A backbone amide linker strategy was chosen for the solidphase synthesis of triazole-containing cyclic tetra-and pentapeptides. An alkyne-substituted linker derived from 4-hydroxy-2-methoxybenzaldehyde was elongated by using standard "Fmoc-based" solid phase chemistry and terminated by coupling of an azido acid. In solution, the peptides were cyclized by a Cu I -catalyzed azide-alkyne cycloaddition reaction. The solid-supported synthesized linear peptides

Our auxiliary-based method for the synthesis of bis(lactams) has been optimized. A novel auxiliary is described that is inserted in the backbone of a linear peptide facilitating the mutually reactive terminal groups to approach one another for a cyclization reaction. A subsequent ring contraction mechanism leads to the bis(lactams) with the remainings of the auxiliary still attached. Functionalized seven-and eight-

Multi-membered N-heterocycles R 0690Improved Auxiliary for the Synthesis of Medium-Sized Bis(lactams). -The novel auxiliary (I) is incorporated into the backbone of linear peptides facilitating the reactive terminal groups to approach one another for intramolecular cyclization. Subsequent ring contraction furnishes medium-sized bis (lactams). -(SPRINGER, J.; JANSEN, T. P.; INGEMANN, S.; HIEMSTRA, H.; VAN MAARSEVEEN*, J. H.; Eur.