Two birds with one stone! An intramolecular traceless Staudinger ligation was employed to synthesize cyclic peptides. The final amide bond formation was induced by deprotection of the azidopeptide phosphinothioesters. Treatment with trifluoroacetic acid (TFA) results in the simultaneous removal of the borane along with the protecting groups on the peptide side chains, and chemoselective amide bond cyclization ensues.

Teraryl-based α-helix mimetics have proven to be useful compounds for the inhibition of protein-protein interactions (PPI). We have developed a modular and flexible approach for the synthesis of teraryl-based α-helix mimetics. Central to our strategy is the use of a benzene core unit featuring two leaving groups of differentiated reactivity in the Pd-catalyzed cross-coupling used for terphenyl assembly. With the halogen/diazonium route and the halogen/triflate route, two strategies have successfully been established. The synthesis of core building blocks with aliphatic (Ala, Val, Leu, Ile), aromatic (Phe), polar (Cys, Lys), hydrophilic (Ser, Gln), and acidic (Glu) amino acid side chains are reported.

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Zwei Fliegen mit einer Klappe! Eine intramolekulare spurlose Staudinger‐Ligation wurde für die Synthese cyclischer Peptide entwickelt. Die abschließende Amidbildung wird durch Entschützung des Azido‐Peptid‐Phosphanylthioesters ermöglicht. Unter Trifluoressigsäure(TFA)‐Bedingungen werden alle Schutzgruppen gleichzeitig entfernt, sodass eine chemoselektive Amidbildung eingeleitet werden kann.