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Griffin LP, Ellwanger MA, Clark J, Myers WK, Roper AF, Heilmann A, Aldridge S. Bis(Aluminyl)Magnesium: A Source of Nucleophilic or Radical Aluminium-Centred Reactivity. Angew Chem Int Ed Engl 2024; 63:e202405053. [PMID: 38536728 DOI: 10.1002/anie.202405053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Indexed: 04/23/2024]
Abstract
The homoleptic magnesium bis(aluminyl) compound Mg[Al(NON)]2 (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene) can be accessed from K2[Al(NON)]2 and MgI2 and shown to possess a non-linear geometry (∠Al-Mg-Al=164.8(1)°) primarily due to the influence of dispersion interactions. This compound acts a four-electron reservoir in the reductive de-fluorination of SF6, and reacts thermally with polar substrates such as MeI via nucleophilic attack through aluminium, consistent with the QT-AIM charges calculated for the metal centres, and a formal description as a Al(I)-Mg(II)-Al(I) trimetallic. On the other hand, under photolytic activation, the reaction with 1,5-cyclooctadiene leads to the stereo-selective generation of transannular cycloaddition products consistent with radical based chemistry, emphasizing the covalent nature of the Mg-Al bonds and a description as a Al(II)-Mg(0)-Al(II) synthon. Consistently, photolysis of Mg[Al(NON)]2 in hexane in the absence of COD generates [Al(NON)]2 together with magnesium metal.
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Affiliation(s)
- Liam P Griffin
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Mathias A Ellwanger
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Jonathon Clark
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - William K Myers
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Aisling F Roper
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Andreas Heilmann
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Simon Aldridge
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
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Wenzel JO, Werner J, Allgaier A, van Slageren J, Fernández I, Unterreiner AN, Breher F. Visible-Light Activation of Diorganyl Bis(pyridylimino) Isoindolide Aluminum(III) Complexes and Their Organometallic Radical Reactivity. Angew Chem Int Ed Engl 2024; 63:e202402885. [PMID: 38511969 DOI: 10.1002/anie.202402885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 03/22/2024]
Abstract
We report on the synthesis and characterization of a series of (mostly) air-stable diorganyl bis(pyridylimino) isoindolide (BPI) aluminum complexes and their chemistry upon visible-light excitation. The redox non-innocent BPI pincer ligand allows for efficient charge transfer homolytic processes of the title compounds. This makes them a universal platform for the generation of carbon-centered radicals. The photo-induced homolytic cleavage of the Al-C bonds was investigated by means of stationary and transient UV/Vis spectroscopy, spin trapping experiments, as well as EPR and NMR spectroscopy. The experimental findings were supported by quantum chemical calculations. Reactivity studies enabled the utilization of the aluminum complexes as reactants in tin-free Giese-type reactions and carbonyl alkylations under ambient conditions, which both indicated radical-polar crossover behavior. A deeper understanding of the physical fundamentals and photochemical process was provided, furnishing in turn a new strategy to control the reactivity of bench-stable aluminum organometallics.
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Affiliation(s)
- Jonas O Wenzel
- Karlsruhe Institute of Technology (KIT), Institute of Inorganic Chemistry (AOC), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Johannes Werner
- Karlsruhe Institute of Technology (KIT), Institute of Physical Chemistry (IPC), Fritz-Haber-Weg 2, 76131, Karlsruhe, Germany
| | - Alexander Allgaier
- University of Stuttgart, Institute of Physical Chemistry, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Joris van Slageren
- University of Stuttgart, Institute of Physical Chemistry, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Israel Fernández
- Universidad Complutense de Madrid, Facultad de Ciencias Químicas, 28040, Madrid, Spain
| | - Andreas-Neil Unterreiner
- Karlsruhe Institute of Technology (KIT), Institute of Physical Chemistry (IPC), Fritz-Haber-Weg 2, 76131, Karlsruhe, Germany
| | - Frank Breher
- Karlsruhe Institute of Technology (KIT), Institute of Inorganic Chemistry (AOC), Engesserstraße 15, 76131, Karlsruhe, Germany
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Krämer F, Wenzel JO, Fernández I, Breher F. Intramolecular dearomative 1,4-addition of silyl and germyl radicals to a phenyl moiety. Dalton Trans 2024. [PMID: 38284266 DOI: 10.1039/d4dt00089g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
Herein, we present that the radicals [Ph3PC(Me)EMes2]˙ (2Si and 2Ge) can be generated from the α-silylated and α-germylated phosphorus ylides Ph3PC(Me)E(Cl)Mes2 (1Si and 1Ge) through one-electron reduction with Jones' dimer (MesNacNacMg)2 in benzene. Although isolation of the free radicals was not possible, the products of the intramolecular addition of the radicals to a phenyl substituent of the phosphorus moiety, followed by subsequent reaction with 2Si or 2Ge to the isolated species 3Si and 3Ge, respectively, were observed. This transformation witnesses a dearomative 1,4-addition of tetryl radical species to the phenyl scaffold in a stereoselective anti-fashion.
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Affiliation(s)
- Felix Krämer
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131 Karlsruhe, Germany.
| | - Jonas O Wenzel
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131 Karlsruhe, Germany.
| | - Israel Fernández
- Departamento de Química Orgánica I, Facultad de Ciencias Químicas and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Frank Breher
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131 Karlsruhe, Germany.
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Zhu H, Fujimori S, Kostenko A, Inoue S. Dearomatization of C 6 Aromatic Hydrocarbons by Main Group Complexes. Chemistry 2023; 29:e202301973. [PMID: 37535350 DOI: 10.1002/chem.202301973] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/04/2023]
Abstract
The dearomatization reaction is a powerful method for transformation of simple aromatic compounds to unique chemical architectures rapidly in synthetic chemistry. Over the past decades, the chemistry in this field has evolved significantly and various important organic compounds such as crucial bioactive molecules have been synthesized through dearomatization. In general, photochemical conditions or assistance by transition metals are required for dearomatization of rigid arenes. Recently, main-group elements, especially naturally abundant elements in the Earth's crust, have attracted attention as they have low toxicity and are cost-effective compared to the late transition metals. In recent decades, a variety of low-valent main-group molecules, which enable the activation of stable aromatic compounds under mild conditions, have been developed. This minireview highlights the developments in the chemistry of dearomatization of C6 aromatic hydrocarbons by main-group compounds leading to the formation of seven-membered EC6 (E=main-group elements) ring or cycloaddition products.
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Affiliation(s)
- Huaiyuan Zhu
- TUM School of Natural Sciences, Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching bei München, Germany
| | - Shiori Fujimori
- TUM School of Natural Sciences, Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching bei München, Germany
| | - Arseni Kostenko
- TUM School of Natural Sciences, Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching bei München, Germany
| | - Shigeyoshi Inoue
- TUM School of Natural Sciences, Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching bei München, Germany
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