Event

Abstract 

Organometallic catalysis is the cornerstone of sustainable fine-chemical transformations, but we are currently exploiting only a small part of its full potential. Our understanding and application of organometallic catalysis is predominantly based on closed-shell two-electron reactivity, and consequently traditional synthetic catalysis is primarily based on diamagnetic organometallic complexes undergoing a limited number of elementary steps. A whole new area of open-shell catalysis largely still needs to be explored, which offers fascinating possibilities to steer and control radical-type single-electron transformations. Understanding such reactions aids in the development of entirely new synthetic protocols using sustainable base metal catalysts instead of noble metals. Furthermore, open-shell reactions play a key role in electro-catalysis and photoredox catalysis. Our group is devoted to developing this field.  

In this presentation we focus on C-C & C-N bond formation reactions proceeding via “substrate radical” intermediates that are capable of C-H bond activation.  

Activation of carbene and nitrene precursors by planar, low-spin cobalt(II) complexes leads to formation of so-called carbene or nitrene radical intermediates.1These are intrinsically reactive metal-bound carbon or nitrogen centered radicals, useful for catalytic synthesis of a variety of ring compounds and other useful organic building blocks. These reactions have in common that they all proceed via selective radical-type transformations and single-electron elementary steps uncommon in traditional organometallic chemistry. The reactive radical-type intermediates are useful in organic synthesis, and mediate a variety of one-pot catalytic transformation leading to among others 2H-chromenes,2 indenes, piperidines,3 dihydronaphtalenes,4a butadienes4a, dibenzocyclooctenes.4b,4c and 1H-2-benzoxocins.

REFERENCES

1. (a) Dzik, W.I; Reek, J.N; de Bruin, B., Chem. Eur. J. 2008, 14, 7594. (b) Dzik, W.I.; Xu, X.; Zhang, X.P.; Reek, J.N.H.; de Bruin, B.; J. Am. Chem. Soc. 2010, 132, 10891. (c) Goswami, M.; Zhang, X.P, de Bruin, B., et al. J. Am. Chem. Soc., 2015, 137, 5468. (d) Epping, R.F.J; Hoeksma, M.M.; Bobylev, E.O.; Mathew, S.; de Bruin, B. Nature Chemistry 2022, 14, 550.
2. Paul, N.D.; Mandal, S. Otte, M. Cui. X. Zhang, X.P.; de Bruin, B., J. Am. Chem. Soc. 2014, 136, 1090.
3. (a) Das, B.G.; Chirila, A.; Tromp, M.; Reek, J.N.H; de Bruin, B., J. Am. Chem. Soc. 2016, 138, 8968. (b) Lankelma, M.; Olivares, A.M; de Bruin, B. Chem. Eur. J. 2019, 25, 5658 .
4. a) te Grotenhuis, C.; Das, B.G.; de Bruin, B. et al., Chemical Science 2017, 8, 8221. b) te Grotenhuis, C.; de Bruin, B. et al., Angew. Chem. Int. Ed. 2018, 57, 140. c) M. Zhou, B. de Bruin, et al., Angew. Chem. Int. Ed. 2020, 59, 11073. d) Zhou, M.; de Bruin, B. et al.J. Am. Chem. Soc. 2021, 143, 20501.

Research

Research aims at understanding and developing (new) homogeneous catalytic reactions. Catalytic topics include late transition metal catalyzed olefin (ep)oxidation, hydrogenation, cyclopropanation and other carbene transfer reactions, aziridination and carbene polymerisation reactions. The group currently focuses at the development of new catalysts, preferably based on abundant first-row transition metals. Detailed insights are gathered through a combination of synthetic modelling, DFT calculations, EPR and NMR spectroscopy, applied catalysis and kinetic investigations.  Experimental results are combined with DFT calculations, not only to obtain deeper insights in the intimate mechanisms but also to search for new transition-state analogies among reactions. Such TS analogies are used to disclose new possibilities for novel catalytic reactions, which are further explored in target-oriented test reactions. The use of unconventional ligands (e.g. redox active and cooperative ligands) and metals in unconventional oxidation states is further used to uncover new reactivity. The group works (amongst others) on the following research topics:

https://www.uva.nl/en/profile/b/r/b.debruin/b.debruin.html

HOST:TOMSON