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Heitmann M, Duvinage D, Golz C, Hupf E, Beckmann J, Fischer M. Structural Snapshots on Stepwise Anionic Oxoborane Formation: Access to an Acyclic BO Ketone Analogue and Its Metathesis Chemistry with CO 2 and CS 2. Inorg Chem 2025; 64:3028-3037. [PMID: 39905796 PMCID: PMC11836929 DOI: 10.1021/acs.inorgchem.4c05354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2024] [Revised: 01/08/2025] [Accepted: 01/27/2025] [Indexed: 02/06/2025]
Abstract
In this work, we disclose the synthesis and characterization of non-acid/base-stabilized anionic oxoboranes [MesTer2BO][K(L)] (MesTer = -C6H3-2,6-(2,4,6-Me3-C6H2)2, L = [2.2.2]-cryptand or 18-crown-6), which are isoelectronic and isostructural with aryl-substituted ketones. The stepwise synthetic formation of these ion-separated oxoboranes is demonstrated on the one hand by the treatment of the parent borinic acid MesTer2BOH with N-heterocyclic carbenes (NHCs) to give [MesTer2BO][HNHC] derivatives, and on the other hand by a deprotonation-sequestration sequence. Bearing polarized boron-oxygen moieties, their inherent reactivity toward both carbon disulfide and carbon dioxide reveals a unique π-bond metathesis reactivity to yield [(MesTer)2B-μ-E2C=E][K(L)] (E = O, S) derivatives.
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Affiliation(s)
- Marius Heitmann
- Institut
für Anorganische Chemie, Georg-August-Universität
Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Daniel Duvinage
- Institut
für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Street 7, D-28359 Bremen, Germany
| | - Christopher Golz
- Institut
für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstraße 2, D-37077 Göttingen, Germany
| | - Emanuel Hupf
- Institut
für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Street 7, D-28359 Bremen, Germany
| | - Jens Beckmann
- Institut
für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Street 7, D-28359 Bremen, Germany
| | - Malte Fischer
- Institut
für Anorganische Chemie, Georg-August-Universität
Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany
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2
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Härterich M, Ritschel B, Arrowsmith M, Böhnke J, Krummenacher I, Phukan AK, Braunschweig H. Hybrid Inorganic-Organic Cross-Metathesis between Diborenes and Acetylene. J Am Chem Soc 2021; 143:18339-18345. [PMID: 34677063 DOI: 10.1021/jacs.1c10131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ruthenium-catalyzed cross-metathesis of alkenes and alkynes, which splits the alkene C═C double bond and couples one-half to each carbon of the alkyne C≡C triple bond, is one of the most efficient tools for the synthesis of 1,3-dienes, with wide-ranging applications, including pharmaceutical and polymer chemistry. In contrast, inorganic main-group metathesis reactions are restricted to a handful of examples of heavier p-block multiple bonds (P═P, Ge═Ge, and E≡E, E = Ge, Sn, Pb). We now report the first examples of thermally induced, transition-metal-free cross-metathesis between an organic alkyne and inorganic cyclic alkyl(amino)carbene (CAAC)-stabilized B═B double bonds, which yield fully planar, π-delocalized 1,8-diaza-3,6-diboraoctatetraenes. Density functional theory studies show that these compounds have an open-shell singlet biradical ground state with a thermally accessible closed-shell state. In-depth computational mechanistic analyses show that they are formed via a biradical cycloaddition-cycloreversion mechanism. Finally, unlike their organic counterparts, these B,N-analogues of octatetraene can undergo two-electron chemical reduction to form diamagnetic dianions.
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Affiliation(s)
- Marcel Härterich
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Benedikt Ritschel
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Merle Arrowsmith
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Julian Böhnke
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Ivo Krummenacher
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Ashwini K Phukan
- Department of Chemical Sciences, Tezpur University, Tezpur 784028, Assam, India
| | - Holger Braunschweig
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
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3
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Löwe P, Feldt M, Röthel MB, Wilm LFB, Dielmann F. Thiophosphonium-Alkyne Cycloaddition Reactions: A Heavy Congener of the Carbonyl-Alkyne Metathesis. Inorg Chem 2021; 60:14509-14514. [PMID: 34524817 PMCID: PMC8493552 DOI: 10.1021/acs.inorgchem.1c02076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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While the metathesis
reaction between alkynes and thiocarbonyl
compounds has been thoroughly studied, the reactivity of alkynes with
isoelectronic main group R2E=S compounds is rarely reported
and unknown for [R2P=S]+ analogues. We show
that thiophosphonium ions, which are the isoelectronic phosphorus
congeners to thiocarbonyl compounds, undergo [2 + 2]-cycloaddition
reactions with different alkynes to generate 1,2-thiaphosphete ions.
The four-membered ring species are in an equilibrium state with the
corresponding P=C–C=S heterodiene structure and thus undergo
hetero-Diels–Alder reactions with acetonitrile. Heteroatom
and substituent effects on the energy profile of the 1,2-thiaphosphete
formation were elucidated by means of quantum chemical methods. We show that thiophosphonium ions, which
are the isoelectronic
phosphorus congeners to thiocarbonyl compounds, undergo [2 + 2]-cycloaddition
reactions with different alkynes to generate 1,2-thiaphosphete ions.
The four-membered ring species are in an equilibrium state with the
corresponding P=C−C=S heterodiene structure and thus undergo
hetero-Diels−Alder reactions with acetonitrile. Heteroatom
and substituent effects on the energy profile of the 1,2-thiaphosphete
formation were elucidated by means of quantum chemical methods.
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Affiliation(s)
- Pawel Löwe
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28-30, 48149 Münster, Germany
| | - Milica Feldt
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Maike B Röthel
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28-30, 48149 Münster, Germany
| | - Lukas F B Wilm
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28-30, 48149 Münster, Germany
| | - Fabian Dielmann
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28-30, 48149 Münster, Germany.,Department of General, Inorganic and Theoretical Chemistry, Leopold-Franzens-Universität Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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4
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Abstract
Main group carbonyl analogues (R2 E=O) derived from p-block elements (E=groups 13 to 15) have long been considered as elusive species. Previously, employment of chemical tricks such as acid- and base-stabilization protocols granted access to these transient species in their masked forms. However, electronic and steric effects inevitably perturb their chemical reactivity and distinguish them from classical carbonyl compounds. A new era was marked by the recent isolation of acid-base free main group carbonyl analogues, ranging from a lighter boracarbonyl to the heavier silacarbonyls, phosphacarbonyls and a germacarbonyl. Most importantly, their unperturbed nature elicits exciting new chemistry, spanning the vista from classical organic carbonyl-type reactions to transition metal-like oxide ion transfer chemistry. In this Review, we survey the strategies used for the isolation of such systems and document their emerging reactivity profiles, with a view to providing fundamental comparisons both with carbon and transition metal oxo species. This highlights the emerging opportunities for exciting "crossover" reactivity offered by these derivatives of the p-block elements.
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Affiliation(s)
- Ying Kai Loh
- Inorganic Chemistry LaboratoryDepartment of ChemistryUniversity of OxfordSouth Parks RoadOxfordOX1 3QRUK
| | - Simon Aldridge
- Inorganic Chemistry LaboratoryDepartment of ChemistryUniversity of OxfordSouth Parks RoadOxfordOX1 3QRUK
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