| Abstract
| - N-Heterocyclic carbenes (NHCs) are valuable ligands in transition metal catalysis, due to their uniqueelectronic properties. However, only a few routes toward unsymmetrically substituted, saturated NHCsare known. We have successfully applied the multicomponent synthesis of 2H-2-imidazolines for thepreparation of a range of diversely substituted imidazolidin-2-ylidene complexes under mild conditions.In the desired NHC precursors the substituents at N-1, N-3, C-4, and C-5 were varied easily andindependently by choosing the appropriate amine, aldehyde, isocyanide, or halide as starting material.Subsequent formation of the imidazolium salts followed by deprotonation with KOtBu and directcomplexation of the in situ-generated NHCs at room temperature affords Rh− and Ir−NHC complexes.Properties of the resulting complexes were studied with 13C NMR spectroscopy and X-ray crystallography.
- A multicomponent synthesis of 2-imidazolines has been successfully applied for the generation of unprecedented types of NHC complexes of rhodium and iridium. The substituents on all positions of the NHC ligand can be varied easily. The resulting complexes have been studied using NMR and X-ray crystallography.
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