Solid‐phase synthesis of macrocyclic peptides via side‐chain anchoring of the ornithine δ‐amine

Cyclic peptides represent a popular class of macrocyclic drug candidates and therefore their solid phase synthesis has attracted much attention. In this contribution we present an efficient method side-chain anchoring for ornithine lysine residues to be used in the standard Fmoc-based cyclic via on-resin cyclization. We demonstrate that side chain protected with N-Boc-group can efficiently converted isocyanate which is then immobilized on Wang-type resin almost quantitative yield. further show four biologically active employing anchoring. Our at least par previously reported methodologies terms yield purity final products arguably operationally more straightforward.