In the last few years, Katritzky salts emerged as a potential tool for the synthesis of unnatural amino acids, and late-stage functionalization of peptides. In this review, we summarized the applications of deaminative functionalization in the peptide chemistry field, including cross-coupling, photocatalysis, α-alkylation, and macrocyclization. Moreover, findings confirmed the on-resin feasibility of using Katritzky salts in solid-phase peptide synthesis.
Peptide drug discovery often benefits from the large structural diversity permitted by unnatural amino acids (UAAs). Indeed, numerous approved peptide drugs include UAAs in their sequences. Therefore, innovative chemical approaches either to synthesize UAAs or to allow late-stage functionalization of peptides are emerging themes in peptide drug discovery. Thanks to the recent advances in deaminative strategies using alkylpyridiniums salts, often referred to as Katritzky salts, a variety of radical alkylation methods have been developed. In recent years the use of Katritzky salts have become popular in peptide chemistry due to their ease of preparation from a primary amine, which is a predominant functional group in amino acids. This review highlights the progress that has been made by using Katritzky salts in the synthesis of UAAs, late-stage peptide functionalization, and peptide macrocyclization.Zum Volltext