1
|
Studies on the ɑ-lithiation-in situ intramolecular nucleophilic addition reactions of 2-acyl-N-sulfonylpyrroles. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.152907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
2
|
Continuous flow multistep synthesis of α-functionalized esters via lithium enolate intermediates. Tetrahedron 2018. [DOI: 10.1016/j.tet.2017.11.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
3
|
Mack KA, Collum DB. Case for Lithium Tetramethylpiperidide-Mediated Ortholithiations: Reactivity and Mechanisms. J Am Chem Soc 2018; 140:4877-4883. [PMID: 29589920 PMCID: PMC6141241 DOI: 10.1021/jacs.8b00590] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Rate and mechanistic studies of ortholithiations by lithium 2,2,6,6-tetramethylpiperidide focus on four arenes: 1,4-bis(trifluoromethyl)benzene, 1,3-bis(trifluoromethyl)benzene, 1,3-dimethoxybenzene, and 4,4-dimethyl-2-phenyl-2-oxazoline. Metalations occur via substrate-dependent combinations of monosolvated monomer, disolvated monomer, and tetrasolvated dimer (triple ions). Density functional theory computational studies augment the experimental data. We discuss the challenges presented by shifting dimer-monomer proportions in determining the observable reaction orders and our mathematical treatment of such shifting in reactant structure.
Collapse
Affiliation(s)
- Kyle A Mack
- 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
| |
Collapse
|
4
|
Algera RF, Gupta L, Hoepker AC, Liang J, Ma Y, Singh KJ, Collum DB. Lithium Diisopropylamide: Nonequilibrium Kinetics and Lessons Learned about Rate Limitation. J Org Chem 2017; 82:4513-4532. [PMID: 28368117 PMCID: PMC6059656 DOI: 10.1021/acs.joc.6b03083] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The kinetics of lithium diisopropylamide (LDA) in tetrahydrofuran under nonequilibrium conditions are reviewed. These conditions correspond to a class of substrates in which the rates of LDA aggregation and solvation events are comparable to the rates at which various fleeting intermediates react with substrate. Substrates displaying these reactivities, by coincidence, happen to be those that react at tractable rates on laboratory time scales at -78 °C. In this strange region of nonlimiting behavior, rate-limiting steps are often poorly defined, sometimes involve deaggregation, and at other times include reaction with substrate. Changes in conditions routinely cause shifts in the rate-limiting steps, and autocatalysis is prevalent and can be acute. The studies are described in three distinct portions: (1) methods and strategies used to deconvolute complex reaction pathways, (2) the resulting conclusions about organolithium reaction mechanisms, and (3) perspectives on the concept of rate limitation reinforced by studies of LDA in tetrahydrofuran at -78 °C under nonequilibrium conditions.
Collapse
Affiliation(s)
- Russell F. Algera
- 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
| | - Alexander C. Hoepker
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
| | - Jun Liang
- 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
| | - Kanwal J. Singh
- 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
| |
Collapse
|
5
|
Samoilichenko Y, Kondratenko V, Ezernitskaya M, Lyssenko K, Peregudov A, Khrustalev V, Maleev V, Moskalenko M, North M, Tsaloev A, Gugkaeva ZT, Belokon Y. A mechanistic study of the Lewis acid–Brønsted base–Brønsted acid catalysed asymmetric Michael addition of diethyl malonate to cyclohexenone. Catal Sci Technol 2017. [DOI: 10.1039/c6cy01697a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction shown to exhibit biomimetic behaviour.
Collapse
Affiliation(s)
- Yuri Samoilichenko
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| | - Veronica Kondratenko
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| | - Mariam Ezernitskaya
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| | - Konstantin Lyssenko
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| | - Alexander Peregudov
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| | - Victor Khrustalev
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
- Peoples' Friendship University of Russia
- Russian Federation
| | - Victor Maleev
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| | - Margarita Moskalenko
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| | - Michael North
- Green Chemistry Centre of Excellence
- Department of Chemistry
- The University of York
- York
- YO10 5DD UK
| | - Alan Tsaloev
- Chemical Diversity Research Institute
- Khimki
- Russian Federation
| | - Zalina T. Gugkaeva
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| | - Yuri Belokon
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Russian Federation
| |
Collapse
|
6
|
Neufeld R, Michel R, Herbst-Irmer R, Schöne R, Stalke D. Introducing a Hydrogen-Bond Donor into a Weakly Nucleophilic Brønsted Base: Alkali Metal Hexamethyldisilazides (MHMDS, M=Li, Na, K, Rb and Cs) with Ammonia. Chemistry 2016; 22:12340-6. [PMID: 27457218 DOI: 10.1002/chem.201600833] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/25/2016] [Indexed: 11/08/2022]
Abstract
Alkali metal 1,1,1,3,3,3-hexamethyldisilazide (MHMDSs) are one of the most utilised weakly nucleophilic Brønsted bases in synthetic chemistry and especially in natural product synthesis. Like lithium organics, they aggregate depending on the employed donor solvents. Thus, they show different reactivity and selectivity as a function of their aggregation and solvation state. To date, monomeric LiHMDS with monodentate donor bases was only characterised in solution. Since the first preparation of LiHMDS in 1959 by Wannagat and Niederprüm, all efforts to crystallise monomeric LiHMDS in the absence of chelating ligands failed. Herein, we present ammonia adducts of LiHMDS, NaHMDS, KHMDS, RbHMDS and CsHMDS with unprecedented aggregation motifs: 1) The hitherto missing monomeric key compound in the LiHMDS aggregation architectures. Monomeric crystal structures of trisolvated LiHMDS (1) and NaHMDS (2), showing unique intermolecular hydrogen bonds, 2) the unprecedented tetrasolvated KHMDS (3) and RbHMDS (4) dimers and 3) the disolvated CsHMDS (5) dimer with very close intermolecular Si-CH3 ⋅⋅⋅Cs s-block "agostic" interactions have been prepared and characterised by single-crystal X-ray structure analysis.
