An IEDDA reaction of propargyl sulfonium salts and tetrazines: a versatile [4 + 2] modular assembly

Abstract

Propargyl sulfonium salts have been reported as novel electron-rich-olefin precursors that undergo an inverse electron-demand Diels–Alder [4 + 2] reaction with tetrazines. This method enables the rapid and modular assembly of structurally diverse propargyl sulfonium salts and tetrazines, offering significant features such as a short reaction time, excellent efficiency, and mild reaction conditions. Notably, this approach has been further extended to propargyl sulfonium–peptide systems for the site-specific labeling of methionine residues in short peptides and the construction of cyclic peptides.