1
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Anderson DE, Tortajada A, Hevia E. New Frontiers in Organosodium Chemistry as Sustainable Alternatives to Organolithium Reagents. Angew Chem Int Ed Engl 2024; 63:e202313556. [PMID: 37801443 DOI: 10.1002/anie.202313556] [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: 09/12/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/08/2023]
Abstract
With their highly reactive respective C-Na and N-Na bonds, organosodium and sodium amide reagents could be viewed as obvious replacements or even superior reagents to the popular, widely utilised organolithiums. However, they have seen very limited applications in synthesis due mainly to poor solubility in common solvents and their limited stability. That notwithstanding in recent years there has been a surge of interest in bringing these sustainable metal reagents into the forefront of organometallics in synthesis. Showcasing the growth in utilisation of organosodium complexes within several areas of synthetic chemistry, this Minireview discusses promising new methods that have been recently reported with the goal of taming these powerful reagents. Special emphasis is placed on coordination and aggregation effects in these reagents which can impart profound changes in their solubility and reactivity. Differences in observed reactivity between more nucleophilic aryl and alkyl sodium reagents and the less nucleophilic but highly basic sodium amides are discussed along with current mechanistic understanding of their reactivities. Overall, this review aims to inspire growth in this exciting field of research to allow for the integration of organosodium complexes within common important synthetic transformations.
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Affiliation(s)
- David E Anderson
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Andreu Tortajada
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Eva Hevia
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
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2
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Day C, Do CD, Odena C, Benet-Buchholz J, Xu L, Foroutan-Nejad C, Hopmann KH, Martin R. Room-Temperature-Stable Magnesium Electride via Ni(II) Reduction. J Am Chem Soc 2022; 144:13109-13117. [PMID: 35830190 PMCID: PMC9345648 DOI: 10.1021/jacs.2c01807] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Herein, we report the synthesis of highly reduced bipyridyl magnesium complexes and the first example of a stable organic magnesium electride supported by quantum mechanical computations and X-ray diffraction. These complexes serve as unconventional homogeneous reductants due to their high solubility, modular redox potentials, and formation of insoluble, non-coordinating byproducts. The applicability of these reductants is showcased by accessing low-valent (bipy)2Ni(0) species that are challenging to access otherwise.
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Affiliation(s)
- Craig
S. Day
- Institute
of Chemical Research of Catalonia (ICIQ), The Barcelona Institute
of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain
- Departament
de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel·lí Domingo, 1, 43007 Tarragona, Spain
| | - Cuong Dat Do
- Hylleraas Center for Quantum Molecular Sciences and Department of
Chemistry, UiT The Arctic University of
Norway, N-9037 Tromsø, Norway
| | - Carlota Odena
- Institute
of Chemical Research of Catalonia (ICIQ), The Barcelona Institute
of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain
- Departament
de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel·lí Domingo, 1, 43007 Tarragona, Spain
| | - Jordi Benet-Buchholz
- Institute
of Chemical Research of Catalonia (ICIQ), The Barcelona Institute
of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain
| | - Liang Xu
- Institute
of Chemical Research of Catalonia (ICIQ), The Barcelona Institute
of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain
| | - Cina Foroutan-Nejad
- Institute
of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Kathrin H. Hopmann
- Hylleraas Center for Quantum Molecular Sciences and Department of
Chemistry, UiT The Arctic University of
Norway, N-9037 Tromsø, Norway
| | - Ruben Martin
- Institute
of Chemical Research of Catalonia (ICIQ), The Barcelona Institute
of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain
- ICREA, Passeig Lluís Companys, 23, 08010 Barcelona, Spain
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3
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Hess A, Guelen HC, Alandini N, Mourati A, Guersoy YC, Knochel P. Preparation of Polyfunctionalized Aromatic Nitriles from Aryl Oxazolines. Chemistry 2022; 28:e202103700. [PMID: 34766655 PMCID: PMC9300023 DOI: 10.1002/chem.202103700] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Indexed: 12/17/2022]
Abstract
A selective ortho,ortho'-functionalization of readily available aryl oxazolines by two successive magnesiations with sBu2 Mg in toluene followed by trapping reactions with electrophiles, such as (hetero)aryl iodides or bromides, iodine, tosyl cyanide, ethyl cyanoformate or allylic bromides (39 examples, 62-99 % yield) is reported. Treatment of these aryl oxazolines with excess oxalyl chloride and catalytic amounts of DMF (50 °C, 4 h) provided the corresponding nitriles (36 examples, 73-99 % yield). Conversions of these nitriles to valuable heterocycles are reported, and a tentative mechanism is proposed.
