Generation of boryl-nitroxide radicals from a boraalkene via the nitroso ene reaction
2022; Royal Society of Chemistry; Volume: 13; Issue: 36 Linguagem: Inglês
10.1039/d2sc02485c
ISSN2041-6539
AutoresChaohuang Chen, Constantin G. Daniliuc, Sina Klabunde, Michael Ryan Hansen, Gerald Kehr, Gerhard Erker,
Tópico(s)Catalytic C–H Functionalization Methods
ResumoExamples of isolated boron substituted nitroxide radicals are rare. The reaction of the reactive cyclic boraalkene 3 with nitrosobenzene yields a mixture of the [2 + 2] cycloaddition product 4a, the B-nitroxide radicals 5a and 6a and the azoxybenzene co-product 7avia a bora nitroso ene reaction pathway, the boron analogue of the nitroso ene reaction. The products were separated by flash chromatography, and the B-nitroxide radicals were characterized by X-ray diffraction and EPR spectroscopy. Radical 5a was shown to be a hydrogen atom abstractor. Both the B-nitroxide radicals are more easily oxidized compared to e.g. TEMPO, as shown by cyclic voltammetry.
Referência(s)