Preparation and conformational analysis of C-glycosyl β2- and β/β2-peptides

Ten C-glycosyl beta(2)- and beta/beta(2)-peptides with three to eight amino acid residues have been prepared. Solution and solid-phase peptide syntheses were employed to assemble beta(2)-amino acids in which C-glycosylic substituents are attached to the C-2 position of beta-amino acids. Conformational analysis of the C-glycosyl beta(2)-peptides using NMR and CD spectra indicates that the tripeptide can form a helical secondary structure. Besides, helix directions of the C-glycosyl beta/beta(2)-peptides are governed by the configuration at the carbon of the peptide backbone that originates from the stereocenter of the C-glycosyl beta(2)-amino acids. (C) 2009 Elsevier Ltd. All rights reserved.