01991nas a2200241   4500008004100000022001400041245009900055210006900154260000800223300001100231490000800242520118300250653001301433653002601446653002401472653002001496653001901516653002201535100001601557700003301573700002001606856012301626       2026                        eng d  a1615-415000aPhotoredox copper catalysis for C3-H Nitroalkylation of Quinoxalinones via Nitroalkyl Radicals0 aPhotoredox copper catalysis for C3H Nitroalkylation of Quinoxali  cJUL  ae706800 v3683 a<p>
	We report a novel copper-catalyzed photocatalytic method for the direct C3-H nitroalkylation of quinoxalin-2(1H)-ones via selective generation of primary alpha-nitroalkyl radicals from simple nitroalkanes. The transformation proceeds under mild conditions at room temperature, uses air as the terminal oxidant, and is without external photocatalyst. A broad range of substituted quinoxalin-2(1H)-ones and unactivated aliphatic nitroalkanes undergo selective C3 functionalization in good to excellent yields, with exclusive C &amp; boxH;H over N &amp; boxH;H alkylation. Mechanistic studies, including radical trapping, UV-visible spectroscopy, EPR, and XPS analysis, support a copper-mediated radical pathway involving ligand exchange, nitronate coordination, and photoinduced ligand-to-metal charge transfer (LMCT) to generate nitroalkyl radicals. Subsequent radical addition and copper-assisted oxidative rearomatization furnish the products while regenerating the active Cu(II) catalyst. The method is operationally simple, scalable, and enables downstream functionalization of the nitro group, providing efficient access to value-added quinoxalinone derivatives.</p>
10aC & boxH10acopper photocatalysis10aH functionalization10anitroalkylation10aquinoxalinones10aradical mechanism1 aDas, Nirmal1 aPansare, Vaibhav, Ramchandra1 aBarsu, Nagaraju  uhttps://library.ncl.res.in/content/photoredox-copper-catalysis-c3-h-nitroalkylation-quinoxalinones-nitroalkyl-radicals