Review Study of Chiral N-Heterocyclic Carbene (NHC) Ligands in Stereoselective Metal-Catalyzed Reduction Reactions


  • Mohamed A. B. Mostafa Chemistry Department, Science Faculty, Tobruk University, Tobruk, Libya



N-Heterocyclic Carbene, Asymmetric Catalysis, Stereoselective Hydrogenation of olefins, Stereoselective Hydrosilylation of olefins, Transfer Hydrogenation of ketones,


Stereoselective metal-catalyzed reactions using N-heterocyclic carbene (NHC) ligands have shown significant recent advances, due to the ability of NHC ligands as strong σ-donor species to coordinate with a wide variety of transition metals. Therefore, the design of new ligands and the subsequent strategies for their synthesis enables new applications of their metal complexes in catalysis to be investigated. This study focuses on the applications of different classes of Ir-, Pd-, Au- and Rh-NHC ligand complexes as promising catalysts in the asymmetric hydrogenation, hydrosilylation and transfer hydrogenation reactions.


César, V., Bellemin-Laponnaz, S., & Gade, L. H. (2004). Chiral N-heterocyclic carbenes as stereodirecting ligands in asymmetric catalysis. Chemical Society Reviews, 33(9), 619-636.

Arduengo, A. J., Harlow, R. L., & Kline, M. (1991). A stable crystalline carbene. Journal of the American Chemical Society, 113(1), 361-363.

Clavier, H., Coutable, L., Toupet, L., Guillemin, J.-C., & Mauduit, M. (2005). Design and synthesis of new bidentate alkoxy-NHC ligands for enantioselective copper-catalyzed conjugate addition. Journal of Organometallic Chemistry, 690(23), 5237-5254.

Perry, M. C., & Burgess, K. (2003). Chiral N-heterocyclic carbene-transition metal complexes in asymmetric catalysis. Tetrahedron: Asymmetry, 14(8), 951-961.

Lightfoot, A., Schnider, P., & Pfaltz, A. (1998). Enantioselective Hydrogenation of Olefins with Iridium-Phosphanodihydrooxazole Catalysts. Angew Chem Int Ed Engl, 37(20), 2897-2899.<2897::AID-ANIE2897>3.0.CO;2-8

Gade, L. H., & Bellemin-Laponnaz, S. (2007). Mixed oxazoline-carbenes as stereodirecting ligands for asymmetric catalysis. Coordination Chemistry Reviews, 251(5), 718-725.

Normand, A. T., & Cavell, K. J. (2008). Donor-Functionalised N-Heterocyclic Carbene Complexes of Group 9 and 10 Metals in Catalysis: Trends and Directions. European Journal of Inorganic Chemistry, 2008(18), 2781-2800.

Källström, K., & Andersson, P. G. (2006). Asymmetric hydrogenation of tri-substituted alkenes with Ir-NHC-thiazole complexes. Tetrahedron Letters, 47(42), 7477-7480.

Focken, T., Raabe, G., & Bolm, C. (2004). Synthesis of iridium complexes with new planar chiral chelating phosphinyl-imidazolylidene ligands and their application in asymmetric hydrogenation. Tetrahedron: Asymmetry, 15(11), 1693-1706.

Passays, J., Ayad, T., Ratovelomanana-Vidal, V., Gaumont, A.-C., Jubault, P., & Leclerc, E. (2011). Synthesis and evaluation of a broad range of new chiral phosphine–carbene ligands for asymmetric hydrogenation. Tetrahedron: Asymmetry, 22(5), 562-574.

Arnanz, A., González-Arellano, C., Juan, A., Villaverde, G., Corma, A., Iglesias, M., & Sánchez, F. (2010). New chiral ligands bearing two N-heterocyclic carbene moieties at a dioxolane backbone. Gold, palladium and rhodium complexes as enantioselective catalysts. Chemical Communications, 46(17), 3001-3003.

Kuang, Y., Sun, X., Chen, H., Liu, P., & Jiang, R. (2009). A novel planar chiral N-heterocyclic carbene–oxazoline ligand for the asymmetric hydrosilylation of ketones. Catalysis Communications, 10(11), 1493-1496.

Malkov, A. V., Stewart-Liddon, A. J. P., Teplý, F., Kobr, L., Muir, K. W., Haigh, D., & Kočovský, P. (2008). New pinene-derived pyridines as bidentate chiral ligands. Tetrahedron, 64(18), 4011-4025.