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Affiliation(s)
- A. Hess
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstrasse 5–13, Haus F81377MünchenGermany
| | - H. C. Guelen
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstrasse 5–13, Haus F81377MünchenGermany
| | - N. Alandini
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstrasse 5–13, Haus F81377MünchenGermany
| | - A. Mourati
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstrasse 5–13, Haus F81377MünchenGermany
| | - Y. C. Guersoy
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstrasse 5–13, Haus F81377MünchenGermany
| | - P. Knochel
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstrasse 5–13, Haus F81377MünchenGermany
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4
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Halogen-sodium exchange enables efficient access to organosodium compounds. Commun Chem 2021; 4:76. [PMID: 36697639 PMCID: PMC9814623 DOI: 10.1038/s42004-021-00513-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/22/2021] [Indexed: 02/04/2023] Open
Abstract
With sodium being the most abundant alkali metal on Earth, organosodium compounds are an attractive choice for sustainable chemical synthesis. However, organosodium compounds are rarely used-and are overshadowed by organolithium compounds-because of a lack of convenient and efficient preparation methods. Here we report a halogen-sodium exchange method to prepare a large variety of (hetero)aryl- and alkenylsodium compounds including tri- and tetrasodioarenes, many of them previously inaccessible by other methods. The key discovery is the use of a primary and bulky alkylsodium lacking β-hydrogens, which retards undesired reactions, such as Wurtz-Fittig coupling and β-hydrogen elimination, and enables efficient halogen-sodium exchange. The alkylsodium is readily prepared in situ from neopentyl chloride and an easy-to-handle sodium dispersion. We believe that the efficiency, generality, and convenience of the present method will contribute to the widespread use of organosodium in organic synthesis, ultimately contributing to the development of sustainable organic synthesis by rivalling the currently dominant organolithium reagents.
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5
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Hess A, Prohaska JP, Doerrich SB, Trauner F, Lutter FH, Lemaire S, Wagschal S, Karaghiosoff K, Knochel P. Directed regioselective ortho, ortho'-magnesiations of aromatics and heterocycles using sBu 2Mg in toluene. Chem Sci 2021; 12:8424-8429. [PMID: 34221323 PMCID: PMC8221067 DOI: 10.1039/d1sc01777b] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/17/2021] [Indexed: 11/25/2022] Open
Abstract
Aryl azoles are ubiquitous as bioactive compounds and their regioselective functionalization is of utmost synthetic importance. Here, we report the development of a toluene-soluble dialkylmagnesium base sBu2Mg. This new reagent allows mild and regioselective ortho-magnesiations of various N-arylated pyrazoles and 1,2,3-triazoles as well as arenes bearing oxazoline, phosphorodiamidate or amide directing groups. The resulting diarylmagnesium reagents were further functionalized either by Pd-catalyzed arylation or by trapping reactions with a broad range of electrophiles (aldehydes, ketones, allylic halides, acyl chlorides, Weinreb amides, aryl halides, hydroxylamine benzoates, terminal alkynes). Furthermore, several double ortho,ortho'-magnesiations were realized in the case of aryl oxazolines, N-aryl pyrazoles as well as 2-aryl-2H-1,2,3-triazoles by simply repeating the magnesiation/electrophile trapping sequence allowing the preparation of valuable 1,2,3-functionalized arenes.
