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Dilchert K, Schmidt M, Großjohann A, Feichtner K, Mulvey RE, Gessner VH. Lösungsmitteleinflüsse auf die Struktur und Stabilität von Alkalimetallcarbenoiden. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202011278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Katharina Dilchert
- Lehrstuhl für Anorganische Chemie II Fakultät für Chemie und Biochemie Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Deutschland
- WestCHEM Department of Pure and Applied Chemistry University of Strathclyde Glasgow G1 1XL UK
| | - Michelle Schmidt
- Lehrstuhl für Anorganische Chemie II Fakultät für Chemie und Biochemie Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Deutschland
| | - Angela Großjohann
- Lehrstuhl für Anorganische Chemie II Fakultät für Chemie und Biochemie Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Deutschland
| | - Kai‐Stephan Feichtner
- Lehrstuhl für Anorganische Chemie II Fakultät für Chemie und Biochemie Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Deutschland
| | - Robert E. Mulvey
- WestCHEM Department of Pure and Applied Chemistry University of Strathclyde Glasgow G1 1XL UK
| | - Viktoria H. Gessner
- Lehrstuhl für Anorganische Chemie II Fakultät für Chemie und Biochemie Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Deutschland
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2
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Dilchert K, Schmidt M, Großjohann A, Feichtner KS, Mulvey RE, Gessner VH. Solvation Effects on the Structure and Stability of Alkali Metal Carbenoids. Angew Chem Int Ed Engl 2021; 60:493-498. [PMID: 33006796 PMCID: PMC7821203 DOI: 10.1002/anie.202011278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Indexed: 12/26/2022]
Abstract
s‐Block metal carbenoids are carbene synthons and applied in a myriad of organic transformations. They exhibit a strong structure–activity relationship, but this is only poorly understood due to the challenging high reactivity and sensitivity of these reagents. Here, we report on systematic VT and DOSY NMR studies, XRD analyses as well as DFT calculations on a sulfoximinoyl‐substituted model system to explain the pronounced solvent dependency of the carbenoid stability. While the sodium and potassium chloride carbenoids showed high stabilities independent of the solvent, the lithium carbenoid was stable at room temperature in THF but decomposed at −10 °C in toluene. These divergent stabilities could be explained by the different structures formed in solution. In contrast to simple organolithium reagents, the monomeric THF‐solvate was found to be more stable than the dimer in toluene, since the latter more readily forms direct Li/Cl interactions which facilitate decomposition via α‐elimination.
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Affiliation(s)
- Katharina Dilchert
- Chair of Inorganic Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801, Bochum, Germany.,WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Michelle Schmidt
- Chair of Inorganic Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801, Bochum, Germany
| | - Angela Großjohann
- Chair of Inorganic Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801, Bochum, Germany
| | - Kai-Stephan Feichtner
- Chair of Inorganic Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801, Bochum, Germany
| | - Robert E Mulvey
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Viktoria H Gessner
- Chair of Inorganic Chemistry II, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801, Bochum, Germany
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3
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Bisballe N, Hedidi M, Demmer CS, Chevallier F, Roisnel T, Dorcet V, Halauko YS, Ivashkevich OA, Matulis VE, Bentabed-Ababsa G, Bunch L, Mongin F. Functionalization of Oxazolo[4,5- b
]pyrazines by Deprotometallation. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800481] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Niels Bisballe
- Univ Rennes, CNRS; ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226; 35000 Rennes France
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Universitetsparken 2 2100 Copenhagen Denmark
| | - Madani Hedidi
- Univ Rennes, CNRS; ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226; 35000 Rennes France
- Laboratoire de Synthèse Organique Appliquée; Faculté des Sciences Exactes et Appliquées; Université d'Oran; 1 Ahmed Ben Bella 31000 Oran Algeria
