101
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McMullen JS, Edwards AJ, Hicks J. C-H and C-F coordination of arenes in neutral alkaline earth metal complexes. Dalton Trans 2021; 50:8685-8689. [PMID: 34160514 DOI: 10.1039/d1dt01532j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A series of neutral magnesium and calcium complexes bearing an extremely bulky diamido ligand have been synthesised and crystallographically characterised. A number of these complexes feature rare group 2 metalaromatic interactions, such as the η6-coordination of benzene and 'agostic-like' C-H coordination, the latter previously unseen in neutral Mg and Ca complexes.
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Affiliation(s)
- Jacob S McMullen
- Research School of Chemistry, Australian National University, ACT 2601, Australia.
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, New South Wales 2234, Australia
| | - Jamie Hicks
- Research School of Chemistry, Australian National University, ACT 2601, Australia.
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102
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Obi AD, Freeman LA, Dickie DA, Gilliard RJ. N-Heterocyclic Carbene-Mediated Ring Opening of Reduced Diazamagnesacycles. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00620] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Akachukwu D. Obi
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
| | - Lucas A. Freeman
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
| | - Diane A. Dickie
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
| | - Robert J. Gilliard
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
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103
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Yang Y, Tsien J, Ben David A, Hughes JME, Merchant RR, Qin T. Practical and Modular Construction of C(sp 3)-Rich Alkyl Boron Compounds. J Am Chem Soc 2020; 143:471-480. [PMID: 33347297 DOI: 10.1021/jacs.0c11964] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alkyl boronic acids and esters play an important role in the synthesis of C(sp3)-rich medicines, agrochemicals, and material chemistry. This work describes a new type of transition-metal-free mediated transformation to enable the construction of C(sp3)-rich and sterically hindered alkyl boron reagents in a practical and modular manner. The broad generality and functional group tolerance of this method is extensively examined through a variety of substrates, including synthesis and late-stage functionalization of scaffolds relevant to medicinal chemistry. The strategic significance of this approach, with alkyl boronic acids as linchpins, is demonstrated through various downstream functionalizations of the alkyl boron compounds. This two-step concurrent cross-coupling approach, resembling formal and flexible alkyl-alkyl couplings, provides a general entry to synthetically challenging high Fsp3-containing drug-like scaffolds.
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Affiliation(s)
- Yangyang Yang
- Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Jet Tsien
- Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Ayala Ben David
- Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Jonathan M E Hughes
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Rohan R Merchant
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, California 94080, United States
| | - Tian Qin
- Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
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104
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Seymen A, Opper U, Voß A, Brieger L, Otte F, Unkelbach C, O'Shea DF, Strohmann C. Aminopotassiation by Mixed Potassium/Lithium Amides: A Synthetic Path to Difficult to Access Phenethylamine Derivates. Angew Chem Int Ed Engl 2020; 59:22500-22504. [PMID: 32846026 PMCID: PMC7756473 DOI: 10.1002/anie.202009318] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 11/24/2022]
Abstract
Insights gained from a comparison of aminometalation reactions with lithium amides, potassium amides and mixed lithium/potassium amides are presented. A combination of structural characterization, DFT calculations and electrophile reactions of aminometalated intermediates has shown the advantages of using a mixed metal strategy. While potassium amides fail to add, the lithium amides are uncontrollable and eliminated, yet the mixed K/Li amides deliver the best of both systems. Aminopotassiation proceeds to form the alkylpotassium species which has enhanced stability over its lithium counterpart allowing for its isolation and thereby its further characterization.
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Affiliation(s)
- Andreas Seymen
- Inorganic Chemistry, TU Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Ulrike Opper
- Inorganic Chemistry, TU Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Andreas Voß
- Inorganic Chemistry, TU Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Lukas Brieger
- Inorganic Chemistry, TU Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Felix Otte
- Inorganic Chemistry, TU Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Christian Unkelbach
- Inorganic Chemistry, TU Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Donal F O'Shea
- Department of Pharmaceutical and Medicinal Chemistry, Royal College Surgeons, 123 St. Stephen's Green, Dublin 2, Ireland
| | - Carsten Strohmann
- Inorganic Chemistry, TU Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
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105
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Hanft A, Jürgensen M, Wolz L, Radacki K, Lichtenberg C. Salicylaldimines: Formation via Ring Contraction and Synthesis of Mono- and Heterobimetallic Alkali Metal Heterocubanes. Inorg Chem 2020; 59:17678-17688. [PMID: 33226783 DOI: 10.1021/acs.inorgchem.0c02920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The formation of salicylaldimine derivatives via ring contraction as byproducts in 2-aminotropone syntheses has been investigated. Salicylaldiminate (SAI) complexes of the alkali metals Li-K have been synthesized and transformed into heterobimetallic complexes. Important findings include an unusual double heterocubane structure of the homometallic sodium SAI, an unprecedented ligand-induced E/Z isomerization of the aldimine functional group in the homometallic potassium SAI, and the first example of a structurally authenticated mixed-metal SAI based on s-block central atoms. Rapid equilibria have been shown to play a crucial role in the solution phase chemistry of mixed-metal SAIs. Analytical techniques applied in this work include (heteronuclear) NMR spectroscopy, VT- and DOSY NMR spectroscopy, high-resolution mass spectrometry, single-crystal X-ray diffraction analysis, and DFT calculations.
