N-Ethylpiperidine → HCID 57233973, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of (3R,4R)-4-acetoxy-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-2-oxoazetidine (2.90 g) and N-ethylpiperidine (1.35 ml) in dichloromethane (15 ml) was added trimethylsilyl trifluoromethanesulfonate (1.95 ml) at -20° C., and the resulting mixture was stirred at 0° C. for 1 hour (Solution A). To a solution of (2S,4R)-1-allyloxycarbonyl-4-methoxy-2-(2-methyl-3-oxo-1-butenyl)pyrrolidine (2.70 g) and N-ethylpiperidine (1.48 ml) in dichloromethane (50 ml) was added trimethylsilyl trifluoromethanesulfonate (2.93 ml) at -20° C. and the resulting mixture was stirred at 0° C. for 1 hour. To this mixture was added dropwise the above obtained Solution A at 0° C. and the resulting mixture was stirred for another 1 hour at 0° C. The reaction mixture was taken up into a mixture of ethyl acetate (300 ml) and water (300 ml) and the mixture was stirred at ambient temperature for 2 hours. After adjusting pH to around 6.5 with aqueous sodium hydrogen carbonate, the organic layer was separated, washed with brine, dried over magnesium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel (120 ml) eluting with a mixture of n-hexane and ethyl acetate (1:1 V/V) to give (3S,4R)-4-[4-{(2S,4R)-1-allyloxycarbonyl-4-methoxypyrrolidin-2-yl}-3-methyl-2-oxo-3-butenyl]-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-2-oxoazetidine (3.24 g).

Provenance & Evidence