1
|
Bousrez G, Harakat D, Chevreux S, Déchamps-Olivier I, Jaroschik F. Choosing between Ti(II) and Ti(III): selective reduction of titanocene dichloride by elemental lanthanides. Dalton Trans 2024. [PMID: 39230327 DOI: 10.1039/d4dt02004a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
The reduction of titanocene dichloride Cp2TiCl2 with lanthanide metals has led to the discovery of a surprising lanthanide effect: while with most lanthanides, a divalent [Cp2Ti] equivalent was obtained, the use of samarium or ytterbium only led to the reduction to trivalent [Cp2TiCl]-type complexes, including the structurally characterized heterobimetallic complex [Cp2Ti(μ-Cl)2SmCl2(THF)3]. These results were corroborated by reactivity studies (alkyne coupling and radical reactions), EPR spectroscopy and electrospray mass spectrometry, providing new insights into the reduction chemistry of lanthanide metals.
Collapse
Affiliation(s)
- Guillaume Bousrez
- Université de Reims Champagne Ardenne, CNRS UMR 7312, ICMR, URCATech, 51100 Reims, France
- Department of Biological and Chemical Engineering, Aarhus University, 8000 Aarhus C, Denmark
| | - Dominique Harakat
- Université de Reims Champagne Ardenne, CNRS UMR 7312, ICMR, URCATech, 51100 Reims, France
| | - Sylviane Chevreux
- Université de Reims Champagne Ardenne, CNRS UMR 7312, ICMR, URCATech, 51100 Reims, France
- Institut de Recherche de Chimie Paris, UMR CNRS 8247, Chimie ParisTech, PSL University, 75005 Paris, France
| | | | - Florian Jaroschik
- Université de Reims Champagne Ardenne, CNRS UMR 7312, ICMR, URCATech, 51100 Reims, France
- ICGM, Univ. Montpellier, CNRS, ENSCM, 34090 Montpellier, France.
| |
Collapse
|
2
|
Álvarez-Ruiz E, Sancho I, Navarro M, Fernández I, Santamaría C, Hernán-Gómez A. A Mixed-Valence Ti(II)/Ti(III) Inverted Sandwich Compound as a Regioselective Catalyst for the Uncommon 1,3,5-Alkyne Cyclotrimerization. Inorg Chem 2024; 63:8642-8653. [PMID: 38690944 PMCID: PMC11094787 DOI: 10.1021/acs.inorgchem.4c00149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
The synthesis, structure, and catalytic activity of a Ti(II)/Ti(III) inverted sandwich compound are presented in this study. Synthesis of the arene-bridged dititanium compound begins with the preparation of the titanium(IV) precursor [TiCl2(MesPDA)(thf)2] (MesPDA = N,N'-bis(2,4,6-trimethylphenyl)-o-phenylenediamide) (2). The reduction of 2 with sodium metal results in species [{Ti(MesPDA)(thf)}2(μ-Cl)3{Na}] (3) in oxidation state III. To achieve the lower oxidation state II, 2 undergoes reduction through alkylation with lithium cyclopentyl. This alkylation approach triggers a cascade of reactions, including β-hydride abstraction/elimination, hydrogen evolution, and chemical reduction, to generate the Ti(II)/Ti(III) compound [Li(thf)4][(TiMesPDA)2(μ-η6: η6-C6H6)] (4). X-ray and EPR characterization confirms the mixed-valence states of the titanium species. Compound 4 catalyzes a mild, efficient, and regiospecific cyclotrimerization of alkynes to form 1,3,5-substituted arenes. Kinetic data support a mechanism involving a binuclear titanium arene compound, similar to compound 4, as the resting state. The active catalyst promotes the oxidative coupling of two alkynes in the rate-limiting step, followed by a rapid [4 + 2] cycloaddition to form the arene product. Computational analysis of the resting state for the cycloaddition of trimethylsilylacetylene indicates a thermodynamic preference for stabilizing the 1,3,5-arene within the space between the two [TiMesPDA] fragments, consistent with the observed regioselectivity.
