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Jansen-van Vuuren RD, Liu S, Miah MAJ, Cerkovnik J, Košmrlj J, Snieckus V. The Versatile and Strategic O-Carbamate Directed Metalation Group in the Synthesis of Aromatic Molecules: An Update. Chem Rev 2024; 124:7731-7828. [PMID: 38864673 PMCID: PMC11212060 DOI: 10.1021/acs.chemrev.3c00923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 04/26/2024] [Accepted: 05/08/2024] [Indexed: 06/13/2024]
Abstract
The aryl O-carbamate (ArOAm) group is among the strongest of the directed metalation groups (DMGs) in directed ortho metalation (DoM) chemistry, especially in the form Ar-OCONEt2. Since the last comprehensive review of metalation chemistry involving ArOAms (published more than 30 years ago), the field has expanded significantly. For example, it now encompasses new substrates, solvent systems, and metalating agents, while conditions have been developed enabling metalation of ArOAm to be conducted in a green and sustainable manner. The ArOAm group has also proven to be effective in the anionic ortho-Fries (AoF) rearrangement, Directed remote metalation (DreM), iterative DoM sequences, and DoM-halogen dance (HalD) synthetic strategies and has been transformed into a diverse range of functionalities and coupled with various groups through a range of cross-coupling (CC) strategies. Of ultimate value, the ArOAm group has demonstrated utility in the synthesis of a diverse range of bioactive and polycyclic aromatic compounds for various applications.
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Affiliation(s)
- Ross D. Jansen-van Vuuren
- Department
of Chemistry, Queen’s University, Chernoff Hall, 9 Bader Lane, Kingston, Ontario K7K 2N1, Canada
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Susana Liu
- Department
of Chemistry, Queen’s University, Chernoff Hall, 9 Bader Lane, Kingston, Ontario K7K 2N1, Canada
| | - M. A. Jalil Miah
- Department
of Chemistry, Rajshahi University, Rajshahi-6205, Bangladesh
| | - Janez Cerkovnik
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Janez Košmrlj
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Victor Snieckus
- Department
of Chemistry, Queen’s University, Chernoff Hall, 9 Bader Lane, Kingston, Ontario K7K 2N1, Canada
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2
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Guang J, Liu Q, Hopson R, Kagan G, Li W, Monroe TB, Williard PG. Conformational Polymorphism of Lithium Pinacolone Enolate. J Am Chem Soc 2016; 138:15177-15188. [PMID: 27762552 DOI: 10.1021/jacs.6b08177] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A metastable, polymorphic hexameric crystal structure of lithium pinacolone enolate (LiOPin) is reported along with three preparation methods. NMR-based structural characterization implies that the lithium pinacolate hexamer deaggregates to a tetramer in toluene but retains mainly the hexameric structure in nonaromatic hydrocarbon solvents such as cyclohexane. Moreover, the presence of a small amount of lithium aldolate (LiOA) dramatically influences the aggregation state of LiOPin by forming a mixed aggregate with a 3:1 ratio (LiOPin3·LiOA).
