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Publisher: Weinheim : Wiley-VCH × Subject: amines × WGL Institute: LIKAT ×

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Now showing 1 - 3 of 3
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    Practical Catalytic Cleavage of C(sp3)−C(sp3) Bonds in Amines
    (Weinheim : Wiley-VCH, 2019) Li, Wu; Liu, Weiping; Leonard, David K.; Rabeah, Jabor; Junge, Kathrin; Brgckner, Angelika; Beller, Matthias
    The selective cleavage of thermodynamically stable C(sp3)−C(sp3) single bonds is rare compared to their ubiquitous formation. Herein, we describe a general methodology for such transformations using homogeneous copper-based catalysts in the presence of air. The utility of this novel methodology is demonstrated for Cα−Cβ bond scission in >70 amines with excellent functional group tolerance. This transformation establishes tertiary amines as a general synthon for amides and provides valuable possibilities for their scalable functionalization in, for example, natural products and bioactive molecules. © 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.
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    Selective Acceptorless Dehydrogenation of Primary Amines to Imines by Core-Shell Cobalt Nanoparticles
    (Weinheim : Wiley-VCH, 2020) Cui, Xinjiang; Li, Wu; Junge, Kathrin; Fei, Zhaofu; Beller, Matthias; Dyson, Paul J.
    Core–shell nanocatalysts are attractive due to their versatility and stability. Here, we describe cobalt nanoparticles encapsulated within graphitic shells prepared via the pyrolysis of a cationic poly-ionic liquid (PIL) with a cobalt(II) chloride anion. The resulting material has a core–shell structure that displays excellent activity and selectivity in the self-dehydrogenation and hetero-dehydrogenation of primary amines to their corresponding imines. Furthermore, the catalyst exhibits excellent activity in the synthesis of secondary imines from substrates with various reducible functional groups (C=C, C≡C and C≡N) and amino acid derivatives. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.
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    Supported CuII Single-Ion Catalyst for Total Carbon Utilization of C2 and C3 Biomass-Based Platform Molecules in the N-Formylation of Amines
    (Weinheim : Wiley-VCH, 2021) Dai, Xingchao; Wang, Xinzhi; Rabeah, Jabor; Kreyenschulte, Carsten; Brückner, Angelika; Shi, Feng
    The shift from fossil carbon sources to renewable ones is vital for developing sustainable chemical processes to produce valuable chemicals. In this work, value-added formamides were synthesized in good yields by the reaction of amines with C2 and C3 biomass-based platform molecules such as glycolic acid, 1,3-dihydroxyacetone and glyceraldehyde. These feedstocks were selectively converted by catalysts based on Cu-containing zeolite 5A through the in situ formation of carbonyl-containing intermediates. To the best of our knowledge, this is the first example in which all the carbon atoms in biomass-based feedstocks could be amidated to produce formamide. Combined catalyst characterization results revealed preferably single CuII sites on the surface of Cu/5A, some of which form small clusters, but without direct linking via oxygen bridges. By combining the results of electron paramagnetic resonance (EPR) spin-trapping, operando attenuated total reflection (ATR) IR spectroscopy and control experiments, it was found that the formation of formamides might involve a HCOOH-like intermediate and .NHPh radicals, in which the selective formation of .OOH radicals might play a key role. © 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH