Triphenylphosphine → p-nitrobenzyl (1R,5S,6S)-2-[1-(4-carboxy-1,3-thiazol-2-yl)azetidin-3-yl]thio-6-[(R)-1-t-butyldimethylsilyloxyethyl]-1-methyl-carbapen-2-em-3-carboxylate

Participants

Reaction Steps

To a solution of p-nitrobenzyl (1R,5S,6S)-2-[1-(4-allyloxycarbonyl-1,3-thiazol-2-yl)azetidin-3-yl]thio-6-[(R)-1-t-butyldimethylsilyloxyethyl]-1-methylcarbapen-2-em-3-carboxylate (3.73 g, 5.2 mmol) (obtained Reference Example 41(6)) in methylene chloride (180 ml) were added dimedone (1.46 g, 10.4 mmol), tetrakis(triphenylphosphine)palladium(0) (603 mg, 0.522 mmol) and triphenylphosphine (205 mg, 0.783 mmol), and the mixture was stirred at room temperature under an atmosphere of nitrogen for 2 hours. After checking the completion of the reaction, the reaction mixture was partitioned between ethyl acetate and saturated aqueous sodium chloride solution. The obtained organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by chromatography on a silica gel column using ethyl acetate:methanol (10:1)→methylene chloride:methanol (10:1) as the eluant to afford p-nitrobenzyl (1R,5S,6S)-2-[1-(4-carboxy-1,3-thiazol-2-yl)azetidin-3-yl]thio-6-[(R)-1-t-butyldimethylsilyloxyethyl]-1-methyl-carbapen-2-em-3-carboxylate (1.91 g, yield 54%) as a pale brown solid.

Provenance & Evidence