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Affiliation(s)
- Andreas Hess
- Ludwig-Maximilians-Universität München, Department Chemie Butenandtstrasse 5-13, Haus F 81377 München Germany
| | - Jan P Prohaska
- Ludwig-Maximilians-Universität München, Department Chemie Butenandtstrasse 5-13, Haus F 81377 München Germany
| | - Sabrina B Doerrich
- Ludwig-Maximilians-Universität München, Department Chemie Butenandtstrasse 5-13, Haus F 81377 München Germany
| | - Florian Trauner
- Ludwig-Maximilians-Universität München, Department Chemie Butenandtstrasse 5-13, Haus F 81377 München Germany
| | - Ferdinand H Lutter
- Ludwig-Maximilians-Universität München, Department Chemie Butenandtstrasse 5-13, Haus F 81377 München Germany
| | - Sébastien Lemaire
- Janssen Pharmaceutica, Chemical Process Research & Development Turnhoutseweg 30 B-2340 Beerse Belgium
| | - Simon Wagschal
- Janssen Pharmaceutica, Chemical Process Research & Development Hochstrasse 201 8200 Schaffhausen Switzerland
| | - Konstantin Karaghiosoff
- Ludwig-Maximilians-Universität München, Department Chemie Butenandtstrasse 5-13, Haus F 81377 München Germany
| | - Paul Knochel
- Ludwig-Maximilians-Universität München, Department Chemie Butenandtstrasse 5-13, Haus F 81377 München Germany
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6
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Bruña S, Kennedy AR, Fairley M, O'Hara CT. Facile Access to Hetero-poly-functional Arenes and meta-Substituted Arenes via Two-Step Dimetalation and Mg/Halogen-Exchange Protocol. Chemistry 2021; 27:4134-4140. [PMID: 33201552 DOI: 10.1002/chem.202004696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Indexed: 11/07/2022]
Abstract
The Grignard reagent, iPrMgCl and its lithium chloride-enhanced 'turbo' derivative iPrMgCl⋅LiCl have been employed to investigate the single iodo/magnesium exchange reactions of the trisubstituted arenes, 2,5-diiodo-N,N-diisopropylbenzamide 1, 1,4-diiodo-2-methoxybenzene 2, and 1,4-diiodo-2-(trifluoromethyl)benzene 3. These three arenes themselves were initially prepared by a double ortho-, meta'-deprotonation of N,N-diisopropylbenzamide, anisole and (trifluoromethyl)benzene, respectively, using the sodium magnesiate reagent [Na4 Mg2 (TMP)6 (nBu)2 ] (where TMP is 2,2,6,6-tetramethylpiperidide), and subsequent electrophilic quenching with iodine/THF solution. Thus, by following a combined deprotonation and magnesium/halogen exchange strategy, the simple monosubstituted arenes can be converted to trisubstituted diiodoarenes, which can ultimately be transformed into the corresponding mono-magnesiated arenes, in THF at -40 °C, within seconds in good yields. The other functional group (OMe, NiPr2 or CF3 respectively) present on the di-iodoarenes helps direct the exchange reaction to the ortho position, whereas subsequent addition of different electrophiles permits the preparation of hetero-poly-functional-arenes, with three different substituents in their structure. Intriguingly, if water is used as the electrophile, a new and facile route to prepare meta-substituted arenes, which cannot be easily obtained by conventional processes, is forthcoming. In contrast to directed ortho-metalation (DoM) chemistry, this reaction sequence can be thought of as InDirect meta-Metalation (IDmM). The scope of the chemistry has been tested further by exposing the initial unreacted iodo-functionality at the meta-position to a second Mg/I-exchange reaction and subsequent functionalization.
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Affiliation(s)
- Sonia Bruña
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, Scotland
| | - Alan R Kennedy
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, Scotland
| | - Michael Fairley
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, Scotland
| | - Charles T O'Hara
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, Scotland
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7
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Lutter FH, Grokenberger L, Perego LA, Broggini D, Lemaire S, Wagschal S, Knochel P. Regioselective functionalization of aryl azoles as powerful tool for the synthesis of pharmaceutically relevant targets. Nat Commun 2020; 11:4443. [PMID: 32895371 PMCID: PMC7477575 DOI: 10.1038/s41467-020-18188-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 08/03/2020] [Indexed: 02/02/2023] Open
Abstract
Aryl azole scaffolds are present in a wide range of pharmaceutically relevant molecules. Their ortho-selective metalation at the aryl ring is challenging, due to the competitive metalation of the more acidic heterocycle. Seeking a practical access to a key Active Pharmaceutical Ingredient (API) intermediate currently in development, we investigated the metalation of 1-aryl-1H-1,2,3-triazoles and other related heterocycles with sterically hindered metal-amide bases. We report here a room temperature and highly regioselective ortho-magnesiation of several aryl azoles using a tailored magnesium amide, TMPMgBu (TMP = 2,2,6,6-tetramethylpiperidyl) in hydrocarbon solvents followed by an efficient Pd-catalyzed arylation. This scalable and selective reaction allows variation of the initial substitution pattern of the aryl ring, the nature of the azole moiety, as well as the nature of the electrophile. This versatile method can be applied to the synthesis of bioactive azole derivatives and complements existing metal-mediated ortho-functionalizations. Aryl azoles are common scaffolds in pharmaceutically relevant molecules. Here, the authors report the mild and highly regioselective ortho magnesiation of aryl azoles using a tailored magnesium amide base in hydrocarbon solvents followed by an efficient Pd-catalyzed arylation.
