Dokument: β‐Lactam Ylidenes: An Overlooked Class of N‐Heterocyclic Carbenes
| Titel: | β‐Lactam Ylidenes: An Overlooked Class of N‐Heterocyclic Carbenes | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=69975 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20250624-121501-4 | |||||||
| Kollektion: | Publikationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Texte » Artikel, Aufsatz | |||||||
| Medientyp: | Text | |||||||
| Autoren: | Karl, Leonard [Autor] Deißenbeck, Daniel [Autor] Meisner, Jan [Autor] Ganter, Christian [Autor] | |||||||
| Dateien: |
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| Stichwörter: | β-lactams, DFT calcula- tions, N-heterocyclic carbene | |||||||
| Beschreibung: | In this study, the underappreciated class of β-lactam carbenes (BLCs) is revisited and systematically explored. The required precursors are available in a highly modular synthetic approach from simple starting materials. Two routes may be followed for the generation of the free BLCs: thermal fragmentation of spiro-fused oxadiazoles (110 °C, toluene), or deprotonation of carbene HCl-adducts at −80 °C with a strong base. TEP values (2065–2072 cm−1), 77Se NMR shifts of selenium-adducts (812–995 ppm), as well as DFT calculations reveal moderate σ-donor and strong π-acceptor character of BLCs, leading to a pronounced ambiphilic reactivity. The formation of a wide variety of products under thermal conditions in the cause of oxadiazole fragmentation (110 °C, toluene) is rationalized by a combination of computational reaction discovery and experimental validation. Products include olefinic dimers as well as unprecedented N2-bridged dimers arising from bimolecular reactions, while sterically more demanding precursors are converted in a monomolecular fragmentation reaction via CO release to form ketenimines as intermediates, which finally form amides. With substituents providing appropriate steric protection, a persistent BLC is available via the low temperature route, characterized by its 13C NMR shift of 287 ppm at −20°C. | |||||||
| Rechtliche Vermerke: | Originalveröffentlichung:
Karl, L., Deißenbeck, D., Meisner, J., & Ganter, C. (2025). β‐Lactam Ylidenes: An Overlooked Class of N‐Heterocyclic Carbenes. Chemistry - a European Journal, 31(31), Article e202501320. https://doi.org/10.1002/chem.202501320 | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät | |||||||
| Dokument erstellt am: | 24.06.2025 | |||||||
| Dateien geändert am: | 24.06.2025 |
