Radical-Mediated Acyl Thiol-Ene Reaction for Rapid Synthesis of Biomolecular Thioester Derivatives

The thiol-ene ‘click’ reaction has emerged as a versatile process for carbon–sulfur bond formation with widespread applications in chemical biology, medicinal chemistry and materials science. Thioesters are key intermediates in a wide range of synthetic and biological processes and efficient methods for their synthesis are of considerable interest. Herein, we report the first examples of acyl-thiol-ene (ATE) for the synthesis of biomolecular thioesters, including peptide, lipid and carbohydrate derivatives. A key finding is the profound effect of the amino acid side chain on the outcome of the ATE reaction. Furthermore, radical generated thioesters underwent efficient S-to-N acyl transfer and desulfurisation to furnish ‘sulfur-free’ ligation products in an overall amidation process with diverse applications for chemical ligation and bioconjugation.