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Affiliation(s)
- Jie Guang
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Qiyong 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
| | - Gerald Kagan
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Weibin Li
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Thomas B Monroe
- 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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3
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Dengel H, Lichtenberg C. Cationic Bismuth Amides: Accessibility, Structure, and Reactivity. Chemistry 2016; 22:18465-18475. [DOI: 10.1002/chem.201604117] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Hannah Dengel
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - Crispin Lichtenberg
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
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4
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Pöppler A, Granitzka M, Herbst‐Irmer R, Chen Y, Iversen BB, John M, Mata RA, Stalke D. Charakterisierung eines Mehrkomponenten‐Lithiumlithats durch eine Kombination von Röntgenstrukturanalyse, NMR‐Spektroskopie und theoretischen Studien. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201406320] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ann‐Christin Pöppler
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße 4, 37077 Göttingen (Deutschland)
| | - Markus Granitzka
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße 4, 37077 Göttingen (Deutschland)
| | - Regine Herbst‐Irmer
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße 4, 37077 Göttingen (Deutschland)
| | | | - Bo B. Iversen
- Center for Materials Crystallography, Department of Chemistry and iNano, Aarhus University (Dänemark)
| | - Michael John
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße 4, 37077 Göttingen (Deutschland)
| | - Ricardo A. Mata
- Institut für Physikalische Chemie der Universität Göttingen (Deutschland)
| | - Dietmar Stalke
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße 4, 37077 Göttingen (Deutschland)
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5
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Pöppler AC, Granitzka M, Herbst-Irmer R, Chen YS, Iversen BB, John M, Mata RA, Stalke D. Characterization of a Multicomponent Lithium Lithiate from a Combined X-Ray Diffraction, NMR Spectroscopy, and Computational Approach. Angew Chem Int Ed Engl 2014; 53:13282-7. [DOI: 10.1002/anie.201406320] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Indexed: 11/10/2022]
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6
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Bluemke TD, Clegg W, García-Alvarez P, Kennedy AR, Koszinowski K, McCall MD, Russo L, Hevia E. Structural and reactivity insights in Mg–Zn hybrid chemistry: Zn–I exchange and Pd-catalysed cross-coupling applications of aromatic substrates. Chem Sci 2014. [DOI: 10.1039/c4sc01263a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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7
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Su C, Guang J, Williard PG. Structures of Lithium N-Monosubstituted Anilides: Trisolvated Monomer to Tetrasolvated Dimer. J Org Chem 2014; 79:1032-9. [DOI: 10.1021/jo402498z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Chicheung Su
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Jie Guang
- 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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8
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Bellomo A, Zhang J, Trongsiriwat N, Walsh PJ. Additive effects on palladium-catalyzed deprotonative-cross-coupling processes (DCCP) of sp3C–H bonds in diarylmethanes. Chem Sci 2013. [DOI: 10.1039/c2sc21673f] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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9
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Bergeron M, Guyader D, Paquin JF. S(N)2' reaction of allylic difluorides with lithium amides and thiolates. Org Lett 2012; 14:5888-91. [PMID: 23145465 DOI: 10.1021/ol302802r] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The synthesis of monofluoroalkenes using an S(N)2' reaction of lithium amides derived from aromatic amines or lithium thiolates with 3,3-difluoropropenes is reported. This transformation features the use of fluoride as a leaving group.
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Affiliation(s)
- Maxime Bergeron
- Canada Research Chair in Organic and Medicinal Chemistry, Département de chimie, Université Laval, 1045 avenue de la Médecine, Québec, Québec G1V 0A6, Canada
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10
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Tatić T, Hermann S, Stalke D. The [(DABCO)7·(LiCH2SiMe3)8] Octamer: More Aggregated than the Parent Starting Material [LiCH2SiMe3]6 but Also Higher in Reactivity. Organometallics 2012. [DOI: 10.1021/om3005806] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tanja Tatić
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße
4, 37077 Göttingen, Germany
| | - Stefanie Hermann
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße
4, 37077 Göttingen, Germany
| | - Dietmar Stalke
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße
4, 37077 Göttingen, Germany
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11
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Granitzka M, Pöppler AC, Schwarze EK, Stern D, Schulz T, John M, Herbst-Irmer R, Pandey SK, Stalke D. Aggregation of Donor Base Stabilized 2-Thienyllithium in a Single Crystal and in Solution: Distances from X-ray Diffraction and the Nuclear Overhauser Effect. J Am Chem Soc 2011; 134:1344-51. [DOI: 10.1021/ja210382c] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Markus Granitzka
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Ann-Christin Pöppler
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Eike K. Schwarze
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Daniel Stern
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Thomas Schulz
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Michael John
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Regine Herbst-Irmer
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Sushil K. Pandey
- Department of Chemistry, University of Jammu, Jammu-180 006, India
| | - Dietmar Stalke
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
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12
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Pöppler AC, Meinholz MM, Faßhuber H, Lange A, John M, Stalke D. Mixed Crystalline Lithium Organics and Interconversion in Solution. Organometallics 2011. [DOI: 10.1021/om2010639] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ann-Christin Pöppler
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
| | - Margret M. Meinholz
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
| | - Hannes Faßhuber
- Max-Planck-Institut für biophysikalische Chemie, Am Faßberg 11, 37077 Göttingen, Germany
| | - Adam Lange
- Max-Planck-Institut für biophysikalische Chemie, Am Faßberg 11, 37077 Göttingen, Germany
| | - Michael John
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
| | - Dietmar Stalke
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
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13
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Gupta L, Ramírez A, Collum DB. Reaction of lithium diethylamide with an alkyl bromide and alkyl benzenesulfonate: origins of alkylation, elimination, and sulfonation. J Org Chem 2010; 75:8392-9. [PMID: 21077695 DOI: 10.1021/jo101505x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A combination of NMR, kinetic, and computational methods are used to examine reactions of lithium diethylamide in tetrahydrofuran (THF) with n-dodecyl bromide and n-octyl benzenesulfonate. The alkyl bromide undergoes competitive S(N)2 substitution and E2 elimination in proportions independent of all concentrations except for a minor medium effect. Rate studies show that both reactions occur via trisolvated-monomer-based transition structures. The alkyl benzenesulfonate undergoes competitive S(N)2 substitution (minor) and N-sulfonation (major) with N-sulfonation promoted at low THF concentrations. The S(N)2 substitution is shown to proceed via a disolvated monomer suggested computationally to involve a cyclic transition structure. The dominant N-sulfonation follows a disolvated-dimer-based transition structure suggested computationally to be a bicyclo[3.1.1] form. The differing THF and lithium diethylamide orders for the two reactions explain the observed concentration-dependent chemoselectivities.