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Affiliation(s)
- Ferdinand H Lutter
- Ludwig-Maximilians-Universität München, Department Chemie, Butenandtstrasse 5-13, Haus F, 81377, München, Germany
| | - Lucie Grokenberger
- Ludwig-Maximilians-Universität München, Department Chemie, Butenandtstrasse 5-13, Haus F, 81377, München, Germany
| | - Luca Alessandro Perego
- Discovery Product Development and Supply, Janssen Pharmaceutica, Hochstrasse 201, 8200, Schaffhausen, Switzerland
| | - Diego Broggini
- Discovery Product Development and Supply, Janssen Pharmaceutica, Hochstrasse 201, 8200, Schaffhausen, Switzerland
| | - Sébastien Lemaire
- Discovery Product Development and Supply, Janssen Pharmaceutica, Turnhoutseweg 30, B-2340, Beerse, Belgium
| | - Simon Wagschal
- Discovery Product Development and Supply, Janssen Pharmaceutica, Hochstrasse 201, 8200, Schaffhausen, Switzerland.
| | - Paul Knochel
- Ludwig-Maximilians-Universität München, Department Chemie, Butenandtstrasse 5-13, Haus F, 81377, München, Germany.
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8
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Balkenhohl M, Jangra H, Makarov IS, Yang S, Zipse H, Knochel P. A Predictive Model Towards Site-Selective Metalations of Functionalized Heterocycles, Arenes, Olefins, and Alkanes using TMPZnCl⋅LiCl. Angew Chem Int Ed Engl 2020; 59:14992-14999. [PMID: 32400069 PMCID: PMC7497272 DOI: 10.1002/anie.202005372] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Indexed: 01/02/2023]
Abstract
The development of a predictive model towards site-selective deprotometalation reactions using TMPZnCl⋅LiCl is reported (TMP=2,2,6,6-tetramethylpiperidinyl). The pKa values of functionalized N-, S-, and O-heterocycles, arenes, alkenes, or alkanes were calculated and compared to the experimental deprotonation sites. Large overlap (>80 %) between the calculated and empirical deprotonation sites was observed, showing that thermodynamic factors strongly govern the metalation regioselectivity. In the case of olefins, calculated frozen state energies of the deprotonated substrates allowed a more accurate prediction. Additionally, various new N-heterocycles were analyzed and the metalation regioselectivities rationalized using the predictive model.
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Affiliation(s)
- Moritz Balkenhohl
- Department of ChemistryLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MunichGermany
| | - Harish Jangra
- Department of ChemistryLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MunichGermany
| | - Ilya S. Makarov
- Department of ChemistryLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MunichGermany
| | - Shu‐Mei Yang
- Department of ChemistryNational (Taiwan) Normal University88, Sec. 4, Tingchow RoadTaipei11677Taiwan, Republic of China
| | - Hendrik Zipse
- Department of ChemistryLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MunichGermany
| | - Paul Knochel
- Department of ChemistryLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MunichGermany
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9
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Balkenhohl M, Jangra H, Makarov IS, Yang S, Zipse H, Knochel P. A Predictive Model Towards Site‐Selective Metalations of Functionalized Heterocycles, Arenes, Olefins, and Alkanes using TMPZnCl⋅LiCl. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005372] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Moritz Balkenhohl
- Department of Chemistry Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 Munich Germany
| | - Harish Jangra
- Department of Chemistry Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 Munich Germany
| | - Ilya S. Makarov
- Department of Chemistry Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 Munich Germany
| | - Shu‐Mei Yang
- Department of Chemistry National (Taiwan) Normal University 88, Sec. 4, Tingchow Road Taipei 11677 Taiwan, Republic of China
| | - Hendrik Zipse
- Department of Chemistry Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 Munich Germany
| | - Paul Knochel
- Department of Chemistry Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 Munich Germany
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10
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Yeardley C, Kennedy AR, Gros PC, Touchet S, Fairley M, McLellan R, Martínez-Martínez AJ, O'Hara CT. Structural and metal-halogen exchange reactivity studies of sodium magnesiate biphenolate complexes. Dalton Trans 2020; 49:5257-5263. [PMID: 32242567 DOI: 10.1039/d0dt00904k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bimetallic sodium magnesiates have been employed in metal-halogen exchange for the first time. Utilising the racemic phenoxide ligand 5,5',6,6'-tetramethyl-3,3'-di-tert-butyl-1,1'-biphenyl-2,2'-diol [(rac)-BIPHEN-H2], the dialkyl sodium magnesiates [(rac)-BIPHEN]Na2MgBu2(TMEDA)23 and [(rac)-BIPHEN]Na2MgBu2(PMDETA)24 have been synthesised. Both 3 and 4 can be easily prepared through co-complexation of di-n-butylmagnesium with the sodiated (rac)-BIPHEN precursor which can be prepared in situ in hydrocarbon solvent. Prior to the main investigation, synthesis of the sodiated precursor [BIPHEN]2Na4(THF)41 was explored in order to better understand the formation of sodium magnesiates utilising the dianionic (rac)-BIPHEN ligand as the parent ligand. In addition, a BIPHEN-rich sodium magnesiate [BIPHEN]2Na2Mg(THF)42 was prepared and characterised, and its formation was rationalised. Complex 1 and 4 have also been fully characterised in both solid and solution state. In terms of onward reactivity, 3 and 4 have been tested as potential exchange reagents with aryl and heteroaryl iodides to produce aryl and heteroaryl magnesium phenoxides utilising toluene as a non-polar hydrocarbon solvent. Complex 3 reacted smoothly to give a range of aryl and heteroaryl magnesium phenoxides, whilst 4's reactivity is more sluggish.
