Difluoro Carbenes: From Genuine Gold Complexes to Unprecedented Metallacyclic Reactivity
David Vesseur1, Shuo Li1, Nina Albouy2
1Université de Toulouse, CNRS, Laboratoire Hetérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 Route de Narbonne, Toulouse, 31062 Cedex 09, France.
Angewandte Chemie (International Ed. in English)
|September 18, 2025
Summary
Researchers developed stable gold(I) difluorocarbenes that react with alkenes and dienes. This breakthrough enables new difluorocyclopentene synthesis via a novel gold-mediated pathway, overcoming previous limitations in carbene chemistry.
Area of Science:
- Organic Chemistry
- Organometallic Chemistry
- Catalysis
Background:
- Difluorocarbene is a potent synthetic tool in organic chemistry.
- Controlling difluorocarbene reactivity is challenging.
- Previous transition metal catalysts (Pd, Cu) were limited to classical transformations.
Purpose of the Study:
- To develop novel gold complexes for stabilizing difluorocarbene.
- To explore the reactivity of these gold-difluorocarbene complexes.
- To achieve challenging cycloaddition reactions for difluorinated compound synthesis.
Main Methods:
- Synthesis of gold(I) difluorocarbene complexes.
- Ligand design to enhance backdonation and stabilize the carbene.
- Spectroscopic and crystallographic characterization of gold(III) intermediates.
- Investigation of reactivity with alkenes and 1,3-dienes under thermal and photochemical conditions.
Main Results:
- Gold(I) difluorocarbenes were stabilized for hours at 0 °C.
- Novel reactivity with alkenes and 1,3-dienes was observed.
- Gold(III) metallacycle intermediates were characterized.
- Ligand choice and conditions directed C─C coupling.
- Difluorocyclopentenes were synthesized via a gold-mediated two-electron redox pathway.
Conclusions:
- Ligand-enhanced backdonation stabilizes gold difluorocarbenes.
- Gold-mediated difluorocarbene chemistry offers new synthetic routes.
- This method overcomes challenges in [1+4] cycloadditions with dienes.
- The developed methodology enables the synthesis of valuable difluorinated compounds.
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