1
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Cai Y, Hua Y, Lu Z, Chen J, Chen D, Xia H. Metallacyclobutadienes: Intramolecular Rearrangement from Kinetic to Thermodynamic Isomers. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2403940. [PMID: 39104029 DOI: 10.1002/advs.202403940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 06/02/2024] [Indexed: 08/07/2024]
Abstract
Metallacyclobutadienes (MCBDs) are key intermediates of alkyne metathesis reactions. There are in principle two isomerization pathway from kinetic to thermodynamic MCBDs, intermolecular and intramolecular. However, systems that simultaneously isolate two kinds of MCBD isomers have not been achieved, thus restricting the mechanistic studies of the isomerization. Here the reactivity of a metallapentalyne that contains an M≡C bond within the aromatic ring, with alkynes to afford a series of MCBD-fused metallapentalenes is studied. In some cases, both kinetic and thermodynamic products are isolated in the same system, which has never been observed in previous MCBD reactions. Furthermore, the isomerization of MCBD-fused metallapentalenes is investigated both experimentally and theoretically, indicating that it is an intramolecular process involving a metallatetrahedrane (MTd) intermediate. This research provides experimental evidence demonstrating that one MCBD can undergo intramolecular rearrangement to transform into another.
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Affiliation(s)
- Yuanting Cai
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yuhui Hua
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518005, China
| | - Zhengyu Lu
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518005, China
| | - Jiangxi Chen
- Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen, 361005, China
| | - Dafa Chen
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518005, China
| | - Haiping Xia
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518005, China
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2
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Tricoire M, Hsueh FC, Keener M, Rajeshkumar T, Scopelliti R, Zivkovic I, Maron L, Mazzanti M. Siloxide tripodal ligands as a scaffold for stabilizing lanthanides in the +4 oxidation state. Chem Sci 2024; 15:6874-6883. [PMID: 38725506 PMCID: PMC11077534 DOI: 10.1039/d4sc00051j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 03/21/2024] [Indexed: 05/12/2024] Open
Abstract
Synthetic strategies to isolate molecular complexes of lanthanides, other than cerium, in the +4 oxidation state remain elusive, with only four complexes of Tb(iv) isolated so far. Herein, we present a new approach for the stabilization of Tb(iv) using a siloxide tripodal trianionic ligand, which allows the control of unwanted ligand rearrangements, while tuning the Ln(iii)/Ln(iv) redox-couple. The Ln(iii) complexes, [LnIII((OSiPh2Ar)3-arene)(THF)3] (1-LnPh) and [K(toluene){LnIII((OSiPh2Ar)3-arene)(OSiPh3)}] (2-LnPh) (Ln = Ce, Tb, Pr), of the (HOSiPh2Ar)3-arene ligand were prepared. The redox properties of these complexes were compared to those of the Ln(iii) analogue complexes, [LnIII((OSi(OtBu)2Ar)3-arene)(THF)] (1-LnOtBu) and [K(THF)6][LnIII((OSi(OtBu)2Ar)3-arene)(OSiPh3)] (2-LnOtBu) (Ln = Ce, Tb), of the less electron-donating siloxide trianionic ligand, (HOSi(OtBu)2Ar)3-arene. The cyclic voltammetry studies showed a cathodic shift in the oxidation potential for the cerium and terbium complexes of the more electron-donating phenyl substituted scaffold (1-LnPh) compared to those of the tert-butoxy (1-LnOtBu) ligand. Furthermore, the addition of the -OSiPh3 ligand further shifts the potential cathodically, making the Ln(iv) ion even more accessible. Notably, the Ce(iv) complexes, [CeIV((OSi(OtBu)2Ar)3-arene)(OSiPh3)] (3-CeOtBu) and [CeIV((OSiPh2Ar)3-arene)(OSiPh3)(THF)2] (3-CePh), were prepared by chemical oxidation of the Ce(iii) analogues. Chemical oxidation of the Tb(iii) and Pr(iii) complexes (2-LnPh) was also possible, in which the Tb(iv) complex, [TbIV((OSiPh2Ar)3-arene)(OSiPh3)(MeCN)2] (3-TbPh), was isolated and crystallographically characterized, yielding the first example of a Tb(iv) supported by a polydentate ligand. The versatility and robustness of these siloxide arene-anchored platforms will allow further development in the isolation of more oxidizing Ln(iv) ions, widening the breadth of high-valent Ln chemistry.