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Affiliation(s)
- Callum Yeardley
- WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Alan R Kennedy
- WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | | | | | - Michael Fairley
- WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Ross McLellan
- WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Antonio J Martínez-Martínez
- Supramolecular Organometallic Chemistry Laboratory CIQSO-Center for Research in Sustainable Chemistry & Department of Chemistry University of Huelva Campus El Camen, 21007 Huelva, Spain
| | - Charles T O'Hara
- WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
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11
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Honeyman GW, Armstrong DR, Clegg W, Hevia E, Kennedy AR, McLellan R, Orr SA, Parkinson JA, Ramsay DL, Robertson SD, Towie S, Mulvey RE. A regioselectively 1,1',3,3'-tetrazincated ferrocene complex displaying core and peripheral reactivity. Chem Sci 2020; 11:6510-6520. [PMID: 34094116 PMCID: PMC8152701 DOI: 10.1039/d0sc01612h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 03/26/2020] [Indexed: 11/21/2022] Open
Abstract
Regioselective 1,1',3,3'-tetrazincation [C-H to C-Zn(tBu)] of ferrocene has been achieved by reaction of a fourfold excess of di-t-butylzinc (tBu2Zn) with sodium 2,2,6,6-tetramethylpiperidide (NaTMP) in hexane solution manifested in the trimetallic iron-sodium-zinc complex [Na4(TMP)4Zn4(tBu)4{(C5H3)2Fe}], 1. X-ray crystallographic studies supported by DFT modelling reveal the structure to be an open inverse crown in which two [Na(TMP)Zn(tBu)Na(TMP)Zn(tBu)]2+ cationic units surround a {(C5H3)2Fe}4- tetraanion. Detailed C6D6 NMR studies have assigned the plethora of 1H and 13C chemical shifts of this complex. It exists in a major form in which capping and bridging TMP groups interchange, as well as a minor form that appears to be an intermediate in this complicated exchange phenomenon. Investigation of 1 has uncovered two distinct reactivities. Two of its peripheral t-butyl carbanions formally deprotonate toluene at the lateral methyl group to generate benzyl ligands that replace these carbanions in [Na4(TMP)4Zn4(tBu)2(CH2Ph)2{(C5H3)2Fe}], 2, which retains its tetrazincated ferrocenyl core. Benzyl-Na π-arene interactions are a notable feature of 2. In contrast, reaction with pyridine affords the crystalline product {[Na·4py][Zn(py*)2(tBu)·py]}∞, 3, where py is neutral pyridine (C5H5N) and py* is the anion (4-C5H4N), a rare example of pyridine deprotonated/metallated at the 4-position. This ferrocene-free complex appears to be a product of core reactivity in that the core-positioned ferrocenyl anions of 1, in company with TMP anions, have formally deprotonated the heterocycle.