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Affiliation(s)
- Anna Hanft
- Department of Inorganic Chemistry, Julius-Maximilians Universität, Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Malte Jürgensen
- Department of Inorganic Chemistry, Julius-Maximilians Universität, Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Laura Wolz
- Department of Inorganic Chemistry, Julius-Maximilians Universität, Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Krzysztof Radacki
- Department of Inorganic Chemistry, Julius-Maximilians Universität, Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Crispin Lichtenberg
- Department of Inorganic Chemistry, Julius-Maximilians Universität, Würzburg, Am Hubland, 97074 Würzburg, Germany
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106
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Hermann A, Opper U, Voß A, Brieger L, Otte F, Unkelbach C, O'Shea DF, Strohmann C. Aminometallierung mit einem gemischten K/Li‐Amid: Eine Syntheseroute zu schwer zugänglichen Phenethylamin‐Derivaten. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Andreas Hermann
- Anorganische Chemie TU Dortmund Otto-Hahn-Str. 6 44227 Dortmund Deutschland
| | - Ulrike Opper
- Anorganische Chemie TU Dortmund Otto-Hahn-Str. 6 44227 Dortmund Deutschland
| | - Andreas Voß
- Anorganische Chemie TU Dortmund Otto-Hahn-Str. 6 44227 Dortmund Deutschland
| | - Lukas Brieger
- Anorganische Chemie TU Dortmund Otto-Hahn-Str. 6 44227 Dortmund Deutschland
| | - Felix Otte
- Anorganische Chemie TU Dortmund Otto-Hahn-Str. 6 44227 Dortmund Deutschland
| | | | - Donal F. O'Shea
- Department of Pharmaceutical and Medicinal Chemistry Royal College Surgeons 123 St. Stephen's Green Dublin 2 Irland
| | - Carsten Strohmann
- Anorganische Chemie TU Dortmund Otto-Hahn-Str. 6 44227 Dortmund Deutschland
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107
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Desaintjean A, Haupt T, Bole LJ, Judge NR, Hevia E, Knochel P. Regioselektiver Brom/Magnesium‐Austausch für die selektive Funktionalisierung von polyhalogenierten Arenen und Heterozyklen. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202012496] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Alexandre Desaintjean
- Ludwig-Maximilians-Universität München Department Chemie Butenandtstraße 5–13, Haus F 81377 München Deutschland
| | - Tobias Haupt
- Ludwig-Maximilians-Universität München Department Chemie Butenandtstraße 5–13, Haus F 81377 München Deutschland
| | - Leonie J. Bole
- Department für Chemie und Biochemie Universität Bern 3012 Bern Schweiz
| | - Neil R. Judge
- Department für Chemie und Biochemie Universität Bern 3012 Bern Schweiz
| | - Eva Hevia
- Department für Chemie und Biochemie Universität Bern 3012 Bern Schweiz
| | - Paul Knochel
- Ludwig-Maximilians-Universität München Department Chemie Butenandtstraße 5–13, Haus F 81377 München Deutschland
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108
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Desaintjean A, Haupt T, Bole LJ, Judge NR, Hevia E, Knochel P. Regioselective Bromine/Magnesium Exchange for the Selective Functionalization of Polyhalogenated Arenes and Heterocycles. Angew Chem Int Ed Engl 2020; 60:1513-1518. [PMID: 33079466 PMCID: PMC7839478 DOI: 10.1002/anie.202012496] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Indexed: 12/20/2022]
Abstract
Using the bimetallic combination sBu2Mg⋅2 LiOR (R=2‐ethylhexyl) in toluene enables efficient and regioselective Br/Mg exchanges with various dibromo‐arenes and ‐heteroarenes under mild reaction conditions and provides bromo‐substituted magnesium reagents. Assessing the role of Lewis donor additives in these reactions revealed that N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDTA) finely tunes the regioselectivity of the Br/Mg exchange on dibromo‐pyridines and quinolines. Combining spectroscopic with X‐ray crystallographic studies, light has been shed on the mixed Li/Mg constitution of the organometallic intermediates accomplishing these transformations. These systems reacted effectively with a broad range of electrophiles, including allyl bromides, ketones, aldehydes, and Weinreb amides in good yields.