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Affiliation(s)
- Lekha Gupta
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University Ithaca, New York 14853-1301, United States
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14
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Li D, Sun C, Liu J, Hopson R, Li W, Williard PG. Aggregation studies of complexes containing a chiral lithium amide and n-Butyllithium. J Org Chem 2008; 73:2373-81. [PMID: 18294002 DOI: 10.1021/jo702655m] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A system consisting of a chiral lithium amide and n-BuLi in tol-d(8) solution was investigated with (1)H and (13)C INEPT DOSY, (6)Li and (15)N NMR, and other 2D NMR techniques. A mixed 2:1 trimeric complex was identified as the major species as the stoichiometry approached 1.5 equiv of n-BuLi to 1 equiv of amine compound. (1)H and (13)C INEPT DOSY spectra confirmed this lithium aggregate in the solution. The formula weight of the aggregate, correlated with diffusion coefficients of internal references, indicated the aggregation number of this complex. Plots of log D(rel) vs log FW are linear (r > 0.9900). (6)Li and (15)N NMR titration experiments also corroborated these results. These NMR experiments indicate that this mixed aggregate is the species that is responsible for asymmetric addition of n-BuLi to aldehydes.
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Affiliation(s)
- Deyu Li
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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15
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Riggs JC, Ramirez A, Cremeens ME, Bashore CG, Candler J, Wirtz MC, Coe JW, Collum DB. Structural and Rate Studies of the Formation of Substituted Benzynes. J Am Chem Soc 2008; 130:3406-12. [DOI: 10.1021/ja0754655] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jason C. Riggs
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, and Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc., Groton, Connecticut 06340
| | - Antonio Ramirez
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, and Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc., Groton, Connecticut 06340
| | - Matthew E. Cremeens
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, and Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc., Groton, Connecticut 06340
| | - Crystal G. Bashore
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, and Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc., Groton, Connecticut 06340
| | - John Candler
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, and Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc., Groton, Connecticut 06340
| | - Michael C. Wirtz
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, and Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc., Groton, Connecticut 06340
| | - Jotham W. Coe
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, and Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc., Groton, Connecticut 06340
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, and Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc., Groton, Connecticut 06340
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16
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Collum DB, McNeil AJ, Ramirez A. Lithium diisopropylamide: solution kinetics and implications for organic synthesis. Angew Chem Int Ed Engl 2007; 46:3002-17. [PMID: 17387670 DOI: 10.1002/anie.200603038] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lithium diisopropylamide (LDA) is a prominent reagent used in organic synthesis. In this Review, rate studies of LDA-mediated reactions are placed in the broader context of organic synthesis in three distinct segments. The first section provides a tutorial on solution kinetics, emphasizing the characteristic rate behavior caused by dominant solvation and aggregation effects. The second section summarizes substrate- and solvent-dependent mechanisms that reveal basic principles of solvation and aggregation. The final section suggests how an understanding of mechanism might be combined with empirical methods to optimize yields, rates, and selectivities of organolithium reactions and applied to organic synthesis.
