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Imidazol-2-ylidene-Based NCCN Ligands for Chiral-at-Iron Catalysis
Lukas Hinterlang1, Sergei I Ivlev1, Eric Meggers1
1Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35043 Marburg, Germany.
Organometallics
|June 26, 2026
Summary
Researchers developed new chiral iron catalysts using tetradentate NCCN ligands. These catalysts exhibit high stability and demonstrate significant success in various asymmetric transformations, showcasing metal-centered chirality for efficient synthesis.
Area of Science:
- Organometallic Chemistry
- Asymmetric Catalysis
- Chiral Ligand Design
Background:
- Development of chiral catalysts is crucial for enantioselective synthesis.
- Iron catalysis offers a sustainable alternative to precious metal catalysts.
- Achiral ligands can induce chirality in metal complexes.
Purpose of the Study:
- To report a new class of achiral tetradentate NCCN ligands.
- To investigate the coordination chemistry of these ligands with iron(II).
- To explore the catalytic applications of the resulting chiral iron complexes.
Main Methods:
- Synthesis of achiral tetradentate NCCN ligands with a tetraphenylene linker.
- Coordination of ligands to iron(II) to form complexes with cis-α geometry.
- Resolution of racemic complexes into enantiomers using a chiral auxiliary.
- Evaluation of catalytic activity in asymmetric transformations.
Main Results:
- A new class of achiral tetradentate NCCN ligands was synthesized.
- Coordination to iron(II) induced metal-centered chirality with high configurational stability.
- Racemic complexes were resolved into enantiomers.
- Catalytic applications demonstrated high enantioselectivity in intramolecular Cannizzaro, C-H amidation, and hetero-Diels-Alder reactions.
Conclusions:
- The tetradentate NCCN ligand architecture effectively stabilizes chiral iron catalysts.
- Metal-centered chirality in these complexes enables efficient asymmetric induction.
- These findings offer a versatile platform for developing novel iron-based asymmetric catalysts.
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