Generation of boryl-nitroxide radicals from a boraalkene via the nitroso ene reaction
Chaohuang Chen1, Constantin G Daniliuc1, Sina Klabunde2
1Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany erker@uni-muenster.de.
Abstract:
Examples 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.
More Related Videos
Related Concept Videos
Hydroboration-Oxidation of Alkenes
Nitrosation of Enols
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
Radical Reactivity: Nucleophilic Radicals
Radical Substitution: Allylic Bromination


