Macrocyclization strategies for cyclic peptides and peptidomimetics

Peptides are a growing therapeutic class due to their unique spatial characteristics that can target traditionally undruggable protein-protein interactions and surfaces. Despite their advantages, peptides must overcome several key shortcomings to be considered as drug leads, including their high conformational flexibility and susceptibility to proteolytic cleavage. As a general approach for overcoming these challenges, macrocyclization of a linear peptide can usually improve these characteristics. Their synthetic accessibility makes peptide macrocycles very attractive, though traditional synthetic methods for macrocyclization can be challenging for peptides, especially for head-to-tail cyclization. This review provides an updated summary of the available macrocyclization chemistries, such as traditional lactam formation, azide-alkyne cycloadditions, ring-closing metathesis as well as unconventional cyclization reactions, and it is structured according to the obtained functional groups. Keeping peptide chemistry and screening in mind, the focus is given to reactions applicable in solution, on solid supports, and compatible with contemporary screening methods.

Automated summary

Peptides are increasingly used as a therapeutic class due to their unique spatial characteristics which can target difficult-to-drug protein-protein interactions and surfaces. Despite their advantages, peptides face challenges such as high conformational flexibility and susceptibility to proteolytic cleavage. Macrocycle formation from linear peptides can help overcome these challenges and improve their characteristics.