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Affiliation(s)
- Alexandre Desaintjean
- Ludwig-Maximilians-Universität München, Department Chemie, Butenandtstrasse 5-13, Haus F, 81377, München, Germany
| | - Tobias Haupt
- Ludwig-Maximilians-Universität München, Department Chemie, Butenandtstrasse 5-13, Haus F, 81377, München, Germany
| | - Leonie J Bole
- Department für Chemie und Biochemie, Universität Bern, 3012, Bern, Switzerland
| | - Neil R Judge
- Department für Chemie und Biochemie, Universität Bern, 3012, Bern, Switzerland
| | - Eva Hevia
- Department für Chemie und Biochemie, Universität Bern, 3012, Bern, Switzerland
| | - Paul Knochel
- Ludwig-Maximilians-Universität München, Department Chemie, Butenandtstrasse 5-13, Haus F, 81377, München, Germany
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109
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Wang B, Li Y, Pang JH, Watanabe K, Takita R, Chiba S. Hydromagnesiation of 1,3‐Enynes by Magnesium Hydride for Synthesis of Tri‐ and Tetra‐substituted Allenes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202012027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Bin Wang
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
| | - Yihang Li
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
| | - Jia Hao Pang
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
| | - Kohei Watanabe
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Ryo Takita
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Shunsuke Chiba
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
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110
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Wang B, Li Y, Pang JH, Watanabe K, Takita R, Chiba S. Hydromagnesiation of 1,3‐Enynes by Magnesium Hydride for Synthesis of Tri‐ and Tetra‐substituted Allenes. Angew Chem Int Ed Engl 2020; 60:217-221. [DOI: 10.1002/anie.202012027] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Indexed: 01/04/2023]
Affiliation(s)
- Bin Wang
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
| | - Yihang Li
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
| | - Jia Hao Pang
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
| | - Kohei Watanabe
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Ryo Takita
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Shunsuke Chiba
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
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111
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Murray-Watson RJ, Pike SD. Exploring the Synthesis and Coordination Chemistry of Pentafluorophenylcopper: Organocopper Polyanions and Coordination Networks. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rebecca J. Murray-Watson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB1 2EW, United Kingdom
| | - Sebastian D. Pike
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB1 2EW, United Kingdom
- Department of Chemistry, University of Warwick, Gibbet Hill, Coventry, CV4 7EQ, United Kingdom
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112
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Gil-Negrete JM, Hevia E. Main group bimetallic partnerships for cooperative catalysis. Chem Sci 2020; 12:1982-1992. [PMID: 34163960 PMCID: PMC8179316 DOI: 10.1039/d0sc05116k] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 10/16/2020] [Indexed: 11/21/2022] Open
Abstract
Over the past decade s-block metal catalysis has undergone a transformation from being an esoteric curiosity to a well-established and consolidated field towards sustainable synthesis. Earth-abundant metals such as Ca, Mg, and Al have shown eye-opening catalytic performances in key catalytic processes such as hydrosilylation, hydroamination or alkene polymerization. In parallel to these studies, s-block mixed-metal reagents have also been attracting widespread interest from scientists. These bimetallic reagents effect many cornerstone organic transformations, often providing enhanced reactivities and better chemo- and regioselectivities than conventional monometallic reagents. Despite a significant number of synthetic advances to date, most efforts have focused primarily on stoichiometric transformations. Merging these two exciting areas of research, this Perspective Article provides an overview on the emerging concept of s/p-block cooperative catalysis. Showcasing recent contributions from several research groups across the world, the untapped potential that these systems can offer in catalytic transformations is discussed with special emphasis placed on how synergistic effects can operate and the special roles played by each metal in these transformations. Advancing the understanding of the ground rules of s-block cooperative catalysis, the application of these bimetalic systems in a critical selection of catalytic transformations encompassing hydroamination, cyclisation, hydroboration to C-C bond forming processes are presented as well as their uses in important polymerization reactions.
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Affiliation(s)
- Jose M Gil-Negrete
- Department für Chemie und Biochemie, Universität Bern CH3012 Bern Switzerland
| | - Eva Hevia
- Department für Chemie und Biochemie, Universität Bern CH3012 Bern Switzerland
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113
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Rösch A, Herzog CM, Schreiner SHF, Görls H, Kretschmer R. Ditopic bis( N, N', N'-substituted 1,2-ethanediamine) ligands: synthesis and coordination chemistry. Dalton Trans 2020; 49:13818-13828. [PMID: 33001083 DOI: 10.1039/d0dt03124k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The synthesis of two different types of bis(N,N',N'-substituted 1,2-ethanediamine)s, bridged either through the secondary (type 1) or tertiary (type 2) amine groups is reported. Selected protio-ligands have been applied in subsequent metallation reactions using aluminium, magnesium, tin, and zinc sources allowing to isolate five mononuclear and eight dinuclear complexes. All complexes have been fully characterized and their solid-state structures have been studied by means of single-crystal X-ray diffraction analysis. Nine of the 13 complexes carry reactive alkyl, amide or hydride groups, which indicates their potential as catalysts or supports for (transition) metals.
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Affiliation(s)
- Andreas Rösch
- Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Christoph M Herzog
- Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Simon H F Schreiner
- Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany
| | - Robert Kretschmer
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany and Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena Philosophenweg 7, 07743 Jena, Germany.
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114
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Abstract
Organometallic chemistry and its applications in homogeneous catalysis have been dominated by mononuclear transition-metal complexes. The catalytic performance and physico-chemical properties of these mononuclear complexes can be rationally tuned by ligand modification, which has also led to the discovery of new reactions. There is a growing body of evidence implicating the participation of two metals in catalytic processes originally believed to follow monometallic mechanisms. Moreover, the deliberate preparation of bimetallic structures has proven popular because these preorganized structures have many tunable features, such as metal-metal bond order and polarity. These structures can exhibit metal-metal complementarity and allow for multisite activation - reactivity unattainable with truly mononuclear species. This Perspective summarizes the features that are exclusive to bimetallic systems and their roles in substrate activation.
