反应详情

温度

-78 °C

To a cooled (−78° C.) solution of 1 M lithium bis(trimethylsilyl)amide in hexanes (1 litre, 1 mol) is added dropwise (R)-2-tert-butyl-5-phenyl-[1,3]dioxolan-4-one (170 g, 0.77 mol) in THF (1.1 litre) over 90 minutes ensuring the temperature does not exceed −70° C. After stirring at −78° C. for 1 hour, cyclohexanone (112 ml, 1.1 mol) is added dropwise over 15 minutes and then stirring continued at −78° C. for another hour. The reaction is quenched by addition of 10% aqueous ammonium chloride solution (170 ml) and after warming to −20° C., a further 2 litres of 10% aqueous ammonium chloride solution is added. The aqueous portion is separated and extracted with EtOAc (500 ml). The organic portions are combined, dried over MgSO4 and concentrated in vacuo. The resulting crude product is slurried in heptane for 20 minutes and then filtered and dried in vacuo to afford the titled compound as a white solid.

1. customdoes not exceed −70° C
2. stirringstirring
3. waitcontinued at −78° C. for another hour
4. customThe reaction is quenched by addition of 10% aqueous ammonium chloride solution (170 ml)
5. temperatureafter warming to −20° C.
6. additiona further 2 litres of 10% aqueous ammonium chloride solution is added
7. customThe aqueous portion is separated
8. extractionextracted with EtOAc (500 ml)
9. dry with materialdried over MgSO4
10. concentrationconcentrated in vacuo
11. waitThe resulting crude product is slurried in heptane for 20 minutes
12. filtrationfiltered
13. customdried in vacuo