1
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Davison N, Hemingway JM, Waddell PG, Lu E. Lithium, sodium and potassium enolate aggregates and monomers: syntheses and structures. Dalton Trans 2024; 53:4719-4728. [PMID: 38362928 DOI: 10.1039/d4dt00211c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
In this Article, we report the syntheses and comparative structural studies of lithium, sodium, and potassium anthracen-9-yl enolates, as their aggregates (Li, Na: hexamer; K: tetramer) and ligand-stabilized monomers (for Li and Na). The monomers add new members to the rare collection of group-1 metal monomeric enolates. Moreover, the series covers different group-1 metal cations (Li+, Na+ and K+) and aggregate sizes, allowing comparative structural studies to elucidate how the metal identity and aggregate size influence the enolate structure.
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Affiliation(s)
- Nathan Davison
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
| | - Jack M Hemingway
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
| | - Paul G Waddell
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
| | - Erli Lu
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
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2
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Krivdin LB. Recent advances in the liquid-phase 6,7 Li nuclear magnetic resonance. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2023; 61:138-161. [PMID: 36330776 DOI: 10.1002/mrc.5323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/01/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
The present review is focused on experimental methods and structural applications, including computational aspects, of classical lithium liquid-phase nuclear magnetic resonance (NMR). It consists of four parts covering accordingly a brief overview, early experimental reports (papers of up to about 2015) and more recent (papers appearing in the interim of about 2015 until 2022) results, together with very few but highly prospective computational results.
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Affiliation(s)
- Leonid B Krivdin
- A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
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3
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Masiuk US, Faletrov YV, Kananovich DG, Mineyeva IV. Stereodivergent Assembly of 2,6- cis- and - trans-Tetrahydropyrans via Base-Mediated Oxa-Michael Cyclization: The Key Role of the TMEDA Additive. J Org Chem 2023; 88:355-370. [PMID: 36495268 DOI: 10.1021/acs.joc.2c02382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The stereodivergent synthesis of cis- and trans-2,6-disubstituted tetrahydropyrans (THPs) via sodium hexamethyldisilazide-promoted oxa-Michael cyclization of (E)-ζ-hydroxy α,β-unsaturated esters is presented. The cyclization affords the kinetically favored trans-THPs with high stereoselectivity (dr up to 93:7) at a low temperature (-78 °C), while the room-temperature reaction does not produce the thermodynamically preferred cis-THPs as major products and occurs with poor stereocontrol. The addition of tetramethylethylenediamine (TMEDA) significantly improves the stereochemical outcome of the room-temperature cyclization and allows attaining high cis-selectivity (dr up to 99:1). The remarkable effect of TMEDA indicates that the sodium cation plays an important role in controlling the stereoselectivity of the thermodynamically driven process, that is, complexation of the cation with the cyclization products results in diminished selectivity. DFT calculations support this conclusion, indicating a greater difference in Gibbs energies of sodium-free cis- and trans-enolates compared to the respective sodium chelate complexes. The synthetic utility of the method has been demonstrated by the formal syntheses of (+)-Neopeltolide and (-)-Diospongin B and the total synthesis of (-)-Diospongin A.
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Affiliation(s)
- Uladzimir S Masiuk
- Department of Chemistry, Belarusian State University, Leningradskaya 14, 220006 Minsk, Belarus.,School of Science, Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Yaroslav V Faletrov
- Department of Chemistry, Belarusian State University, Leningradskaya 14, 220006 Minsk, Belarus.,Research Institute for Physical Chemical Problems, Belarusian State University, Leningradskaya 14, 220006 Minsk, Belarus
| | - Dzmitry G Kananovich
- School of Science, Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Iryna V Mineyeva
- Department of Chemistry, Belarusian State University, Leningradskaya 14, 220006 Minsk, Belarus
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4
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Han S, Lee Y, Jung Y, Cho SH. Stereoselective Access to Tetra‐ and Tri‐Substituted Fluoro‐ and Chloro‐Borylalkenes via Boron‐Wittig Reaction. Angew Chem Int Ed Engl 2022; 61:e202210532. [DOI: 10.1002/anie.202210532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Seungcheol Han
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Yeosan Lee
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Yujin Jung
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Seung Hwan Cho
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
- Institute for Convergence Research and Education in Advanced Technology (I–CREATE) Yonsei University Seoul 03722 Republic of Korea
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5
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Karpov VV, Antonov AS, Tupikina EY. Choice of computational protocol for carbon-lithium spin-spin coupling constants 1 J CLi. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:985-995. [PMID: 35881390 DOI: 10.1002/mrc.5299] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
In this work, we tested various computational schemes for calculations of 1 JCLi constants with a high accuracy. On the example of six organolithium reagents (phenyllithium monomer and dimer, monomer s-butyllithium, monomers of 1- and 2-lithionaphthalenes, and a methyllithium tetramer), the following aspects are discussed: (i) the role of a model system geometry, (ii) influence of solvent effects, and (iii) the choice of a functional and basis set. Practical recommendations for calculation of 1 JCLi with an accuracy ±2 Hz are formulated.
