Pyridine → Diethyl 2-(1-(tert-butoxycarbonyl)piperidin-4-ylidene)malonate

Participants

Reaction Steps

To anhydrous THF (50 mL) at 0° C. a solution of TiCl4 (13.75 mL, 0.126 mol) in CCl4 (10 mL) was added dropwise. To the resulting yellow suspension were a solution of 4-oxopiperidine-1-carboxylic acid tert-butyl ester (10 g, 0.05 mol) and diethylmalonate (6.85 mL, 0.05 mol) in anhydrous THF (50 mL) added, followed by addition of pyridine (26 mL). The dark yellow suspension was allowed to warm to ambient temperature and stirred at ambient temperature for 17 h, then partitioned between EtOAc and citric acid (10%, aq.). The organic layer was separated and washed with water and brine, then dried (MgSO4) and concentrated in vacuo to afford 2-(1-(tert-Butoxycarbonyl)piperidin-4-ylidene)malonic acid diethyl ester as a brown oil (17 g, 100%). 1H NMR (CDCl3, 400 MHz) δ 4.27-4.18 (m, 4 H); 3.55-3.44 (m, 4 H); 2.65 (m, 4 H); 1.49 (s, 9 H) and 1.32-1.26 (m, 6 H).

Provenance & Evidence