A new generation of terminal copper nitrenes and their application in aromatic C–H amination reactions
In the project A1 microgels functionalized with molecular copper bis(pyrazolyl)methane complexes were synthesized and the catalytic activity was shown by the oxidation of different benzyl alcohols to the corresponding benzaldehydes. These copper loaded microgels are an interesting platform and for future application more challenging copper catalyzed reactions were investigated in this work. Therefore, the aziridination of styrene derivatives and the C─H amination reaction catalyzed by copper bis(pyrazolyl)methane complexes were performed. For both reactions good yields were achieved and challenging substrates, like benzene or cyclohexane, could be converted. The central intermediates of these reactions are copper nitrene complexes. The copper nitrene complexes could be stabilized at low temperature and analyzed with different spectrometric methods and with DFT calculations. It could be shown that the ligand design has a huge influence on the stability and reactivity of the copper nitrene complexes. Furthermore, the mechanism of the aziridination was investigated experimentally and theoretically.
Fabian Thomas, Matthias Oster, Florian Schön, Kai C. Göbgen, Benedikt Amarouch, Dominik Steden, Alexander Hoffmann and Sonja Herres-Pawlis
DOI Paper: 10.1039/D1DT00832C
DOI Cover: 10.1039/D1DT90082J