Design of the peptide C-terminus protecting group and application for the peptide fragment coupling reaction

Herein, the design and synthesis of the C-terminus protecting groups of peptides and application for peptide fragment coupling reaction are described. We prepared iv-Wang handle (1) and 5 analogs (2-6), and each peptide-handle was synthesized by Fmoc-solid phase peptide synthesis. Additionally, the fragment coupling reactions between the protected peptides and the peptide-handles were performed to afforded the corresponding peptides (20, 23, 25 and 27). This strategy is beneficial for the synthesis of protected peptides with long sequences.