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Affiliation(s)
- David B Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853-1301, USA.
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17
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Collum D, McNeil A, Ramirez A. Lithiumdiisopropylamid: Reaktionskinetik in Lösung und Folgerungen für die organische Synthese. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200603038] [Citation(s) in RCA: 53] [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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18
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Ma Y, Ramirez A, Singh KJ, Keresztes I, Collum DB. Lithium Diisopropylamide Solvated by Hexamethylphosphoramide: Substrate-Dependent Mechanisms for Dehydrobrominations. J Am Chem Soc 2006; 128:15399-404. [PMID: 17132006 DOI: 10.1021/ja060964b] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lithium diisopropylamide-mediated dehydrobrominations of exo-2-bromonorbornane, 1-bromocyclooctene, and cis-4-bromo-tert-butylcyclohexane were studied in THF solutions and THF solutions with added hexamethylphosphoramide (HMPA). Rate studies reveal a diverse array of mechanisms based on mono-, di-, and trisolvated monomers as well as triple ions. The results are contrasted with analogous eliminations in THF in the absence of HMPA.
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Affiliation(s)
- Yun Ma
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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19
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Ramirez A, Sun X, Collum DB. Lithium Diisopropylamide-Mediated Enolization: Catalysis by Hemilabile Ligands. J Am Chem Soc 2006; 128:10326-36. [PMID: 16881665 DOI: 10.1021/ja062147h] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structural, kinetic, and computational studies reveal the mechanistic complexities of a lithium diisopropylamide (LDA)-mediated ester enolization. Hemilabile amino ether MeOCH2CH2NMe2, binding as an eta1 (ether-bound) ligand in the reactant and as an eta2 (chelating) ligand in the transition structure, accelerates the enolization 10,000-fold compared with n-BuOMe. At the onset of the reaction, a dimer-based enolization prevails. As the reaction proceeds, significantly less reactive LDA-enolate mixed dimers appear and divert the reaction through monomer- and mixed dimer-based pathways. The mechanistic and computational investigations lead to a proof-of-principle ligand-catalyzed enolization in which an ancillary ligand allows the catalytic ligand to re-enter the catalytic cycle.
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Affiliation(s)
- Antonio Ramirez
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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20
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Qu B, Collum DB. Structure of n-Butyllithium in Mixtures of Ethers and Diamines: Influence of Mixed Solvation on 1,2-Additions to Imines. J Am Chem Soc 2006; 128:9355-60. [PMID: 16848470 DOI: 10.1021/ja0609654] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
n-BuLi in diamine/dialkyl ether mixtures forms ensembles of hetero- and homosolvated dimers. Solutions in TMEDA/THF (TMEDA = N,N,N',N'-tetramethylethylenediamine) are not amenable to detailed investigation because of rapid ligand exchange. TMCDA/THF mixtures (TMCDA = trans-N,N,N',N'-tetramethylcyclohexanediamine) afford clean assignments for a mixture of homo- and heterosolvated dimers but demonstrate poor control over structure. TMCDA/tetrahydropyran (THP) mixtures and TMEDA/Et2O mixtures afford clean structural assignments as well as excellent structural control. Rate studies of the 1,2-addition of n-BuLi using TMCDA/THP mixtures reveal cooperative solvation in which both THP and TMCDA coordinate to lithium at the monomer- and dimer-based transition structures. The two mechanisms are affiliated with markedly different stereochemistries of the 1,2-addition to imines. The results show strong parallels with previous investigations of 1,2-additions in TMEDA/Et2O mixtures.
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Affiliation(s)
- Bo Qu
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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21
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Zuend SJ, Ramirez A, Lobkovsky E, Collum DB. Lithiated Imines: Solvent-Dependent Aggregate Structures and Mechanisms of Alkylation. J Am Chem Soc 2006; 128:5939-48. [PMID: 16637662 DOI: 10.1021/ja060363k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe efforts to understand the structure and reactivity of lithiated cyclohexanone N-cyclohexylimine. The lithioimine affords complex solvent-dependent distributions of monomers, dimers, and trimers in a number of ethereal solvents. Careful selection of solvent provides exclusively monosolvated dimers. Rate studies on the C-alkylations reveal chronic mixtures of monomer- and dimer-based pathways. We explore the factors influencing reactants and alkylation transition structures and the marked differences between lithioimines and isostructural lithium dialkylamides with the aid of density functional theory calculations.
