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Kroesen U, Unkelbach C, Schildbach D, Strohmann C. Controlling the Coordination Sphere of Alkyllithiums Results in Selective Reactions with Allylic Amines. Angew Chem Int Ed Engl 2017; 56:14164-14168. [PMID: 28940968 DOI: 10.1002/anie.201708620] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Indexed: 11/09/2022]
Abstract
Described herein is a selective way to control the reaction of allylic amines with metalorganic bases depending on the amine handle as well as the metalorganic base is used. Depending on the number of coordinating groups within the amine handle either a selective carbometalation or deprotonation reaction can be performed. By changing the alkali metal within the base from lithium to either sodium or potassium, a change of chemoselectivity takes place and the reaction of piperidinoallylamine can be controlled.
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Affiliation(s)
- Ulrike Kroesen
- Anorganische Chemie, Technische, Universität Dortmund, Otto-Hahn-Straße 6, 44227, Dortmund, Germany
| | - Christian Unkelbach
- Anorganische Chemie, Technische, Universität Dortmund, Otto-Hahn-Straße 6, 44227, Dortmund, Germany
| | - Daniel Schildbach
- Anorganische Chemie, Technische, Universität Dortmund, Otto-Hahn-Straße 6, 44227, Dortmund, Germany
| | - Carsten Strohmann
- Anorganische Chemie, Technische, Universität Dortmund, Otto-Hahn-Straße 6, 44227, Dortmund, Germany
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2
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Kroesen U, Unkelbach C, Schildbach D, Strohmann C. Controlling the Coordination Sphere of Alkyllithiums Results in Selective Reactions with Allylic Amines. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ulrike Kroesen
- Anorganische Chemie; Technische; Universität Dortmund; Otto-Hahn-Straße 6 44227 Dortmund Germany
| | - Christian Unkelbach
- Anorganische Chemie; Technische; Universität Dortmund; Otto-Hahn-Straße 6 44227 Dortmund Germany
| | - Daniel Schildbach
- Anorganische Chemie; Technische; Universität Dortmund; Otto-Hahn-Straße 6 44227 Dortmund Germany
| | - Carsten Strohmann
- Anorganische Chemie; Technische; Universität Dortmund; Otto-Hahn-Straße 6 44227 Dortmund Germany
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3
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Houghton MJ, Huck CJ, Wright SW, Collum DB. Lithium Enolates Derived from Pyroglutaminol: Mechanism and Stereoselectivity of an Azaaldol Addition. J Am Chem Soc 2016; 138:10276-83. [PMID: 27500546 PMCID: PMC5240537 DOI: 10.1021/jacs.6b05481] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A lithium enolate derived from an acetonide-protected pyroglutaminol undergoes a highly selective azaaldol addition with (E)-N-phenyl-1-[2-(trifluoromethyl)phenyl]methanimine. The selectivity is sensitive to tetrahydrofuran (THF) concentration, temperature, and the presence of excess lithium diisopropylamide base. Rate studies show that the observable tetrasolvated dimeric enolate undergoes reversible deaggregation, with the reaction proceeding via a disolvated-monomer-based transition structure. Limited stereochemical erosion stems from the intervention of a trisolvated-monomer-based pathway, which is suppressed at low THF concentrations and elevated temperature. Endofacial selectivity observed with excess lithium diisopropylamide (LDA) is traced to an intermediate dianion formed by subsequent lithiation of the monomeric azaaldol adduct, which is characterized as both a dilithio form and a trilithio dianion-LDA mixed aggregate.
