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Synthetic Diversity from a Versatile and Radical Nitrating Reagent
Author(s) -
Zhang Kun,
Jelier Benson,
Passera Alessandro,
Jeschke Gunnar,
Katayev Dmitry
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201902966
Subject(s) - chemistry , nitrile , nitrone , chemoselectivity , reagent , cycloaddition , regioselectivity , combinatorial chemistry , photochemistry , bond cleavage , ketone , organic chemistry , catalysis
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.