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Author: Beller, Matthias × End date: 2022 × Start date: 2022 × End date: 2024 × Start date: 2020 × DDC: 660 × Type: Article ×

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    Aerobic iron-catalyzed site-selective C(sp3)–C(sp3) bond cleavage in N-heterocycles
    (Amsterdam : Elsevier, 2021) Leonard, David K.; Li, Wu; Rockstroh, Nils; Junge, Kathrin; Beller, Matthias
    The kinetic and thermodynamic stability of C(sp3)–C(sp3) bonds makes the site-selective activation of these motifs a real synthetic challenge. In view of this, herein a site-selective method of C(sp3)–C(sp3) bond scission of amines, specifically morpholine and piperazine derivatives, using a cheap iron catalyst and air as a sustainable oxidant is reported. Furthermore, a statistical design of experiments (DoE) is used to evaluate multiple reaction parameters thereby allowing for the rapid development of a catalytic process. © 2021
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    Ruthenium-Catalyzed Deuteration of Aromatic Carbonyl Compounds with a Catalytic Transient Directing Group
    (Weinheim : Wiley-VCH, 2021) Kopf, Sara; Ye, Fei; Neumann, Helfried; Beller, Matthias
    A novel ruthenium-catalyzed C−H activation methodology for hydrogen isotope exchange of aromatic carbonyl compounds is presented. In the presence of catalytic amounts of specific amine additives, a transient directing group is formed in situ, which directs selective deuteration. A high degree of deuteration is achieved for α-carbonyl and aromatic ortho-positions. In addition, appropriate choice of conditions allows for exclusive labeling of the α-carbonyl position while a procedure for the preparation of merely ortho-deuterated compounds is also reported. This methodology proceeds with good functional group tolerance and can be also applied for deuteration of pharmaceutical drugs. Mechanistic studies reveal a kinetic isotope effect of 2.2, showing that the C−H activation is likely the rate-determining step of the catalytic cycle. Using deuterium oxide as a cheap and convenient source of deuterium, the methodology presents a cost-efficient alternative to state-of-the-art iridium-catalyzed procedures. © 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH