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

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 beta-turns which eventually evolve to 3(10)-helices in the highest oligomers