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115
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Münch A, Knauer L, Ott H, Sindlinger C, Herbst-Irmer R, Strohmann C, Stalke D. Insight into the Bonding and Aggregation of Alkyllithiums by Experimental Charge Density Studies and Energy Decomposition Analyses. J Am Chem Soc 2020; 142:15897-15906. [PMID: 32811141 DOI: 10.1021/jacs.0c06035] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this Article, the organolithiums [((-)-sparteine)LitBu] (1), [(ABCO)LitBu]2 (2), and [(ABCO)2(LiiPr)4] (3) are investigated by means of experimental and theoretical charge density determination to elucidate the nature of the Li-C and Li-N bonds. Furthermore, the valence shell charge concentrations (VSCCs) in the nonbonding region of the deprotonated Cα-atom will provide some insight on the localization of the carbanionic lone pair. Analysis of the electron density (ρ(rBCP)), Laplacian (∇2ρ(rBCP)), and the energy decomposition (EDA) confirmed that the Li-C/N bond exhibits astonishingly similar characteristics, to reveal an increasingly polar contact with decreasing aggregate size. This explains former observations on the incorporation of halide salts in organolithium reagents. Furthermore, it could be shown that the bonding properties of the iPr group are similar to those of the tBu substituent. The accuracy of fit to all previously determined properties in organolithiums is remarkable.
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Affiliation(s)
- Annika Münch
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraβe 4, Göttingen 37077, Germany
| | - Lena Knauer
- Institut für Anorganische Chemie, Technische Universität Dortmund, Otto-Hahn-Straβe 6, Dortmund 44227, Germany
| | - Holger Ott
- Bruker AXS GmbH, Östliche Rheinbrückenstraβe 49, Karlsruhe 76187, Germany
| | - Christian Sindlinger
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraβe 4, Göttingen 37077, Germany
| | - Regine Herbst-Irmer
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraβe 4, Göttingen 37077, Germany
| | - Carsten Strohmann
- Institut für Anorganische Chemie, Technische Universität Dortmund, Otto-Hahn-Straβe 6, Dortmund 44227, Germany
| | - Dietmar Stalke
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraβe 4, Göttingen 37077, Germany
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116
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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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117
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Grams S, Eyselein J, Langer J, Färber C, Harder S. Boosting Low-Valent Aluminum(I) Reactivity with a Potassium Reagent. Angew Chem Int Ed Engl 2020; 59:15982-15986. [PMID: 32449816 PMCID: PMC7540686 DOI: 10.1002/anie.202006693] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Indexed: 12/11/2022]
Abstract
The reagent RK [R=CH(SiMe3 )2 or N(SiMe3 )2 ] was expected to react with the low-valent (DIPP BDI)Al (DIPP BDI=HC[C(Me)N(DIPP)]2 , DIPP=2,6-iPr-phenyl) to give [(DIPP BDI)AlR]- K+ . However, deprotonation of the Me group in the ligand backbone was observed and [H2 C=C(N-DIPP)-C(H)=C(Me)-N-DIPP]Al- K+ (1) crystallized as a bright-yellow product (73 %). Like most anionic AlI complexes, 1 forms a dimer in which formally negatively charged Al centers are bridged by K+ ions, showing strong K+ ⋅⋅⋅DIPP interactions. The rather short Al-K bonds [3.499(1)-3.588(1) Å] indicate tight bonding of the dimer. According to DOSY NMR analysis, 1 is dimeric in C6 H6 and monomeric in THF, but slowly reacts with both solvents. In reaction with C6 H6 , two C-H bond activations are observed and a product with a para-phenylene moiety was exclusively isolated. DFT calculations confirm that the Al center in 1 is more reactive than that in (DIPP BDI)Al. Calculations show that both AlI and K+ work in concert and determines the reactivity of 1.
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Affiliation(s)
- Samuel Grams
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Jonathan Eyselein
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Jens Langer
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Christian Färber
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Sjoerd Harder
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
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118
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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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119
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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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120
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Batuecas M, Gorgas N, Crimmin MR. Catalytic C-H to C-M (M = Al, Mg) bond transformations with heterometallic complexes. Chem Sci 2020; 12:1993-2000. [PMID: 34163961 PMCID: PMC8179254 DOI: 10.1039/d0sc03695a] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 08/16/2020] [Indexed: 12/20/2022] Open
Abstract
C-H functionalisation is one of the cornerstones of modern catalysis and remains a topic of contemporary interest due its high efficiency and atom-economy. Among these reactions, C-H borylation, that is the transformation of C-H to C-B bonds, has experienced a fast development because of the wide utility of organoboron reagents as synthetic intermediates. The mechanistic background is now well-understood and the role of transition metal boryl or σ-borane intermediates in this transformation is well documented. This mini-review focuses on efforts made by our group, and others, to establish palladium- and calcium-catalysed methods for C-H metalation employing heavier main group elements (M = Al, Mg). These are new catalytic reactions first accomplished in our group that we have termed C-H alumination and magnesiation respectively. Unusual heterometallic complexes have been identified as key on-cycle intermediates and their unique reactivity is discussed in the context of new catalytic pathways for C-H functionalisation. Hence, this mini-review summarises the recent progress in the area of C-H metalation reactions as well as the new opportunities that may arise from this concept.