Collapse
Affiliation(s)
- Elena Álvarez-Ruiz
- Departamento
de Química Orgánica y Química Inorgánica,
Instituto de Investigación Química “Andrés
M. del Río” (IQAR), Universidad
de Alcalá, Campus Universitario, Alcalá de Henares, Madrid E-28805, Spain
| | - Ignacio Sancho
- Departamento
de Química Orgánica y Química Inorgánica,
Instituto de Investigación Química “Andrés
M. del Río” (IQAR), Universidad
de Alcalá, Campus Universitario, Alcalá de Henares, Madrid E-28805, Spain
| | - Marta Navarro
- Departamento
de Química Inorgánica, Orgánica y Bioquímica,
Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Ciudad Real 13071, Spain
| | - Israel Fernández
- Departamento
de Química Orgánica I, Facultad de Ciencias Químicas
and Centro de Innovación en Química Avanzada (ORFEO−CINQA), Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Cristina Santamaría
- Departamento
de Química Orgánica y Química Inorgánica,
Instituto de Investigación Química “Andrés
M. del Río” (IQAR), Universidad
de Alcalá, Campus Universitario, Alcalá de Henares, Madrid E-28805, Spain
| | - Alberto Hernán-Gómez
- Departamento
de Química Orgánica y Química Inorgánica,
Instituto de Investigación Química “Andrés
M. del Río” (IQAR), Universidad
de Alcalá, Campus Universitario, Alcalá de Henares, Madrid E-28805, Spain
| |
Collapse
|
3
|
Sen A, Sato T, Ohno A, Baek H, Muranaka A, Yamada YMA. Polymer-Supported-Cobalt-Catalyzed Regioselective Cyclotrimerization of Aryl Alkynes. JACS AU 2021; 1:2080-2087. [PMID: 34841419 PMCID: PMC8611791 DOI: 10.1021/jacsau.1c00360] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Indexed: 05/04/2023]
Abstract
A convoluted poly(4-vinylpyridine) cobalt(II) (P4VP-CoCl2) system was developed as a stable and reusable heterogeneous catalyst. The local structure near the Co atom was determined on the basis of experimental data and theoretical calculations. This immobilized cobalt catalyst showed high selectivity and catalytic activity in the [2 + 2 + 2] cyclotrimerization of terminal aryl alkynes. With 0.033 mol % P4VP-CoCl2, the regioselective formation of 1,3,5-triarylbenzene was realized without 1,2,4-triarylbenzene formation. Further, a multigram-scale (11 g) reaction proceeded efficiently. In addition, the polymer-supported catalyst was successfully recovered and used three times. X-ray photoelectron spectroscopy analysis of the recovered catalyst suggested that cobalt was in the +2 oxidation state. The 1,3,5-triarylbenzene derivatives were applied to the synthesis of a molecular beam electron resist and a polycyclic aromatic hydrocarbon.
Collapse
Affiliation(s)
- Abhijit Sen
- Center for Sustainable Resource Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Takuma Sato
- Center for Sustainable Resource Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Aya Ohno
- Center for Sustainable Resource Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Heeyoel Baek
- Center for Sustainable Resource Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Atsuya Muranaka
- Center for Sustainable Resource Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Yoichi M. A. Yamada
- Center for Sustainable Resource Science, RIKEN, Wako, Saitama 351-0198, Japan
| |
Collapse
|
4
|
Del Horno E, Jover J, Mena M, Pérez-Redondo A, Yélamos C. Low-Valent Titanium Species Stabilized with Aluminum/Boron Hydride Fragments. Chemistry 2021; 28:e202103085. [PMID: 34735025 DOI: 10.1002/chem.202103085] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Indexed: 11/09/2022]
Abstract
Low-valent titanium species were prepared by reaction of [TiCp*X3 ] (Cp*=η5 -C5 Me5 ; X=Cl, Br, Me) with LiEH4 (E=Al, B) or BH3 (thf), and their structures elucidated by experimental and theoretical methods. The treatment of trihalides [TiCp*X3 ] with LiAlH4 in ethereal solvents (L) leads to the hydride-bridged heterometallic complexes [{TiCp*(μ-H)}2 {(μ-H)2 AlX(L)}2 ] (L=thf, X=Cl, Br; L=OEt2 , X=Cl). Density functional theory (DFT) calculations for those compounds reveal an open-shell singlet ground state with a Ti-Ti bond and can be described as titanium(II) species. The theoretical analyses also show strong interactions between the Ti-Ti bond and the empty s orbitals of the Al atom of the AlH2 XL fragments, which behave as σ-accepting (Z-type) ligands. Analogous reactions of [TiCp*X3 ] with LiBH4 (2 and 3 equiv.) in tetrahydrofuran at room temperature and at 85 °C lead to the titanium(III) compounds [{TiCp*(BH4 )(μ-X)}2 ] (X=Cl, Br) and [{TiCp*(BH4 )(μ-BH4 )}2 ], respectively. The treatment of [TiCp*Me3 ] with 4 and 5 equiv. of BH3 (thf) produces the diamagnetic [{TiCp*(BH3 Me)}2 (μ-B2 H6 )] and paramagnetic [{TiCp*(μ-B2 H6 )}2 ] complexes, respectively.
