Fmoc-aza-beta(3)-Lys-OAllyl and Fmoc-aza-beta(3)-Asp-OAllyl for on-resin head-to-tail cyclization of aza-beta(3)-peptides

A rapid and efficient Fmoc/t-Bu solid-phase peptide synthesis (SPPS) of cyclic aza-beta(3)-peptide analogs by allyl strategy is described. Our synthetic approach includes the synthesis of two new aza-beta(3)-amino acids, Fmoc-aza-beta(3)-Lys-OAllyl and Fmoc-aza-beta(3)-Asp-OAllyl, then the resin attachment of the first aza-beta(3)-amino acid via its side chain, successful use of combination of three orthogonal removable protecting groups, stepwise solid-phase synthesis of linear peptide analog, and on-resin head-to-tail cyclization. (C) 2012 Elsevier Ltd. All rights reserved.