858643-92-2

Methylmagnesium bromide (1.4 M toluene/THF 75/25, 268 mL) was slowly added dropwise to a solution of 1-Boc-N-methoxy-N-methylpiperidine-3-carboxamide (59 g, 0.22 mol) in tetrahydrofuran (THF, 250 mL) at 0 °C and protected by nitrogen, and the temperature of the reaction was controlled not to exceed 15 °C. After dropwise addition, the reaction mixture was stirred at room temperature for 1 hour. Subsequently, the reaction mixture was slowly poured into an ice-water mixture containing 100 mL of ice-acetic acid. The product was extracted with ether (Et2O) and the organic layer was washed with 5% sodium bicarbonate (NaHCO3) solution. The organic layer was dried over anhydrous magnesium sulfate (MgSO4), filtered and concentrated under reduced pressure to give tert-butyl 3-acetylpiperidine-1-carboxylate (50 g, quantitative yield).

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