Electro-induced C-H/S-H cross-coupling for the functionalization/macrocyclization of cysteine-containing peptides

Herein, an electro-induced umpolung approach that enables the efficient functionalization/macrocyclization of cysteine-containing peptides is reported. Notably, this method utilizes simple halogen source and takes metal-mediated halogen atom transfer as the main pathway to enable the in-situ polarity reversal, highlighting the unique possibilities associated with electrochemical activation methods. Under simple and mild conditions, cysteine residue can be well-labelled with high chemo-selectivity and excellent conversion. This transformation can tolerate a wide range of valuable enamines, azoles, and peptides partners, and can also be utilized as a macrocyclization tactic for cyclic peptide synthesis and other areas. In comparison to the well-developed electrochemical transformations of thiophenols, the electrochemical modification of peptides and proteins through cysteine remains rather underdeveloped. Here the authors report an electro-induced umpolung approach that enables the efficient functionalization/macrocyclization of cysteine-containing peptides.