Development of a Tripeptide Mimetic Strategy for the Inhibition of Protein Farnesyltransferase

This paper describes the development of a novel terphenyl-based tripeptide mimetic of the CAAX carboxy terminal sequence of Ras. We employ a concise synthesis to form a series of differently functionalized terphenyl inhibitors of protein farnesyltransferase (PFTase), exemplified by 5, 6 and 7. The key reaction in the synthesis of the terphenyl methyl ester 13, and therefore 6 and 7, was the Pd-catalyzed chemoselective Suzuki cross-coupling of 3-bromo-4-chloronitrobenzene 16 with an appropriate boronic acid derivative utilizing a commercially available, electron rich phosphine ligand. We further show that one member of this series is a potent inhibitor of PFTase.