Collapse
Affiliation(s)
- Roman Neufeld
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Reent Michel
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Regine Herbst-Irmer
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Ralf Schöne
- 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.
| |
Collapse
|
7
|
Neufeld R, Stalke D. Solution Structure of Turbo-Hauser Base TMPMgCl⋅LiCl in [D8]THF. Chemistry 2016; 22:12624-8. [DOI: 10.1002/chem.201601494] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Roman Neufeld
- 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
| |
Collapse
|
8
|
Knorr R, Behringer C, Lattke E, von Roman U, Knittl M. How Microsolvation Numbers at Li Control Aggregation Modes, sp(2)-Stereoinversion, and NMR Coupling Constants (2)JH,H of H2C═C in α-(2,6-Dimethylphenyl)vinyllithium. J Org Chem 2015; 80:6313-22. [PMID: 26029794 DOI: 10.1021/acs.joc.5b00762] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The title compound 4 is a trisolvated monomer 4&3THF in THF solution and dimerizes endothermically to form (4&THF)2 with a strongly positive (!) dimerization entropy in toluene as the solvent. In the absence of electron-pair donor ligands, 4 aggregates (>dimer) in hydrocarbon solutions. These results followed from the (13)C-α splitting patterns and the magnitudes of the one-bond (13)C,(6)Li NMR coupling constants in combination with lithiation NMR shifts as secondary NMR criteria. The rate constants of cis/trans sp(2)-stereoinversion could be measured on the (1)H NMR time scale in THF, in which solvent the preinversion lifetime is 0.24 s at 25 °C. This inversion proceeds according to the pseudomonomolecular, ionic mechanism with the typical, strongly negative pseudoactivation entropy. In a different mechanism, the lifetimes are much longer at 25 °C for the dimer (4&t-BuOMe)2 in toluene (ca. 2.5 min) and for donor-free, aggregated 4 in hexane solution (roughly 1 min). The olefinic interproton two-bond coupling constants (2)JH,H of the H2C═CLi part are proposed as an indicator of microsolvation at Li, because they were found to increase linearly with the "explicit" solvation of α-arylvinyllithiums by 0, 1, 2, and 3 electron-pair donor ligands.
Collapse
Affiliation(s)
- Rudolf Knorr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| | - Claudia Behringer
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| | - Ernst Lattke
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| | - Ulrich von Roman
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| | - Monika Knittl
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| |
Collapse
|
9
|
Liang J, Hoepker AC, Algera RF, Ma Y, Collum DB. Mechanism of Lithium Diisopropylamide-Mediated Ortholithiation of 1,4-Bis(trifluoromethyl)benzene under Nonequilibrium Conditions: Condition-Dependent Rate Limitation and Lithium Chloride-Catalyzed Inhibition. J Am Chem Soc 2015; 137:6292-303. [PMID: 25900574 PMCID: PMC4788392 DOI: 10.1021/jacs.5b01668] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lithiation of 1,4-bis(trifluoromethyl)benzene with lithium diisopropylamide in tetrahydrofuran at -78 °C occurs under conditions at which the rates of aggregate exchanges are comparable to the rates of metalation. Under such nonequilibrium conditions, a substantial number of barriers compete to be rate limiting, making the reaction sensitive to trace impurities (LiCl), reactant concentrations, and isotopic substitution. Rate studies using the perdeuterated arene reveal odd effects of LiCl, including catalyzed rate acceleration at lower temperature and catalyzed rate inhibition at higher temperatures. The catalytic effects are accompanied by corresponding changes in the rate law. A kinetic model is presented that captures the critical features of the LiCl catalysis, focusing on the influence of LiCl-catalyzed re-aggregation of the fleeting monomer that can reside above, at, or below the equilibrium population without catalyst.
Collapse
Affiliation(s)
- Jun Liang
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
| | - Alexander C. Hoepker
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
| | - Russell F. Algera
- 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
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
| |
Collapse
|