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 (258 mg), triphenylphosphine (472 mg) and triethylamine (502 μl) in dichloromethane (7.7 ml) cooled to 0° C. was added carbon tetrabromide (596 mg). The reaction mixture was stirred at room temperature for 2.5 hours and cooled to 4° C. Then, thereto were added triethylamine (279 μl) and benzyl chloroformate (267 μl), and the mixture was stirred for 40 minutes. To the mixture was added water, and the mixture was extracted with ethyl acetate. The separated organic layer was sequentially washed with saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=20/1 to 2/1) to give the titled compound (85 mg).

Provenance & Evidence