反应详情

To a solution of the product of step H (506 mg, 1.9 mmol) in dichloromethane (15 mL) at 0° C. was added pyridinium chlorochromate (4.0 g, 19 mmol). The reaction was allowed to warm to ambient temperature and stirred for a further 2 h. The reaction mixture was filtered through celite and the filtrate was concentrated in vacuo to afford the crude product which was purified by flash column chromatography (SiO2, 19:1 to 4:1, hexanes/ethyl acetate) to afford tert-butyl 2-(acetoxymethyl)-4-oxopiperidine-1-carboxylate (220 mg, 43%) as a colorless oil: 1H NMR (CDCl3, 400 MHz) δ 4.57 (br s, 1H), 4.03-3.99 (m, 2H), 3.91-3.87 (m, 1H), 3.28-3.21 (s, 1H), 2.52-2.46 (m, 1H), 2.35-2.31 (m, 1H), 2.26-2.18 (m, 2H), 1.83 (s, 3H), 1.50 (s, 9H).

1. filtrationThe reaction mixture was filtered through celite
2. concentrationthe filtrate was concentrated in vacuo
3. customto afford the crude product which
4. customwas purified by flash column chromatography (SiO2, 19:1 to 4:1, hexanes/ethyl acetate)