| | - Charles S. Demmer
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Universitetsparken 2 2100 Copenhagen Denmark
| | - Floris Chevallier
- Univ Rennes, CNRS; ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226; 35000 Rennes France
| | - Thierry Roisnel
- Univ Rennes, CNRS; ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226; 35000 Rennes France
| | - Vincent Dorcet
- Univ Rennes, CNRS; ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226; 35000 Rennes France
| | - Yury S. Halauko
- UNESCO Chair of Belarusian State University; 14 Leningradskaya Str. 220030 Minsk Belarus
| | - Oleg A. Ivashkevich
- UNESCO Chair of Belarusian State University; 14 Leningradskaya Str. 220030 Minsk Belarus
| | - Vadim E. Matulis
- Research Institute for Physico-Chemical Problems of Belarusian State University; 14 Leningradskaya Str. 220030 Minsk Belarus
| | - Ghenia Bentabed-Ababsa
- Laboratoire de Synthèse Organique Appliquée; Faculté des Sciences Exactes et Appliquées; Université d'Oran; 1 Ahmed Ben Bella 31000 Oran Algeria
| | - Lennart Bunch
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Universitetsparken 2 2100 Copenhagen Denmark
| | - Florence Mongin
- Univ Rennes, CNRS; ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226; 35000 Rennes France
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4
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Fused Systems Based on 2-Aminopyrimidines: Synthesis Combining Deprotolithiation-in situ Zincation withN-Arylation Reactions and Biological Properties. European J Org Chem 2017. [DOI: 10.1002/ejoc.201701004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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5
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Barozzino-Consiglio G, Hamdoun G, Fressigné C, Harrison-Marchand A, Maddaluno J, Oulyadi H. A Combined 1
H/6
Li NMR DOSY Strategy Finally Uncovers the Structure of Isopropyllithium in THF. Chemistry 2017; 23:12475-12479. [DOI: 10.1002/chem.201702990] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Indexed: 11/09/2022]
Affiliation(s)
| | - Ghanem Hamdoun
- Normandie Université, UNIROUEN, INSA de Rouen, CNRS; Laboratoire COBRA (UMR 6014 & FR 3038); 76000 Rouen France
| | - Catherine Fressigné
- Normandie Université, UNIROUEN, INSA de Rouen, CNRS; Laboratoire COBRA (UMR 6014 & FR 3038); 76000 Rouen France
| | - Anne Harrison-Marchand
- Normandie Université, UNIROUEN, INSA de Rouen, CNRS; Laboratoire COBRA (UMR 6014 & FR 3038); 76000 Rouen France
| | - Jacques Maddaluno
- Normandie Université, UNIROUEN, INSA de Rouen, CNRS; Laboratoire COBRA (UMR 6014 & FR 3038); 76000 Rouen France
| | - Hassan Oulyadi
- Normandie Université, UNIROUEN, INSA de Rouen, CNRS; Laboratoire COBRA (UMR 6014 & FR 3038); 76000 Rouen France
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Fuentes MÁ, Zabala A, Kennedy AR, Mulvey RE. Structural Diversity in Alkali Metal and Alkali Metal Magnesiate Chemistry of the Bulky 2,6-Diisopropyl-N-(trimethylsilyl)anilino Ligand. Chemistry 2016; 22:14968-14978. [PMID: 27573676 PMCID: PMC5096043 DOI: 10.1002/chem.201602683] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Indexed: 11/07/2022]
Abstract
Bulky amido ligands are precious in s-block chemistry, since they can implant complementary strong basic and weak nucleophilic properties within compounds. Recent work has shown the pivotal importance of the base structure with enhancement of basicity and extraordinary regioselectivities possible for cyclic alkali metal magnesiates containing mixed n-butyl/amido ligand sets. This work advances alkali metal and alkali metal magnesiate chemistry of the bulky arylsilyl amido ligand [N(SiMe3 )(Dipp)]- (Dipp=2,6-iPr2 -C6 H3 ). Infinite chain structures of the parent sodium and potassium amides are disclosed, adding to the few known crystallographically characterised unsolvated s-block metal amides. Solvation by N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) or N,N,N',N'-tetramethylethylenediamine (TMEDA) gives molecular variants of the lithium and sodium amides; whereas for potassium, PMDETA gives a molecular structure, TMEDA affords a novel, hemi-solvated infinite chain. Crystal structures of the first magnesiate examples of this amide in [MMg{N(SiMe3 )(Dipp)}2 (μ-nBu)]∞ (M=Na or K) are also revealed, though these breakdown to their homometallic components in donor solvents as revealed through NMR and DOSY studies.
