1-Formyl-3-bromodibenzofuran (I) was converted to oxime (II) by reaction with hydroxylamine.HCl in pyridine-ethanol. Dehydration of oxime (II) to nitrile (III) was accomplished by treatment with trifluoromethanesulfonic anhydride and triethylamine. Subsequent reaction of (III) with hexamethylditin in the presence of palladium catalyst produced the trimethylstannane (IV). Addition of methyl-chloroaluminum amide (V) to the cyano group of (IV) then furnished the amidinium chloride (VI). The known 2-oxocarbapenam (VII) was converted to enol triflate by treatment with trifluoromethanesulfonic anhydride and diisopropyl ethylamine and subsequently protected as the trimethylsilyl ether (VIII) with trimethylsilyl triflate. Coupling of vinyl triflate (VIII) with stannane (VI) employing Pd2(dba)3.CHCl3 as the catalyst produced the dibenzofuranyl carbapenem (IX). Then, acid hydrolysis of the silyl group of (IX), followed by hydrogenolysis of the p-nitrobenzyl ester gave the title compound.

1-Formyl-3-bromodibenzofuran (I) was converted to oxime (II) by reaction with hydroxylamine.HCl in pyridine-ethanol. Dehydration of oxime (II) to nitrile (III) was accomplished by treatment with trifluoromethanesulfonic anhydride and triethylamine. Subsequent reaction of (III) with hexamethylditin in the presence of palladium catalyst produced the trimethylstannane (IV). Addition of methyl-chloroaluminum amide (V) to the cyano group of (IV) then furnished the amidinium chloride (VI). The known 2-oxocarbapenam (VII) was converted to enol triflate by treatment with trifluoromethanesulfonic anhydride and diisopropyl ethylamine and subsequently protected as the trimethylsilyl ether (VIII) with trimethylsilyl triflate. Coupling of vinyl triflate (VIII) with stannane (VI) employing Pd2(dba)3.CHCl3 as the catalyst produced the dibenzofuranyl carbapenem (IX). Then, acid hydrolysis of the silyl group of (IX), followed by hydrogenolysis of the p-nitrobenzyl ester gave the title compound.