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Affiliation(s)
- Maxime Tricoire
- Group of Coordiantion Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Fang-Che Hsueh
- Group of Coordiantion Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Megan Keener
- Group of Coordiantion Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées Cedex 4 31077 Toulouse France
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Ivica Zivkovic
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées Cedex 4 31077 Toulouse France
| | - Marinella Mazzanti
- Group of Coordiantion Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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3
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Rütter D, van Gastel M, Leutzsch M, Nöthling N, SantaLucia D, Neese F, Fürstner A. Molybdenum(VI) Nitrido Complexes with Tripodal Silanolate Ligands. Structure and Electronic Character of an Unsymmetrical Dimolybdenum μ-Nitrido Complex Formed by Incomplete Nitrogen Atom Transfer. Inorg Chem 2024; 63:8376-8389. [PMID: 38663089 PMCID: PMC11080062 DOI: 10.1021/acs.inorgchem.4c00762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/05/2024] [Accepted: 04/11/2024] [Indexed: 05/07/2024]
Abstract
In contrast to a tungsten nitrido complex endowed with a tripodal silanolate ligand framework, which was reported in the literature to be a dimeric species with a metallacyclic core, the corresponding molybdenum nitrides 3 are monomeric entities comprising a regular terminal nitride unit, as proven by single-crystal X-ray diffraction (SC-XRD). Their electronic character is largely determined by the constraints imposed on the metal center by the podand ligand architecture. 95Mo nuclear magnetic resonance (NMR) and, to a lesser extent, 14N NMR spectroscopy allow these effects to be studied, which become particularly apparent upon comparison with the spectral data of related molybdenum nitrides comprising unrestrained silanolate, alkoxide, or amide ligands. Attempted nitrogen atom transfer from these novel terminal nitrides to [(tBuArN)3Mo] (Ar = 3,5-dimethylphenyl) as the potential acceptor stopped at the stage of unsymmetric dimolybdenum μ-nitrido complex 13a as the first intermediate along the reaction pathway. SC-XRD, NMR, electron paramagnetic resonance, and ultraviolet-visible spectroscopy as well as magnetometry in combination with density functional theory allowed a clear picture of the geometric and electronic structure of this mixed-valent species to be drawn. 13a is formally best described as an adduct of the type [(Mo[O])+III-(μN)-III-(Mo[N])+VI], S = 1/2 complex with (Mo[O])+III in the low-spin configuration, whereas related complexes such as [(AdS)3Mo-(μN)-Mo(NtBuAr)3] (19; Ad = 1-adamantyl) have previously been regarded in the literature as mixed-valent Mo+IV/Mo+V species. The spin population at the two Mo centers is uneven and notably larger at the more reduced Mo[O] atom, whereas the only spin present at the (μN) bridge is derived from spin polarization.
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Affiliation(s)
- Daniel Rütter
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | | | - Markus Leutzsch
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Nils Nöthling
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Daniel SantaLucia
- Max-Planck-Institut
für Chemische Energiekonversion, 45470 Mülheim/Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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4
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Tomasini M, Gimferrer M, Caporaso L, Poater A. Rhenium Alkyne Catalysis: Sterics Control the Reactivity. Inorg Chem 2024; 63:5842-5851. [PMID: 38507560 PMCID: PMC10988556 DOI: 10.1021/acs.inorgchem.3c04235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/27/2024] [Accepted: 03/05/2024] [Indexed: 03/22/2024]
Abstract
Metathesis reactions, including alkane, alkene, and alkyne metatheses, have their origins in the fundamental understanding of chemical reactions and the development of specialized catalysts. These reactions stand as transformative pillars in organic chemistry, providing efficient rearrangement of carbon-carbon bonds and enabling synthetic access to diverse and complex compounds. Their impact spans industries such as petrochemicals, pharmaceuticals, and materials science. In this work, we present a detailed mechanistic study of the Re(V) catalyzed alkyne metathesis through density functional theory calculations. Our findings are in agreement with the experimental evidence from Jia and co-workers and unveil critical factors governing catalyst performance. Our work not only enhances our understanding of alkyne metathesis but also contributes to the broader landscape of catalytic processes, facilitating the design of more efficient and selective transformations in organic synthesis.
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Affiliation(s)
- Michele Tomasini
- Institut
de Química Computacional i Catàlisi, Departament de
Química, Universitat de Girona, c/Ma Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
- Dipartimento
di Chimica e Biologia, Università
di Salerno, Via Ponte
don Melillo, Fisciano 84084, Italy
| | - Martí Gimferrer
- Institut
für Physikalische Chemie, Georg-August
Universität Göttingen, Tammannstraße 6, Göttingen 37077, Germany
| | - Lucia Caporaso
- Dipartimento
di Chimica e Biologia, Università
di Salerno, Via Ponte
don Melillo, Fisciano 84084, Italy
- CIRCC, Interuniversity Consortium Chemical Reactivity and Catalysis, via Celso Ulpiani 27, Bari 70126, Italy
| | - Albert Poater
- Institut
de Química Computacional i Catàlisi, Departament de
Química, Universitat de Girona, c/Ma Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
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5
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Hsueh FC, Chen D, Rajeshkumar T, Scopelliti R, Maron L, Mazzanti M. Two-Electron Redox Reactivity of Thorium Supported by Redox-Active Tripodal Frameworks. Angew Chem Int Ed Engl 2024; 63:e202317346. [PMID: 38100190 DOI: 10.1002/anie.202317346] [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: 11/14/2023] [Indexed: 12/31/2023]
Abstract
The high stability of the + IVoxidation state limits thorium redox reactivity. Here we report the synthesis and the redox reactivity of two Th(IV) complexes supported by the arene-tethered tris(siloxide) tripodal ligands [(KOSiR2 Ar)3 -arene)]. The two-electron reduction of these Th(IV) complexes generates the doubly reduced [KTh((OSi(Ot Bu)2 Ar)3 -arene)(THF)2 ] (2OtBu ) and [K(2.2.2-cryptand)][Th((OSiPh2 Ar)3 -arene)(THF)2 ](2Ph -crypt) where the formal oxidation state of Th is +II. Structural and computational studies indicate that the reduction occurred at the arene anchor of the ligand. The robust tripodal frameworks store in the arene anchor two electrons that become available at the metal center for the two-electron reduction of a broad range of substrates (N2 O, COT, CHT, Ph2 N2 , Ph3 PS and O2 ) while retaining the ligand framework. This work shows that arene-tethered tris(siloxide) tripodal ligands allow implementation of two-electron redox chemistry at the thorium center while retaining the ligand framework unchanged.