Song, H., Liu, Y., Fan, D., & Zi, G. (2011). Synthesis, structure, and catalytic activity of rhodium complexes with new chiral binaphthyl-based NHC-ligands. Journal of Organometallic Chemistry, 696(23), 3714-3720.

Liu, L.-j., Wang, F., & Shi, M. (2009). Synthesis of Chiral Bis(N-heterocyclic carbene) Palladium and Rhodium Complexes with 1,1′-Biphenyl Scaffold and Their Application in Asymmetric Catalysis. Organometallics, 28(15), 4416-4420.

Duan, W.-L., Shi, M., & Rong, G.-B. (2003). Synthesis of novel axially chiral Rh–NHC complexes derived from BINAM and application in the enantioselective hydrosilylation of methyl ketones. Chemical Communications, (23), 2916-2917.

Song, C., Ma, C., Ma, Y., Feng, W., Ma, S., Chai, Q., & Andrus, M. B. (2005). Bis-paracyclophane N-heterocyclic carbene–ruthenium catalyzed asymmetric ketone hydrosilylation. Tetrahedron Letters, 46(18), 3241-3244.

César, V., Bellemin-Laponnaz, S., Wadepohl, H., & Gade, L. H. (2005). Designing the “Search Pathway” in the Development of a New Class of Highly Efficient Stereoselective Hydrosilylation Catalysts. Chemistry – A European Journal, 11(9), 2862-2873.

Swamy P, C. A., Varenikov, A., & Ruiter, G. d. (2020). Chiral Imidazo[1,5-a]pyridine–Oxazolines: A Versatile Family of NHC Ligands for the Highly Enantioselective Hydrosilylation of Ketones. Organometallics, 39(2), 247-257.

Jiang, R., Sun, X., He, W., Chen, H., & Kuang, Y. (2009). Asymmetric transfer hydrogenation catalyzed by a novel planar chiral N-heterocyclic carbene–rhodium(I) complex. Applied Organometallic Chemistry, 23(5), 179-182.

Chiyojima, H., & Sakaguchi, S. (2011). Iridium complex bearing a chiral hydroxy-amide functionalized N-heterocyclic carbene: a catalyst precursor for asymmetric transfer hydrogenation. Tetrahedron Letters, 52(50), 6788-6791.

Seo, H., Kim, B. Y., Lee, J. H., Park, H.-J., Son, S. U., & Chung, Y. K. (2003). Synthesis of Chiral Ferrocenyl Imidazolium Salts and Their Rhodium(I) and Iridium(I) Complexes. Organometallics, 22(23), 4783-4791.

Hodgson, R., & Douthwaite, R. E. (2005). Synthesis and asymmetric catalytic application of chiral imidazolium–phosphines derived from (1R,2R)-trans-diaminocyclohexane. Journal of Organometallic Chemistry, 690(24), 5822-5831.

Dyson, G., Frison, J.-C., Whitwood, A. C., & Douthwaite, R. E. (2009). Synthesis of rhodium(I) and iridium(I) complexes of chiral N-heterocyclic carbenes and their application to asymmetric transfer hydrogenation. Dalton Transactions, (35), 7141-7151. doi:10.1039/B909290K.

Diez, C., & Nagel, U. (2010). Chiral iridium(I) bis(NHC) complexes as catalysts for asymmetric transfer hydrogenation. Applied Organometallic Chemistry, 24(7), 509-516.

Aupoix, A., Bournaud, C., & Vè Thanh, G. (2011). Asymmetric Transfer Hydrogenation of Aromatic Ketones Using Rhodium Complexes of Chiral N Heterocyclic Carbenes Derived from (S) Pyroglutamic Acid. European Journal of Organic Chemistry, 2011, 2772-2776.

Yoshida, K., Kamimura, T., Kuwabara, H., & Yanagisawa, A. (2015). Chiral bicyclic NHC/Ir complexes for catalytic asymmetric transfer hydrogenation of ketones. Chemical Communications, 51(84), 15442-15445.




How to Cite

Mostafa, M. A. B. (2022). Review Study of Chiral N-Heterocyclic Carbene (NHC) Ligands in Stereoselective Metal-Catalyzed Reduction Reactions. Scientific Journal for Faculty of Science-Sirte University, 2(1), 116–125.