Ammonium Chloride → Benzyl 4-hydroxy-4-methylpiperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Benzyl(4-oxopiperidin-1-yl)carboxylate (4.7 g, 20 mmol) was dissolved in tetrahydrofuran (200 ml); methyllithium-diethylether solution (9.0 ml (1.02 M)+11.6 ml (1.14 M), total 22 mmol) was added dropwise thereto (internal temperature: −60° C. or below) while stirred at −78° C. under nitrogen atmosphere; and then the reaction mixture was stirred for 1.5 hours as it stands. On the other hand, a similar reaction was performed by using piperidin-4-one-1-carboxylate (1.1 g, 5.0 mmol) in another container. After the saturated aqueous solution of ammonium chloride was added to each reaction mixture, the two reaction mixtures were mixed. Extraction was performed with ethyl acetate, washed with brine, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and purified by silica gel column chromatography (Fuji Silysia BW-300, hexane-ethyl acetate system) to yield the title compound (4.5 g, 18 mmol, 73%) as colorless crystals.

Provenance & Evidence