1
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Burns M, Perkins D, Chan LC, Pilling MJ, Jawor-Baczynska A, Mullen AK, Steven A, Wimsey C, Elmekawy A, Lamacraft A, Dobson BC, McMillan AE, Hose DRJ, Inglesby PA, Raw SA, Jones MF. Route Design to Manufacture: Synthesis of the Heterocyclic Fragment of AZD5718 Using a Non-cryogenic Lithiation-Alkoxycarbonylation Reaction. Org Process Res Dev 2021. [DOI: 10.1021/acs.oprd.0c00533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Matthew Burns
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Dave Perkins
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Lai C. Chan
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Michael J. Pilling
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Anna Jawor-Baczynska
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Alexander K. Mullen
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Alan Steven
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Chris Wimsey
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Ahmed Elmekawy
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Alex Lamacraft
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Benjamin C. Dobson
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Angus E. McMillan
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - David R. J. Hose
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Phillip A. Inglesby
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Steven A. Raw
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Martin F. Jones
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
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2
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Algera RF, Ma Y, Collum DB. Sodium Diisopropylamide in Tetrahydrofuran: Selectivities, Rates, and Mechanisms of Alkene Isomerizations and Diene Metalations. J Am Chem Soc 2017; 139:11544-11549. [PMID: 28735535 PMCID: PMC6059566 DOI: 10.1021/jacs.7b05218] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sodium diisopropylamide in tetrahydrofuran is an effective base for the metalation of 1,4-dienes and isomerization of alkenes. Dienes metalate via tetrasolvated sodium amide monomers, whereas 1-pentene is isomerized by trisolvated monomers. Facile, highly Z-selective isomerizations are observed for allyl ethers under conditions that compare favorably to those of existing protocols. The selectivity is independent of the substituents on the allyl ethers; rate and computational data show that the rates, mechanisms, and roles of sodium-oxygen contacts are substituent-dependent. The competing influences of substrate coordination and solvent coordination to sodium are discussed.
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Affiliation(s)
- Russell F Algera
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University , Ithaca, New York 14853-1301, United States
| | - Yun Ma
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University , Ithaca, New York 14853-1301, United States
| | - David B Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University , Ithaca, New York 14853-1301, United States
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3
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Abstract
Solution characterizations and ligand binding constants were determined for n-butyllithium in hydrocarbon and ethereal solvents using diffusion-ordered NMR. In hydrocarbon solvents, n-butyllithium exists primarily as an octamer at -40 °C and deaggregates to a hexamer when the temperature is increased. In the presence of THF or diethyl ether, n-butyllithium exists predominantly as a tetra-solvated tetramer and deaggregates to a tetra-solvated dimer in the presence of a large excess or neat THF. The ligand binding constants for the tetra-solvated tetramers were measured using 1H NMR/DOSY titration.
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Affiliation(s)
- Onkei Tai
- 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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4
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Abstract
The solution structures, stabilities, physical properties, and reactivities of sodium diisopropylamide (NaDA) in a variety of coordinating solvents are described. NaDA is stable for months as a solid or as a 1.0 M solution in N,N-dimethylethylamine (DMEA) at -20 °C. A combination of NMR spectroscopic and computational studies show that NaDA is a disolvated symmetric dimer in DMEA, N,N-dimethyl-n-butylamine, and N-methylpyrrolidine. Tetrahydrofuran (THF) readily displaces DMEA, affording a tetrasolvated cyclic dimer at all THF concentrations. Dimethoxyethane (DME) and N,N,N',N'-tetramethylethylenediamine quantitatively displace DMEA, affording doubly chelated symmetric dimers. The trifunctional ligands N,N,N',N″,N″-pentamethyldiethylenetriamine and diglyme bind the dimer as bidentate rather than tridentate ligands. Relative rates of solvent decompositions are reported, and rate studies for the decomposition of THF and DME are consistent with monomer-based mechanisms.
