Evidence for a High-Valent Iron-Fluoride That Mediates Oxidative C(sp3)-H Fluorination

Chakadola Panda; Onyinyechukwuka Anny-Nzekwue; Lorna M Doyle; Robert Gericke; Aidan R McDonald

doi:10.1021/jacsau.3c00021

Evidence for a High-Valent Iron-Fluoride That Mediates Oxidative C(sp³)-H Fluorination

JACS Au. 2023 Mar 3;3(3):919-928. doi: 10.1021/jacsau.3c00021. eCollection 2023 Mar 27.

Authors

Chakadola Panda¹, Onyinyechukwuka Anny-Nzekwue¹, Lorna M Doyle¹, Robert Gericke¹, Aidan R McDonald¹

Affiliation

¹ School of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland.

Abstract

[Fe^II(NCCH₃)(NTB)](OTf)₂ (NTB = tris(2-benzimidazoylmethyl)amine, OTf = trifluoromethanesulfonate) was reacted with difluoro(phenyl)-λ³-iodane (PhIF₂) in the presence of a variety of saturated hydrocarbons, resulting in the oxidative fluorination of the hydrocarbons in moderate-to-good yields. Kinetic and product analysis point towards a hydrogen atom transfer oxidation prior to fluorine radical rebound to form the fluorinated product. The combined evidence supports the formation of a formally Fe^IV(F)₂ oxidant that performs hydrogen atom transfer followed by the formation of a dimeric μ-F-(Fe^III)₂ product that is a plausible fluorine atom transfer rebound reagent. This approach mimics the heme paradigm for hydrocarbon hydroxylation, opening up avenues for oxidative hydrocarbon halogenation.