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Affiliation(s)
- Fang-Che Hsueh
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Damien Chen
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, 31077, Toulouse Cedex 4, France
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, 31077, Toulouse Cedex 4, France
| | - Marinella Mazzanti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
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6
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Korber JN, Wille C, Leutzsch M, Fürstner A. From the Glovebox to the Benchtop: Air-Stable High Performance Molybdenum Alkylidyne Catalysts for Alkyne Metathesis. J Am Chem Soc 2023; 145:26993-27009. [PMID: 38032858 PMCID: PMC10722517 DOI: 10.1021/jacs.3c10430] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 12/02/2023]
Abstract
Molybdenum alkylidynes endowed with tripodal silanolate ligands belong to the most active and selective catalysts for alkyne metathesis known to date. This paper describes a new generation that is distinguished by an unprecedented level of stability and practicality without sacrificing the chemical virtues of their predecessors. Specifically, pyridine adducts of type 16 are easy to make on gram scale, can be routinely weighed and handled in air, and stay intact for many months outside the glovebox. When dissolved in toluene, however, spontaneous dissociation of the stabilizing pyridine ligand releases an active species of excellent performance and functional group tolerance. Specifically, a host of polar and apolar groups, various protic sites, and numerous basic functionalities proved compatible. The catalysts are characterized by crystallographic and spectroscopic means, including 95Mo NMR; their activity and stability are benchmarked in detail, and the enabling properties are illustrated by advanced applications to natural product synthesis. For the favorable overall application profile and ease of handling, complexes of this new series are expected to replace earlier catalyst generations and help encourage a more regular use of alkyne metathesis in general.
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Affiliation(s)
- J. Nepomuk Korber
- Max-Planck-Institut
für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Christian Wille
- Max-Planck-Institut
für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Markus Leutzsch
- Max-Planck-Institut
für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut
für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
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7
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Varlet T, Portmann S, Fürstner A. Total Synthesis of Njaoamine C by Concurrent Macrocycle Formation. J Am Chem Soc 2023; 145:21197-21202. [PMID: 37734001 PMCID: PMC10557140 DOI: 10.1021/jacs.3c08410] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Indexed: 09/23/2023]
Abstract
In conceptual terms, the first total synthesis of the cytotoxic marine natural product njaoamine C differs from all known approaches toward related alkaloids of the manzamine superfamily in that both macrocyclic rings enveloping the diazatricyclic core are concomitantly formed; this goal was reached by double ring closing alkyne metathesis (dRCAM). The success of this maneuver does not merely reflect a favorable preorientation of the four alkyne chains that need to be concatenated in the proper pairwise manner but is also the outcome of dynamic covalent chemistry involving error correction by the chosen "canopy" molybdenum alkylidyne catalyst. The end game downstream of dRCAM capitalizes on the striking chemoselectivity of palladium-catalyzed hydrostannation, which selects for (hetero)arylalkynes even in the presence of sterically much more accessible dialkylalkynes or alkenes; for this preference, the method complements the classical repertoire of hydrometalation and semireduction reactions.
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Affiliation(s)
- Thomas Varlet
- Max-Planck-Institut für
Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Sören Portmann
- Max-Planck-Institut für
Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für
Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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8
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Hsueh FC, Rajeshkumar T, Maron L, Scopelliti R, Sienkiewicz A, Mazzanti M. Isolation and redox reactivity of cerium complexes in four redox states. Chem Sci 2023; 14:6011-6021. [PMID: 37293643 PMCID: PMC10246686 DOI: 10.1039/d3sc01478a] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/04/2023] [Indexed: 06/10/2023] Open
Abstract
The chemistry of lanthanides is limited to one electron transfer reactions due to the difficulty of accessing multiple oxidation states. Here we report that a redox-active ligand combining three siloxides with an arene ring in a tripodal ligand can stabilize cerium complexes in four different redox states and can promote multielectron redox reactivity in cerium complexes. Ce(iii) and Ce(iv) complexes [(LO3)Ce(THF)] (1) and [(LO3)CeCl] (2) (LO3 = 1,3,5-(2-OSi(OtBu)2C6H4)3C6H3) were synthesized and fully characterized. Remarkably the one-electron reduction and the unprecedented two-electron reduction of the tripodal Ce(iii) complex are easily achieved to yield reduced complexes [K(2.2.2-cryptand)][(LO3)Ce(THF)] (3) and [K2{(LO3)Ce(Et2O)3}] (5) that are formally "Ce(ii)" and "Ce(i)" analogues. Structural analysis, UV and EPR spectroscopy and computational studies indicate that in 3 the cerium oxidation state is in between +II and +III with a partially reduced arene. In 5 the arene is doubly reduced, but the removal of potassium results in a redistribution of electrons on the metal. The electrons in both 3 and 5 are stored onto δ-bonds allowing the reduced complexes to be described as masked "Ce(ii)" and "Ce(i)". Preliminary reactivity studies show that these complexes act as masked Ce(ii) and Ce(i) in redox reactions with oxidizing substrates such as Ag+, CO2, I2 and S8 effecting both one- and two-electron transfers that are not accessible in classical cerium chemistry.
