Via Ugi reactions to conformationally fixed cyclic peptides.

A simple approach to several cyclopeptidmimetics containing an N-alkylated amino acid was found via a multicomponent reaction followed by a ring-closing metathesis starting from readily available precursors. The combinatorial technique has the advantage that different polar, hydrophilic or hydrophobic moieties can be placed at any position in the cycles and unnatural amino acids can also be incorporated.