Collapse
Affiliation(s)
- Estefanía Del Horno
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá, 28805 Alcalá de, Henares-Madrid, Spain
| | - Jesús Jover
- Secció de Química Inorgànica, Departament de Química Inorgànica i Orgànica, Institut de Química Teòrica i Computacional (IQTC-UB), Universitat de Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain
| | - Miguel Mena
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá, 28805 Alcalá de, Henares-Madrid, Spain
| | - Adrián Pérez-Redondo
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá, 28805 Alcalá de, Henares-Madrid, Spain
| | - Carlos Yélamos
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá, 28805 Alcalá de, Henares-Madrid, Spain
| |
Collapse
|
5
|
Ratovelomanana-Vidal V, Matton P, Huvelle S, Haddad M, Phansavath P. Recent Progress in Metal-Catalyzed [2+2+2] Cycloaddition Reactions. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/s-0040-1719831] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AbstractMetal-catalyzed [2+2+2] cycloaddition is a powerful tool that allows rapid construction of functionalized 6-membered carbo- and heterocycles in a single step through an atom-economical process with high functional group tolerance. The reaction is usually regio- and chemoselective although selectivity issues can still be challenging for intermolecular reactions involving the cross-[2+2+2] cycloaddition of two or three different alkynes and various strategies have been developed to attain high selectivities. Furthermore, enantioselective [2+2+2] cycloaddition is an efficient means to create central, axial, and planar chirality and a variety of chiral organometallic complexes can be used for asymmetric transition-metal-catalyzed inter- and intramolecular reactions. This review summarizes the recent advances in the field of [2+2+2] cycloaddition.1 Introduction2 Formation of Carbocycles2.1 Intermolecular Reactions2.1.1 Cyclotrimerization of Alkynes2.1.2 [2+2+2] Cycloaddition of Two Different Alkynes2.1.3 [2+2+2] Cycloaddition of Alkynes/Alkenes with Alkenes/Enamides2.2 Partially Intramolecular [2+2+2] Cycloaddition Reactions2.2.1 Rhodium-Catalyzed [2+2+2] Cycloaddition2.2.2 Molybdenum-Catalyzed [2+2+2] Cycloaddition2.2.3 Cobalt-Catalyzed [2+2+2] Cycloaddition2.2.4 Ruthenium-Catalyzed [2+2+2] Cycloaddition2.2.5 Other Metal-Catalyzed [2+2+2] Cycloaddition2.3 Totally Intramolecular [2+2+2] Cycloaddition Reactions3 Formation of Heterocycles3.1 Cycloaddition of Alkynes with Nitriles3.2 Cycloaddition of 1,6-Diynes with Cyanamides3.3 Cycloaddition of 1,6-Diynes with Selenocyanates3.4 Cycloaddition of Imines with Allenes or Alkenes3.5 Cycloaddition of (Thio)Cyanates and Isocyanates3.6 Cycloaddition of 1,3,5-Triazines with Allenes3.7 Cycloaddition of Aldehydes with Enynes or Allenes/Alkenes3.8 Totally Intramolecular [2+2+2] Cycloaddition Reactions4 Conclusion
Collapse
|
6
|
Ohta S, Miura N, Saitoh K, Itoh K, Satoh S, Miyamoto R, Okazaki M. Synthesis and Structures of Bis(indolyl)-Coordinated Titanium Dichlorido Complexes and Their Catalytic Application in the Cyclotrimerization of Alkynes. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Shun Ohta
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
| | - Narumi Miura
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
| | - Keiichiro Saitoh
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
| | - Keigo Itoh
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
| | - Sora Satoh
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
| | - Ryo Miyamoto
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
| | - Masaaki Okazaki
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
| |
Collapse
|
7
|
