Synthesis of Cyclic (α2β)-Tripeptides as Potential Peptide Turn Mimetics

The solid-supported synthesis followed by cyclization in solution of cyclic (α2β)-tripeptides, potential peptide β-turn mimetics, is described. The cyclization takes advantage of facilitating the rotation between trans- and cis-rotamers of two amide bonds. The method is amenable to combinatorial approaches as is illustrated by the synthesis of a small array of cyclic (α2β)-tripeptides.