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Mao X, Lu Z, Zhang J, Xie Z. Catalyst-Free Regioselective Diborylation of Aryllithium with Tetra(o-tolyl)diborane(4). Angew Chem Int Ed Engl 2024; 63:e202317614. [PMID: 38123525 DOI: 10.1002/anie.202317614] [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: 11/19/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 12/23/2023]
Abstract
A catalyst-free 1,2-diborylation of aryllithium with tetra(o-tolyl)diborane(4) has been achieved, giving a series of 1,2-diborylaryl lithium species in excellent yields under mild reaction conditions, which leads to 1,2-di(tolyl)borylarenes in 60-91 % yields upon treatment with the hydride-abstracting reagent. In these transformations, one sp2 C-H of arene is activated and both boryl units are utilized to build two new (sp2 )C-B bonds. This represents a new strategy for selective arene diborylation. Density functional theory (DFT) calculations suggest that an aromatic nucleophilic substitution is a key step in the formation of the products.
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Affiliation(s)
- Xiaofeng Mao
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
| | - Zhenpin Lu
- Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - Jie Zhang
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
| | - Zuowei Xie
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
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2
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Pradhan AN, Bairagi S, Ghosh S. Diborane and Triborane Species in the Coordination Sphere of Group-8 Transition Metals. Inorg Chem 2023; 62:14790-14803. [PMID: 37624926 DOI: 10.1021/acs.inorgchem.3c02286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
The synthesis and structural elucidation of a series of ruthenium diborane and triborane compounds are described. Treatment of [Cp*Ru(PPh3)2Cl] (1) (Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl; PPh3 = triphenylphosphine) with [BH3·THF] (THF = tetrahydrofuran) at 60 °C led to the formation of the hydrogen-rich ruthena-octahydrotetraborane arachno-[2-{Cp*Ru(PPh3)B3H8}] (2). The chemistry of 2 is explored with [Fe2(CO)9] at room temperature, which resulted in the formation of a metal-stabilized triborane species, [{Cp*Ru(PPh3)}(μ3-η1:η2:η2-B3H6){Fe2(CO)7}] (3). Compound 3 can be considered as a triborane analogue [B3H6]3- that stabilizes in the coordination sphere of two iron and one ruthenium atoms. Further, the photolysis of nido-[1,2-(Cp*Ru)2(μ-H)2(B3H7)] (4) with [M(CO)5·THF] (M = Mo and W) afforded an arachno-[1,2-(Cp*Ru)(Cp*RuCO)(μ-H)(B3H8)] (5), in which the [M(CO)5·THF] acted as a CO source. In an attempt to convert arachno-5 into a closo or nido species, we have pyrolyzed arachno-5 in toluene at 90 °C for 20 h that afforded nido-[2,3-(Cp*Ru)2(μ-CO)(μ3-H)(B3H6)] (6) having two ruthenium atoms at the basal position. Irradiation of arachno-5 with an intermediate generated from CS2 and [LiBH4·THF] in THF afforded the diborane(5) species [(Cp*RuCO)(Cp*Ru)(μ-H)(μ-η1:η2-B2H4)(CS2H)] (7) in which a dithioformato ligand (SHC═S) is attached to one Ru-B bond. Compound 7 can be considered as a diborane(5) species, which is stabilized by a dithioformato ligand. All the synthesized compounds have been characterized by employing electrospray ionization-mass spectrometry, multinuclear NMR, and IR spectroscopy techniques. The single-crystal X-ray diffraction studies of compounds 2, 3, 6, and 7 helped to establish the structural integrity of these compounds. Further, density functional theory studies were performed to provide insight into the bonding of these metal-stabilized diborane and triborane species.
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Affiliation(s)
- Alaka Nanda Pradhan
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Subhash Bairagi
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sundargopal Ghosh
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
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3
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Millet CRP, Pahl J, Noone E, Yuan K, Nichol GS, Uzelac M, Ingleson MJ. Synthesis of Electrophiles Derived from Dimeric Aminoboranes and Assessing Their Utility in the Borylation of π Nucleophiles. Organometallics 2022; 41:2638-2647. [PMID: 36185396 PMCID: PMC9516688 DOI: 10.1021/acs.organomet.2c00393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Indexed: 11/30/2022]
Abstract
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Dimeric aminoboranes,
[H2BNR2]2 (R = Me or CH2CH2) containing B2N2 cores, can
be activated by I2, HNTf2 (NTf2 =
[N(SO2CF3)2]), or [Ph3C][B(C6F5)4] to form isolable H2B(μ-NR2)2BHX (for X = I or NTf2). For X = [B(C6F5)4]− further reactivity, presumably
between [H2B(μ-NMe2)2BH][B(C6F5)4] and aminoborane, forms a B3N3-based monocation containing a three-center two
electron B-(μ-H)-B moiety. The structures of H2B(μ-NMe2)2BH(I) and [(μ-NMe2)BH(NTf2)]2 indicated a sterically crowded environment
around boron, and this leads to the less common O-bound mode of NTf2 binding. While the iodide congener reacted very slowly with
alkynes, the NTf2 analogues were more reactive, with hydroboration
of internal alkynes forming (vinyl)2BNR2 species
and R2NBH(NTf2) as the major products. Further
studies indicated that the B2N2 core is maintained
during the first hydroboration, and that it is during subsequent steps
that B2N2 dissociation occurs. In the mono-boron
systems, for example, iPr2NBH(NTf2), NTf2 is N-bound; thus, they have less steric
crowding around boron relative to the B2N2 systems.
