Benzyl chloroformate → 1-Benzyl6-tert-butyl3-methyl-1,6-diazaspiro[3.5]nonane-1,6-dicarboxylate

Participants

Reaction Steps

To a solution of an optically-active compound of 3-amino-3-(2-hydroxy-1-methylethyl)piperidine-1-carboxylic acid tert-butyl ester (12.9 g), triphenylphosphine (20.3 g) and triethylamine (21.6 ml) in dichloromethane (400 ml) cooled to 0° C. was added carbon tetrabromide (25.9 g) in small batches. The reaction mixture was stirred at room temperature for 1 hour, and the mixture was cooled to 4° C. Then, thereto were added triethylamine (10.8 ml) and benzyl chloroformate (10.3 ml), and the mixture was stirred at room temperature for 40 minutes. To the mixture was added 5% aqueous sodium bicarbonate solution (125 ml), and the mixture was extracted with chloroform (125 ml). The separated aqueous layer was extracted with chloroform (125 ml) again. The combined organic layer was washed with water (125 ml), 10% aqueous sodium chloride solution (125 ml), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=1/0 to 7/3) to give the titled compound (12.4 g).

Provenance & Evidence