N-Heterocyclic Carbene (NHC) Ligands

NHC (N-heterocyclic carbenes) have evolved to become universal ligands for the rapid synthesis of novel organometallic complexes.¹ In particular, NHC ligands have practical use when bound to metals that display high catalytic activity in related organophosphane metal coordination chemistry.^2-4 Heterocyclic carbenes are a useful class of ligands due to several attractive features, including the following: 1) facile tuning of the electronics and/or sterics of a metal catalyst system; 2) ease of synthetic preparation from conveniently available starting materials; and 3) strong binding to the metal thus creating a highly productive catalyst. We offer a diverse array of NHC ligands that have been successfully applied in reactions ranging from amination⁵ to C–C bond formation⁶ to hydrosilylation.⁷

Product Highlights

• Mediate an incredible breadth of transformations
• Provide robust stability to the metal center
• More active in many reactions than the related phosphine catalysts
• Readily modified to incorporate chirality, immobilization, and water solubility

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References

1. Herrmann W. 2002. Angew. Chem. Int. Ed. Engl. 41, 1290. https://doi.org/10.1002/1521-3773(20020415)41:8%3C1290::AID-ANIE1290%3E3.0.CO;2-Y

2. Herrmann W, et al. 1992. Chem. Ber. 125, 1795.

3. Ofele K, et al. 1993. J. Organomet. Chem. 459, 177.

4. Herrmann W, et al. 1994. J. Organomet. Chem. 480, C7.

5. Stauffer SR, Lee S, Stambuli JP, Hauck SI, Hartwig JF. 2000. High Turnover Number and Rapid, Room-Temperature Amination of Chloroarenes Using Saturated Carbene Ligands. Org. Lett.. 2(10):1423-1426. https://doi.org/10.1021/ol005751k

6. Hadei N, Kantchev EAB, O'Brie CJ, Organ MG. 2005. The First Negishi Cross-Coupling Reaction of Two Alkyl Centers Utilizing a Pd?N-Heterocyclic Carbene (NHC) Catalyst?. Org. Lett.. 7(17):3805-3807. https://doi.org/10.1021/ol0514909

7. Yun J, Kim D, Yun H. 2005. A new alternative to Stryker's reagent in hydrosilylation: synthesis, structure, and reactivity of a well-defined carbene?copper(ii) acetate complex. Chem. Commun..(41):5181. https://doi.org/10.1039/b509964a