Control of helicity in C3-symmetric systems by peptide-like β-turns

Cyclic imidazole-containing hexapeptides with three arms bound to the peptide scaffold via the secondary nitrogen atoms of the imidazoles are presented; these arms, together with a part of the macrocycle, form peptide-like β-turns making their helicity predeterminable and allowing the diastereoselective synthesis of Λ-metal complexes.