反应详情

Dess-Martin periodinane (9.49 g, 22.39 mmol) was added to a solution of cis/trans mixture of benzyl 3-hydroxy-2,2-dimethylcyclopentylcarbamate (3.93 g, 14.92 mmol, from Step 1 of Intermediate 21) in dichloromethane (150 mL) at room temperature. After 2 h at room temperature, the mixture was filtered to remove the precipitate. The filtrate was washed with 10% aqueous sodium thiosulfate (10 mL), saturated sodium bicarbonate (20 mL), brine (20 mL), dried (MgSO4), filtered and concentrated. Silica gel chromatography, eluting with 10 to 50% ethyl acetate in hexanes, gave benzyl 2,2-dimethyl-3-oxocyclopentylcarbamate (3.20 g, 82% yield). 1H NMR (400 MHz, chloroform-d) δ ppm 7.30-7.74 (5 H, m), 4.97-5.33 (2 H, m), 4.60-4.93 (1 H, m), 2.17-2.42 (2 H, m), 1.47-1.82 (2 H, m), 1.12 (3 H, s), 0.91 (3 H, s); MS (ES+) m/z: 262.3 (M+H); HPLC retention time: 2.643 min (analytical HPLC Method A).

1. filtrationthe mixture was filtered
2. customto remove the precipitate
3. washThe filtrate was washed with 10% aqueous sodium thiosulfate (10 mL), saturated sodium bicarbonate (20 mL), brine (20 mL)
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated
7. washSilica gel chromatography, eluting with 10 to 50% ethyl acetate in hexanes