反应详情

A 1.6 M ether solution of methyllithium (13.59 mL, 21.75 mmol) was added to a stirred suspension of tert-butyl 2-oxocyclopentylcarbamate (1.97 g, 9.89 mmol, from Step 2) and cerium(III) chloride (5.36 g, 21.75 mmol) in tetrahydrofuran (50 mL) at −78° C. under nitrogen. After 2.5 h at −78° C., the mixture was quenched with saturated ammonium chloride, allowed to warm to room temperature, and filtered through a short bed of Celite to remove insoluble cerium salt. The filter cake was rinsed with ethyl acetate. The filtrated was extracted with ethyl acetate three times. The combined ethyl acetate phase was washed with saturated ammonium chloride and brine respectively, dried (MgSO4), filtered and concentrated. Silica gel chromatography, eluting with 0 to 50% ethyl acetate in hexanes, gave tert-butyl 2-hydroxy-2-methylcyclopentylcarbamate as yellow solid (1.47 g, 82% yield). 1H NMR analysis indicated the presence of approximately a 3:1 diastereomeric mixture.

1. customthe mixture was quenched with saturated ammonium chloride
2. filtrationfiltered through a short bed of Celite
3. customto remove insoluble cerium salt
4. washThe filter cake was rinsed with ethyl acetate
5. extractionThe filtrated was extracted with ethyl acetate three times
6. washThe combined ethyl acetate phase was washed with saturated ammonium chloride and brine respectively
7. dry with materialdried (MgSO4)
8. filtrationfiltered
9. concentrationconcentrated
10. washSilica gel chromatography, eluting with 0 to 50% ethyl acetate in hexanes