反应详情

(Diethylamino)sulphur trifluoride (2.75 mL, 20.84 mmol) was added to a solution of tert-butyl 2-hydroxy-2-methylcyclopentylcarbamate (2.243 g, 10.42 mmol, from Step 3) in dichloromethane (40 mL) at −78° C. under nitrogen. After 4 h at −78° C., the mixture was quenched with saturated sodium bicarbonate, allowed to warm to room temperature, and extracted with dichloromethane. The dichloromethane phase was concentrated and purified by silica gel chromatography, eluting with 0 to 50% ethyl acetate in hexanes, to give tert-butyl 2-fluoro-2-methylcyclopentylcarbamate as brown oil (1.095 g, 48% yield). 1H NMR analysis indicated approximately 3.5:1 mixture of two diastereomers.

1. customthe mixture was quenched with saturated sodium bicarbonate
2. extractionextracted with dichloromethane
3. concentrationThe dichloromethane phase was concentrated
4. custompurified by silica gel chromatography
5. washeluting with 0 to 50% ethyl acetate in hexanes