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Affiliation(s)
- Gordon W Honeyman
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - David R Armstrong
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - William Clegg
- Chemistry, School of Natural and Environmental Sciences, Newcastle University Newcastle upon Tyne NE1 7RU UK
| | - Eva Hevia
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - Alan R Kennedy
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - Ross McLellan
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - Samantha A Orr
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - John A Parkinson
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - Donna L Ramsay
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - Stuart D Robertson
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - Stephen Towie
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
| | - Robert E Mulvey
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde Glasgow G1 1XL UK
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12
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Martínez-Martínez AJ, Kennedy AR, Paprocki V, Fantuzzi F, Dewhurst RD, O'Hara CT, Braunschweig H, Mulvey RE. Selective mono- and dimetallation of a group 3 sandwich complex. Chem Commun (Camb) 2019; 55:9677-9680. [PMID: 31347619 DOI: 10.1039/c9cc03825f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The scandium Cp/COT hybrid sandwich compound [(η5-C5H5)Sc(η8-C8H8)] is resistant to metallation via conventional alkyllithium and lithium amide bases. In this work, clean, selective, stoichiometric and high-yielding mono- and dimetallation is accomplished using tandem trans-metal-trapping (TMT) involving LiTMP and iBu2AlTMP with deprotonation occurring selectively at the Cp and Cp/COT rings respectively, providing the first examples of selective metallation of a sandwich complex featuring a group 3 element.
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Affiliation(s)
- Antonio J Martínez-Martínez
- Supramolecular Organometallic Chemistry Laboratory CIQSO-Center for Research in Sustainable Chemistry & Department of Chemistry University of Huelva Campus El Camen, 21007 Huelva, Spain
| | - Alan R Kennedy
- WestCHEM, Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL, UK.
| | - Valerie Paprocki
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland, 97074 Würzburg, Germany.
| | - Felipe Fantuzzi
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland, 97074 Würzburg, Germany.
| | - Rian D Dewhurst
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland, 97074 Würzburg, Germany.
| | - Charles T O'Hara
- WestCHEM, Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL, UK.
| | - Holger Braunschweig
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland, 97074 Würzburg, Germany.
| | - Robert E Mulvey
- WestCHEM, Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL, UK.
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Fairley M, Davin L, Hernán-Gómez A, García-Álvarez J, O'Hara CT, Hevia E. s-Block cooperative catalysis: alkali metal magnesiate-catalysed cyclisation of alkynols. Chem Sci 2019; 10:5821-5831. [PMID: 31293771 PMCID: PMC6568277 DOI: 10.1039/c9sc01598a] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/26/2019] [Indexed: 01/04/2023] Open
Abstract
Through mixed metal cooperativity, alkali metal magnesiates efficiently catalyse the cyclisation of alkynols.
Mixed s-block metal organometallic reagents have been successfully utilised in the catalytic intramolecular hydroalkoxylation of alkynols. This success has been attributed to the unique manner in which these reagents can overcome the challenges of the reaction: namely OH activation and coordination to and then addition across a C
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C bond. In order to optimise the reaction conditions and to garner vital catalytic system requirements, a series of alkali metal magnesiates were enlisted for the catalytic intramolecular hydroalkoxylation of 4-pentynol. In a prelude to the main investigation, the homometallic magnesium dialkyl reagent MgR2 (where R = CH2SiMe3) was utilised. This reagent was unsuccessful in cyclising the alcohol into 2-methylenetetrahydrofuran 2a or 5-methyl-2,3-dihydrofuran 2b, even in the presence of multidentate Lewis donor molecules such as N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PMDETA). Alkali metal magnesiates MIMgR3 (when MI = Li, Na or K) performed the cyclisation unsatisfactorily both in the absence/presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) or PMDETA. When higher-order magnesiates (i.e., MI2MgR4) were employed, in general a marked increase in yield was observed for MI = Na or K; however, the reactions were still sluggish with long reaction times (22–36 h). A major improvement in the catalytic activity of the magnesiates was observed when the crown ether molecule 15-crown-5 was combined with sodium magnesiate Na2MgR4(TMEDA)2 furnishing yields of 87% with 2a : 2b ratios of 95 : 5 after 5 h. Similar high yields of 88% with 2a : 2b ratios of 90 : 10 after 3 h were obtained combining 18-crown-6 with potassium magnesiate K2MgR4(PMDETA)2. Having optimised these systems, substrate scope was examined to probe the range and robustness of 18-crown-6/K2MgR4(PMDETA)2 as a catalyst. A wide series of alkynols, including terminal and internal alkynes which contain a variety of potentially reactive functional groups, were cyclised. In comparison to previously reported monometallic systems, bimetallic 18-crown-6/K2MgR4(PMDETA)2 displays enhanced reactivity towards internal alkynol-cyclisation. Kinetic studies revealed an inhibition effect of substrate on the catalysts via adduct formation and requiring dissociation prior to the rate limiting cyclisation step.