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Affiliation(s)
- Fang-Che Hsueh
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées 31077 Toulouse, Cedex 4 France
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées 31077 Toulouse, Cedex 4 France
| | - Rosario Scopelliti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Andrzej Sienkiewicz
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
- ADSresonances Sàrl 1920 Martigny Switzerland
| | - Marinella Mazzanti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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9
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Zhu QH, Zhang L, Zhang GH, Tao GH, Qin S, Chen H, Yuan WL, Wang YH, Jin Y, Ma L, He L, Zhang W. Promoting productive metathesis pathway and tuning activity of multidentate molybdenum catalysts in alkyne metathesis: A theoretical perspective. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2022.112696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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10
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Cui M, Jia G. Organometallic Chemistry of Transition Metal Alkylidyne Complexes Centered at Metathesis Reactions. J Am Chem Soc 2022; 144:12546-12566. [PMID: 35793547 DOI: 10.1021/jacs.2c01192] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transition metals form a variety of alkylidyne complexes with either a d0 metal center (high-valent) or a non-d0 metal center (low-valent). One of the most interesting properties of alkylidyne complexes is that they can undergo or mediate metathesis reactions. The most well-studied metathesis reactions are alkyne metathesis involving high-valent alkylidynes. High-valent alkylidynes can also undergo metathesis reactions with heterotriple bonded species such as N≡CR, P≡CR, and N≡NR+. Metathesis reactions involving low-valent alkylidynes are less known. Highly efficient alkyne metathesis catalysts have been developed based on Mo(VI) and W(VI) alkylidynes. Catalytic cross-metathesis of nitriles with alkynes has also been achieved with M(VI) (M = W, Mo) alkylidyne or nitrido complexes. The metathesis activity of alkylidyne complexes is sensitively dependent on metals, supporting ligands and substituents of alkylidynes. Beyond metathesis, metal alkylidynes can also promote other reactions including alkyne polymerization. The remaining shortcomings and opportunities in the field are assessed.
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Affiliation(s)
- Mingxu Cui
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, SAR, Hong Kong, China
| | - Guochen Jia
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, SAR, Hong Kong, China.,HKUST Shenzhen Research Institute, Shenzhen, 518057, China
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11
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Greenlee AJ, Chen H, Wendell CI, Moore JS. Tandem Imine Formation and Alkyne Metathesis Enabled by Catalyst Choice. J Org Chem 2022; 87:8429-8436. [PMID: 35678630 DOI: 10.1021/acs.joc.2c00538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Three-rung molecular ladder 8 was prepared in one pot via tandem imine condensation and alkyne metathesis. Catalyst VI is demonstrated to successfully engender the metathesis of imine-bearing substrate 7, while catalyst III does not. The susceptibility of catalyst VI to deactivation by hydrolysis and ligand exchange is demonstrated. Assembly and disassembly of ladder 8 in one pot were demonstrated in the presence and absence of a Lewis acid catalyst.
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Affiliation(s)
- Andrew J Greenlee
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Heyu Chen
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Chloe I Wendell
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jeffrey S Moore
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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12
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Cui M, Sung HHY, Williams ID, Jia G. Alkyne Metathesis with d 2 Re(V) Alkylidyne Complexes Supported by Phosphino-Phenolates: Ligand Effect on Catalytic Activity and Applications in Ring-Closing Alkyne Metathesis. J Am Chem Soc 2022; 144:6349-6360. [PMID: 35377156 DOI: 10.1021/jacs.2c00368] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A family of d2 Re(V) alkylidyne complexes bearing two decorated phosphino-phenolates (POs) and a labile pyridine ligand were prepared that can efficiently promote alkyne metathesis reactions in toluene. The relative activity of these complexes varies with the PO ligands. Complexes with an electron-rich metal center have a higher activity. Ligand exchange experiments suggest that the pyridine ligands of the Re(V) alkylidynes with more electron-donating PO ligands are more labile and are more easily released to generate catalytically active species. However, complexes with electron-withdrawing PO ligands are more air-stable than those with electron-donating PO ligands. These Re(V) alkylidyne catalysts can promote the homometathesis of functionalized internal alkyl- and aryl-alkynes, as well as ring-closing alkyne metathesis (RCAM) of methyl-capped diynes, forming macrocycles with a ring size ≥12 efficiently for concentrations ≤5 mM. These reactions represent the first examples of RCAM mediated by non-d0 alkylidyne complexes. The Re(V) alkylidyne catalysts tolerate a wide range of functional groups including ethers, esters, ketones, aldehydes, alcohols, phenols, amines, amides, and heterocycles. Moreover, the catalytic RCAM reactions promoted by robust Re(V) alkylidyne catalysts could also proceed normally in wet toluene.
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Affiliation(s)
- Mingxu Cui
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, SAR 000000, China
| | - Herman H Y Sung
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, SAR 000000, China
| | - Ian D Williams
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, SAR 000000, China
| | - Guochen Jia
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, SAR 000000, China.,HKUST Shenzhen Research Institute, Shenzhen 518057, China
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13
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Ge Y, Hu Y, Duan G, Jin Y, Zhang W. Advances and challenges in user-friendly alkyne metathesis catalysts. TRENDS IN CHEMISTRY 2022. [DOI: 10.1016/j.trechm.2022.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Acceleration of alkyne metathesis in multicomponent catalytic systems by use of alternative Mo(0) sources under optimised conditions. CATAL COMMUN 2022. [DOI: 10.1016/j.catcom.2022.106410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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15
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Hillenbrand J, Korber JN, Leutzsch M, Nöthling N, Fürstner A. Canopy Catalysts for Alkyne Metathesis: Investigations into a Bimolecular Decomposition Pathway and the Stability of the Podand Cap. Chemistry 2021; 27:14025-14033. [PMID: 34293239 PMCID: PMC8518412 DOI: 10.1002/chem.202102080] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 11/28/2022]
Abstract
Molybdenum alkylidyne complexes with a trisilanolate podand ligand framework ("canopy catalysts") are the arguably most selective catalysts for alkyne metathesis known to date. Among them, complex 1 a endowed with a fence of lateral methyl substituents on the silicon linkers is the most reactive, although fairly high loadings are required in certain applications. It is now shown that this catalyst decomposes readily via a bimolecular pathway that engages the Mo≡CR entities in a stoichiometric triple-bond metathesis event to furnish RC≡CR and the corresponding dinuclear complex, 8, with a Mo≡Mo core. In addition to the regular analytical techniques, 95 Mo NMR was used to confirm this unusual outcome. This rapid degradation mechanism is largely avoided by increasing the size of the peripheral substituents on silicon, without unduly compromising the activity of the resulting complexes. When chemically challenged, however, canopy catalysts can open the apparently somewhat strained tripodal ligand cages; this reorganization leads to the formation of cyclo-tetrameric arrays composed of four metal alkylidyne units linked together via one silanol arm of the ligand backbone. The analogous tungsten alkylidyne complex 6, endowed with a tripodal tris-alkoxide (rather than siloxide) ligand framework, is even more susceptible to such a controlled and reversible cyclo-oligomerization. The structures of the resulting giant macrocyclic ensembles were established by single-crystal X-ray diffraction.