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Affiliation(s)
- M Ángeles Fuentes
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Andoni Zabala
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Alan R Kennedy
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Robert E Mulvey
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
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Schnegelsberg C, Bachmann S, Kolter M, Auth T, John M, Stalke D, Koszinowski K. Association and Dissociation of Grignard Reagents RMgCl and Their Turbo Variant RMgCl⋅LiCl. Chemistry 2016; 22:7752-62. [DOI: 10.1002/chem.201600699] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Christoph Schnegelsberg
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität Göttingen; Tammannstraße 2 37077 Göttingen Germany
| | - Sebastian Bachmann
- Institut für Anorganische Chemie; Georg-August-Universität Göttingen; Tammannstraße 4 37077 Göttingen Germany
| | - Marlene Kolter
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität Göttingen; Tammannstraße 2 37077 Göttingen Germany
| | - Thomas Auth
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität Göttingen; Tammannstraße 2 37077 Göttingen Germany
| | - Michael John
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität Göttingen; Tammannstraße 2 37077 Göttingen Germany
| | - Dietmar Stalke
- Institut für Anorganische Chemie; Georg-August-Universität Göttingen; Tammannstraße 4 37077 Göttingen Germany
| | - Konrad Koszinowski
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität Göttingen; Tammannstraße 2 37077 Göttingen Germany
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Fuentes MÁ, Kennedy AR, Mulvey RE, Parkinson JA, Rantanen T, Robertson SD, Snieckus V. Adding a Structural Context to the Deprotometalation and Trans-Metal Trapping Chemistry of Phenyl-Substituted Benzotriazole. Chemistry 2015; 21:14812-22. [DOI: 10.1002/chem.201502534] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Indexed: 11/06/2022]
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9
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Oikonomou M, Asencio-Hernández J, Velders AH, Delsuc MA. Accurate DOSY measure for out-of-equilibrium systems using permutated DOSY (p-DOSY). JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 258:12-16. [PMID: 26150378 DOI: 10.1016/j.jmr.2015.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/06/2015] [Accepted: 06/11/2015] [Indexed: 06/04/2023]
Abstract
NMR spectroscopy is a excellent tool for monitoring in-situ chemical reactions. In particular, DOSY measurement is well suited to characterize transient species by the determination of their sizes. However, here we bring to light a difficulty in the DOSY experiments performed in out-of-equilibrium systems. On such a system, the evolution of the concentration of species interferes with the measurement process, and creates a bias on the diffusion coefficient determination that may lead to erroneous interpretations. We show that a random permutation of the series of gradient strengths used during the DOSY experiment allows to average out this bias. This approach, that we name p-DOSY does not require changes in the pulse sequences nor in the processing software, and restores completely the full accuracy of the measure. This technique is demonstrated on the monitoring of the anomerization reaction of α- to β-glucose.
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Affiliation(s)
- Maria Oikonomou
- Laboratory of BioNanoTechnology, Wageningen University, PO Box 8038, 6700 EK Wageningen, The Netherlands
| | - Julia Asencio-Hernández
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM, U596, CNRS, UMR 7104, Université de Strasbourg, 67404 Illkirch-Graffenstaden, France; NMRTEC, bioparc, 1 Bd Brandt, Illkirch-Graffenstaden 67400, France
| | - Aldrik H Velders
- Laboratory of BioNanoTechnology, Wageningen University, PO Box 8038, 6700 EK Wageningen, The Netherlands; Instituto Regional de Investigación Científica Aplicada (IRICA), Universidad de Castilla-La Mancha, Avda. Camilo José Cela, s/n, 13071 Ciudad Real, Spain
| | - Marc-André Delsuc
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM, U596, CNRS, UMR 7104, Université de Strasbourg, 67404 Illkirch-Graffenstaden, France.