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Affiliation(s)
- Michael Fairley
- WestCHEM , Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow , G1 1XL , UK .
| | - Laia Davin
- WestCHEM , Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow , G1 1XL , UK .
| | - Alberto Hernán-Gómez
- WestCHEM , Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow , G1 1XL , UK .
| | - Joaquín García-Álvarez
- Departamento de Química Orgánica e Inorgánica , Facultad de Química , Universidad de Oviedo , E-33071 Oviedo , Spain
| | - Charles T O'Hara
- WestCHEM , Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow , G1 1XL , UK .
| | - Eva Hevia
- WestCHEM , Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow , G1 1XL , UK .
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Zhang Y, Liu L, Chen T, Huang Z, Zhang WX, Xi Z. Dilithio Spiro Zincacyclopentadienes and Dizinca[10]cycles: Synthesis and Structural Characterization. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00154] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yongliang Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Liang Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Tianyang Chen
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Zhe Huang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Wen-Xiong Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Zhenfeng Xi
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry (SIOC), Shanghai 200032, China
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15
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Peel AJ, Tezuka N, D'Rozario JM, Uchiyama M, Wheatley AEH. A new route for the efficient metalation of unfunctionalized aromatics. Chem Sci 2019; 10:3385-3400. [PMID: 30996927 PMCID: PMC6429619 DOI: 10.1039/c8sc04325f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/01/2019] [Indexed: 11/21/2022] Open
Abstract
The synthesis and isolation of a novel bimetallic species formed by reacting two equivalents of TMPLi with CuCl in the presence of Et2O are reported. X-ray crystallography reveals the Et2O-free tetranuclear aggregate (TMPCu)2(TMPLi)2 1, which formally results from the catenation of dimers of TMPLi and TMPCu. NMR spectroscopy confirms that, upon dissolution in hydrocarbon media, the crystals fail to form a conventional Gilman cuprate dimer. Instead they exhibit a spectrum which is consistent with that recently proposed for an isomer of dimeric Gilman cuprate. Moreover, while pre-isolated Gilman cuprate is inert to benzene solvent, this new isomer smoothly affects aromatic deprotonation to give mainly Ph(TMP)3Cu2Li2 3, which is formally a heterodimer of Gilman cuprate TMPCu(μ-TMP)Li 2 and PhCu(μ-TMP)Li 4. Attempts to synthesise 3 through explicit combination of pre-isolated 2 and 4 were successful; additionally, this permitted the preparation of Ph(TMP)3Cu3Li 5 and Ph(TMP)3CuLi3 7 when 4 was combined in 1 : 2 ratios with TMPCu or TMPLi, respectively. 5 was characterised as metallacyclic in the solid-state, its structural features resembling those in 3 but with reduced Li-π interactions. It also proved possible to perform Cu/Li exchange on 5 (using t BuOCu) to give a novel mixed organo(amido)copper species Ph(TMP)3Cu4 6. Remarkably, the unprecedented reactivity of 1 towards benzene is reproduced by heating a 1 : 1 mixture of TMPLi and TMPCu in the same solvent; this gives predominantly 3. On the other hand, mixtures which are rich in either Cu or Li can lead to the selective in situ formation of 5 or 7. Though crystallographic data on 7 could not be obtained, DFT calculations accurately corroborated the observed structures of 3 and 5 and could be used to support 7 having the same structure type, albeit with enhanced Li-π interactions. This was consistent with NMR spectroscopic data. However, in contrast to 3 and 5, for which 2D NMR spectroscopy indicated only conformational changes, 7 was additionally found to exhibit fluxionality in a manner consistent with a dissociative process.
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Affiliation(s)
- Andrew J Peel
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
| | - Noriyuki Tezuka
- Cluster of Pioneering Research (CPR) , Advanced Elements Chemistry Laboratory , RIKEN , 2-1 Hirosawa, Wako-shi , Saitama 351-0198 , Japan.,Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-0033 , Japan .
| | - James M D'Rozario
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
| | - Masanobu Uchiyama
- Cluster of Pioneering Research (CPR) , Advanced Elements Chemistry Laboratory , RIKEN , 2-1 Hirosawa, Wako-shi , Saitama 351-0198 , Japan.,Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-0033 , Japan .
| | - Andrew E H Wheatley
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK .
