Synthetic Diversity from a Versatile and Radical Nitrating Reagent |
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Authors: | Kun Zhang Dr Benson Jelier Alessandro Passera Prof Dr Gunnar Jeschke Dr Dmitry Katayev |
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Institution: | 1. Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
These authors contributed equally to this work.;2. Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland |
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Abstract: | We leverage the slow liberation of nitrogen dioxide from a newly discovered, inexpensive succinimide-derived reagent to allow for the C−H diversification of alkenes and alkynes. Beyond furnishing a library of aryl β-nitroalkenes, this reagent provides unparalleled access to β-nitrohydrins and β-nitroethers. Detailed mechanistic studies strongly suggest that a mesolytic N−N bond fragmentation liberates a nitryl radical. Using in situ photo-sensitized, electron paramagnetic resonance spectroscopy, we observed direct evidence of a nitryl radical in solution by nitrone spin-trapping. To further exhibit versatility of N-nitrosuccinimide under photoredox conditions, the late-stage diversification of an extensive number of C−H partners to prepare isoxazolines and isoxazoles is presented. This approach allows for the formation of an in situ nitrile oxide from a ketone partner, the presence of which is detected by the formation of the corresponding furoxan when conducted in the absence of a dipolarophile. This 1,3-dipolar cycloaddition with nitrile oxides and alkenes or alkynes proceeds in a single-operational step using a mild, regioselective, and general protocol with broad chemoselectivity. |
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Keywords: | alkenes C−H nitration photoredox radicals reaction mechanisms |
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