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Affiliation(s)
- Michael J. Houghton
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University Ithaca, New York 14853–1301
| | - Christopher J. Huck
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University Ithaca, New York 14853–1301
| | - Stephen W. Wright
- Worldwide Medicinal Chemistry, Pfizer Global Research and Development, 445 Eastern Point Road, Groton, CT 06340
| | - David B. Collum
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University Ithaca, New York 14853–1301
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Flynn MT, Stott R, Blair VL, Andrews PC. Loss of Chirality through Facile Lewis Base Mediated Aza-enolate Formation in Na and K (S)-N-(α-Methylbenzyl)methallylamides. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00445] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matthew T. Flynn
- School of Chemistry, Monash University, Clayton, Melbourne, Victoria, Australia 3800
| | - Rachel Stott
- School of Chemistry, Monash University, Clayton, Melbourne, Victoria, Australia 3800
| | - Victoria L. Blair
- School of Chemistry, Monash University, Clayton, Melbourne, Victoria, Australia 3800
| | - Philip C. Andrews
- School of Chemistry, Monash University, Clayton, Melbourne, Victoria, Australia 3800
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5
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Guang J, Liu QP, Hopson R, Williard PG. Lithium pinacolone enolate solvated by hexamethylphosphoramide. J Am Chem Soc 2015; 137:7347-56. [PMID: 25933508 DOI: 10.1021/jacs.5b01906] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the crystal structure of a substoichiometric, HMPA-trisolvated lithium pinacolone enolate tetramer (LiOPin)4·HMPA3 abbreviated as T3. In this tetramer one HMPA binds to lithium more strongly than the other two causing a reduction in spatial symmetry with corresponding loss of C3 symmetry. A variety of NMR experiments, including HMPA titration, diffusion coefficient-formula weight (D-FW) analysis, and other multinuclear one- and two-dimensional NMR techniques reveal that T3 is the major species in hydrocarbon solution when more than 0.6 equiv of HMPA is present. Due to a small amount of moisture from HMPA or air leaking into the solution, a minor complex was identified and confirmed by X-ray diffraction analysis as a mixed aggregate containing enolate, lithium hydroxide, and HMPA in a 4:2:4 ratio, [(LiOPin)4·(LiOH)2·HMPA4], that we refer to as pseudo-T4. A tetra-HMPA-solvated lithium cyclopentanone enolate tetramer was also prepared and characterized by X-ray diffraction, leading to the conclusion that steric effects dominate the formation and solvation of the pinacolone aggregates. An unusual mixed aggregate consisting of pinacolone enolate, lithium diisopropyl amide, lithium oxide, and HMPA in the ratio 5:1:1:2 is also described.
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Affiliation(s)
- Jie Guang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Qiyong Peter Liu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Russell Hopson
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Paul G Williard
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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Ma Y, Stivala CE, Wright AM, Hayton T, Liang J, Keresztes I, Lobkovsky E, Collum DB, Zakarian A. Enediolate-dilithium amide mixed aggregates in the enantioselective alkylation of arylacetic acids: structural studies and a stereochemical model. J Am Chem Soc 2013; 135:16853-64. [PMID: 23654300 PMCID: PMC3818356 DOI: 10.1021/ja403076u] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A combination of X-ray crystallography, (6)Li, (15)N, and (13)C NMR spectroscopies, and density functional theory computations affords insight into the structures and reactivities of intervening aggregates underlying highly selective asymmetric alkylations of carboxylic acid dianions (enediolates) mediated by the dilithium salt of a C2-symmetric chiral tetraamine. Crystallography shows a trilithiated n-butyllithium-dilithiated amide that has dimerized to a hexalithiated form. Spectroscopic studies implicate the non-dimerized trilithiated mixed aggregate. Reaction of the dilithiated amide with the dilithium enediolate derived from phenylacetic acid affords a tetralithio aggregate comprised of the two dianions in solution and the dimerized octalithio form in the solid state. Computational studies shed light on the details of the solution structures and afford a highly predictive stereochemical model.
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Affiliation(s)
- Yun Ma
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, Telephone: (607)-255-4879; Fax: (850)-644-8281
| | - Craig E. Stivala
- Contribution from the Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106; Telephone: (805)-893-3717; Fax: (805)-893-4120
| | - Ashley M. Wright
- Contribution from the Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106; Telephone: (805)-893-3717; Fax: (805)-893-4120
| | - Trevor Hayton
- Contribution from the Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106; Telephone: (805)-893-3717; Fax: (805)-893-4120
| | - Jun Liang
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, Telephone: (607)-255-4879; Fax: (850)-644-8281
| | - Ivan Keresztes
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, Telephone: (607)-255-4879; Fax: (850)-644-8281
| | - Emil Lobkovsky
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, Telephone: (607)-255-4879; Fax: (850)-644-8281
| | - David B. Collum
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, Telephone: (607)-255-4879; Fax: (850)-644-8281
| | - Armen Zakarian
- Contribution from the Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106; Telephone: (805)-893-3717; Fax: (805)-893-4120
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Gruver JM, West SP, Collum DB, Sarpong R. Experimental characterization and computational study of unique C,N-chelated lithium dianions. J Am Chem Soc 2010; 132:13212-3. [PMID: 20822143 DOI: 10.1021/ja106852n] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structure of a unique C,N-chelated dilithio dianion has been established as a solvated monomeric species using a combination of NMR and computational techniques. The highly ordered structure of the dianion may be important in its reactivity in an oxidative C-N bond-forming process.