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Affiliation(s)
- Maria Batuecas
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Nikolaus Gorgas
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Mark R Crimmin
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
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121
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Whitelaw MT, Kennedy AR, Mulvey RE. Structural Similarity in a Series of Alkali Metal Aluminates with Heteroleptic
tert
‐Butoxide–Isobutyl Ligand Sets. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael T. Whitelaw
- WestCHEM Department of Pure and Applied Chemistry University of Strathclyde 295 Cathedral Street G1 1XL Glasgow U.K
| | - Alan R. Kennedy
- WestCHEM Department of Pure and Applied Chemistry University of Strathclyde 295 Cathedral Street G1 1XL Glasgow U.K
| | - R. E. Mulvey
- WestCHEM Department of Pure and Applied Chemistry University of Strathclyde 295 Cathedral Street G1 1XL Glasgow U.K
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122
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Guo Z, Xu Y, Chao J, Wei X. Lithium Organoaluminate Complexes as Catalysts for the Conversion of CO
2
into Cyclic Carbonates. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zhiqiang Guo
- Scientific Instrument Center Shanxi University 030006 Taiyuan P. R. China
| | - Yuan Xu
- School of Chemistry and Chemical Engineering Shanxi University 030006 Taiyuan P. R. China
| | - Jianbin Chao
- Scientific Instrument Center Shanxi University 030006 Taiyuan P. R. China
| | - Xuehong Wei
- Institute of Applied Chemistry Shanxi University 030006 Taiyuan P. R. China
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123
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Zhong T, Zhao J, Lei H. Trianionic binucleating bis(trityl)/aryloxide ligands and their lithium, magnesium, and zinc complexes. CAN J CHEM 2020. [DOI: 10.1139/cjc-2020-0139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A series of lithium complexes with trianionic bis(trityl)/aryloxide ligands were prepared by triple deprotonation of phenols with two ortho-diarylmethyl substituents. Transmetalation with one of the lithium complexes via salt metathesis resulted in the synthesis of corresponding Mg and Zn complexes, which showed distinct coordination stoichiometry and structures. The metal complexes were characterized by multi-nuclear NMR, UV–vis, and infrared spectroscopy. Additionally, the redox property of a trilithium compound was investigated by electrochemical methods. X-ray crystallography revealed that the new bis(trityl)/aryloxide ligands could simultaneously bind to two nearby metal centers both in chelating κ2-O,C fashion, making themselves rare examples of tridentate binucleating alkyl/aryloxo scaffolds.
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Affiliation(s)
- Tingshan Zhong
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, China
| | - Jixing Zhao
- Analysis and Testing Center, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Hao Lei
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, China
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124
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García-Domínguez A, West TH, Primozic JJ, Grant KM, Johnston CP, Cumming GG, Leach AG, Lloyd-Jones GC. Difluorocarbene Generation from TMSCF3: Kinetics and Mechanism of NaI-Mediated and Si-Induced Anionic Chain Reactions. J Am Chem Soc 2020; 142:14649-14663. [DOI: 10.1021/jacs.0c06751] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Andrés García-Domínguez
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Thomas H. West
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Johann J. Primozic
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Katie M. Grant
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Craig P. Johnston
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Grant G. Cumming
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Andrew G. Leach
- School of Health Sciences, Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT, U.K
| | - Guy C. Lloyd-Jones
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
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125
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Mastropierro P, Livingstone Z, Robertson SD, Kennedy AR, Hevia E. Structurally Mapping Alkyl and Amide Basicity in Zincate Chemistry: Diversity in the Synthesis of Mixed Sodium–Zinc Complexes and Their Applications in Enolate Formation. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00339] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Zoe Livingstone
- Department of Pure and Applied Chemistry, University of Strathclyde Glasgow G1 1XL, United Kingdom
| | - Stuart D. Robertson
- Department of Pure and Applied Chemistry, University of Strathclyde Glasgow G1 1XL, United Kingdom
| | - Alan R. Kennedy
- Department of Pure and Applied Chemistry, University of Strathclyde Glasgow G1 1XL, United Kingdom
| | - Eva Hevia
- Department für Chemie und Biochemie, Universität Bern, CH3012 Bern, Switzerland
- Department of Pure and Applied Chemistry, University of Strathclyde Glasgow G1 1XL, United Kingdom
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126
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Dell'Aera M, Perna FM, Vitale P, Altomare A, Palmieri A, Maddock LCH, Bole LJ, Kennedy AR, Hevia E, Capriati V. Boosting Conjugate Addition to Nitroolefins Using Lithium Tetraorganozincates: Synthetic Strategies and Structural Insights. Chemistry 2020; 26:8742-8748. [PMID: 32181938 DOI: 10.1002/chem.202001294] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Indexed: 11/09/2022]
Abstract
We report the first transition metal catalyst- and ligand-free conjugate addition of lithium tetraorganozincates (R4 ZnLi2 ) to nitroolefins. Displaying enhanced nucleophilicity combined with unique chemoselectivity and functional group tolerance, homoleptic aliphatic and aromatic R4 ZnLi2 provide access to valuable nitroalkanes in up to 98 % yield under mild conditions (0 °C) and short reaction time (30 min). This is particularly remarkable when employing β-nitroacrylates and β-nitroenones, where despite the presence of other electrophilic groups, selective 1,4 addition to the C=C is preferred. Structural and spectroscopic studies confirmed the formation of tetraorganozincate species in solution, the nature of which has been a long debated issue, and allowed to unveil the key role played by donor additives on the aggregation and structure of these reagents. Thus, while chelating N,N,N',N'-tetramethylethylenediamine (TMEDA) and (R,R)-N,N,N',N'-tetramethyl-1,2-diaminocyclohexane (TMCDA) favour the formation of contacted-ion pair zincates, macrocyclic Lewis donor 12-crown-4 triggers an immediate disproportionation process of Et4 ZnLi2 into equimolar amounts of solvent-separated Et3 ZnLi and EtLi.
