Design and synthesis of very strong pi-acceptor ancillary ligands. Applications in Au(I) and Pt(II) catalysis and the synthesis of natural products
Final Report Abstract
Over the past several years and thanks to the research project, we have demonstrated that a-cationic phosphines of different structures can be easily synthesized and effectively employed as ancillary ligands. Due to their strong acceptor properties, these ligands efficiently accept electron density from the metal centers they coordinate and, for this reason, they facilitate catalytic cycles requiring strong Lewis acidity at the metal center during the rate determining step. This has been efficiently exploited in our group in the framework of Au(I) and Pt(II)-catalysis. α-Cationic arsines have also been prepared; they have found to depict even enhanced acceptor properties than these of their lighter analogues. We anticipate that the intensive acceleration effects observed in π-acid catalysis by the use of α-cationic phosphines might have tremendous implications in the area of asymmetric catalysis, where catalysts able to work at lower temperatures are usually required to obtain good enantiomeric excess. The profitable employment of a-cationic phosphines beyond π-acid catalysis is another challenge still remaining in this area. We look forward to addressing both of these in the near future; in fact this is the main topic of the most recent application to the DFG.
Publications
- "Bis- and Tris(pyrazolyl)borate/Methane-Stabilized PIII-Centered Cations." Chem.–Eur. J. 2014, 20, 8575- 8578
L. Gu, G. Gopakumar, P. Gualco, W. Thiel, M Alcarazo
(See online at https://doi.org/10.1002/chem.201402636) - "Synthese, Struktur und Anwendungen von Pyridiniumphosphanen." Angew. Chem. 2014, 126, 8877-8881. "Synthesis, Structure, and Applications of Pyridiniophosphines." Angew. Chem. Int. Ed. 2014, 53, 8732-8736
H. Tinnermann, C. Wille, M. Alcarazo
(See online at https://doi.org/10.1002/ange.201401073) - "α-Cationic Phosphines: Synthesis and Applications." Chem.–Eur. J. 2014, 20, 7868-7877
M. Alcarazo
(See online at https://doi.org/10.1002/chem.201402375) - "Bis[(dialkylamino)cyclopropenimine]-Stabilized PIII- and PV-Centered Dications." Chem.–Eur. J. 2015, 21, 10829-10834
Á. Kozma, J. Rust, M. Alcarazo
(See online at https://doi.org/10.1002/chem.201500688) - "Bis(cyclopropenium)phosphines: Synthesis, Reactivity, and Applications." Chem. Eur. J. 2016, 22, 15320-15327
G. Mehler, P. Linowski, J. Carreras, A. Zanardi, J. W. Dube, M. Alcarazo
(See online at https://doi.org/10.1002/chem.201601759) - "Synthesis and Reactivity of α-Cationic Phosphines: The Effect of Imidazolinium and Amidinium Substituents." Dalton Trans. 2016, 45, 1872-1876
E. Haldón, Á. Kozma, H. Tinnermann, L. Gu, R. Goddard, M. Alcarazo
(See online at https://doi.org/10.1039/C5DT02341F)