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Affiliation(s)
- Russell F. Algera
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, United States,
| | - Yun Ma
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, United States,
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, United States,
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5
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Tai O, Hopson R, Williard PG. Ligand Binding Constants to Lithium Hexamethyldisilazide Determined by Diffusion-Ordered NMR Spectroscopy. J Org Chem 2017; 82:6223-6231. [PMID: 28562035 DOI: 10.1021/acs.joc.7b00800] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the direct measurement of ligand-binding constants of organolithium complexes using a 1H NMR/diffusion-ordered NMR spectroscopy (DOSY) titration technique. Lithium hexamethyldisilazide complexes with ethereal and ester donor ligands (THF, diethyl ether, MTBE, THP, tert-butyl acetate) are characterized using 1H NMR and X-ray crystallography. Their aggregation and solvation states are confirmed using diffusion coefficient-formula weight correlation analysis, and the 1H NMR/DOSY titration technique is applied to obtain their binding constants. Our work suggests that steric hindrance of ethereal ligands plays an important role in the aggregation, solvation, and reactivity of these complexes. It is noteworthy that diffusion methodology is utilized to obtain binding constants.
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Affiliation(s)
- Onkei Tai
- 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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6
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Streng ES, Lee DS, George MW, Poliakoff M. Continuous N-alkylation reactions of amino alcohols using γ-Al 2O 3 and supercritical CO 2: unexpected formation of cyclic ureas and urethanes by reaction with CO 2. Beilstein J Org Chem 2017; 13:329-337. [PMID: 28326142 PMCID: PMC5331277 DOI: 10.3762/bjoc.13.36] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/02/2017] [Indexed: 12/19/2022] Open
Abstract
The use of γ-Al2O3 as a heterogeneous catalyst in scCO2 has been successfully applied to the amination of alcohols for the synthesis of N-alkylated heterocycles. The optimal reaction conditions (temperature and substrate flow rate) were determined using an automated self-optimising reactor, resulting in moderate to high yields of the target products. Carrying out the reaction in scCO2 was shown to be beneficial, as higher yields were obtained in the presence of CO2 than in its absence. A surprising discovery is that, in addition to cyclic amines, cyclic ureas and urethanes could be synthesised by incorporation of CO2 from the supercritical solvent into the product.
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Affiliation(s)
- Emilia S Streng
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Darren S Lee
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Michael W George
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK; Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, 199 Taikang East Road, Ningbo 315100, China
| | - Martyn Poliakoff
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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7
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Ojeda-Amador AI, Martínez-Martínez AJ, Kennedy AR, Armstrong DR, O'Hara CT. Monodentate coordination of the normally chelating chiral diamine (R,R)-TMCDA. Chem Commun (Camb) 2016; 53:324-327. [PMID: 27958607 DOI: 10.1039/c6cc07190b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
After isolating an unusual binuclear, but monosolvated NaHMDS complex [{(R,R)-TMCDA}·(NaHMDS)2]∞ which polymerises via intermolecular electrostatic NaMeHMDS interactions, further (R,R)-TMCDA was added to produce the discrete binuclear amide [{κ2-(R,R)-TMCDA}·(NaHMDS)2{κ1-(R,R)-TMCDA}], whose salient feature is the unique monodentate coordination of one of the chiral diamine ligands.
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Affiliation(s)
- Ana I Ojeda-Amador
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Antonio J Martínez-Martínez
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Alan R Kennedy
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - David R Armstrong
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Charles T O'Hara
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
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8
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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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9
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Marchois J, Fressigné C, Lecachey B, Maddaluno J. Base or nucleophile? DFT finally elucidates the origin of the selectivity between the competitive reactions triggered by MeLi or LDA on propanal. Chem Commun (Camb) 2015; 51:9801-4. [PMID: 25925129 DOI: 10.1039/c5cc01549a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The competition between basicity and nucleophilicity of two standard organolithium reagents was studied using DFT. Comparing the reactivity of solvated (MeLi)2 and (LDA)2 toward propanal finally explains why methyllithium adds onto the carbonyl while LDA deprotonates the α-position, in accord with experiment and Ireland's deprotonation TS.
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Affiliation(s)
- J Marchois
- Laboratoire COBRA, CNRS UMR 6014 & FR 3038, Université de Rouen and INSA de Rouen, 76821-Mont St Aignan Cedex, France.
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10
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Neufeld R, John M, Stalke D. The Donor-Base-Free Aggregation of Lithium Diisopropyl Amide in Hydrocarbons Revealed by a DOSY Method. Angew Chem Int Ed Engl 2015; 54:6994-8. [PMID: 26014367 DOI: 10.1002/anie.201502576] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Indexed: 11/08/2022]
Abstract
Lithium diisopropyl amide (LDA) is a very prominent reagent that plays a key role in organic synthesis, serving as a base par excellence for a broad range of deprotonation reactions. However, the state of aggregation in solution in the absence of donor bases was unclear. In this paper we solved this problem by employing DOSY NMR experiments based on a newly elaborated external calibration curve (ECC) approach with normalized diffusion coefficients.
