MODEL STUDIES ON THE SYNTHESIS OF CARBOXYLATE-BINDING POCKET ANALOGS OF VANCOMYCIN USING ARENE RUTHENIUM CHEMISTRY

Preparation of several protected (D)-chlorophenylalanine derivatives in high optical purity and their complex formation with the [RuCp]+ moiety are described. The complexation reaction, as well as subsequent photochemical decomplexations, proceeds with retention of optical purity. Reactions of these chloroarene complexes with 3-hydroxyphenylglycine derivatives proceed under mild conditions to give aryl ether-ruthenium complexes, which can be converted to diaryl ethers in which both aromatic rings have protected amino acid or peptide side chains. Efforts to effect cycloamidation to give vancomycin carboxylate-binding pocket analogues, using a number of known coupling reagents, were unsuccessful.