4-Nitrobenzyl chloroformate → HCID 56624843, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 2-[(3S,4R)-3-{(1S)-1-hydroxyethyl}-4-methylthio-2-oxoazetidin-1-yl]-3-methylbut-2-enoate (376 mg) and 4-dimethylaminopyridine (336 mg) in dichloromethane (3 ml) was added p-nitrobenzyl chloroformate (358 mg) at -30° C. under a nitrogen atmosphere. After stirring for one hour at 0° C., the mixture was diluted with ethyl acetate and washed with dilute hydrochloric acid, water, a dilute aqueous sodium bicarbonate, and brine. Drying over magnesium sulfate and the removal of the solvent left an oil (635 mg), which was chromatographed on silica gel (25 g) eluting with 10-25% ethyl acetate in hexane to afford methyl 3-methyl-2-[(3S,4R)-4-methylthio-3-{(1S)-1-(p-nitrobenzyloxycarbonyloxy)ethyl}-2-oxoazetidin-1-yl]-but-2-enoate (566 mg) as an oil.

Provenance & Evidence