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Affiliation(s)
- Roman Neufeld
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077 Göttingen (Germany)
| | - Michael John
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077 Göttingen (Germany)
| | - Dietmar Stalke
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077 Göttingen (Germany).
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11
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Neufeld R, John M, Stalke D. Aufklärung der donorbasenfreien Aggregation von Lithiumdiisopropylamid in Kohlenwasserstoffen mithilfe einer DOSY-Methode. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502576] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Rathman T‘L, Schwindeman JA. Preparation, Properties, and Safe Handling of Commercial Organolithiums: Alkyllithiums, Lithium sec-Organoamides, and Lithium Alkoxides. Org Process Res Dev 2014. [DOI: 10.1021/op500161b] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Terry ‘Li’ Rathman
- t-Links Consulting, 3843 Gardner Park Drive, Gastonia, North Carolina 28054, United States
| | - James A. Schwindeman
- Rohner Inc., 4066 Belle
Meade Circle, Belmont, North
Carolina 28012, United States
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13
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Lampland NL, Ellern A, Sadow AD. β-SiH rich zinc silyl compounds: Reductive elimination and β-hydrogen abstraction. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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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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15
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Hamdoun G, Sebban M, Cossoul E, Harrison-Marchand A, Maddaluno J, Oulyadi H. 1H Pure Shift DOSY: a handy tool to evaluate the aggregation and solvation of organolithium derivatives. Chem Commun (Camb) 2014; 50:4073-5. [DOI: 10.1039/c4cc00111g] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The first successful application of 1H PS-DOSY for a quantitative estimation of the degree of solvation and aggregation state of organolithium derivatives.
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Affiliation(s)
- G. Hamdoun
- Normandie Université
- COBRA, UMR6014 and FR3038 CNRS
- Université de Rouen
- INSA de Rouen
- 76821 Mont-Saint-Aignan Cedex, France
| | - M. Sebban
- Normandie Université
- COBRA, UMR6014 and FR3038 CNRS
- Université de Rouen
- INSA de Rouen
- 76821 Mont-Saint-Aignan Cedex, France
| | - E. Cossoul
- Normandie Université
- COBRA, UMR6014 and FR3038 CNRS
- Université de Rouen
- INSA de Rouen
- 76821 Mont-Saint-Aignan Cedex, France
| | - A. Harrison-Marchand
- Normandie Université
- COBRA, UMR6014 and FR3038 CNRS
- Université de Rouen
- INSA de Rouen
- 76821 Mont-Saint-Aignan Cedex, France
| | - J. Maddaluno
- Normandie Université
- COBRA, UMR6014 and FR3038 CNRS
- Université de Rouen
- INSA de Rouen
- 76821 Mont-Saint-Aignan Cedex, France
| | - H. Oulyadi
- Normandie Université
- COBRA, UMR6014 and FR3038 CNRS
- Université de Rouen
- INSA de Rouen
- 76821 Mont-Saint-Aignan Cedex, France
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16
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Su C, Hopson R, Williard PG. Isotopically Enriched 13C Diffusion-Ordered NMR Spectroscopy: Analysis of Methyllithium. J Org Chem 2013; 78:11733-46. [DOI: 10.1021/jo401740g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Chicheung Su
- 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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17
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Gao M, Patwardhan NN, Carlier PR. Stereochemical Inversion of a Cyano-Stabilized Grignard Reagent: Remarkable Effects of the Ethereal Solvent Structure and Concentration. J Am Chem Soc 2013; 135:14390-400. [DOI: 10.1021/ja407348s] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ming Gao
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Neeraj N. Patwardhan
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Paul R. Carlier
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
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18
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Harrison-Marchand A, Mongin F. Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 1. Structural Data. Chem Rev 2013; 113:7470-562. [DOI: 10.1021/cr300295w] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Anne Harrison-Marchand
- Laboratoire COBRA de l′Université de Rouen, INSA de Rouen, CNRS, UMR 6014 & FR 3038, IRCOF, Rue Tesnière, 76821 Mont St Aignan Cédex, France
| | - Florence Mongin
- Équipe Chimie et Photonique Moléculaires, Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes 1, Bâtiment 10A, case 1003, Avenue du Général Leclerc, 35042 Rennes Cédex, France
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19
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Tomasevich LL, Collum DB. Structure determination using the method of continuous variation: lithium phenolates solvated by protic and dipolar aprotic ligands. J Org Chem 2013; 78:7498-507. [PMID: 23806055 PMCID: PMC3759316 DOI: 10.1021/jo401080n] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The method of continuous variation (MCV) was used in conjunction with (6)Li NMR spectroscopy to characterize four lithium phenolates solvated by a range of solvents, including N,N,N',N'-tetramethylethylenediamine, Et2O, pyridine, protic amines, alcohols, and highly dipolar aprotic solvents. Dimers, trimers, and tetramers were observed, depending on the precise lithium phenolate-solvent combinations. Competition experiments (solvent swaps) provide insights into the relative propensities toward mixed solvation.
