Carbanionic and ylidic reagents
Carbanionic compounds such as organolithium or Grignard reagents are important organometallic reagents and commonly used in organic synthesis such as for difficult metalation reactions or the formation of C-C bonds. Due to the strongly polarized metal-carbon bond and the resulting high negative charge at the carbon atom, these s-block metal reagents are usually highly reactive and sensitive towards air and moisture. Nonetheless, owing to their unique reactivity, they are indispensable for chemical synthesis including large scale processes.
We are designing carbanionic compounds to open-up new applications and to access new types of reagents. Ongoing research endeavors focus fir example on the synthesis of metalated ylides, ketenyl anions and the application of highly stabilized carbanions.
Selected publications:
F. Krischer, V. S. V. S. Swamy, K.-S. Feichtner, R. J. Ward, V. H. Gessner*
The Cyanoketene Anion [NC3O]-
ChemRxiv preprint: DOI: 10.26434/chemrxiv-2024-gjvnc
F. Krischer, M. Jörges, T.-F. Leung, H. Darmandeh, V. H. Gessner*
Selectivity Control of the Ligand Exchange at Carbon in α-Metallated Ylides as Route to Ketenyl Anions
Angew. Chem. Int. Ed. 2023, 62, e202309629. (https://doi.org/10.1002/anie.202309629)
M. Jörges+, F. Krischer+, V. H. Gessner*
Transition metal-free ketene formation from carbon monoxide through isolable ketenyl anions.
Science 2022, 378, 1331-1336. (DOI: 10.1126/science.ade4563).
C. Schwarz, L. T. Scharf, T. Scherpf, J. Weismann, V. H. Gessner*
Isolation of the Metalated Ylide [Ph3P-C-CN]M (M = Li, Na, K): Influence of the Metal Ion on the Structure and Bonding Situation
Chem. Eur. J. 2019, 25, 2793-2802 ( https://doi.org/10.1002/chem.201805421)
J.-A. Zur+, M. Schmidt+, K.-S. Feichtner, P. Duari, J. Löffler, T. Scherpf, V. H. Gessner*
From Stable PH-Ylides to α-Carbanionic Phosphines as Ligands for Zwitterionic Catalysts
Angew. Chem. Int. Ed. 2022, e202203950. https://doi.org/10.1002/anie.202203950