Intermolecular C-H alkylation of simple arenes in the presence of an iron catalyst has been achieved in a cascade manner with an aminative cyclization triggered by N-O bond cleavage of an alkene-tethered oxime ester. Various arenes, including electron-rich and electron-poor arenes, and heteroarenes can be employed in the reaction system. Regioselectivity and radical trapping experiments support the involvement of alkyl radical species, which undergo a homolytic aromatic substitution (HAS) to afford the arylation products.
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http://dx.doi.org/10.1002/asia.201701634 | DOI Listing |
Org Biomol Chem
November 2024
State Key Laboratory of Chemical Resource Engineering, Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China.
The thermal and acid-catalyzed rearrangement mechanisms of -methyl--nitroanilines were theoretically investigated density functional theory (DFT) calculations for all possible proposed mechanisms. The results indicate that the thermal rearrangement of -methyl--nitroanilines undergoes a radical pair complex mechanism through the homolysis of their N-N bond to generate a radical pair complex and the recombination of the radical pairs followed by aromatization. For the acid-catalyzed rearrangements, -methyl--nitroanilines are first protonated on the nitrogen atom of their aniline moiety and then generate protonated -methyl--nitroso--phenylhydroxylamines through a three-membered spirocyclic oxadiaziridine transition state.
View Article and Find Full Text PDFBioresour Technol
October 2024
Bioenergy and Environment Science & Technology Laboratory, College of Engineering, China Agricultural University, Beijing 100107, PR China; Department of Power Supply and Renewable Energy Sources, National Research University TIIAME, 39 Kari Niyazov, 100000 Tashkent, Uzbekistan.
The utilization of biomass pyrolysis is a crucial approach for sustainable development. This study used the typical biomass of pine (PI), rice husk (RH), and corn straw (ST) as feedstocks to evaluate the pyrolysis mechanisms, features and conversion mechanisms of the phenol tar product. The phenolic gaseous products were more trailing in ST, which mostly concentrated around 320-500 °C.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Weijin Rd. 94, Tianjin, 300071, China.
7-Aminoindoles are important synthetic intermediates to a broad range of bioactive molecules. Transition metal-catalyzed directed C-H amination is among the most straightforward route for their synthesis, whereas methods that could directly incorporate an NH group in a highly selective manner remains elusive. Moreover, there is still high demand for the development of earth-abundant metal catalysis for such attractive reactivity.
View Article and Find Full Text PDFJ Am Chem Soc
July 2024
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China.
Metal radicals have shown versatile reactivity in modern synthetic chemistry. However, the use of zinc radicals for molecular synthesis has been barely explored. Here, we show that a transient zinc radical can be formed through photoactivation of a zinc-zinc bonded compound, which is able to mediate the selective dimerization of alkenes and allenes.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Institut Català d'Investigació Química (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans 16, 43007, Tarragona, España.
Dichloromethane, as a readily available and inexpensive C synthon is proposed as a powerful building block for cyclopropanation of alkenes under mild conditions. Herein, we report a highly efficient and versatile dual photoredox system, involving a nickel aminopyridine coordination complex and a photocatalyst, for the cyclopropanation of aromatic olefins using dichloromethane, under visible-light irradiation. The cyclopropanation protocol has been successfully applied at gram scale.
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