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10
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Neufeld R, Stalke D. Accurate molecular weight determination of small molecules via DOSY-NMR by using external calibration curves with normalized diffusion coefficients. Chem Sci 2015; 6:3354-3364. [PMID: 29142693 PMCID: PMC5656982 DOI: 10.1039/c5sc00670h] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 03/18/2015] [Indexed: 01/12/2023] Open
Abstract
Determination of the aggregation and solvation numbers of organometallic complexes in solution is an important task to increase insight in reaction mechanisms. Thus knowing which aggregates are formed during a reaction is of high interest to develop better selectivity and higher yields. Diffusion-ordered spectroscopy (DOSY), which separates NMR signals according to the diffusion coefficient, finds increasing use to identify species in solution. However, there still is no simple relationship between diffusion coefficient and molecular weight (MW). Some methods have been developed to estimate the MW but still with a significant error of ±30%. Here we describe a novel development of MW-determination by using an external calibration curve (ECC) approach with normalized diffusion coefficients. Taking the shape of the molecules into account enables accurate MW-predictions with a maximum error of smaller than ±9%. Moreover we show that the addition of multiple internal references is dispensable. One internal reference (that also can be the solvent) is sufficient. If the solvent signal is not accessible, 16 other internal standards (aliphatics and aromatics) are available to avoid signal overlapping problems and provide flexible choice of analytes. This method is independent of NMR-device properties and diversities in temperature or viscosity and offers an easy and robust method to determine accurate MWs in solution.
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Affiliation(s)
- Roman Neufeld
- Institut für Anorganische Chemie , Georg-August-Universität , Tammannstrasse 4 , Göttingen , Germany .
| | - Dietmar Stalke
- Institut für Anorganische Chemie , Georg-August-Universität , Tammannstrasse 4 , Göttingen , Germany .
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11
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Neufeld R, John M, Stalke D. The Donor-Base-Free Aggregation of Lithium Diisopropyl Amide in Hydrocarbons Revealed by a DOSY Method. Angew Chem Int Ed Engl 2015; 54:6994-8. [PMID: 26014367 DOI: 10.1002/anie.201502576] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Indexed: 11/08/2022]
Abstract
Lithium diisopropyl amide (LDA) is a very prominent reagent that plays a key role in organic synthesis, serving as a base par excellence for a broad range of deprotonation reactions. However, the state of aggregation in solution in the absence of donor bases was unclear. In this paper we solved this problem by employing DOSY NMR experiments based on a newly elaborated external calibration curve (ECC) approach with normalized diffusion coefficients.
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Affiliation(s)
- Roman Neufeld
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077 Göttingen (Germany)
| | - Michael John
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077 Göttingen (Germany)
| | - Dietmar Stalke
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077 Göttingen (Germany).
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12
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Neufeld R, John M, Stalke D. Aufklärung der donorbasenfreien Aggregation von Lithiumdiisopropylamid in Kohlenwasserstoffen mithilfe einer DOSY-Methode. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502576] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Sung S, Braddock DC, Armstrong A, Brennan C, Sale D, White AJP, Davies RP. Synthesis, characterisation and reactivity of copper(I) amide complexes and studies on their role in the modified Ullmann amination reaction. Chemistry 2015; 21:7179-92. [PMID: 25788223 PMCID: PMC4471577 DOI: 10.1002/chem.201405699] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Indexed: 11/29/2022]
Abstract
A series of copper(I) alkylamide complexes have been synthesised; copper(I) dicyclohexylamide (1), copper(I) 2,2,6,6-tetramethylpiperidide (2), copper(I) pyrrolidide (3), copper(I) piperidide (4), and copper(I) benzylamide (5). Their solid-state structures and structures in [D6 ]benzene solution are characterised, with the aggregation state in solution determined by a combination of DOSY NMR spectroscopy and DFT calculations. Complexes 1, 2 and 4 are shown to exist as tetramers in the solid state by X-ray crystallography. In [D6 ]benzene solution, complexes 1, 2 and 5 were found by using (1) H DOSY NMR to exist in rapid equilibrium between aggregates with average aggregation numbers of 2.5, 2.4 and 3.3, respectively, at 0.05 M concentration. Conversely, distinct trimeric, tetrameric and pentameric forms of 3 and 4 were distinguishable by one-dimensional (1) H and (1) H DOSY NMR spectroscopy. Complexes 3-5 are found to react stoichiometrically with iodobenzene, in the presence or absence of 1,10-phenanthroline as an ancillary ligand, to give arylamine products indicative of their role as potential intermediates in the modified Ullmann reaction. The role of phenanthroline has also been explored both in the stoichiometric reaction and in the catalytic Ullmann protocol.
