Helical peptide-foldamers having a chiral five-membered ring amino acid with two azido functional groups.

A chiral five-membered ring α,α-disubstituted α-amino acid (R,R)-Ac5c(dN3) having two azido functional groups has been designed and synthesized. The cyclic amino acid (R,R)-Ac5c(dN3) could be efficiently converted into several cyclic amino acids with various two 1,2,3-triazole functional groups. (R,R)-Ac5c(dN3) homochiral peptides (up to hexapeptide) and (R,R)-Ac5c(dN3)-containing l-Leu-based peptides were prepared, and their conversion of azido functional groups into triazole groups was completed.