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Brieger L, Schrimpf T, Scheel R, Unkelbach C, Strohmann C. Towards Substrate-Reagent Interaction of Lochmann-Schlosser Bases in THF: Bridging THF Hides Potential Reaction Site of a Chiral Superbase. Chemistry 2022; 28:e202202660. [PMID: 36098179 PMCID: PMC10092790 DOI: 10.1002/chem.202202660] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Indexed: 12/14/2022]
Abstract
The metalation of N,N-dimethylaminomethylferrocene in THF by the superbasic mixture of n BuLi/KOt Bu proceeds readily at low temperatures to afford a bimetallic Li2 K2 aggregate containing ferrocenyl anions and tert-butoxide. Starting from an enantiomerically enriched ortho-lithiated aminomethylferrocene, an enantiomerically pure superbase can be prepared. The molecular compound exhibits superbasic behavior deprotonating N,N-dimethylbenzylamine in the α-position and is also capable of deprotonating toluene. Quantum chemical calculations provide insight into the role of the bridging THF molecule to the possible substrate-reagent interaction. In addition, a benzylpotassium alkoxide adduct gives a closer look into the corresponding reaction site of the Lochmann-Schlosser base that is reported herein.
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Affiliation(s)
- Lukas Brieger
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
| | - Tobias Schrimpf
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
| | - Rebecca Scheel
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
| | - Christian Unkelbach
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
| | - Carsten Strohmann
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
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2
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Brieger L, Unkelbach C, Strohmann C. THF-solvated Heavy Alkali Metal Benzyl Compounds (Na, Rb, Cs): Defined Deprotonation Reagents for Alkali Metal Mediation Chemistry. Chemistry 2021; 27:17780-17784. [PMID: 34633717 PMCID: PMC9298144 DOI: 10.1002/chem.202103430] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Indexed: 12/15/2022]
Abstract
The incorporation of heavy alkali metals into substrates is both challenging and essential for many reactions. Here, we report the formation of THF-solvated alkali metal benzyl compounds [PhCH2 M ⋅ (thf)n ] (M=Na, Rb, Cs). The synthesis was carried out by deprotonation of toluene with the bimetallic mixture n-butyllithium/alkali metal tert-butoxide and selective crystallization from THF of the defined benzyl compounds. Insights into the molecular structure in the solid as well as in solution state are gained by single crystal X-ray experiments and NMR spectroscopic studies. The compounds could be successfully used as alkali metal mediating reagents. The example of caesium showed the convenient use by deprotonating acidic C-H as well as N-H compounds to gain insight into the aminometalation using these reagents.
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Affiliation(s)
- Lukas Brieger
- Inorganic ChemistryTU Dortmund UniversityOtto-Hahn-Str. 6/6a44227DortmundGermany
| | - Christian Unkelbach
- Inorganic ChemistryTU Dortmund UniversityOtto-Hahn-Str. 6/6a44227DortmundGermany
| | - Carsten Strohmann
- Inorganic ChemistryTU Dortmund UniversityOtto-Hahn-Str. 6/6a44227DortmundGermany
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3
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Huang BH, Ko BT, Athar T, Lin CC. Synthesis, Characterization, and Structural Determination of Polynuclear Lithium Aggregates and Factors Affecting Their Aggregation. Inorg Chem 2006; 45:7348-56. [PMID: 16933937 DOI: 10.1021/ic060467w] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of [(mu3,mu3-EDBP)Li2]2[(mu3-nBu)Li(0.5Et2O)]2 (1) [EDBP-H2 = 2,2'-ethylidenebis(4,6-di-tert-butylphenol)] with 1 equiv of ROH in toluene gave [(mu3,mu3-EDBP)Li2]2[(mu3-OR)Li]2 [R = Bn (2), CH2CH2OEt (3), and nBu (4)]. In the presence of 3 equiv of tetrahydrofuran (THF), the hexanuclear compound 1 slowly decomposed to an unusual pentanuclear Li complex, [(mu2,mu3-EDBP)2Li4(THF)2][(mu3-nBu)Li] (5). Further reaction of 5 with ROH gave [(mu2,mu3-EDBP)2Li4(THF)3][(mu4-OR)Li] [R = Bn (6), nBu (7), and CH2CH2OEt (8)] without a major change in its skeleton. Treatment of 2 with an excess of hexamethylphosphoramide (HMPA) yields [(mu2,mu2-EDBP)Li2(HMPA)2][(mu3-OBn)Li(HMPA)] (9). Compounds [(mu2,mu3-EDBP)2Li4(THF)][(mu4-OCH2CH2OEt)Li]2 (10) and [(mu2,mu2-EDBP)2Li4(mu4-OCH2CH2OEt)(HMPA)]-[Li(HMPA)4]+ (11) can be obtained by the reaction of 3 with an "oxygen-donor solvent" such as THF and HMPA, respectively. Among the compounds described above, 8 has shown great reactivity toward ring-opening polymerization of L-lactide, yielding polymers with very low polydispersity indexes in a wide range of monomer-to-initiator ratios.