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Affiliation(s)
- Stephan J Zuend
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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22
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Solvent effects on the mixed aggregates of chiral 3-aminopyrrolidine lithium amides and alkyllithiums. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.01.095] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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23
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Wiedemann SH, Ramírez A, Collum DB. Lithium 2,2,6,6-Tetramethylpiperidide-Mediated α- and β-Lithiations of Epoxides: Solvent-Dependent Mechanisms. J Am Chem Soc 2003; 125:15893-901. [PMID: 14677981 DOI: 10.1021/ja0304087] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lithium 2,2,6,6-tetramethylpiperidide (LiTMP)-mediated alpha- and beta-lithiations of epoxides are described. LiTMP displays a markedly higher reactivity than does lithium diisopropylamide, consistent with literature reports. Detailed rate studies of LiTMP/THF and LiTMP/Me(2)NEt mixtures reveal similar rates but significant mechanistic differences. LiTMP-mediated alpha-lithiation of cis-cyclooctene oxide with subsequent oxacarbenoid formation and transannular C-H insertion proceeds via monosolvated dimers in both THF and Me(2)NEt. LiTMP-mediated beta-lithiation of 2,3-dimethyl-2-butene oxide affords the corresponding allylic alcohol via a monosolvated monomer in THF and a monosolvated dimer in Me(2)NEt. We discuss how the solvent-dependent aggregation of LiTMP markedly influences the rate profile. The reaction transition structures are examined with density functional computations.
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Affiliation(s)
- Sean H Wiedemann
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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Ramírez A, Lobkovsky E, Collum DB. Hemilabile Ligands in Organolithium Chemistry: Substituent Effects on Lithium Ion Chelation. J Am Chem Soc 2003; 125:15376-87. [PMID: 14664582 DOI: 10.1021/ja030322d] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The lithium diisopropylamide-mediated 1,2-elimination of 1-bromocyclooctene to provide cyclooctyne is investigated using approximately 50 potentially hemilabile polyethers and amino ethers. Rate laws for selected ligands reveal chelated monomer-based pathways. The dependence of the rates on ligand structure shows that anticipated rate accelerations based on the gem-dimethyl effect are nonexistent and that substituents generally retard the reaction. With the aid of semiempirical and DFT computational studies, the factors influencing chelation are discussed. It seems that severe buttressing within chelates of the substitutionally rich ligands precludes a net stabilization of the chelates relative to nonchelated (eta(1)-solvated) forms. One ligand-MeOCH(2)CH(2)NMe(2)-appears to promote elimination uniquely by a higher-coordinate monomer-based pathway.
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Affiliation(s)
- Antonio Ramírez
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853-1301, USA
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25
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Zhao P, Lucht BL, Kenkre SL, Collum DB. Lithium Hexamethyldisilazide-Mediated Ketone Enolization: The Influence of Hindered Dialkyl Ethers and Isostructural Dialkylamines on Reaction Rates and Mechanisms. J Org Chem 2003; 69:242-9. [PMID: 14725435 DOI: 10.1021/jo030221y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mechanistic studies of the enolization of 2-methylcyclohexanone mediated by lithium hexamethyldisilazide (LiHMDS; TMS(2)NLi) solvated by hindered dialkyl ethers (ROR') are described. Rate studies using in situ IR spectroscopy show that enolizations in the presence of i-Pr(2)O, 2,2,5,5-tetramethyltetrahydrofuran, and cineole proceed via dimer-based transition structures [(TMS(2)NLi)(2)(ROR')(ketone)]. Comparing the relative solvation energies and the corresponding solvent-dependent activation energies shows that the highly substituted ethers accelerate the enolizations by sterically destabilizing the reactants and stabilizing the transition structures. Comparisons of hindered dialkyl ethers with their isostructural dialkylamines reveal that the considerably higher rates elicited by the amines derive from an analogous relative destabilization of the reactants and relative stabilization of the transition structures.
