The Parasram Lab just reported a C(sp3)–H hydroxylation mediated solely by inexpensive, commercially available nitroarenes and visible light. The unique ability of the nitroarene to sequentially perform the HAT step and the oxygen atom transfer step expands the scope of feasible oxidations in this class. The work, entitled “Anaerobic Hydroxylation of C(sp3)–H Bonds Enabled by the Synergistic Nature of Photoexcited Nitroarenes” was published in the Journal of the American Chemical Society. The contributing authors include co-first authors Joshua Paolillo and Alana Duke, co-second authors Emma Gogarnoiu and Dan Wise, and Principal Investigator Assistant Professor Marvin Parasram. Click here to read the full article in JACS.
Abstract: A photoexcited-nitroarene-mediated anaerobic C–H hydroxylation of aliphatic systems is reported. The success of this reaction is due to the bifunctional nature of the photoexcited nitroarene, which serves as the C–H bond activator and the oxygen atom source. Compared to previous methods, this approach is cost- and atom-economical due to the commercial availability of the nitroarene, the sole mediator of the reaction. Because of the anaerobic conditions of the transformation, a noteworthy expansion in substrate scope can be obtained compared to prior reports. Mechanistic studies support that the photoexcited nitroarenes engage in successive hydrogen atom transfer and radical recombination events with hydrocarbons, leading to N-arylhydroxylamine ether intermediates. Spontaneous fragmentation of these intermediates leads to the key oxygen atom transfer products.