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Affiliation(s)
- Simon Sung
- Department of Chemistry, Imperial College LondonSouth Kensington, London, SW7 2AZ (UK)
| | | | - Alan Armstrong
- Department of Chemistry, Imperial College LondonSouth Kensington, London, SW7 2AZ (UK)
| | - Colin Brennan
- Process Studies Group, Syngenta, Jealott*s Hill Research CentreBracknell, Berkshire RG42 6EY (UK)
| | - David Sale
- Process Studies Group, Syngenta, Jealott*s Hill Research CentreBracknell, Berkshire RG42 6EY (UK)
| | - Andrew J P White
- Department of Chemistry, Imperial College LondonSouth Kensington, London, SW7 2AZ (UK)
| | - Robert P Davies
- Department of Chemistry, Imperial College LondonSouth Kensington, London, SW7 2AZ (UK)
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Khairallah GN, da Silva G, O'Hair RAJ. Molecular salt effects in the gas phase: tuning the kinetic basicity of [HCCLiCl]⁻ and [HCCMgCl₂]⁻ by LiCl and MgCl₂. Angew Chem Int Ed Engl 2014; 53:10979-83. [PMID: 25079912 DOI: 10.1002/anie.201404362] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/11/2014] [Indexed: 11/09/2022]
Abstract
A combination of gas-phase ion-molecule reaction experiments and theoretical kinetic modeling is used to examine how a salt can influence the kinetic basicity of organometallates reacting with water. [HC≡CLiCl](-) reacts with water more rapidly than [HC≡CMgCl2](-), consistent with the higher reactivity of organolithium versus organomagnesium reagents. Addition of LiCl to [HC≡CLiCl](-) or [HC≡CMgCl2](-) enhances their reactivity towards water by a factor of about 2, while addition of MgCl2 to [HC≡CMgCl2](-) enhances its reactivity by a factor of about 4. Ab initio calculations coupled with master equation/RRKM theory kinetic modeling show that these reactions proceed via a mechanism involving formation of a water adduct followed by rearrangement, proton transfer, and acetylene elimination as either discrete or concerted steps. Both the energy and entropy requirements for these elementary steps need to be considered in order to explain the observed kinetics.
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Affiliation(s)
- George N Khairallah
- School of Chemistry and Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010 (Australia); ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology.
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15
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Khairallah GN, da Silva G, O'Hair RAJ. Molecular Salt Effects in the Gas Phase: Tuning the Kinetic Basicity of [HCCLiCl]−and [HCCMgCl2]−by LiCl and MgCl2. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201404362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Frischmuth A, Fernández M, Barl NM, Achrainer F, Zipse H, Berionni G, Mayr H, Karaghiosoff K, Knochel P. In-situ-Abfangmethode zur Metallierung funktionalisierter Arene und Heteroarene mit TMPLi in Gegenwart von ZnCl2und anderen Metallsalzen. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201403688] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Frischmuth A, Fernández M, Barl NM, Achrainer F, Zipse H, Berionni G, Mayr H, Karaghiosoff K, Knochel P. New In Situ Trapping Metalations of Functionalized Arenes and Heteroarenes with TMPLi in the Presence of ZnCl2and Other Metal Salts. Angew Chem Int Ed Engl 2014; 53:7928-32. [DOI: 10.1002/anie.201403688] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Indexed: 12/31/2022]
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18
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Hevia E, Kennedy AR, Mulvey RE, Ramsay DL, Robertson SD. Concealed Cyclotrimeric Polymorph of Lithium 2,2,6,6-Tetramethylpiperidide Unconcealed: X-Ray Crystallographic and NMR Spectroscopic Studies. Chemistry 2013; 19:14069-75. [DOI: 10.1002/chem.201302709] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Indexed: 11/06/2022]
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19
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Armstrong DR, Garden JA, Kennedy AR, Leenhouts SM, Mulvey RE, O'Keefe P, O'Hara CT, Steven A. Evaluating cis-2,6-dimethylpiperidide (cis-DMP) as a base component in lithium-mediated zincation chemistry. Chemistry 2013; 19:13492-503. [PMID: 23955639 PMCID: PMC4517102 DOI: 10.1002/chem.201301180] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Indexed: 11/14/2022]