Notably, the monoboron systems are much less reactive in alkyne hydroboration
than the B2N2-based bis-boranes, despite the
former being three coordinate at boron while the latter are four coordinate
at boron. Finally, these B2N2 electrophiles
are much more prone to dissociate into mono-borane species than pyrazabole
[H2B(μ-N2C3H3)]2 analogues, making them less useful for the directed diborylation
of a single substrate.
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Affiliation(s)
| | - Jürgen Pahl
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Emily Noone
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Kang Yuan
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Gary S. Nichol
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Marina Uzelac
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
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4
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Mohapatra S, Gayen S, Bag R, Das A, Ramalakshmi R, Cordier M, Ghosh S. Structures and Bonding of Early Transition Metallaborane Clusters. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stutee Mohapatra
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sourav Gayen
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Ranjit Bag
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Arpita Das
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Rongala Ramalakshmi
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Marie Cordier
- Univ Rennes, CNRS, Institut des Sciences Chimiques de Rennes, UMR 6226, F-35000 Rennes, France
| | - Sundargopal Ghosh
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
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5
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Trageser T, Bebej D, Bolte M, Lerner HW, Wagner M. B-B vs. B-H Bond Activation in a (μ-Hydrido)diborane(4) Anion upon Cycloaddition with CO 2 , Isocyanates, or Carbodiimides. Angew Chem Int Ed Engl 2021; 60:13500-13506. [PMID: 33740318 PMCID: PMC8252796 DOI: 10.1002/anie.202103427] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Indexed: 11/11/2022]
Abstract
The intriguing (μ‐hydrido)diboranes(4) with their prominent pristine representative [B2H5]− have mainly been studied theoretically. We now describe the behavior of the planarized tetraaryl (μ‐hydrido)diborane(4) anion [1H]− in cycloaddition reactions with the homologous series of heterocumulenes CO2, iPrNCO, and iPrNCNiPr. We show that a C=O bond of CO2 selectively activates the B−B bond of [1H]−, while the μ‐H ligand is left untouched ([2H]−). The carbodiimide iPrNCNiPr, in contrast, neglects the B−B bond and rather adds the B‐bonded H− ion to its central C atom to generate a formamidinate bridge across the B2 pair ([3]−). As a hybrid, the isocyanate iPrNCO combines the reactivity patterns of both its congeners and gives two products: one of them ([4H]−) is related to [2H]−, the other ([5]−) is an analog of [3]−. We finally propose a mechanistic scenario that rationalizes the individual reaction outcomes and combines them to a coherent picture of B–B vs. B–H bond activation.
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Affiliation(s)
- Timo Trageser
- Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany
| | - Dariusz Bebej
- Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany
| | - Michael Bolte
- Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany
| | - Hans-Wolfram Lerner
- Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany
| | - Matthias Wagner
- Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany
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6
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Trageser T, Bebej D, Bolte M, Lerner H, Wagner M. B–B vs. B–H Bond Activation in a (μ‐Hydrido)diborane(4) Anion upon Cycloaddition with CO
2
, Isocyanates, or Carbodiimides. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103427] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Timo Trageser
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Dariusz Bebej
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Michael Bolte
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Hans‐Wolfram Lerner
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Matthias Wagner
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
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7
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Schmidt U, Werner L, Arrowsmith M, Deissenberger A, Hermann A, Hofmann A, Ullrich S, Mattock JD, Vargas A, Braunschweig H. trans-Selective Insertional Dihydroboration of a cis-Diborene: Synthesis of Linear sp 3 -sp 2 -sp 3 -Triboranes and Subsequent Cationization. Angew Chem Int Ed Engl 2020; 59:325-329. [PMID: 31621993 PMCID: PMC6972689 DOI: 10.1002/anie.201911645] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Indexed: 12/11/2022]
Abstract
The reaction of aryl- and amino(dihydro)boranes with dibora[2]ferrocenophane 1 leads to the formation 1,3-trans-dihydrotriboranes by formal hydrogenation and insertion of a borylene unit into the B=B bond. The aryltriborane derivatives undergo reversible photoisomerization to the cis-1,2-μ-H-3-hydrotriboranes, while hydride abstraction affords cationic triboranes, which represent the first doubly base-stabilized B3 H4 + analogues.
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Affiliation(s)
- Uwe Schmidt
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Wüzburg, Am Hubland, 97074, Würzburg, Germany
| | - Luis Werner
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Wüzburg, Am Hubland, 97074, Würzburg, Germany
| | - Merle Arrowsmith
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Wüzburg, Am Hubland, 97074, Würzburg, Germany
| | - Andrea Deissenberger
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Wüzburg, Am Hubland, 97074, Würzburg, Germany
| | - Alexander Hermann
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Wüzburg, Am Hubland, 97074, Würzburg, Germany
| | - Alexander Hofmann
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Wüzburg, Am Hubland, 97074, Würzburg, Germany
| | - Stefan Ullrich
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Wüzburg, Am Hubland, 97074, Würzburg, Germany
| | - James D Mattock
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton, BN1 9QJ, Sussex, UK
| | - Alfredo Vargas
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton, BN1 9QJ, Sussex, UK
| | - Holger Braunschweig
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Wüzburg, Am Hubland, 97074, Würzburg, Germany
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