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Affiliation(s)
- Laura L. Tomasevich
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
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20
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Yan K, Upton BM, Zhu J, Ellern A, Sadow AD. Nucleophilicity of Neutral versus Cationic Magnesium Silyl Compounds. Organometallics 2013. [DOI: 10.1021/om400447q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- KaKing Yan
- Department of Chemistry, Iowa State University, 1605 Gilman Hall, Ames Iowa
50011, United States
| | - Brianna M. Upton
- Department of Chemistry, Iowa State University, 1605 Gilman Hall, Ames Iowa
50011, United States
| | - Jing Zhu
- Department of Chemistry, Iowa State University, 1605 Gilman Hall, Ames Iowa
50011, United States
| | - Arkady Ellern
- Department of Chemistry, Iowa State University, 1605 Gilman Hall, Ames Iowa
50011, United States
| | - Aaron D. Sadow
- Department of Chemistry, Iowa State University, 1605 Gilman Hall, Ames Iowa
50011, United States
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21
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De Vries TS, Bruneau AM, Liou LR, Subramanian H, Collum DB. Azaaldol condensation of a lithium enolate solvated by N,N,N',N'-tetramethylethylenediamine: dimer-based 1,2-addition to imines. J Am Chem Soc 2013; 135:4103-9. [PMID: 23413774 PMCID: PMC3715612 DOI: 10.1021/ja400345c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The lithium enolate of tert-amylacetate solvated by N,N,N',N'-tetramethylethylenediamine (TMEDA) is shown to be a doubly chelated dimer. Adding the dimeric enolate to 4-fluorobenzaldehyde-N-phenylimine affords an N-lithiated β-amino ester shown to be monomeric using (6)Li and (15)N NMR spectroscopies. Rate studies using (19)F NMR spectroscopy reveal reaction orders consistent with a transition structure of stoichiometry [(ROLi)2(TMEDA)2(imine)](‡). Density functional theory computations explore several possible dimer-based transition structures with monodentate and bidentate coordination of TMEDA. Supporting rate studies using trans-N,N,N',N'-1,2-tetramethylcyclohexanediamine showing analogous rates and rate law suggest that TMEDA is fully chelated.
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Affiliation(s)
- Timothy S. De Vries
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
| | - Angela M. Bruneau
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
| | - Lara R. Liou
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
| | | | - David B. Collum
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
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22
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Moorhouse RS, Moxey GJ, Ortu F, Reade TJ, Lewis W, Blake AJ, Kays DL. Structural Diversity in Alkali Metal Complexes of Sterically Demanding Carbazol-9-yl Ligands. Inorg Chem 2013; 52:2678-83. [DOI: 10.1021/ic302727w] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rhiannon S. Moorhouse
- School of
Chemistry, University of Nottingham, University
Park, Nottingham NG7 2RD, United Kingdom
| | - Graeme J. Moxey
- School of
Chemistry, University of Nottingham, University
Park, Nottingham NG7 2RD, United Kingdom
| | - Fabrizio Ortu
- School of
Chemistry, University of Nottingham, University
Park, Nottingham NG7 2RD, United Kingdom
| | - Thomas J. Reade
- School of
Chemistry, University of Nottingham, University
Park, Nottingham NG7 2RD, United Kingdom
| | - William Lewis
- School of
Chemistry, University of Nottingham, University
Park, Nottingham NG7 2RD, United Kingdom
| | - Alexander J. Blake
- School of
Chemistry, University of Nottingham, University
Park, Nottingham NG7 2RD, United Kingdom
| | - Deborah L. Kays
- School of
Chemistry, University of Nottingham, University
Park, Nottingham NG7 2RD, United Kingdom
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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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24
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Beng TK, Woo JS, Gawley RE. Synthetic applications and inversion dynamics of configurationally stable 2-lithio-2-arylpyrrolidines and -piperidines. J Am Chem Soc 2012; 134:14764-71. [PMID: 22881214 PMCID: PMC3443602 DOI: 10.1021/ja306276w] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In diethyl ether, N-Boc-2-lithio-2-arylpiperidines have been found to be configurationally stable at -80 °C, whereas N-Boc-2-lithio-2-arylpyrrolidines are configurationally stable at -60 °C. Several tertiary benzylic carbanions derived from enantioenriched 2-aryl heterocycles have been successfully alkylated or acylated with little to no loss of enantiopurity. The scope of the reactions has been explored. The enantiomerization dynamics of N-Boc-2-lithio-2-phenylpyrrolidine and N-Boc-2-lithio-2-phenylpiperidine have been studied in the presence of different solvents and achiral ligands.