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Affiliation(s)
- Bor-Hunn Huang
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan, Republic of China
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4
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Scott N, Schareina T, Tok O, Kempe R. Lithium and Potassium Amides of Sterically Demanding Aminopyridines. Eur J Inorg Chem 2004. [DOI: 10.1002/ejic.200400228] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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5
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Andrews P, Maguire M, Pombo‐Villar E. Synthesis and Structure of a Monomeric Chiral Lithium Dialkylaluminium Amide Derived from Schöllkopf’s Bis‐lactim Ether and α‐(Methylbenzyl)benzylamine. Eur J Inorg Chem 2003. [DOI: 10.1002/ejic.200300186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Philip C. Andrews
- School of Chemistry, Monash University, PO Box 23, Melbourne, Vic. 3800, Australia, Fax:(internat.) +61‐3/9905‐4597
| | - Melissa Maguire
- School of Chemistry, Monash University, PO Box 23, Melbourne, Vic. 3800, Australia, Fax:(internat.) +61‐3/9905‐4597
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6
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Lutz M, Haukka M, Pakkanen TA, Gade LH. Syntheses and structural characterization of the heavier alkali-metal stannates bearing the tripodal triamino framework: structural trends in the series of [MeSi(SiMe2N(4-CH3C6H4))3Sn][M] (M = Na, K, Rb). Inorg Chem 2003; 42:2798-804. [PMID: 12691591 DOI: 10.1021/ic026226f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Treatment of the lithium stannate [MeSi(SiMe(2)N(4-CH(3)C(6)H(4)))(3)SnLi(OEt(2))] (1) with AgCl yielded the corresponding distannane [MeSi(SiMe(2)N(4-CH(3)C(6)H(4)))(3)Sn](2) (2) as the product of an oxidative coupling in good yield. The distannane (2) underwent reductive cleavage with the heavier alkali metals (sodium, potassium, rubidium) in a non-coordinating solvent (toluene or cyclohexane), to afford the solvate-free stannates(II) [MeSi(SiMe(2)N(4-CH(3)C(6)H(4)))(3)Sn][M] (M = Na (3), K (4), and Rb (5)), which were structurally characterized. The Na atom in 3 is directly bonded to two of the three amido-N atoms of the stannate cage and additionally solvated by pi-coordination of a tolyl substituent of a neighboring stannate cage. In contrast, the group 1 metal cations in the two isomorphous compounds 4 and 5 are further removed from the nitrogen functions and are pi-coordinated by three tolyl arene rings. The Sn-K distances in 4 were found to be 3.635 and 3.870 A, whereas the Sn-Rb contacts in 5 are 3.708 and 3.908 A; these are the first such Sn-Rb bonding contacts to be characterized in a molecular compound by X-ray diffraction.
