Heteroscorpionate ligands of the bis(pyrazolyl)methane family have been applied in the stabilisation of terminal copper tosyl nitrenes. These species are highly active intermediates in the copper-catalysed direct C-H amination and nitrene transfer. Novel perfluoroalkyl-pyrazolyl- and pyridinyl-containing ligands were synthesized to coordinate to a reactive copper nitrene centre. Four distinct copper tosyl nitrenes were prepared at low temperatures by the reaction with SO tBuPhINTs and copper(I) acetonitrile complexes. Their stoichiometric reactivity has been elucidated regarding the imination of phosphines and the aziridination of styrenes. The formation and thermal decay of the copper nitrenes were investigated by UV/Vis spectroscopy of the highly coloured species. Additionally, the compounds were studied by cryo-UHR-ESI mass spectrometry and DFT calculations. In addition, a mild catalytic procedure has been developed where the copper nitrene precursors enable the C-H amination of cyclohexane and toluene and the aziridination of styrenes.
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http://dx.doi.org/10.1002/anie.201713171 | DOI Listing |
Chemistry
January 2025
Shihezi University, School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, North 4th Road, 832003, Shihezi, CHINA.
An N,N,N-type Cu(Ⅱ) complex-catalyzed desaturation method for converting alcohols, ketones, lactones, and lactams to their α,β-unsaturated carbonyl compounds is reported. The dehydrogenation reaction can be conducted with a green terminal oxidant O2 without requiring strong acid/base or stoichiometric oxidants. The Cu(Ⅱ) complex/TEMPO/O2 system uses a non-noble catalyst, and a green terminal oxidant as well as demonstrates high activity and functional group tolerance.
View Article and Find Full Text PDFBiomolecules
December 2024
LABRMN, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico.
Cataracts are diseases characterized by the opacity of the ocular lens and the subsequent deterioration of vision. Metal ions are one of the factors that have been reported to induce crystallin aggregation. For HγS crystallin, several equivalent ratios of Cu(II) promote protein aggregation.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Institut für Chemie, Technische Universität Chemnitz, Straße der Nationen 62, 09111 Chemnitz, Germany.
We present a bifunctional catalyst consisting of a copper(I)/N-heterocyclic carbene and an organocatalytic guanidine moiety that enables, for the first time, a copper(I)-catalyzed reduction of amides with H as the terminal reducing agent. The guanidine allows for reactivity tuning of the originally weakly nucleophilic copper(I) hydrides - formed in situ - to be able to react with difficult-to-reduce amides. Additionally, the guanidine moiety is key for the selective recognition of "privileged" amides based on simple and readily available heterocycles in the presence of other amides within one molecule, giving rise to hitherto unknown site-selective catalytic amide hydrogenation.
View Article and Find Full Text PDFJ Org Chem
January 2025
National Engineering Research Center of Pesticide, College of Chemistry, Nankai University, Tianjin 300071, China.
This study introduces a novel methodology for the direct construction of tetrasubstituted centers, utilizing secondary C(sp)-H and C(sp)-H substrates, specifically indolin-2-ones and indoles, through an innovative oxidative cross-coupling reaction. Facilitated by a straightforward copper salt catalyst, this reaction proceeds efficiently at a mild temperature of 40 °C under operationally streamlined conditions. Emphasizing sustainability, this method is notably enhanced by employing air (molecular oxygen) as an eco-friendly oxidant.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid and Interface and Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences, Center for Carbon Neutral Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Adiponitrile (ADN) has wide applications, especially in the polymer industry. With the substantial and increasing global demand for ADN, effective production of ADN using safe and abundant starting materials is highly desirable but very challenging. Herein, we discovered that CuBr, combined with 1,10-phenanthroline (phen), could effectively promote the ammoxidation reaction of cyclohexanone to ADN with a yield of >99% using aqueous ammonia as the nitrogen source and O as the terminal oxidant under mild reaction conditions (80 °C, 5 atm O).
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