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16
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Robertson SD, Uzelac M, Mulvey RE. Alkali-Metal-Mediated Synergistic Effects in Polar Main Group Organometallic Chemistry. Chem Rev 2019; 119:8332-8405. [DOI: 10.1021/acs.chemrev.9b00047] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Stuart D. Robertson
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, U.K
| | - Marina Uzelac
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, U.K
| | - Robert E. Mulvey
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, U.K
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Evans KJ, Mansell SM. Synergic Deprotonation Generates Alkali-Metal Salts of Tethered Fluorenide-NHC Ligands Co-Complexed to Alkali-Metal Amides. Chemistry 2019; 25:3766-3769. [PMID: 30667554 PMCID: PMC6492165 DOI: 10.1002/chem.201806278] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Indexed: 11/23/2022]
Abstract
Synergic combinations of alkali-metal hydrocarbyl/amide reagents were used to synthesise saturated N-heterocyclic carbene (NHC) ligands tethered to a fluorenide anion through deprotonation of a spirocyclic precursor, whereas conventional bases were not successful. The Li2 derivatives displayed a bridging amide between two Li atoms within the fluorenide-NHC pocket, whereas the Na2 and K2 analogues displayed extended solid-state structures with the fluorenide-NHC ligand chelating one alkali metal centre.
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Affiliation(s)
- Kieren J. Evans
- Institute of Chemical SciencesHeriot-Watt UniversityEdinburghEH14 4ASUK
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18
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Stevens MA, Hashim FH, Gwee ESH, Izgorodina EI, Mulvey RE, Blair VL. Contrasting Synergistic Heterobimetallic (Na-Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities. Chemistry 2018; 24:15669-15677. [PMID: 30101451 DOI: 10.1002/chem.201803477] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Indexed: 01/01/2023]
Abstract
A series of dialkylphenylphosphines and their analogous aniline substrates have been metallated with the synergistic mixed-metal base [(TMEDA)Na(TMP)(CH2 SiMe3 )Mg(TMP)] 1. Different metallation regioselectivities for the substrates were observed, with predominately lateral or meta-magnesiated products isolated from solution. Three novel heterobimetallic complexes [(TMEDA)Na(TMP)(CH2 PCH3 Ph)Mg(TMP)] 2, [(TMEDA)Na(TMP)(m-C6 H4 PiPr2 )Mg(TMP)] 3 and [(TMEDA)Na(TMP)(m-C6 H4 NEt2 )Mg(TMP)] 4 and two homometallic complexes [{(TMEDA)Na(EtNC6 H5 )}2 ] 5 and [(TMEDA)Na2 (TMP)(C6 H5 PEt)]2 6 derived from homometallic metallation have been crystallographically characterised. Complex 6 is an unprecedented sodium-amide, sodium-phosphide hybrid with a rare (NaNNaP)2 ladder motif. These products reveal contrasting heterobimetallic deprotonation with homometallic induced ethene elimination reactivity. Solution studies of metallation mixtures and electrophilic iodine quenching reactions confirmed the metallation sites. In an attempt to rationalise the regioselectivity of the magnesiation reactions the C-H acidities of the six substrates were determined in THF solution using DFT calculations employing the M06-2X functional and cc-pVTZ Dunning's basis set.
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Affiliation(s)
- Michael A Stevens
- School of Chemistry, Monash University, Melbourne, VIC, 3800, Australia
| | - Fairuz H Hashim
- School of Chemistry, Monash University, Melbourne, VIC, 3800, Australia
| | - Eunice S H Gwee
- School of Chemistry, Monash University, Melbourne, VIC, 3800, Australia
| | | | - Robert E Mulvey
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - Victoria L Blair
- School of Chemistry, Monash University, Melbourne, VIC, 3800, Australia
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19
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Uzelac M, Mulvey RE. Trans-Metal-Trapping: Concealed Crossover Complexes En Route to Transmetallation? Chemistry 2018; 24:7786-7793. [PMID: 29603459 DOI: 10.1002/chem.201800489] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/28/2018] [Indexed: 12/14/2022]
Abstract
Defined as the transfer of ligands from one metal to another, transmetallation is a common reaction in organometallic chemistry. Its chemical celebrity stems from its role in important catalytic cycles of cross-coupling reactions such as those of Negishi, Sonogashira, Stille, or Suzuki. This article focuses on trans-metal-trapping (TMT), which could be construed as partially complete transmetallations. On mixing two distinct organometallic compounds, of for example lithium with aluminium or gallium, the two metals meet in a crossover co-complex, but the reaction ceases at that point and full transmetallation is not reached. Though in its infancy, trans-metal-trapping shows promise in transforming failed lithiations into successful lithiations and in stabilising sensitive carbanions through cooperative bimetallic effects making them more amenable to onward reactivity.
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Affiliation(s)
- Marina Uzelac
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - Robert E Mulvey
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
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