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Affiliation(s)
- Julius Hillenbrand
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - J. Nepomuk Korber
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
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16
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Abstract
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For numerous enabling features and strategic virtues, contemporary
alkyne metathesis is increasingly recognized as a formidable synthetic
tool. Central to this development was the remarkable evolution of
the catalysts during the past decades. Molybdenum alkylidynes carrying
(tripodal) silanolate ligands currently set the standards; their functional
group compatibility is exceptional, even though they comprise an early
transition metal in its highest oxidation state. Their performance
is manifested in case studies in the realm of dynamic covalent chemistry,
advanced applications to solid-phase synthesis, a revival of transannular
reactions, and the assembly of complex target molecules at sites,
which one may not intuitively trace back to an acetylenic ancestor.
In parallel with these innovations in material science and organic
synthesis, new insights into the mode of action of the most advanced
catalysts were gained by computational means and the use of unconventional
analytical tools such as 95Mo and 183W NMR spectroscopy.
The remaining shortcomings, gaps, and desiderata in the field are
also critically assessed.
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Affiliation(s)
- Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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17
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Meng Z, Spohr SM, Tobegen S, Farès C, Fürstner A. A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I. J Am Chem Soc 2021; 143:14402-14414. [PMID: 34448391 PMCID: PMC8431342 DOI: 10.1021/jacs.1c07955] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Many
polycyclic marine
alkaloids are thought to derive from partly
reduced macrocyclic alkylpyridine derivatives via a transannular Diels–Alder
reaction that forms their common etheno-bridged diaza-decaline core
(“Baldwin–Whitehead hypothesis”). Rather than
trying to emulate this biosynthesis pathway, a route to these natural
products following purely chemical logic was pursued. Specifically,
a Michael/Michael addition cascade provided rapid access to this conspicuous
tricyclic scaffold and allowed different handles to be introduced
at the bridgehead quarternary center. This flexibility opened opportunities
for the formation of the enveloping medium-sized and macrocyclic rings.
Ring closing alkyne metathesis (RCAM) proved most reliable and became
a recurrent theme en route to keramaphidin B, ingenamine, xestocyclamine
A, and nominal njaoamine I (the structure of which had to be corrected
in the aftermath of the synthesis). Best results were obtained with
molybdenum alkylidyne catalysts endowed with (tripodal) silanolate
ligands, which proved fully operative in the presence of tertiary
amines, quinoline, and other Lewis basic sites. RCAM was successfully
interlinked with macrolactamization, an intricate hydroboration/protonation/alkyl-Suzuki
coupling sequence, or ring closing olefin metathesis (RCM) for the
closure of the second lateral ring; the use of RCM for the formation
of an 11-membered cycle is particularly noteworthy. Equally rare are
RCM reactions that leave a pre-existing triple bond untouched, as
the standard ruthenium catalysts are usually indiscriminative vis-à-vis
the different π-bonds. Of arguably highest significance, however,
is the use of two consecutive or even concurrent RCAM reactions en
route to nominal njaoamine I as the arguably most complex of the chosen
targets.
