The discovery and synthesis of the arylcarbapenem 2b possessing potent activity against highly resistant strains of m_ethicillin resistant staphylococci are disclosed.Recently, we reported on the in vitro antimicrobial activity of quatemary ammoniomethyl-phenylcarbapenems, such as 1, which were shown to be potent, broad spectrum antibacterial agents with stability toward mammalian dehydropeptidase. 1 In an attempt to further improve upon the activity profile and pharmacokinetics of 1, we focused on increasing serum protein binding by increasing the overall lipophilicity of the molecule, and thus initially targeted the biphenyl variants 2. Of the three possible biphenyl arrays, we opted to synthesize the more readily accessible para and meta dispositions utilizing the chemistry previously developed for the construction of the related carbapenems 1.The synthesis of molecules 2 is outlined in the Scheme in which the key doubly protected 2-pyridylthioesterazetidinone synthon 3, prepared by a modification of the route detailed by Guthikonda, 2 underwent Grignard reaction with the magnesium reagents derived from either 4'-dimethyl-t-butylsilyloxymethyl-4-bromobiphenyl (4a) or the 3-bromobiphenyl isomer 4b in THF solution at -10oc for 0.5 hour to afford adducts 5a,b. 3 Desilylation of the TBDMS group was accomplished with a 10% H2SO4 methanolic solution at ambient temperature for one hour to give alcohols 6a,b, which then underwent intramolecular Wittig reaction in refluxing p-xylene during the course of one hour to provide the requisite, doubly protected carbapenem biphenylcarbinols 7a,b. Activation of the benzylic position by conversion of the hydroxyl group to the more reactive iodide was accomplished in a straight forward manner as previously described. 1 Displacement reactions of the iodides were performed in acetonitrile at ambient temperature with 4-N,Ndimethylaminopyridine and 2-aminopyridine, respectively, to generate the pyridinium salts ga,b. As previously detailed, 1 the removal of the two allyl derived protecting groups was simultaneously accomplished by the method of McCombie and Jeffrey 4 to provide the target class 2.