“Amino Acids as Stable Radical Precursors for C–H Functionalizations”
By: Professor Ryan Baxter
University of California, Merced
Hosted By: Dr. Alexander “Leggy” Arnold

Abstract

Due to their terrestrial abundance and structural variety, amino acids are ideal source material for initiating radical chain reactions. While the inclusion of amino acids into molecular scaffolds via peptide coupling is well-known, direct incorporation of amino acids or their sidechains into synthetic targets via C–C bond formation is less common. We have recently developed a mild method for the radical acylation or alkylation of aromatic heterocycles using unprotected amino acids as stable radical precursors. In addition, radical hydrogen-atom transfer (HAT) initiated by amino acid decomposition can be utilized to promote fluorination of activated C–H bonds. Mechanistic studies suggest that amino acids modulate the oxidation potential of silver catalysts through dative interactions, allowing for fluorination under mildly oxidizing conditions. Additional radical C–H functionalizations inspired by mechanistic investigations will also be discussed.