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Affiliation(s)
- Marzia Dell'Aera
- Dipartimento di Farmacia-Scienze del Farmaco, Università di Bari "A. Moro", Consorzio C.I.N.M.P.I.S., Via E. Orabona 4, 70125, Bari, Italy.,Istituto di Cristallografia (IC-CNR), Via Amendola 122/o, 70125, Bari, Italy
| | - Filippo Maria Perna
- Dipartimento di Farmacia-Scienze del Farmaco, Università di Bari "A. Moro", Consorzio C.I.N.M.P.I.S., Via E. Orabona 4, 70125, Bari, Italy
| | - Paola Vitale
- Dipartimento di Farmacia-Scienze del Farmaco, Università di Bari "A. Moro", Consorzio C.I.N.M.P.I.S., Via E. Orabona 4, 70125, Bari, Italy
| | - Angela Altomare
- Istituto di Cristallografia (IC-CNR), Via Amendola 122/o, 70125, Bari, Italy
| | - Alessandro Palmieri
- School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino 1, 62032, Camerino, Italy
| | - Lewis C H Maddock
- Department of Pure and Applied Chemistry, University of Strathclyde Glasgow, G1 1XL, Glasgow, UK
| | - Leonie J Bole
- Department für Chemie und Biochemie, Universität Bern, 3012, Bern, Switzerland
| | - Alan R Kennedy
- Department of Pure and Applied Chemistry, University of Strathclyde Glasgow, G1 1XL, Glasgow, UK
| | - Eva Hevia
- Department für Chemie und Biochemie, Universität Bern, 3012, Bern, Switzerland
| | - Vito Capriati
- Dipartimento di Farmacia-Scienze del Farmaco, Università di Bari "A. Moro", Consorzio C.I.N.M.P.I.S., Via E. Orabona 4, 70125, Bari, Italy.,Dipartimento di Chimica, Istituto di Chimica dei Composti Organometallici (ICCOM)-CNR, Università di Bari "A. Moro", Via E. Orabona 4, 70125, Bari, Italy
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127
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Grams S, Eyselein J, Langer J, Färber C, Harder S. Boosting Low‐Valent Aluminum(I) Reactivity with a Potassium Reagent. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006693] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Samuel Grams
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Jonathan Eyselein
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Jens Langer
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Christian Färber
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Sjoerd Harder
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
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128
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Wang B, Ong DY, Li Y, Pang JH, Watanabe K, Takita R, Chiba S. Stereo-controlled anti-hydromagnesiation of aryl alkynes by magnesium hydrides. Chem Sci 2020; 11:5267-5272. [PMID: 34122983 PMCID: PMC8159320 DOI: 10.1039/d0sc01773f] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A concise protocol for anti-hydromagnesiation of aryl alkynes was established using 1 : 1 molar combination of sodium hydride (NaH) and magnesium iodide (MgI2) without the aid of any transition metal catalysts. The resulting alkenylmagnesium intermediates could be trapped with a series of electrophiles, thus providing facile accesses to stereochemically well-defined functionalized alkenes. Mechanistic studies by experimental and theoretical approaches imply that polar hydride addition from magnesium hydride (MgH2) is responsible for the process. Anti-hydromagnesiation of aryl alkynes was facilitated solely by magnesium hydride. The resulting alkenylmagnesium intermediates were functionalized with various electrophiles to afford stereochemically defined tri-substituted alkenes.![]()
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Affiliation(s)
- Bin Wang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University 637371 Singapore
| | - Derek Yiren Ong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University 637371 Singapore
| | - Yihang Li
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University 637371 Singapore
| | - Jia Hao Pang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University 637371 Singapore
| | - Kohei Watanabe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Ryo Takita
- Graduate School of Pharmaceutical Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Shunsuke Chiba
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University 637371 Singapore
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129
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Koby RF, Doerr AM, Rightmire NR, Schley ND, Long BK, Hanusa TP. An η
3
‐Bound Allyl Ligand on Magnesium in a Mechanochemically Generated Mg/K Allyl Complex. Angew Chem Int Ed Engl 2020; 59:9542-9548. [DOI: 10.1002/anie.201916410] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 02/07/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Ross F. Koby
- Department of Chemistry Vanderbilt University Nashville TN 37235 USA
| | - Alicia M. Doerr
- Department of Chemistry University of Tennessee Knoxville TN 37996-1600 USA
| | | | - Nathan D. Schley
- Department of Chemistry Vanderbilt University Nashville TN 37235 USA
| | - Brian K. Long
- Department of Chemistry University of Tennessee Knoxville TN 37996-1600 USA
| | - Timothy P. Hanusa
- Department of Chemistry Vanderbilt University Nashville TN 37235 USA
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130
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Fromm KM. Chemistry of alkaline earth metals: It is not all ionic and definitely not boring! Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213193] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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131
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Koby RF, Doerr AM, Rightmire NR, Schley ND, Long BK, Hanusa TP. An η
3
‐Bound Allyl Ligand on Magnesium in a Mechanochemically Generated Mg/K Allyl Complex. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201916410] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ross F. Koby
- Department of Chemistry Vanderbilt University Nashville TN 37235 USA
| | - Alicia M. Doerr
- Department of Chemistry University of Tennessee Knoxville TN 37996-1600 USA
| | | | - Nathan D. Schley
- Department of Chemistry Vanderbilt University Nashville TN 37235 USA
| | - Brian K. Long
- Department of Chemistry University of Tennessee Knoxville TN 37996-1600 USA
| | - Timothy P. Hanusa
- Department of Chemistry Vanderbilt University Nashville TN 37235 USA
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132
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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] [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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Sandl S, Jacobi von Wangelin A. The Role of Organoferrates in Iron-Catalyzed Cross-Couplings. Angew Chem Int Ed Engl 2020; 59:5434-5437. [PMID: 31999050 DOI: 10.1002/anie.201914844] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Indexed: 02/06/2023]
Abstract
Recent groundbreaking studies on organoferrates have demonstrated that coordinatively unsaturated three-coordinate-σ-alkylferrates are active catalysts in Fe-catalyzed cross-couplings with Grignard reagents and that pronounced solvent and counterion effects dictate metalate speciation and catalyst activity. Thanks to modern spectroscopic methods, sensitive catalyst intermediates could be analyzed.