Dual-mode coupling copolymerization of aryl dialdehyde and alkynylaldehyde monomers via Concurrent McMurry olefination and alkyne [2+2+2] cycloaddition trimerization reactions mediated by a low-valent titanium reagent. POLYMER 2021. [DOI: 10.1016/j.polymer.2020.123344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
8
|
An Y, Zhang F, Cai Z, Du G. Direct Assembly of Polysubstituted Benzenes via Base-Catalyzed Benzannulation Reaction of α-Cyano- β-methylalkenyl-(hetero)aryl Ketones. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202104056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
9
|
Roldan-Molina E, Nievas MM, Navarro JAR, Oltra JE. CpTiCl 2 -Catalyzed Cross-Coupling between Internal Alkynes and Ketones: A Novel Concept in the Synthesis of Halogenated, Conjugated Dienes. Chemistry 2020; 26:8296-8301. [PMID: 32212287 DOI: 10.1002/chem.202001023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/20/2020] [Indexed: 11/10/2022]
Abstract
A novel concept for the synthesis of halogenated, conjugated dienes is disclosed: the CpTiCl2 -catalyzed coupling of keto-alkynes, in the presence of Me3 SiBr/Et3 N⋅HBr. This reaction provided five-, six-, and seven-membered carbocycles, nitrogenated heterocycles, as well as six-membered oxygenated heterocycles leading to a brominated conjugate diene. These products showed high reactivity in the Diels-Alder, Suzuki, and Sonogashira reactions, giving complex chemical structures in only three steps from the corresponding acyclic keto-alkyne. Hopefully, this strategy will pave the way towards the synthesis of bioactive natural products and new materials.
Collapse
Affiliation(s)
- Esther Roldan-Molina
- Department of Organic Chemistry, Faculty of Sciences, University of Granada, Campus Fuentenueva s/n, 18071, Granada, Spain
| | - Maria M Nievas
- Department of Organic Chemistry, Faculty of Sciences, University of Granada, Campus Fuentenueva s/n, 18071, Granada, Spain
| | - Jorge A R Navarro
- Department of Inorganic Chemistry, University of Granada, Campus Fuentenueva s/n, 18071, Granada, Spain
| | - J Enrique Oltra
- Department of Organic Chemistry, Faculty of Sciences, University of Granada, Campus Fuentenueva s/n, 18071, Granada, Spain
| |
Collapse
|
10
|
Horno ED, Jiménez-Aparicio R, Mena M, Pérez-Redondo A, Priego JL, Yélamos C. Preparation of Dimeric Monopentamethylcyclopentadienyltitanium(III) Dihalides and Related Derivatives. Inorg Chem 2020; 59:3740-3752. [PMID: 32101433 DOI: 10.1021/acs.inorgchem.9b03399] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis, crystal structure, and reactivity of a series of half-sandwich titanium(III) dihalide complexes [Ti(η5-C5Me5)X2] (X = Cl, Br, I) and several of its Lewis base derivatives were investigated. The reaction of the trihalides [Ti(η5-C5Me5)X3] (X = Cl (1), Br (2), I (3)) with LiAlH4 (≥1 equiv) in toluene at room temperature results in the formation of the halide-bridged dimers [{Ti(η5-C5Me5)X(μ-X)}2] (X = Cl (4), Br (5), I (6)). The treatment of 4 with [Li{N(SiMe3)2}] (≥2 equiv) at room temperature affords the precipitation of the amido titanium(III) complex [{Ti(η5-C5Me5)(μ-Cl){N(SiMe3)2}}2] (7), but analogous reactions of 4 with other lithium reagents [LiR] (R = Me, CH2SiMe3, NMe2) lead to disproportionation into titanium(IV) [Ti(η5-C5Me5)R3] and presumably titanium(II) derivatives. Similarly, complex 4 in solution at temperatures higher than 100 °C undergoes disproportionation as demonstrated by its reactions with cobaltocene and N-(4-methylbenzylidene)aniline yielding the ionic paramagnetic compound [Co(η5-C5H5)2][Ti(η5-C5Me5)Cl3] (8) and the diamagnetic diazatitanacyclopentane [Ti(η5-C5Me5)Cl{N(Ph)CH(p-tolyl)}2], respectively. Treatment of complex 4 with 2 equiv of 2,6-dimethylphenylisocyanide