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Affiliation(s)
- Jocelyn M Gruver
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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Fischer R, Görls H, Westerhausen M. A dilithium 1,4-butanediide with a chlorine-centered Li12 icosahedral structure. Angew Chem Int Ed Engl 2009; 48:9958-61. [PMID: 19937881 DOI: 10.1002/anie.200904793] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Reinald Fischer
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, August-Bebel-Strasse 2, 07743 Jena, Germany
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Fischer R, Görls H, Westerhausen M. Eine Dilithium-1,4-butandiid-Struktur mit einem chlorzentrierten Li12-Ikosaeder. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200904793] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Blaszykowski C, Brancour C, Dhimane AL, Fensterbank L, Malacria M. Towards the Synthesis of 3-Silapiperidines. European J Org Chem 2009. [DOI: 10.1002/ejoc.200801197] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Li D, Keresztes I, Hopson R, Williard PG. Characterization of reactive intermediates by multinuclear diffusion-ordered NMR spectroscopy (DOSY). Acc Chem Res 2009; 42:270-80. [PMID: 19105594 DOI: 10.1021/ar800127e] [Citation(s) in RCA: 239] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nuclear magnetic resonance (NMR) is the most powerful and widely utilized technique for determining molecular structure. Although traditional NMR data analysis involves the correlation of chemical shift, coupling constant, and NOE interactions to specific structural features, a largely overlooked method introduced more than 40 years ago, pulsed gradient spin-echo (PGSE), measures diffusion coefficients of molecules in solution, thus providing their relative particle sizes. In the early 1990s, the PGSE sequence was incorporated into a two-dimensional experiment, dubbed diffusion-ordered NMR spectroscopy (DOSY), in which one dimension represents chemical shift data while the second dimension resolves species by their diffusion properties. This combination provides a powerful tool for identifying individual species in a multicomponent solution, earning the nickname "chromatography by NMR". In this Account, we describe our efforts to utilize DOSY techniques to characterize organometallic reactive intermediates in solution in order to correlate structural data to solid-state crystal structures determined by X-ray diffraction and to discover the role of aggregate formation and solvation states in reaction mechanisms. In 2000, we reported our initial efforts to employ DOSY techniques in the characterization of reactive intermediates such as organolithium aggregates. Since then, we have explored DOSY experiments with various nuclei beyond (1)H, including (6)Li, (7)Li, (11)B, (13)C, and (29)Si. Additionally, we proposed a diffusion coefficient-formula weight relationship to determine formula weight, aggregation number, and solvation state of reactive intermediates. We also introduced an internal reference system to correlate the diffusion properties of unknown reactive intermediates with known inert molecular standards, such as aromatic compounds, terminal olefins, cycloolefins, and tetraalkylsilanes. Furthermore, we utilized DOSY to interpret the role of aggregation number and solvation state of organometallic intermediates in the reactivity, kinetics, and mechanism of organic reactions. By utilizing multinuclear DOSY methodologies at various temperatures, we also correlated solid-state X-ray structures with those in solution and discovered new reactive complexes, including a monomeric boron enolate, a product-inhibition aggregate, and a series of intermediates in the vinyl lithiation of allyl amines. As highlighted by our efforts, DOSY techniques provide practical and feasible NMR procedures and hold the promise of even more powerful insights when extended to three-dimensional experiments.
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Affiliation(s)
- Deyu Li
- Department of Chemistry, Brown University, Providence, Rhode Island 02912
| | - Ivan Keresztes
- Department of Chemistry, Brown University, Providence, Rhode Island 02912
| | - Russell Hopson
- Department of Chemistry, Brown University, Providence, Rhode Island 02912
| | - Paul G. Williard
- Department of Chemistry, Brown University, Providence, Rhode Island 02912
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Nie W, Liao L, Xu W, Borzov MV, Krut’ko DP, Churakov AV, Howard JA, Lemenovskii DA. 1-Methylimidazolin-2-yl functionalized cyclopentadienyl complexes of titanium and zirconium. Crystal structure of {[η5:η1-κN-C5H4CPh2CH2-(1-Me–C3H4N2)]ZrCl2}2(μ-Cl)2. J Organomet Chem 2008. [DOI: 10.1016/j.jorganchem.2008.04.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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[{(C7H7LiO)6(thf)2(μ-diglyme-κO,κO′)}Li2O]: aμ6-O2– Ion Encapsulating Aryllithium Compound. Z Anorg Allg Chem 2007. [DOI: 10.1002/zaac.200700167] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Andrews PC, Minopoulos M, Roberston EG. Coordination and Reduction of HMPA in the Lithiation of (S)-N-(α-Methylbenzyl)allylamine: Crystal Structures of {(S)-α-[PhC(H)CH3](CH2CH=CH2)NLi·HMPA}2 and [(Me2N)2POLi]6. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600191] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jacobson MA, Keresztes I, Williard PG. On the mechanism of THF catalyzed vinylic lithiation of allylamine derivatives: structural studies using 2-D and diffusion-ordered NMR spectroscopy. J Am Chem Soc 2005; 127:4965-75. [PMID: 15796563 DOI: 10.1021/ja0479540] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
N-Lithio-N-(trialkylsilyl)allylamines can be deprotonated in the presence of ethereal solvents exclusively at the cis-vinylic position to yield 3,N-dilithio-N-(trialkylsilyl)allylamines under mild conditions. Low temperature (1)H and (7)Li NMR ((1)H NOESY, TOCSY, (1)H/(7)Li HSQC, and DO-NMR) studies on the solution structure of 3,N-dilithio-N-(tert-butyldimethylsilyl)allylamine identified three major aggregates in THF (monomer, dimer and tetramer), but the aggregate structures failed to explain the solvent dependence and regiochemical outcome of the reaction. Low temperature (1)H NMR (NOESY, TOCSY, DO-NMR) studies on the solution structure of N-lithio-N-(tert-butyldimethylsilyl)allylamine in the presence of nBuLi identified amide/nBuLi mixed aggregates in both the ethereal solvent THF (1:1 dimer) and the hydrocarbon solvent toluene (1:3 tetramer). Addition of 2 equiv of THF to toluene solutions induces the formation of the same THF solvated 1:1 dimer as observed in neat THF. NMR evidence suggests that in THF the mixed aggregate has close contact between the olefin and the beta-CH(2) of nBuLi, while in the absence of THF, the allyl chain appears to be pointed away from the nearest nBuLi residues.