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Affiliation(s)
- Timothy K. Beng
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701
| | - Jin Sun Woo
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701
| | - Robert E. Gawley
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701
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25
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Davies SG, Foster EM, Frost AB, Lee JA, Roberts PM, Thomson JE. On the origins of diastereoselectivity in the conjugate additions of the antipodes of lithium N-benzyl-(N-α-methylbenzyl)amide to enantiopure cis- and trans-dioxolane containing α,β-unsaturated esters. Org Biomol Chem 2012; 10:6186-200. [DOI: 10.1039/c2ob25099c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Kolonko KJ, Wherritt DJ, Reich HJ. Mechanistic studies of the lithium enolate of 4-fluoroacetophenone: rapid-injection NMR study of enolate formation, dynamics, and aldol reactivity. J Am Chem Soc 2011; 133:16774-7. [PMID: 21939211 DOI: 10.1021/ja207218f] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lithium enolates are widely used nucleophiles with a complicated and only partially understood solution chemistry. Deprotonation of 4-fluoroacetophenone in THF with lithium diisopropylamide occurs through direct reaction of the amide dimer to yield a mixed enolate-amide dimer (3), then an enolate homodimer (1-Li)(2), and finally an enolate tetramer (1-Li)(4), the equilibrium structure. Aldol reactions of both the metastable dimer and the stable tetramer of the enolate were investigated. Each reacted directly with the aldehyde to give a mixed enolate-aldolate aggregate, with the dimer only about 20 times as reactive as the tetramer at -120 °C.
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Affiliation(s)
- Kristopher J Kolonko
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, USA
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27
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Hoepker AC, Gupta L, Ma Y, Faggin MF, Collum DB. Regioselective lithium diisopropylamide-mediated ortholithiation of 1-chloro-3-(trifluoromethyl)benzene: role of autocatalysis, lithium chloride catalysis, and reversibility. J Am Chem Soc 2011; 133:7135-51. [PMID: 21500823 PMCID: PMC3102585 DOI: 10.1021/ja200906z] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ortholithiation of 1-chloro-3-(trifluoromethyl)benzene with lithium diisopropylamide (LDA) in tetrahydrofuran at -78 °C displays characteristics of reactions in which aggregation events are rate limiting. Metalation with lithium-chloride-free LDA involves a rate-limiting deaggregation via dimer-based transition structures. The post-rate-limiting proton transfers are suggested to involve highly solvated triple ions. Autocatalysis by the resulting aryllithiums or catalysis by traces (<100 ppm) of LiCl diverts the reaction through di- and trisolvated monomer-based pathways for metalation at the 2 and 6 positions, respectively. The regiochemistry is dictated by a combination of kinetically controlled metalations overlaid by an equilibration involving diisopropylamine that is shown to occur by the microscopic reverse of the monomer-based metalations.