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Affiliation(s)
- Zhanchao Meng
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Simon M Spohr
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Sandra Tobegen
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Christophe Farès
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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18
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Trzmiel S, Langmann J, Werner D, Maichle‐Mössmer C, Scherer W, Anwander R. Über Takais Olefinierungsreagenz hinaus: Anhaltende Dehalogenierung mündet in einem Chrom(III)‐μ
3
‐Methylidin‐Komplex. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Simon Trzmiel
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Deutschland
| | - Jan Langmann
- Institut für Physik Universität Augsburg Universitätsstr. 1 86159 Augsburg Deutschland
| | - Daniel Werner
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Deutschland
| | - Cäcilia Maichle‐Mössmer
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Deutschland
| | - Wolfgang Scherer
- Institut für Physik Universität Augsburg Universitätsstr. 1 86159 Augsburg Deutschland
| | - Reiner Anwander
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Deutschland
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19
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Trzmiel S, Langmann J, Werner D, Maichle‐Mössmer C, Scherer W, Anwander R. Beyond Takai's Olefination Reagent: Persistent Dehalogenation Emerges in a Chromium(III)-μ 3 -Methylidyne Complex. Angew Chem Int Ed Engl 2021; 60:20049-20054. [PMID: 34213805 PMCID: PMC8456800 DOI: 10.1002/anie.202106608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/01/2021] [Indexed: 11/05/2022]
Abstract
Reaction of CHI3 with six equivalents of CrCl2 in THF at low temperatures affords [Cr3 Cl3 (μ2 -Cl)3 (μ3 -CH)(thf)6 ] as the first isolable high-yield CrIII μ3 -methylidyne complex. Substitution of the terminal chlorido ligands via salt metathesis with alkali-metal cyclopentadienides generates isostructural half-sandwich chromium(III)-μ3 -methylidynes [CpR 3 Cr3 (μ2 -Cl)3 (μ3 -CH)] (CpR =C5 H5 , C5 Me5 , C5 H4 SiMe3 ). Side and decomposition products of the Cl/CpR exchange reactions were identified and structurally characterized for [Cr4 (μ2 -Cl)4 (μ2 -I)2 (μ4 -O)(thf)4 ] and [(η5 -C5 H4 SiMe3 )CrCl(μ2 -Cl)2 Li(thf)2 ]. The Cl/CpR exchange drastically changed the ambient-temperature effective magnetic moment μeff from 9.30/9.11 μB (solution/solid) to 3.63/4.32 μB (CpR =C5 Me5 ). Reactions of [Cr3 Cl3 (μ2 -Cl)3 (μ3 -CH)(thf)6 ] with aldehydes and ketones produce intricate mixtures of species through oxy/methylidyne exchange, which were partially identified as radical recombination products through GC/MS analysis and 1 H NMR spectroscopy.
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Affiliation(s)
- Simon Trzmiel
- Institut für Anorganische ChemieEberhard-Karls-Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Jan Langmann
- Institut für PhysikUniversität AugsburgUniversitätsstr. 186159AugsburgGermany
| | - Daniel Werner
- Institut für Anorganische ChemieEberhard-Karls-Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Cäcilia Maichle‐Mössmer
- Institut für Anorganische ChemieEberhard-Karls-Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Wolfgang Scherer
- Institut für PhysikUniversität AugsburgUniversitätsstr. 186159AugsburgGermany
| | - Reiner Anwander
- Institut für Anorganische ChemieEberhard-Karls-Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
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20
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Haack A, Hillenbrand J, van Gastel M, Fürstner A, Neese F. Spectroscopic and Theoretical Study on Siloxy-Based Molybdenum and Tungsten Alkylidyne Catalysts for Alkyne Metathesis. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01587] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Alexander Haack
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | | | | | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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21
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Zier ML, Colombel-Rouen S, Ehrhorn H, Bockfeld D, Trolez Y, Mauduit M, Tamm M. Catalytic Alkyne and Diyne Metathesis with Mixed Fluoroalkoxy-Siloxy Molybdenum Alkylidyne Complexes. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00290] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Manuel L. Zier
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Sophie Colombel-Rouen
- Univ Rennes; Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR−UMR 6226, F-35000 Rennes, France
| | - Henrike Ehrhorn
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Dirk Bockfeld
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Yann Trolez
- Univ Rennes; Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR−UMR 6226, F-35000 Rennes, France
| | - Marc Mauduit
- Univ Rennes; Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR−UMR 6226, F-35000 Rennes, France
| | - Matthias Tamm
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
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22
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Thompson RR, Rotella ME, Zhou X, Fronczek FR, Gutierrez O, Lee S. Impact of Ligands and Metals on the Formation of Metallacyclic Intermediates and a Nontraditional Mechanism for Group VI Alkyne Metathesis Catalysts. J Am Chem Soc 2021; 143:9026-9039. [PMID: 34110130 PMCID: PMC8227475 DOI: 10.1021/jacs.1c01843] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
The
intermediacy of metallacyclobutadienes as part of a [2 + 2]/retro-[2
+ 2] cycloaddition-based mechanism is a well-established paradigm
in alkyne metathesis with alternative species viewed as off-cycle
decomposition products that interfere with efficient product formation.
Recent work has shown that the exclusive intermediate isolated from
a siloxide podand-supported molybdenum-based catalyst was not the
expected metallacyclobutadiene but instead a dynamic metallatetrahedrane.
Despite their paucity in the chemical literature, theoretical work
has shown these species to be thermodynamically more stable as well
as having modest barriers for cycloaddition. Consequentially, we report
the synthesis of a library of group VI alkylidynes as well as the
roles metal identity, ligand flexibility, secondary coordination sphere,
and substrate identity all have on isolable intermediates. Furthermore,
we report the disparities in catalyst competency as a function of
ligand sterics and metal choice. Dispersion-corrected DFT calculations
are used to shed light on the mechanism and role of ligand and metal
on the intermediacy of metallacyclobutadiene and metallatetrahedrane
as well as their implications to alkyne metathesis.