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Affiliation(s)
- Matthias Lutz
- Laboratoire de Chimie Organométallique et de Catalyse (UMR 7513), Institut Le Bel, Université Louis Pasteur, 4, rue Blaise Pascal, 67070 Strasbourg, France
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7
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Micha-Screttas M, Screttas CG, Steele BR, Heropoulos GA. Chemical and physical evidence for metal–metal interchange between lithium alkoxides and di-n-butylmagnesium. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00841-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Pauls J, Chitsaz S, Neumüller B. Direct Synthesis of a Cesium Azaallyl Compound. Organometallics 2002. [DOI: 10.1021/om011046j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jochen Pauls
- Fachbereich Chemie der Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
| | - Soheila Chitsaz
- Fachbereich Chemie der Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
| | - Bernhard Neumüller
- Fachbereich Chemie der Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
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9
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Kennedy AR, MacLellan JG, Mulvey RE. Landmark Crystal Structure of an Experimentally Utilized Tetralithium–Tetrapotassium Amide–Alkoxide Superbase. Angew Chem Int Ed Engl 2001. [DOI: 10.1002/1521-3757(20010903)113:17<3345::aid-ange3345>3.0.co;2-#] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alan R. Kennedy
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL (UK) Fax: (+44) 141‐552‐0876
| | - Jonathan G. MacLellan
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL (UK) Fax: (+44) 141‐552‐0876
| | - Robert E. Mulvey
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL (UK) Fax: (+44) 141‐552‐0876
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10
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Kennedy AR, MacLellan JG, Mulvey RE. Landmark Crystal Structure of an Experimentally Utilized Tetralithium-Tetrapotassium Amide-Alkoxide Superbase. Angew Chem Int Ed Engl 2001; 40:3245-3247. [PMID: 29712050 DOI: 10.1002/1521-3773(20010903)40:17<3245::aid-anie3245>3.0.co;2-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2001] [Indexed: 11/09/2022]
Affiliation(s)
- Alan R Kennedy
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL (UK) Fax: (+44) 141-552-0876
| | - Jonathan G MacLellan
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL (UK) Fax: (+44) 141-552-0876
| | - Robert E Mulvey
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow, G1 1XL (UK) Fax: (+44) 141-552-0876
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11
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Jiang RW, He ZD, But PP, Chan YM, Ma SC, Mak TC. A novel 1:1 complex of potassium mikanin-3-O-sulfate with methanol. Chem Pharm Bull (Tokyo) 2001; 49:1166-9. [PMID: 11558604 DOI: 10.1248/cpb.49.1166] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mikanin-3-O-sulfate (1), in the form of its potassium salt, together with mikanin (2) and alpinetin (3) were isolated from Mikania micrantha. The crystal structures of K(1) x CH3OH, 2 and 3 x H2O were established by X-ray crystallography. The potassium ions in K(1) x CHO3H are bridged by O5, O7 and O8 to form a chain of face-sharing KO8 coordination polyhedra, from which the aglycon units are outstretched to form a polymeric molecular column. Adjacent molecular columns are linked by pi-pi stacking between parallel, intercalating aglycon units to form layers matching the (101) family of planes, which are further interconnected into a three-dimensional supramolecular assembly. Sulfation at 3-OH induced better co-planarity and conjugation of the rings.
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Affiliation(s)
- R W Jiang
- Department of Chemistry, The Chinese University of Hong Kong, Hong Kong SAR, PR China
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12
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Ko BT, Lin CC. Synthesis, characterization, and catalysis of mixed-ligand lithium aggregates, excellent initiators for the ring-opening polymerization of L-lactide. J Am Chem Soc 2001; 123:7973-7. [PMID: 11506552 DOI: 10.1021/ja010604i] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three novel mixed-ligand lithium aggregates, [(mu(3)-EDBP)Li(2)](2)[(mu(3)-(n)Bu)Li(0.5Et(2)O)](2) (1), [(mu(3)-EDBP)Li(2)](2)[(mu(3)-OBn)Li](2) (2), and [(mu(3)-EDBP)Li(2)](2)[(mu(3)-OCH(2)CH(2)OCH(2)CH(3))Li](2) (3), have been synthesized and structurally characterized. The reaction of 2,2'-ethylidene-bis(4,6-di-tert-butylphenol) (EDBP-H(2)) with 3.6 molar equiv of (n)BuLi gives 1 in high yield. 1 further reacts with benzyl alcohol and 2-ethoxyethanol respectively to yield the corresponding products 2 and 3. Experimental results show that 2 and 3 efficiently initiate the ring-opening polymerization of L-lactide in a controlled fashion, yielding polymers with very narrow polydispersity indexes in a wide range of monomer-to-initiator ratios.
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Affiliation(s)
- B T Ko
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan, ROC
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13
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Andrews PC, Deacon GB, Forsyth CM, Scott NM. A Striking, Multifaceted, Decalithium Aggregate with Carbanion, Organoamide, and Alkoxide Functionalities. Angew Chem Int Ed Engl 2001. [DOI: 10.1002/1521-3757(20010601)113:11<2166::aid-ange2166>3.0.co;2-o] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Andrews PC, Deacon GB, Forsyth CM, Scott NM. A Striking, Multifaceted, Decalithium Aggregate with Carbanion, Organoamide, and Alkoxide Functionalities. Angew Chem Int Ed Engl 2001; 40:2108-2111. [DOI: 10.1002/1521-3773(20010601)40:11<2108::aid-anie2108>3.0.co;2-c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2001] [Indexed: 11/10/2022]
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