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Affiliation(s)
- Alexander C. Hoepker
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - Lekha Gupta
- 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
| | - Marc F. Faggin
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - David B. Collum
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
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Fressigné C, Maddaluno J. Are sp Lithiated Carbons More Nucleophilic than sp2or sp3Ones? A Comparative DFT Study of the Condensation of Propynyllithium Aggregates on Formaldehyde. J Org Chem 2010; 75:1427-36. [DOI: 10.1021/jo902315t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Catherine Fressigné
- Laboratoire de Chimie Théorique, CNRS UMR 7616, Université Pierre et Marie Curie, Case Courrier 137, 4, place Jussieu, 75252 Paris Cedex 05, France
- Institut de Recherche en Chimie Organique Fine, CNRS UMR 6014 & FR 3038, Université de Rouen, 76821-Mont St Aignan Cedex, France
| | - Jacques Maddaluno
- Institut de Recherche en Chimie Organique Fine, CNRS UMR 6014 & FR 3038, Université de Rouen, 76821-Mont St Aignan Cedex, France
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29
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De Vries TS, Goswami A, Liou LR, Gruver JM, Jayne E, Collum DB. Lithium phenolates solvated by tetrahydrofuran and 1,2-dimethoxyethane: structure determination using the method of continuous variation. J Am Chem Soc 2009; 131:13142-54. [PMID: 19702308 PMCID: PMC2752606 DOI: 10.1021/ja9047784] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The method of continuous variation in conjunction with (6)Li NMR spectroscopy was used to characterize lithium phenolates solvated by tetrahydrofuran and 1,2-dimethoxyethane. The strategy relies on the formation of ensembles of homo- and heteroaggregated phenolates. The symmetries and concentration dependencies of the heteroaggregates attest to the aggregation numbers of the homoaggregates. The structurally diverse phenols afford substrate- and solvent-dependent combinations of lithium phenolate monomers, dimers, trimers, tetramers, and pentamers. We discuss the refinement of protocols for characterizing O-lithiated species. Computational studies examine further the substituent and solvent dependencies of aggregation.
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Affiliation(s)
- Timothy S De Vries
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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30
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Pratt LM, Fujiwara SI, Kambe N. Structure, bonding, and aggregation of selenium-containing organolithium species. Tetrahedron 2009. [DOI: 10.1016/j.tet.2008.11.087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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31
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Davies SG, Durbin MJ, Goddard EC, Kelly PM, Kurosawa W, Lee JA, Nicholson RL, Price PD, Roberts PM, Russell AJ, Scott PM, Smith AD. Doubly diastereoselective conjugate addition of homochiral lithium amides to homochiral α,β-unsaturated esters containing cis- and trans-dioxolane units. Org Biomol Chem 2009; 7:761-76. [DOI: 10.1039/b818298a] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Jasiewicz B, Wyrzykiewicz E. Mass spectrometry of metal complexes of bis-quinolizidine alkaloids: electron ionization and fast atom bombardment mass spectral study of copper(II) (-)-sparteine and (-)-alpha- isosparteine complexes. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2009; 15:487-495. [PMID: 19661557 DOI: 10.1255/ejms.1003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The electron ionization (EI) and fast atom bombardment (FAB) mass spectral fragmentations of ten copper(II) dichloride (dibromide, diformate, diacetate and dithiocyanate) complexes of (-)-sparteine and (-)-alpha-isosparteine were investigated. Fragmentation pathways, elucidation of which was assisted by accurate mass measurements and metastable transitions (EI-MS), as well as FAB/collision-induced dissociation (CID) mass spectral measurements are discussed. The data obtained create the basis for the differentiation of the ligand (sparteine or alpha-isosparteine) in the investigated complexes. The comparison of the results with those obtained previously for corresponding zinc(II) complexes forms the basis for the differentiation of metals in these compounds. The results show that both EI-MS and FAB-MS are very useful tools for the differentiation of ligands, as well as metals in the series of Zn(II) and Cu(II) dichloride (dibromide, diacetate, diformate, dithioacetate) complexes of (-)-sparteine and (-)-alpha-isosparteine.
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Affiliation(s)
- Beata Jasiewicz
- Faculty of Chemistry, Adam Mickiewicz University, Grunwałdzka 6, 60-780, Poznań, Poland.