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Affiliation(s)
- Pinjing Zhao
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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26
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Corset J, Castellà-Ventura M, Froment F, Strzalko T, Wartski L. Study of the lithiated phenylacetonitrile monoanions and dianions formed according to the lithiated base used (LHMDS, LDA, or n-BuLi). 1. Evidence of heterodimer ("Quadac") or dianion formation by vibrational spectroscopy. J Org Chem 2003; 68:3902-11. [PMID: 12737570 DOI: 10.1021/jo020492t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is evidenced through vibrational spectroscopy that a heterodimer or "Quadac" is formed when an excess of base (LHMDS, LDA, or n-BuLi) is added to PhCH(2)CN in THF, THF-hexane, or THF-toluene solution. The amount of heterodimer increases with the pK(H)(a) of the lithiated base. A dianionic species may be formed through decomposition of this heterodimer if the pK(H)(a) of the base is sufficiently high, as in the case of n-BuLi. With LDA, only a very small amount of dianion is observed, and with LHMDS, no dianion is detected. The predominant dianionic species observed are the linear and bridged separated ion pairs of the dilithiated dianion. The presence of the amine in the medium is of paramount importance. The PhCHCNLi monomer-dimer equilibrium is entropy driven toward the dimer solvated by the amine.
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Affiliation(s)
- Jacques Corset
- LADIR - CNRS (UMR 7075), 2 Rue Henri Dunant, BP 28, 94320 Thiais, France
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Yandulov DV, Huffman JC, Caulton KG. Conventional Lithium Bases as Unconventional Sources of Methyl Anion: Facile Me−Si and Me−C Bond Cleavage in RLi, R2NLi, and BR4- by an Electrophilic Osmium Dihydride. Organometallics 2002. [DOI: 10.1021/om0200104] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dmitry V. Yandulov
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001
| | - John C. Huffman
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001
| | - Kenneth G. Caulton
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001
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28
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Rutherford JL, Hoffmann D, Collum DB. Consequences of correlated solvation on the structures and reactivities of RLi-diamine complexes: 1,2-addition and alpha-lithiation reactions of imines by TMEDA-solvated n-butyllithium and phenyllithium. J Am Chem Soc 2002; 124:264-71. [PMID: 11782178 DOI: 10.1021/ja002979u] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
6Li and (13)C NMR spectroscopic studies were carried out on [(6)Li]n-BuLi and [(6)Li]PhLi (RLi) in toluene-d(8) containing the following diamines: N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetraethylethylenediamine, 1,2-dipyrrolidinoethane, 1,2-dipiperidinoethane, N,N,N',N'-tetramethylpropanediamine, trans-(R,R)-N,N,N',N'-tetramethylcyclohexanediamine, and (-)-sparteine. Dimers of general structure (RLi)(2)S(2) (S = chelating diamine) are formed in each case. Treatment of RLi with two different diamines (S and S') affords homosolvates (RLi)(2)S(2) and (RLi)(2)S'(2) along with a heterosolvate (RLi)(2)SS'. Relative binding constants and associated free energies for the sequential solvent substitutions are obtained by competing pairs of diamines. The high relative stabilities of certain heterosolvates indicate that solvent binding to the RLi dimer can be highly correlated. Rate studies of both the 1,2-addition of RLi/TMEDA to the N-isopropylimine of cyclohexane carboxaldehyde and the RLi/TMEDA-mediated alpha-lithiation of the N-isopropylimine of cyclohexanone reveal monomer-based transition structures, [(RLi)(TMEDA)(imine)], in all cases. The complex relationships of solvent binding constants and relative reactivities toward 1,2-additions and alpha-lithiations are discussed.
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Affiliation(s)
- Jennifer L Rutherford
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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Enantioselective α-alkylation of unsaturated carboxylic acids using a chiral lithium amide. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0957-4166(01)00152-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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30
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Ramírez A, Collum DB. Hemi-Labile Ligands in Organolithium Chemistry: Rate Studies of the LDA-Mediated α- and β-Metalations of Epoxides. J Am Chem Soc 1999. [DOI: 10.1021/ja992166+] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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31
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Arvidsson PI, Hilmersson G, Ahlberg P. Stereoselective Diamine Chelates of a Chiral Lithium Amide Dimer: New Insights into the Coordination Chemistry of Chiral Lithium Amides. J Am Chem Soc 1999. [DOI: 10.1021/ja9827550] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Per I. Arvidsson
- Contribution from the Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Göran Hilmersson
- Contribution from the Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Per Ahlberg
- Contribution from the Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
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