Dual-role iron species in photoelectrocatalytic radical trifluoromethylation with trifluoroacetates

Abstract

Abstract Trifluoromethylation remains a fundamental transformation in drug discovery, underpinning many top-selling pharmaceuticals. Emerging developments in iron ligand-to-metal charge transfer (LMCT) catalysis have redefined fluoroalkylation chemistry by unlocking the repurposing of readily available trifluoroacetates as radical trifluoromethyl sources. Recent (hetero)arene trifluoromethylation methods generally require stoichiometric inorganic oxidants to turnover photoactive iron catalysts, thereby limiting their broader applicability. Herein, we present an integrated photoelectrocatalytic strategy employing in situ-generated multifunctional iron species to achieve C(sp²)–H trifluoromethylation without stoichiometric oxidants and generating only traceless byproducts. Mechanistic studies identify catalytically active iron species exhibiting a dual synergistic function: promoting the photodecarboxylation of trifluoroacetates and mediating catalytic redox turnover. This protocol offers mild, tunable, and scalable conditions powered by visible light and electric current. It features a broad substrate scope, enabling the functionalization of diverse (hetero)cyclic scaffolds, including challenging electron-rich and easily oxidizable substrates, thus demonstrating its potential for sustainable late-stage modification in pharmaceutical synthesis.