50 to 100% EtOAc/hexanes)