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Affiliation(s)
- Richard R Thompson
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Madeline E Rotella
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Xin Zhou
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Frank R Fronczek
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Osvaldo Gutierrez
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Semin Lee
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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23
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Huang S, Lei Z, Jin Y, Zhang W. By-design molecular architectures via alkyne metathesis. Chem Sci 2021; 12:9591-9606. [PMID: 34349932 PMCID: PMC8293811 DOI: 10.1039/d1sc01881g] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 05/14/2021] [Indexed: 12/26/2022] Open
Abstract
Shape-persistent purely organic molecular architectures have attracted tremendous research interest in the past few decades. Dynamic Covalent Chemistry (DCvC), which deals with reversible covalent bond formation reactions, has emerged as an efficient synthetic approach for constructing these well-defined molecular architectures. Among various dynamic linkages, the formation of ethynylene linkages through dynamic alkyne metathesis is of particular interest due to their high chemical stability, linearity, and rigidity. In this review, we focus on the synthetic strategies of discrete molecular architectures (e.g., macrocycles, molecular cages) containing ethynylene linkages using alkyne metathesis as the key step, and their applications. We will introduce the history and challenges in the synthesis of those architectures via alkyne metathesis, the development of alkyne metathesis catalysts, the reported novel macrocycle structures, molecular cage structures, and their applications. In the end, we offer an outlook of this field and remaining challenges. The recent synthesis of novel shape-persistent 2D and 3D molecular architectures via alkyne metathesis is reviewed and the critical role of catalysts is also highlighted.![]()
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Affiliation(s)
- Shaofeng Huang
- Department of Chemistry, University of Colorado Boulder 80309 USA
| | - Zepeng Lei
- Department of Chemistry, University of Colorado Boulder 80309 USA
| | - Yinghua Jin
- Department of Chemistry, University of Colorado Boulder 80309 USA
| | - Wei Zhang
- Department of Chemistry, University of Colorado Boulder 80309 USA
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24
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Haack A, Hillenbrand J, Leutzsch M, van Gastel M, Neese F, Fürstner A. Productive Alkyne Metathesis with "Canopy Catalysts" Mandates Pseudorotation. J Am Chem Soc 2021; 143:5643-5648. [PMID: 33826335 PMCID: PMC8154524 DOI: 10.1021/jacs.1c01404] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
![]()
Molybdenum alkylidyne
complexes of the “canopy catalyst”
series define new standards in the field of alkyne metathesis. The
tripodal ligand framework lowers the symmetry of the metallacyclobutadiene
complex formed by [2 + 2] cycloaddition with the substrate and imposes
constraints onto the productive [2 + 2] cycloreversion; pseudorotation
corrects this handicap and makes catalytic turnover possible. A combined
spectroscopic, crystallographic, and computational study provides
insights into this unorthodox mechanism and uncovers the role that
metallatetrahedrane complexes play in certain cases.
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Affiliation(s)
- Alexander Haack
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | | | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | | | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
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25
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Ge Y, Huang S, Hu Y, Zhang L, He L, Krajewski S, Ortiz M, Jin Y, Zhang W. Highly active alkyne metathesis catalysts operating under open air condition. Nat Commun 2021; 12:1136. [PMID: 33602910 PMCID: PMC7893043 DOI: 10.1038/s41467-021-21364-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 01/21/2021] [Indexed: 01/17/2023] Open
Abstract
Alkyne metathesis represents a rapidly emerging synthetic method that has shown great potential in small molecule and polymer synthesis. However, its practical use has been impeded by the limited availability of user-friendly catalysts and their generally high moisture/air sensitivity. Herein, we report an alkyne metathesis catalyst system that can operate under open-air conditions with a broad substrate scope and excellent yields. These catalysts are composed of simple multidentate tris(2-hydroxyphenyl)methane ligands, which can be easily prepared in multi-gram scale. The catalyst substituted with electron withdrawing cyano groups exhibits the highest activity at room temperature with excellent functional group tolerance (-OH, -CHO, -NO2, pyridyl). More importantly, the catalyst provides excellent yields (typically >90%) in open air, comparable to those operating under argon. When dispersed in paraffin wax, the active catalyst can be stored on a benchtop under ambient conditions without any decrease in activity for one day (retain 88% after 3 days). This work opens many possibilities for developing highly active user-friendly alkyne metathesis catalysts that can function in open air. Alkyne metathesis catalysts usually suffer from high moisture/air sensitivity, which limit their wide applicability. Here, the authors report efficient alkyne metathesis catalysts that can operate under open-air conditions with a broad functional group tolerance.
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Affiliation(s)
- Yanqing Ge
- School of Chemistry and Pharmaceutical Engineering, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Department of Chemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Shaofeng Huang
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Yiming Hu
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Lei Zhang
- College of Chemistry, Sichuan University, Chengdu, China
| | - Ling He
- College of Chemistry, Sichuan University, Chengdu, China
| | | | - Michael Ortiz
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Yinghua Jin
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Wei Zhang
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, USA.
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26
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Hillenbrand J, Leutzsch M, Gordon CP, Copéret C, Fürstner A. 183 W NMR Spectroscopy Guides the Search for Tungsten Alkylidyne Catalysts for Alkyne Metathesis. Angew Chem Int Ed Engl 2020; 59:21758-21768. [PMID: 32820864 PMCID: PMC7756321 DOI: 10.1002/anie.202009975] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/21/2020] [Indexed: 12/12/2022]
Abstract
Triarylsilanolates are privileged ancillary ligands for molybdenum alkylidyne catalysts for alkyne metathesis but lead to disappointing results and poor stability in the tungsten series. 1 H,183 W heteronuclear multiple bond correlation spectroscopy, exploiting a favorable 5 J-coupling between the 183 W center and the peripheral protons on the alkylidyne cap, revealed that these ligands upregulate the Lewis acidity to an extent that the tungstenacyclobutadiene formed in the initial [2+2] cycloaddition step is over-stabilized and the catalytic turnover brought to a halt. Guided by the 183 W NMR shifts as a proxy for the Lewis acidity of the central atom and by an accompanying chemical shift tensor analysis of the alkylidyne unit, the ligand design was revisited and a more strongly π-donating all-alkoxide ligand prepared. The new expanded chelate complex has a tempered Lewis acidity and outperforms the classical Schrock catalyst, carrying monodentate tert-butoxy ligands, in terms of rate and functional-group compatibility.