or tert-butylisocyanide in toluene at room temperature affords the paramagnetic titanium(III) dinuclear adducts [{Ti(η5-C5Me5)Cl(μ-Cl)(CNR)}2] (R = 2,6-Me2C6H3 (9), tBu (10)). Magnetic studies for polycrystalline 9 show that it displays a weak intramolecular antiferromagnetic coupling between the Ti ions, which is consistent with the long Ti-Ti distance of 3.857(1) Å determined by X-ray diffraction. The isocyanide ligands in complex 10 undergo a reductive coupling reaction in toluene to give the titanium(IV) iminoacyl derivative [{Ti(η5-C5Me5)Cl2}2(μ-η2:η2-tBuN═C-C═NtBu)] (11). Whereas an analogous dinuclear structure was found in the aqua titanium(III) complex [{Ti(η5-C5Me5)Cl(μ-Cl)(OH2)}2] (12), resulting from the reaction of 4 with adventitious amounts of water, compound 4 reacts with excess ammonia to give a mononuclear adduct [Ti(η5-C5Me5)Cl2(NH3)2] (13) with a robust layered pattern in the solid state.
Collapse
Affiliation(s)
| | - Reyes Jiménez-Aparicio
- Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | | | | | - José Luis Priego
- Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | | |
Collapse
|
11
|
Torres‐García I, López‐Martínez JL, Martínez‐Martínez R, Oltra JE, Muñoz‐Dorado M, Rodríguez‐García I, Álvarez‐Corral M. The half‐sandwich titanocene CpTi
III
Cl
2
as efficient system for the preparation of 2,5‐dihydrofurans
via
α‐allenols. Appl Organomet Chem 2020. [DOI: 10.1002/aoc.5244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | | | | | - J. Enrique Oltra
- Dpto. Química Orgánica, Facultad de CienciasUniversidad de Granada Granada E18071 Spain
| | | | | | | |
Collapse
|
12
|
Manßen M, Schafer LL. Titanium catalysis for the synthesis of fine chemicals – development and trends. Chem Soc Rev 2020; 49:6947-6994. [DOI: 10.1039/d0cs00229a] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Atlas as a Titan(ium) is holding the earth-abundant chemistry world. Titanium is the second most abundant transition metal, is a key player in important industrial processes (e.g. polyethylene) and shows much promise for diverse applications in the future.
Collapse
Affiliation(s)
- Manfred Manßen
- The Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
| | - Laurel L. Schafer
- The Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
| |
Collapse
|
13
|
Reiner BR, Tonks IA. Group 4 Diarylmetallocenes as Bespoke Aryne Precursors for Titanium-Catalyzed [2 + 2 + 2] Cycloaddition of Arynes and Alkynes. Inorg Chem 2019; 58:10508-10515. [PMID: 31188580 DOI: 10.1021/acs.inorgchem.9b01082] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Despite the ubiquity of reports describing titanium (Ti)-catalyzed [2 + 2 + 2] cyclotrimerization of alkynes, the incorporation of arynes into this potent manifold has never been reported. The in situ generation of arynes often requires fluoride, which instead will react with the highly fluorophilic Ti center, suppressing productive catalysis. Herein, we describe the use of group 4 diarylmetallocenes, CpR2MAr2 (CpR = C5H5, C5Me5; M = Ti, Zr), as aryne precursors for the Ti-catalyzed synthesis of substituted naphthalenes via coupling with 2 equiv of an alkyne. Fair-to-good yields of the desired naphthalene products could be obtained with 1% catalyst loadings, which is roughly an order of magnitude lower than similar reactions catalyzed by palladium or nickel. Additionally, naphthalenes find broad applications in the electronics, photovoltaics, and pharmaceutical industries, urging the discovery of more economic syntheses. These results indicate that aryne transfer from a CpR2M(η2-aryne) complex to another metal is a viable route for the introduction of aryne fragments into organometallic catalytic processes.