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Affiliation(s)
- Sebastian Sandl
- Department of Chemistry, University of Hamburg, Martin Luther King Platz 6, 20146, Hamburg, Germany
| | - Axel Jacobi von Wangelin
- Department of Chemistry, University of Hamburg, Martin Luther King Platz 6, 20146, Hamburg, Germany
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135
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Abstract
For the preparation of zinc organometallics bearing highly sensitive functional groups such as ketones, aldehydes or nitro groups, especially mild halogen-zinc exchange reagents have proven to be of great potential. In this Minireview, the latest research in the area of the halogen-zinc exchange reaction is reported, with a special focus lying on novel dialkylzinc reagents complexed with lithium alkoxides. Additionally, the preparation and application of organofluorine zinc reagents and transition-metal-catalyzed halogen-zinc exchange reactions are reviewed.
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Affiliation(s)
- Moritz Balkenhohl
- Department Chemie und PharmazieLudwig-Maximilians-Universität MünchenButenandtstrasse 5–13, Haus F81377MünchenGermany
| | - Paul Knochel
- Department Chemie und PharmazieLudwig-Maximilians-Universität MünchenButenandtstrasse 5–13, Haus F81377MünchenGermany
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136
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Peltzer RM, Gauss J, Eisenstein O, Cascella M. The Grignard Reaction – Unraveling a Chemical Puzzle. J Am Chem Soc 2020; 142:2984-2994. [DOI: 10.1021/jacs.9b11829] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Raphael Mathias Peltzer
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O. Box 1033 Blindern, Oslo 0315, Norway
| | - Jürgen Gauss
- Department Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, Mainz 55128, Germany
| | - Odile Eisenstein
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O. Box 1033 Blindern, Oslo 0315, Norway
- ICGM, Université de Montpellier, CNRS, ENSCM, Montpellier 34095 Cedex 5, France
| | - Michele Cascella
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O. Box 1033 Blindern, Oslo 0315, Norway
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137
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Knauer L, Strohmann C. The structure-defining incorporation of chloride in methyllithium dimers. Chem Commun (Camb) 2020; 56:13543-13546. [DOI: 10.1039/d0cc05547f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Two polymeric solid-state structures of pmdta-stabilized methyllithium with co-existing tetrameric and dimeric units were obtained, linked by the structure-giving “contaminant” LiCl, incorporated only in dimeric entities.
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Affiliation(s)
- Lena Knauer
- Institute for Inorganic Chemistry
- TU Dortmund University
- 44227 Dortmund
- Germany
| | - Carsten Strohmann
- Institute for Inorganic Chemistry
- TU Dortmund University
- 44227 Dortmund
- Germany
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138
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Espinosa-Jalapa NA, Berg N, Seidl M, Shenderovich IG, Gschwind RM, Bauer JO. Complexation behaviour of LiCl and LiPF6– model studies in the solid-state and in solution using a bidentate picolyl-based ligand. Chem Commun (Camb) 2020; 56:13335-13338. [DOI: 10.1039/d0cc05682k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Using a new bulky bidentate ligand and combining various structure elucidation methods, coordination modes of [ligand·LiX] (X = Cl, PF6) complexes both in solid-state and in solution have been revealed.
