Synthesis of β,β-Dinaphthyl Amino Acids: Towards Molecular Gearing in Peptides and Mini-Proteins

We report the synthesis of β,β-dinaphthyl amino acids by directed CH-activation and their subsequent utilization in peptides. The synthesis of aromatic β-branched amino acids is limited by sterical crowding for large aromatic ring systems. The amino acids are transformed into adequately protected building blocks for solid-phase peptide synthesis by using our amide weakening strategy. Our aim was to study the interactions of the side chain aryl groups in solution and solid state. Based on quantitative analysis of ¹H NMR reference nuclei, we investigate conformational equilibria and compare them to established gearing systems.