Abstract
Most recent advances in metallation chemistry have centred on the bulky secondary amide 2,2,6,6-tetramethylpiperidide (TMP) within mixed metal, often ate, compositions. However, the precursor amine TMP(H) is rather expensive so a cheaper substitute would be welcome. Thus this study was aimed towards developing cheaper non-TMP based mixed-metal bases and, as cis-2,6-dimethylpiperidide (cis-DMP) was chosen as the alternative amide, developing cis-DMP zincate chemistry which has received meagre attention compared to that of its methyl-rich counterpart TMP. A new lithium diethylzincate, [(TMEDA)LiZn(cis-DMP)Et2] (TMEDA=N,N,N′,N′-tetramethylethylenediamine) has been synthesised by co-complexation of Li(cis-DMP), Et2Zn and TMEDA, and characterised by NMR (including DOSY) spectroscopy and X-ray crystallography, which revealed a dinuclear contact ion pair arrangement. By using N,N-diisopropylbenzamide as a test aromatic substrate, the deprotonative reactivity of [(TMEDA)LiZn(cis-DMP)Et2] has been probed and contrasted with that of the known but previously uninvestigated di-tert-butylzincate, [(TMEDA)LiZn(cis-DMP)tBu2]. The former was found to be the superior base (for example, producing the ortho-deuteriated product in respective yields of 78 % and 48 % following D2O quenching of zincated benzamide intermediates). An 88 % yield of 2-iodo-N,N-diisopropylbenzamide was obtained on reaction of two equivalents of the diethylzincate with the benzamide followed by iodination. Comparisons are also drawn using 1,1,1,3,3,3-hexamethyldisilazide (HMDS), diisopropylamide and TMP as the amide component in the lithium amide, Et2Zn and TMEDA system. Under certain conditions, the cis-DMP base system was found to give improved results in comparison to HMDS and diisopropylamide (DA), and comparable results to a TMP system. Two novel complexes isolated from reactions of the di-tert-butylzincate and crystallographically characterised, namely the pre-metallation complex [{(iPr)2N(Ph)C=O}LiZn(cis-DMP)tBu2] and the post-metallation complex [(TMEDA)Li(cis-DMP){2-[1-C(=O)N(iPr)2]C6H4}Zn(tBu)], shed valuable light on the structures and mechanisms involved in these alkali-metal-mediated zincation reactions. Aspects of these reactions are also modelled by DFT calculations.
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Affiliation(s)
- David R Armstrong
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL (UK)
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Kadiyala RR, Tilly D, Nagaradja E, Roisnel T, Matulis VE, Ivashkevich OA, Halauko YS, Chevallier F, Gros PC, Mongin F. Computed CH Acidity of Biaryl Compounds and Their Deprotonative Metalation by Using a Mixed Lithium/Zinc-TMP Base. Chemistry 2013; 19:7944-60. [DOI: 10.1002/chem.201300552] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Indexed: 11/06/2022]
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Unsinn A, Wunderlich SH, Knochel P. Accelerated Zincations for an Efficient and Mild Functionalization of Aromatics and Heterocycles. Adv Synth Catal 2013. [DOI: 10.1002/adsc.201300049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Knorr R, Menke T, Ferchland K. Entropies of Organolithium Aggregation Based on Measured Microsolvation Numbers. Organometallics 2013. [DOI: 10.1021/om3009348] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rudolf Knorr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5−13 (Haus F),
81377 München, Germany
| | - Thomas Menke
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5−13 (Haus F),
81377 München, Germany
| | - Kathrin Ferchland
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5−13 (Haus F),
81377 München, Germany
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Dayaker G, Tilly D, Chevallier F, Hilmersson G, Gros PC, Mongin F. Enantioselective Metalation ofN,N-Diisopropylferrocenecarboxamide and Methyl Ferrocenecarboxylate Using Lithium-Metal Chiral Bases. European J Org Chem 2012. [DOI: 10.1002/ejoc.201200965] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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