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Affiliation(s)
- Noel Angel Espinosa-Jalapa
- Institut für Anorganische Chemie
- Fakultät für Chemie und Pharmazie
- Universität Regensburg
- D-93053 Regensburg
- Germany
| | - Nele Berg
- Institut für Organische Chemie
- Fakultät für Chemie und Pharmazie
- Universität Regensburg
- D-93053 Regensburg
- Germany
| | - Michael Seidl
- Institut für Anorganische Chemie
- Fakultät für Chemie und Pharmazie
- Universität Regensburg
- D-93053 Regensburg
- Germany
| | - Ilya G. Shenderovich
- Institut für Organische Chemie
- Fakultät für Chemie und Pharmazie
- Universität Regensburg
- D-93053 Regensburg
- Germany
| | - Ruth M. Gschwind
- Institut für Organische Chemie
- Fakultät für Chemie und Pharmazie
- Universität Regensburg
- D-93053 Regensburg
- Germany
| | - Jonathan O. Bauer
- Institut für Anorganische Chemie
- Fakultät für Chemie und Pharmazie
- Universität Regensburg
- D-93053 Regensburg
- Germany
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139
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Woltornist RA, Ma Y, Algera RF, Zhou Y, Zhang Z, Collum DB. Structure, Reactivity, and Synthetic Applications of Sodium Diisopropylamide. SYNTHESIS-STUTTGART 2020; 52:1478-1497. [PMID: 34349297 DOI: 10.1055/s-0039-1690846] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The 60-year history of sodium diisopropylamide (NaDA) is described herein. We review various preparations, solvent-dependent stabilities, and solution structures. Synthetic applications of NaDA reported to date are framed by a mechanism-driven approach, emphasizing selectivities when appropriate. We conclude with examples beyond metalation in which NaDA plays a central role and a few thoughts on where future applications could be focused.
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Affiliation(s)
- Ryan A Woltornist
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - Yun Ma
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - Russell F Algera
- Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Yuhui Zhou
- Frontage Laboratories, Inc., 75 E Uwchlan Avenue, Suite 100, Exton, PA, 19341
| | - Zirong Zhang
- Department of Chemistry, University of Michigan, CHEM 3614 930 North University Ave, Ann Arbor, MI, 48109
| | - David B Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301.,Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States.,Frontage Laboratories, Inc., 75 E Uwchlan Avenue, Suite 100, Exton, PA, 19341.,Department of Chemistry, University of Michigan, CHEM 3614 930 North University Ave, Ann Arbor, MI, 48109
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140
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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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141
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Freeman LA, Walley JE, Obi AD, Wang G, Dickie DA, Molino A, Wilson DJD, Gilliard RJ. Stepwise Reduction at Magnesium and Beryllium: Cooperative Effects of Carbenes with Redox Non-Innocent α-Diimines. Inorg Chem 2019; 58:10554-10568. [PMID: 31124671 DOI: 10.1021/acs.inorgchem.9b01058] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In the past two decades, the organometallic chemistry of the alkaline earth elements has experienced a renaissance due in part to developments in ligand stabilization strategies. In order to expand the scope of redox chemistry known for magnesium and beryllium, we have synthesized a set of reduced magnesium and beryllium complexes and compared their resulting structural and electronic properties. The carbene-coordinated alkaline earth-halides, (Et2CAAC)MgBr2 (1), (SIPr)MgBr2 (2), (Et2CAAC)BeCl2 (3), and (SIPr)BeCl2 (4) [Et2CAAC = diethyl cyclic(alkyl)(amino) carbene; SIPr = 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazole-2-ylidene] were combined with an α-diimine [2,2-bipyridine (bpy) or bis(2,6-diisopropylphenyl)-1,4-diazabutadiene (DippDAB)] and the appropriate stoichiometric amount of potassium graphite to form singly- and doubly-reduced compounds (Et2CAAC)MgBr(DippDAB) (5), (Et2CAAC)MgBr(bpy) (6), (Et2CAAC)Mg(DippDAB) (7), (Et2CAAC)Be(bpy) (8), and (SIPr)Be(bpy) (9). The doubly-reduced compounds 7-9 exhibit substantial π-bonding interactions across the diimine core, metal center, and π-acidic carbene. Each complex was fully characterized by UV-vis, FT-IR, X-ray crystallography, 1H, 13C, and 9Be NMR, or EPR where applicable. We use these compounds to highlight the differences in the organometallic chemistry of the lightest alkaline earth metals, magnesium and beryllium, in an otherwise identical chemical environment.
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Affiliation(s)
- Lucas A Freeman
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Jacob E Walley
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Akachukwu D Obi
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Guocang Wang
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Diane A Dickie
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Andrew Molino
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Bundoora , Victoria 3083 , Australia
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Bundoora , Victoria 3083 , Australia
| | - Robert J Gilliard
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
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142
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Pollard VA, Young A, McLellan R, Kennedy AR, Tuttle T, Mulvey RE. Lithium-Aluminate-Catalyzed Hydrophosphination Applications. Angew Chem Int Ed Engl 2019; 58:12291-12296. [PMID: 31260154 PMCID: PMC6771573 DOI: 10.1002/anie.201906807] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Indexed: 01/23/2023]
Abstract
Synthesized, isolated, and characterized by X‐ray crystallography and NMR spectroscopic studies, lithium phosphidoaluminate iBu3AlPPh2Li(THF)3 has been tested as a catalyst for hydrophosphination of alkynes, alkenes, and carbodiimides. Based on the collective evidence of stoichiometric reactions, NMR monitoring studies, kinetic analysis, and DFT calculations, a mechanism involving deprotonation, alkyne insertion, and protonolysis is proposed for the [iBu3AlHLi]2 aluminate catalyzed hydrophosphination of alkynes with diphenylphosphine. This study enhances further the development of transition‐metal‐free, atom‐economical homogeneous catalysis using common sustainable main‐group metals.
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Affiliation(s)
- Victoria A Pollard
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Allan Young
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Ross McLellan
- 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
| | - Tell Tuttle
- 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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143
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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
Created by potrace 1.16, written by Peter Selinger 2001-2019
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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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