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Haeffner F, Jacobson MA, Keresztes I, Williard PG. Density Functional Theory Studies on the Mechanisms of Regioselective Allylic and cis-Vinylic Deprotonation of Allyl Amides and Allylamines. J Am Chem Soc 2004; 126:17032-9. [PMID: 15612742 DOI: 10.1021/ja0487731] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A density functional theory (B3LYP/6-31+G) study was undertaken in an effort to learn more about the mechanisms controlling the regioselective deprotonations of the synthetically versatile N-lithio-N-(tert-butyl)allylamide 1 and N-lithio-N-(trimethylsilyl)allylamine 2 compounds. The calculations suggest that deprotonation of 1 occurs exclusively at the allylic position. This agrees with experimental results. The calculations also suggest that deprotonation of allylamine 2 exclusively at the cis-vinylic position is due to kinetic control.
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Affiliation(s)
- Fredrik Haeffner
- Department of Chemistry, Brown University, Providence, RI 02912, USA.
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Carey D, Mair F, Pritchard R, Warren J, Woods R. Structures and Reactions of 1,3-Diamidodilithium Complexes: the Hemisolvatedl-[CMe2{CHMeN(R)}2Li2·OEt2], the Unsolvated 1:1 Mixed Organo-amidolithiumu-[CMe2{CHMeN(R′)}2·Li2·(nBuLi)2], and the Product of Oxidative Ring Closure, the Pyrazolidinel-[(RNCHMe)2CMe2] (R = 2-iPr-C6H4; R′ = 2,6-iPr2-C6H3). Eur J Inorg Chem 2003. [DOI: 10.1002/ejic.200300373] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Jacobson MA, Williard PG. Generation of 1-azapentadienyl anion from N-(tert-butyldimethylsilyl)-3-buten-1-amine. J Org Chem 2002; 67:3915-8. [PMID: 12027714 DOI: 10.1021/jo0162336] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
N-(tert-Butyldimethylsilyl)-3-buten-1-amine undergoes allylic deprotonation at the 2-position when exposed to 2 equiv of nBuLi in THF. This allylic anion undergoes lithium hydride elimination to generate a 1-azapentadienyl anion. The anion is generated cleanly and completely.
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Jacobson MA, Williard PG. Synthesis of 2,3-disubstituted pyrroles from 3,N-dilithio-N-(tert-butyldimethylsilyl)-2-buten-1-amine. J Org Chem 2002; 67:32-7. [PMID: 11777436 DOI: 10.1021/jo015638n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
N-(Trialkylsilyl)allylamines can be deprotonated at the cis-vinylic position to yield 3,N-dilithio-N-(trialkylsilyl)allylamines under mild conditions. N-(Trialkylsilyl)allylamines with terminal alkyl substituents were reported not to form dianions under the same conditions. During our investigations we found that N-(tert-butyldimethylsilyl)-2-buten-1-amine (1) is deprotonated under the reaction conditions reported in the literature, but the resulting dianion is quenched by ethereal solvents. Consequently, new reaction conditions were developed that allow the generation of stable dianions from allylamines with terminal alkyl substituents. Thus, 2,3-disubstituted pyrroles hitherto unattainable via this methodology were formed from 3,N-dilithio-N-(tert-butyldimethylsilyl)-2-buten-1-amine (2) and various carbonyl electrophiles in good yields.
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