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33
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Knorr R, Menke T, Ferchland K, Mehlstäubl J, Stephenson DS. Microsolvation and 13C-Li NMR coupling. J Am Chem Soc 2008; 130:14179-88. [PMID: 18828636 DOI: 10.1021/ja8026828] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The empirical expression (1)J(CLi) = L[n(a + d)](-1) is proposed; it claims a reciprocal dependence of the NMR coupling constant (1)J((13)C, Li) in a C-Li compound on two factors: (i) the number n of lithium nuclei in bonding contact with the observed carbanion center and (ii) the sum (a + d) of the numbers a of anions and d of donor ligands coordinated at the Li nucleus that generates the observed (1)J(CLi) value. The expression was derived from integrations of separate NMR resonances of coordinated and free monodentate donor ligands (t-BuOMe, Et2O, or THF) in toluene solutions of dimeric and monomeric 2-(alpha-aryl-alpha-lithiomethylidene)-1,1,3,3-tetramethylindan at moderately low temperatures. This unusually slow ligand interchange is ascribed to steric congestion in these compounds, which is further characterized by measurements of nuclear Overhauser correlations and by solid-state structures of the dimers bearing only one donor per lithium atom (d = 1). Increasing microsolvation numbers d are also accompanied by typical changes of the NMR chemical shifts delta (positive for the carbanionic (13)C(alpha), negative for C(para) and p-H). The aforementioned empirical expression for (1)J(CLi) appears to be applicable to other cases of solvated monomeric, dimeric, or tetrameric C-Li compounds (alkyl, alkenyl, alkynyl, and aryl) and even to unsolvated (d approximately 0) trimeric, tetrameric, or hexameric organolithium aggregates, indicating that (1)J(CLi) might serve as a tool for assessing unknown microsolvation numbers. The importance of obtaining evidence about the (13)C NMR C-Li multiplet splitting of both the nonfluxional and fluxional aggregates is emphasized.
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Affiliation(s)
- Rudolf Knorr
- Department of Chemistry and Biochemistry, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, 81377 München, Germany.
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34
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Riggs JC, Singh KJ, Yun M, Collum DB. Anionic Snieckus-Fries rearrangement: solvent effects and role of mixed aggregates. J Am Chem Soc 2008; 130:13709-17. [PMID: 18798619 PMCID: PMC2626637 DOI: 10.1021/ja804087r] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lithiated aryl carbamates (ArLi) bearing methoxy or fluoro substituents in the meta position are generated from lithium diisopropylamide (LDA) in THF, n-BuOMe, Me2NEt, dimethoxyethane (DME), N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetramethylcyclohexanediamine (TMCDA), and hexamethylphosphoramide (HMPA). The aryllithiums are shown with (6)Li, (13)C, and (15)N NMR spectroscopies to be monomers, ArLi-LDA mixed dimers, and ArLi-LDA mixed trimers, depending on the choice of solvent. Subsequent Snieckus-Fries rearrangements afford ArOLi-LDA mixed dimers and trimers of the resulting phenolates. Rate studies of the rearrangement implicate mechanisms based on monomers, mixed dimers, and mixed trimers.
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Affiliation(s)
- Jason C Riggs
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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35
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Liou LR, McNeil AJ, Ramirez A, Toombes GES, Gruver JM, Collum DB. Lithium enolates of simple ketones: structure determination using the method of continuous variation. J Am Chem Soc 2008; 130:4859-68. [PMID: 18336025 PMCID: PMC2636850 DOI: 10.1021/ja7100642] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The method of continuous variation in conjunction with 6Li NMR spectroscopy was used to characterize lithium enolates derived from 1-indanone, cyclohexanone, and cyclopentanone in solution. The strategy relies on forming ensembles of homo- and heteroaggregated enolates. The enolates form exclusively chelated dimers in N,N,N',N'-tetramethylethylenediamine and cubic tetramers in tetrahydrofuran and 1,2-dimethoxyethane.
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Affiliation(s)
- Lara R Liou
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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36
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Jasiewicz B, Wyrzykiewicz E. Electron ionization and fast atom bombardment mass spectral study for differentiation of ligand of zinc(II) (-)-sparteine and (-)-alpha-isosparteine complexes. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:1325-1328. [PMID: 18383215 DOI: 10.1002/rcm.3464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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37
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Ma Y, Collum DB. Lithium diisopropylamide-mediated reactions of imines, unsaturated esters, epoxides, and aryl carbamates: influence of hexamethylphosphoramide and ethereal cosolvents on reaction mechanisms. J Am Chem Soc 2007; 129:14818-25. [PMID: 17985891 DOI: 10.1021/ja074554e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several reactions mediated by lithium diisopropylamide (LDA) with added hexamethylphosphoramide (HMPA) are described. The N-isopropylimine of cyclohexanone lithiates via an ensemble of monomer-based pathways. Conjugate addition of LDA/HMPA to an unsaturated ester proceeds via di- and tetra-HMPA-solvated dimers. Deprotonation of norbornene epoxide by LDA/HMPA proceeds via an intermediate metalated epoxide as a mixed dimer with LDA. Ortholithiation of an aryl carbamate proceeds via a mono-HMPA-solvated monomer-based pathway. Dependencies on THF and other ethereal cosolvents suggest that secondary-shell solvation effects are important in some instances. The origins of the inordinate mechanistic complexity are discussed.
