反应详情

温度

0 °C

Tert-butyl 4-((trimethylsilyl)oxy)-5,6-dihydropyridine-1(2H)-carboxylate, 2.2 (300 g, 1.102 mol) was dissolved in dry Acetonitrile (300 mL) and cooled to 0° C. and Selectfluor (430 g, 1.21 mol) was added in portion wise over a period of 45 min. under N2 atmosphere. After addition completed, the reaction mixture was allowed to room temperature and stirred for 2 h. The reaction was monitored by TLC (50% EtOAc/hexane). After completion of reaction by TLC the reaction mixture poured into ice cold saturated brine solution (300 mL) and extracted with EtOAc (2×200 mL). The combined EtOAc layers were washed with brine solution, water, dried over Na2SO4 and evaporated under vacuum. The residue was purified by column chromatography on silica gel (10-40% EtOAc-Hexane) to afford tert-butyl 3-fluoro-4-oxopiperidine-1-carboxylate 2.3 (170 g; 70.7%). 1HNMR (CDCl3, 400 MHz): δ 4.88 (dd, 0.5H), 4.77 (dd, 0.5H), 4.47 (brs, 1H), 4.17 (ddd, 1H), 3.25 (brs, 1H), 3.23 (ddd, 1H), 2.58 (m, 1H), 2.51 (m, 1H), 1.49 (s, 9H).

1. additionAfter addition
2. customwas allowed to room temperature
3. customAfter completion of reaction by TLC the reaction mixture
4. extractionextracted with EtOAc (2×200 mL)
5. washThe combined EtOAc layers were washed with brine solution, water
6. dry with materialdried over Na2SO4
7. customevaporated under vacuum
8. customThe residue was purified by column chromatography on silica gel (10-40% EtOAc-Hexane)