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Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes
Published on: September 8, 2013
Photocatalytic Controlled Halodefluorination of Perfluoroalkyl Compounds Using N-Arylphenothiazines
Michael G J Doyle1, Maria Elgaard Jespersen1, Shana Noureen1
1Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom.
Journal of the American Chemical Society
|July 2, 2026
Summary
New photocatalysts enable selective C-F bond breaking in fluorochemicals. This research offers a precise method for monodefluorination, advancing the functionalization of challenging per- and polyfluoroalkyl substances (PFAS).
Area of Science:
- Organic Chemistry
- Photochemistry
- Fluorine Chemistry
Background:
- Per- and polyfluoroalkyl substances (PFAS) present significant environmental challenges due to the strength of the carbon-fluorine (C-F) bond.
- Complete degradation of PFAS is achievable, but selective C-F bond activation, specifically monodefluorination, remains a synthetic hurdle.
Purpose of the Study:
- To develop a method for site-selective monodefluorination of perfluoroalkyl compounds.
- To explore the utility of N-arylphenothiazine photocatalysts in C-F bond functionalization.
- To elucidate the mechanism of photocatalytic halodefluorination.
Main Methods:
- Utilized N-arylphenothiazine photocatalysts with simple halide salts.
- Employed single- or multiwavelength irradiation.
- Conducted mechanistic studies to support a consecutive photoinduced electron transfer (conPET) manifold.
Main Results:
- Achieved controlled halodefluorination of perfluoroalkyl compounds.
- Demonstrated high fidelity in net halogen metathesis.
- Identified N-arylphenothiazine photocatalysts as potent excited-state reductants and oxidants.
Conclusions:
- N-arylphenothiazine photocatalysts enable precise, site-selective monodefluorination of perfluoroalkyl compounds.
- The conPET mechanism highlights the redox versatility of these photosensitizers.
- This work contributes novel methods for functionalizing strong C-F bonds in polyfluorinated molecules.
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