反应详情

温度

-78 °C

THF, 20 ml, is placed under N2, treated with 1.54 ml diisopropylamine and cooled to -78° C. A solution of n-butyl lithium, 1.97 M in hexane (5.6 ml) is added dropwise over 5 min. The reaction mixture is stirred at -78° C. for 10 min and then treated with 8-oxo-2,2,5-trimethyl-3-oxa-1-azabicyclo[4.2.0]octane (1.55 g) in 15 ml THF which is added dropwise over 5 min. After another 10 min hexamethylphosphoramide (1.97 ml) is added. The mixture is stirred another 10 min, then treated with 2 ml of isopropyl iodide. The reaction mixture is stirred at -78° C. for 15 min and allowed to warm to 25° C. and stirred for 15 min. The reaction mixture is diluted with EtOAc, washed once with pH 7 phosphate buffer then dried and evaporated. The residue is chromatographed on silica gel using 25% EtOAc/C6H6 as eluant to give 8-oxo-2,2,5-trimethyl-7α-isopropyl-3-oxa-1-azabicyclo[4.2.0]octane.

1. additionis added dropwise over 5 min
2. stirringThe mixture is stirred another 10 min
3. stirringThe reaction mixture is stirred at -78° C. for 15 min
4. temperatureto warm to 25° C.
5. stirringstirred for 15 min
6. washwashed once with pH 7 phosphate buffer
7. customthen dried
8. customevaporated
9. customThe residue is chromatographed on silica gel using 25% EtOAc/C6H6 as eluant