Development of Ferrocene-Based Planar Chiral Imidazopyridinium Salts for Catalysis
| Autor: | Christopher T. Check, C. Benjamin Schwamb, Karl A. Scheidt, David N. Barsoum, Ki Po Jang, Keegan P. Fitzpatrick |
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| Rok vydání: | 2020 |
| Předmět: |
Steric effects
Imidazopyridine 010405 organic chemistry Organic Chemistry Enantioselective synthesis Planar chirality 010402 general chemistry 01 natural sciences 0104 chemical sciences Catalysis Inorganic Chemistry chemistry.chemical_compound chemistry Ferrocene Computational chemistry Organocatalysis Physical and Theoretical Chemistry Metallocene |
| Zdroj: | Organometallics. 39:2705-2712 |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/acs.organomet.0c00312 |
| Popis: | Imidazol-2-ylidenes and their N,N′-diaryl derivatives constitute an important class of N-heterocyclic carbenes (NHCs) which possess a unique level of versatility in both organocatalysis and transition-metal catalysis. However, there remain few examples of carbenes of this type that are chiral. Here we describe the development of a family of closely related imidazopyridine-based NHCs that derive their asymmetry purely from planar chirality through the incorporation of the classic metallocene framework. An NMR analysis of 77Se complexes of this family is used to assess their degrees of σ donicity and π acidity in comparison to a larger family of NHCs. Percent buried volume (%Vbur) calculations were performed to measure the steric bulk of this distinct class of NHCs. Additionally, these NHCs were employed in various enantioselective transformations to survey their use as organocatalysts as well as ligands for transition-metal-catalyzed processes. |
| Databáze: | OpenAIRE |
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