Synthesis and conformational study of homo-peptides based on ( S)-Bin, a C2-symmetric binaphthyl-derived C α,α-disubstituted glycine with only axial chirality

Abstract

We synthesised the [( S)-Bin] n ( n=2–5) homo-peptides by solution methods. Only the acid fluoride derivative Fmoc-( S)-Bin-F could be efficiently coupled with H-[( S)-Bin] n -OMe ( n=2–4). Spectroscopic experimental analyses of the [( S)-Bin] n homo-peptides in solution performed by CD, FT-IR absorption, and VCD, supported by VCD calculations, confirmed the ( S) configuration of the Bin residues and identified the most largely populated secondary structures as right-handed β-turns which eventually evolve to 3 10-helices in the highest oligomers.