Mn-Mediated Electrochemical Trifluoromethylation/C(sp2)–H Functionalization Cascade for the Synthesis of Azaheterocycles

A general electrohemical strategy for the combined trifluoromethylation/C(sp2)–H functionalization using Langlois' reagent as the CF3 source under oxidant-free conditions was developed. Using Mn salts as the redox mediator, this method provides an efficient and sustainable means to access a variety of functionalized heterocycles bearing a CF3 moiety. Detailed mechanistic studies are consistent with the formation of CF3-bound high oxidation state Mn species, suggesting a transition-metal-mediated CF3 transfer mechanism for this trifluoromethylation/C(sp2)–H functionalization process.