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Affiliation(s)
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Christopher P. Gordon
- Department of Chemistry and Applied BiosciencesETH ZürichVladimir-Prelog-Weg 1–58093ZürichSwitzerland
| | - Christophe Copéret
- Department of Chemistry and Applied BiosciencesETH ZürichVladimir-Prelog-Weg 1–58093ZürichSwitzerland
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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27
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Hillenbrand J, Leutzsch M, Gordon CP, Copéret C, Fürstner A. 183
W NMR Spectroscopy Guides the Search for Tungsten Alkylidyne Catalysts for Alkyne Metathesis. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Christopher P. Gordon
- Department of Chemistry and Applied Biosciences ETH Zürich Vladimir-Prelog-Weg 1–5 8093 Zürich Switzerland
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences ETH Zürich Vladimir-Prelog-Weg 1–5 8093 Zürich Switzerland
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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28
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Hillenbrand J, Leutzsch M, Yiannakas E, Gordon CP, Wille C, Nöthling N, Copéret C, Fürstner A. "Canopy Catalysts" for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework. J Am Chem Soc 2020; 142:11279-11294. [PMID: 32463684 PMCID: PMC7322728 DOI: 10.1021/jacs.0c04742] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
![]()
A new family of structurally well-defined
molybdenum alkylidyne
catalysts for alkyne metathesis, which is distinguished by a tripodal
trisilanolate ligand architecture, is presented. Complexes of type 1 combine the virtues of previous generations of silanolate-based
catalysts with a significantly improved functional group tolerance.
They are easy to prepare on scale; the modularity of the ligand synthesis
allows the steric and electronic properties to be fine-tuned and hence
the application profile of the catalysts to be optimized. This opportunity
is manifested in the development of catalyst 1f, which
is as reactive as the best ancestors but exhibits an unrivaled scope.
The new catalysts work well in the presence of unprotected alcohols
and various other protic groups. The chelate effect entails even a
certain stability toward water, which marks a big leap forward in
metal alkylidyne chemistry in general. At the same time, they tolerate
many donor sites, including basic nitrogen and numerous heterocycles.
This aspect is substantiated by applications to polyfunctional (natural)
products. A combined spectroscopic, crystallographic, and computational
study provides insights into structure and electronic character of
complexes of type 1. Particularly informative are a density
functional theory (DFT)-based chemical shift tensor analysis of the
alkylidyne carbon atom and 95Mo NMR spectroscopy; this
analytical tool had been rarely used in organometallic chemistry before
but turns out to be a sensitive probe that deserves more attention.
The data show that the podand ligands render a Mo-alkylidyne a priori
more electrophilic than analogous monodentate triarylsilanols; proper
ligand tuning, however, allows the Lewis acidity as well as the steric
demand about the central atom to be adjusted to the point that excellent
performance of the catalyst is ensured.
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Affiliation(s)
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Ektoras Yiannakas
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Christopher P Gordon
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, 8093 Zürich, Switzerland
| | - Christian Wille
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, 8093 Zürich, Switzerland
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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29
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Zaranek M, Robaszkiewicz J, Janica I, Gauvin RM, Pawluć P, Mortreux A. In situ Mo(CO)₆-based catalysts for alkyne metathesis: Silanols vs phenols as co-catalysts under thermal and photochemical activation. CATAL COMMUN 2020. [DOI: 10.1016/j.catcom.2020.105944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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30
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Jiang X, Laffoon JD, Chen D, Pérez-Estrada S, Danis AS, Rodríguez-López J, Garcia-Garibay MA, Zhu J, Moore JS. Kinetic Control in the Synthesis of a Möbius Tris((ethynyl)[5]helicene) Macrocycle Using Alkyne Metathesis. J Am Chem Soc 2020; 142:6493-6498. [PMID: 32208689 DOI: 10.1021/jacs.0c01430] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The synthesis of conjugated Möbius molecules remains elusive since twisted and macrocyclic structures are low-entropy species sporting their own synthetic challenges. Here we report the synthesis of a Möbius macrocycle in 84% yield via alkyne metathesis of 2,13-bis(propynyl)[5]helicene. MALDI-MS, NMR spectroscopy, and X-ray diffraction indicated a trimeric product of twofold symmetry with PPM/MMP configurations in the helicene subunits. Alternatively, a threefold-symmetric PPP/MMM structure was determined by DFT calculations to be more thermodynamically stable, illustrating remarkable kinetic selectivity for this alkyne metathesis cyclooligomerization. Computational studies provided insight into the kinetic selectivity, demonstrating a difference of 15.4 kcal/mol between the activation barriers for the PPM/MMP and PPP/MMM diastereodetermining steps. Computational (ACID and EDDB) and experimental (UV-vis and fluorescence spectroscopy and cyclic voltammetry) studies revealed weak conjugation between the alkyne and adjacent helicene groups as well as the lack of significant global aromaticity. Separation of the PPM and MMP enantiomers was achieved via chiral HPLC at the analytical scale.
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Affiliation(s)
- Xing Jiang
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Joshua D Laffoon
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Dandan Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Salvador Pérez-Estrada
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Andrew S Danis
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Joint Center for Energy Storage Research, Argonne, Illinois 60439, United States
| | - Joaquín Rodríguez-López
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Joint Center for Energy Storage Research, Argonne, Illinois 60439, United States
| | - Miguel A Garcia-Garibay
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jeffrey S Moore
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Joint Center for Energy Storage Research, Argonne, Illinois 60439, United States
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