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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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38
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Strohmann C, Gessner VH. From MonomerictBuLi⋅(R,R)-TMCDA to α-Lithiated (R,R)-TMCDA. Angew Chem Int Ed Engl 2007; 46:8281-3. [PMID: 17899584 DOI: 10.1002/anie.200702116] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Carsten Strohmann
- Institut für Anorganische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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39
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Strohmann C, Gessner V. Von monomeremtBuLi⋅(R,R)-TMCDA zu α-lithiiertem (R,R)-TMCDA. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200702116] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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40
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Godenschwager PF, Collum DB. Lithium Hexamethyldisilazide-Mediated Enolizations: Influence of Chelating Ligands and Hydrocarbon Cosolvents on the Rates and Mechanisms. J Am Chem Soc 2007; 129:12023-31. [PMID: 17850084 DOI: 10.1021/ja074018m] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Enolizations of 2-methylcyclohexanone by lithium hexamethyldisilazide (LiHMDS) in the presence of three chelating ligands--trans-N,N,N',N'-tetramethylcyclohexanediamine, N,N,N',N'-tetramethylethylenediamine, and dimethoxyethane--reveal an approximate 40-fold range of rates. NMR spectroscopic analyses and rate studies reveal isostructural transition structures based on monomeric LiHMDS for the diamines. Rate studies of LiHMDS/dimethoxyethane-mediated enolizations implicate a substantial number of monomer- and dimer-based mechanisms. The rate laws vary for the three ligands because of ligand-dependent structural differences in both the reactants and the transition structures. The importance of LiHMDS-ketone complexes and the role of hydrocarbon cosolvents are discussed.
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Affiliation(s)
- Peter F Godenschwager
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University Ithaca, New York 14853-1301, USA
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41
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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: 169] [Impact Index Per Article: 9.9] [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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42
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43
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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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44
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Sott R, Håkansson M, Hilmersson G. Studies of Complexes between Phenyllithium and (−)-Sparteine in Ether Solutions. Organometallics 2006. [DOI: 10.1021/om050872f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Richard Sott
- Department of Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Mikael Håkansson
- Department of Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Göran Hilmersson
- Department of Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
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45
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Singh KJ, Collum DB. Lithium Diisopropylamide-Mediated Ortholithiation and Anionic Fries Rearrangement of Aryl Carbamates: Role of Aggregates and Mixed Aggregates. J Am Chem Soc 2006; 128:13753-60. [PMID: 17044703 DOI: 10.1021/ja064655x] [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: 11/30/2022]
Abstract
Structural and mechanistic studies of the lithium diisopropylamide (LDA)-mediated anionic Fries rearrangements of aryl carbamates are described. Substituents at the meta position of the arene (H, OMe, F) and the dialkylamino moiety of the carbamate (Me(2)N, Et(2)N, and i-Pr(2)N) markedly influence the relative rates of ortholithiation and subsequent Fries rearrangement. Structural studies using (6)Li and (15)N NMR spectroscopies on samples derived from [(6)Li,(15)N]LDA reveal an LDA dimer, LDA dimer-arene complexes, an aryllithium monomer, LDA-aryllithium mixed dimers, an LDA-lithium phenolate mixed dimer, and homoaggregated lithium phenolates. The highly insoluble phenolate was characterized as a dimer by X-ray crystallography. Rate studies show monomer- and dimer-based ortholithiations as well as monomer- and mixed dimer-based Fries rearrangements. Density functional theory computational studies probe experimentally elusive structural and mechanistic details.
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Affiliation(s)
- Kanwal Jit Singh
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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46
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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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47
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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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48
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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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Brandau S, Hoppe D. Asymmetric synthesis of (2-carbamoyloxy-1-alkenyl)cyclopropanes by intramolecular cycloalkylation. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.09.110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Khedkar V, Tillack A, Benisch C, Melder JP, Beller M. Base-catalyzed hydroamination of ethylene with diethylamine. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcata.2005.06.068] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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