Collapse
Affiliation(s)
- Benjamin R Reiner
- Department of Chemistry , University of Minnesota-Twin Cities , 207 Pleasant Street SE , Minneapolis , Minnesota 55455 , United States
| | - Ian A Tonks
- Department of Chemistry , University of Minnesota-Twin Cities , 207 Pleasant Street SE , Minneapolis , Minnesota 55455 , United States
| |
Collapse
|
14
|
García-Castro M, García-Iriepa C, Del Horno E, Martín A, Mena M, Pérez-Redondo A, Temprado M, Yélamos C. The Puzzling Monopentamethylcyclopentadienyltitanium(III) Dichloride Reagent: Structure and Properties. Inorg Chem 2019; 58:5314-5324. [PMID: 30943022 DOI: 10.1021/acs.inorgchem.9b00437] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Following the track of the useful titanocene [Ti(η5-C5H5)2Cl] reagent in organic synthesis, the related half-sandwich titanium(III) derivatives [Ti(η5-C5R5)Cl2] are receiving increasing attention in radical chemistry of many catalyzed transformations. However, the structure of the active titanium(III) species remains unknown in the literature. Herein, we describe the synthesis, crystal structure, and electronic structure of titanium(III) aggregates of composition [{Ti(η5-C5Me5)Cl2} n]. The thermolysis of [Ti(η5-C5Me5)Cl2Me] (1) in benzene or hexane at 180 °C results in the clean formation of [{Ti(η5-C5Me5)Cl(μ-Cl)}2] (2), methane, and ethene. The treatment of 1 with excess pinacolborane in hexane at 65 °C leads to a mixture of 2 and the paramagnetic trimer [{Ti(η5-C5Me5)(μ-Cl)2}3] (3). The X-ray crystal structures of compounds 2 and 3 show Ti-Ti distances of 3.267(1) and 3.219(12) Å, respectively. Computational studies (CASPT2//CASSCF and BS DFT methods) for dimer 2 reveal a singlet ground state and a relatively large singlet-triplet energy gap. Nuclear magnetic resonance spectroscopy of 2 in aromatic hydrocarbon solutions and DFT calculations for several [{Ti(η5-C5Me5)Cl2} n] aggregates are consistent with the existence of an equilibrium between the diamagnetic dimer [{Ti(η5-C5Me5)Cl(μ-Cl)}2] and a paramagnetic tetramer [{Ti(η5-C5Me5)(μ-Cl)2}4] in solution. In contrast, complex 2 readily dissolves in tetrahydrofuran to give a green-blue solution from which blue crystals of the mononuclear adduct [Ti(η5-C5Me5)Cl2(thf)] (4) were grown.
Collapse
Affiliation(s)
- María García-Castro
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Cristina García-Iriepa
- Departamento de Química Analítica, Química Física e Ingeniería Química , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Departamento de Química , Universidad de La Rioja, Centro de Investigación en Síntesis Química (CISQ) , 26006 Logroño , Spain
| | - Estefanía Del Horno
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Avelino Martín
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Miguel Mena
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Adrián Pérez-Redondo
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Manuel Temprado
- Departamento de Química Analítica, Química Física e Ingeniería Química , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Carlos Yélamos
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| |
Collapse
|
15
|
Shen L, Zhao Y, Luo Q, Li QS, Liu B, Redshaw C, Wu B, Yang XJ. Cyclotrimerization of alkynes catalyzed by a self-supported cyclic tri-nuclear nickel(0) complex with α-diimine ligands. Dalton Trans 2019; 48:4643-4649. [DOI: 10.1039/c9dt00819e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The cyclic tri-nickel(0) complex [{Ni(μ-LMe-2,4)}3] (LMe-2,4 = [(2,4-Me2C6H3)NC(Me)]2) self-supported by the α-diimines catalyzes cyclotrimerization of alkynes to form substituted benzenes.
Collapse
Affiliation(s)
- Lingyi Shen
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Yanxia Zhao
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Qiong Luo
- Center for Computational Quantum Chemistry
- South China Normal University
- Guangzhou 510631
- China
| | - Qian-Shu Li
- Center for Computational Quantum Chemistry
- South China Normal University
- Guangzhou 510631
- China
| | - Bin Liu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Carl Redshaw
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Biao Wu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Xiao-Juan Yang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| |
Collapse
|