Trifluoromethanesulfonic anhydride → 4-Nitrobenzyl (5R,6S)-2-(4-dimethylaminocarbonylphenyl)-6-((1R)-1-hydroxyethyl)-1-carbapen-2-em-3-carboxylate

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Reaction Steps

Under a nitrogen atmosphere, to a solution of 128 mg (0.368 mmol) of 4-nitrobenzyl (3R,5R,6S)-6-((1R)-1-hydroxyethyl) -2-oxo-1-carbapenam-3-carboxylate in acetonitrile (3 ml) was added 0.065 ml (0.37 mmol) of diisopropylethylamine followed by 0.062 ml (0.37 mmol) of trifluoromethanesulfonic anhydride at -45° C., and the mixture was stirred for 30 minutes. To the mixture was added ethyl acetate, and the organic layer was washed with saturated aqueous sodium bicarbonate followed by saturated aqueous sodium chloride. After the extract was dried over anhydrous magnesium sulfate, the solvent was removed. To the crude triflate was added 113 mg (0.83 mmol) of zinc chloride, 5.3 mg (0.0091 mmol) of bis(benzylideneacetone)palladium(0) and 4.4 mg (0.019 mmol) of tri(2-furyl)phosphine. Under a nitrogen atmosphere, to the mixture was added a solution of 191 mg (0.4436 mmol) of (4-dimethylaminocarbonylphenyl)tri-n-butyltin in N-methylpyrrolidinone (6 ml), and the mixture was stirred for 2 hours at room temperature. To the reaction mixture was added ethyl acetate, and the organic layer was washed with water (50 ml×2) followed by saturated aqueous sodium chloride. After the extract was dried over anhydrous magnesium sulfate, the solvent was removed. The residue was purified by silica gel column chromatography (elution with 3% methanol-chloroform) to give 9.lmg (yield: 27.9%) of the title compound.

Provenance & Evidence