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Affiliation(s)
- Valerii V Karpov
- Institute of Chemistry, St. Petersburg State University, St. Petersburg, Russia
| | - Alexander S Antonov
- Institute of Chemistry, St. Petersburg State University, St. Petersburg, Russia
| | - Elena Yu Tupikina
- Institute of Chemistry, St. Petersburg State University, St. Petersburg, Russia
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6
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Han S, Lee Y, Jung Y, Cho SH. Stereoselective Access to Tetra‐ and Tri‐Substituted Fluoro‐ and Chloro‐borylalkenes via Boron‐Wittig Reaction. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202210532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Seungcheol Han
- POSTECH: Pohang University of Science and Technology Chemistry KOREA, REPUBLIC OF
| | - Yeosan Lee
- POSTECH: Pohang University of Science and Technology Chemistry KOREA, REPUBLIC OF
| | - Yujin Jung
- POSTECH: Pohang University of Science and Technology Chemistry KOREA, REPUBLIC OF
| | - Seung Hwan Cho
- Pohang University of Science and Technology (POSTECH) Chemistry San 31, HyojadongNamgu 37673 Pohang KOREA, REPUBLIC OF
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7
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Bojaryn K, Hirschhäuser C. Transition Metal Catalyst Free Synthesis of Olefins from Organoboron Derivatives**. Chemistry 2022; 28:e202104125. [PMID: 35137987 PMCID: PMC9303902 DOI: 10.1002/chem.202104125] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Indexed: 11/29/2022]
Abstract
Stereoselective preparation of highly substituted olefins is still a severe challenge that requires well defined elimination precursors. Organoboron chemistry is particularly suited for the preparation of molecules with adjacent stereocenters. As organo boron substrates with leaving groups in β‐position can undergo stereospecific syn‐ or anti‐elimination, this chemistry harbors great potential for the synthesis of complex olefins. In recent years three main strategies emerged, which differ in their approach to the β‐functionalized organoboron elimination precursor. (i) Stereoselective preparation of such elimination precursor can be achieved by addition of a boron‐stabilized anion (d1) to an aldehyde or ketone (a1) or diastereoselective 1,3‐rearrangement of suitable boron‐ate‐complexes. Stereospecific methods rely either on (ii) diastereospecific 1,2‐metalate rearrangement of boron‐ate‐complexes that involve opening of appropriate heterocycles or (iii) addition of chiral carbenoids (d1*) to chiral boronates (a1*) with a leaving group in α‐position.
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Affiliation(s)
- K. Bojaryn
- Institut für Organische Chemie Universität Duisburg-Essen Universitätsstraße 7 45141 Essen Germany
| | - C. Hirschhäuser
- Institut für Organische Chemie Universität Duisburg-Essen Universitätsstraße 7 45141 Essen Germany
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8
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Unusual (3 THF)-microsolvated dimers and donor-free aggregates of two lithium enolates. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Abstract
Boron-Wittig reaction as the condensation of lithium α-bis(boryl)carbanions with carbonyl derivatives on route to substituted borylalkenes.
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Affiliation(s)
- Ana B. Cuenca
- Dept. Organic and Pharmaceutic Chemistry
- Institut Químic de Sarrià
- Universitat Ramon Llull
- Barcelona
- Spain
| | - Elena Fernández
- Dept. Química Física e Inorgánica
- University Rovira i Virgili
- Tarragona
- Spain
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10
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Javorskis T, Karpavičienė I, Jurys A, Snarskis G, Bukšnaitienė R, Orentas E. An Enolate‐Structure‐Enabled Anionic Cascade Cyclization Reaction: Easy Access to Complex Scaffolds with Contiguous Six‐, Five‐, and Four‐Membered Rings. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tomas Javorskis
- Department of Organic Chemistry Vilnius University Naugarduko 24 03225 Vilnius Lithuania
- Center for Physical Sciences and Technology Saulėtekio av. 3 10257 Vilnius Lithuania
| | - Ieva Karpavičienė
- Department of Organic Chemistry Vilnius University Naugarduko 24 03225 Vilnius Lithuania
| | - Arminas Jurys
- Department of Organic Chemistry Vilnius University Naugarduko 24 03225 Vilnius Lithuania
| | - Gustautas Snarskis
- Center for Physical Sciences and Technology Saulėtekio av. 3 10257 Vilnius Lithuania
| | - Rita Bukšnaitienė
- Department of Organic Chemistry Vilnius University Naugarduko 24 03225 Vilnius Lithuania
| | - Edvinas Orentas
- Department of Organic Chemistry Vilnius University Naugarduko 24 03225 Vilnius Lithuania
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11
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Javorskis T, Karpavičienė I, Jurys A, Snarskis G, Bukšnaitienė R, Orentas E. An Enolate-Structure-Enabled Anionic Cascade Cyclization Reaction: Easy Access to Complex Scaffolds with Contiguous Six-, Five-, and Four-Membered Rings. Angew Chem Int Ed Engl 2020; 59:20120-20128. [PMID: 32697013 DOI: 10.1002/anie.202008317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/12/2020] [Indexed: 01/07/2023]
Abstract
Catalyst-free addition of ketone enolate to non-activated multiple C-C bonds involves non-complementary reaction partners and typically requires super-basic conditions. On the other hand, highly aggregated or solvated enolates are not reactive enough to undergo direct addition to alkenes or alkynes. Herein, we report a new anionic cascade reaction for one-step assembly of intriguing molecular scaffolds possessing contiguous six-, five-, and four-membered rings, representing a formal [2+2] enol-allene cycloaddition. Reaction proceeds under very mild conditions and with excellent diastereoselectivity. Deeper mechanistic and computational studies revealed unusually slow proton transfer phenomenon in cyclic ketone intermediate and explained peculiar stereochemical outcome.
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Affiliation(s)
- Tomas Javorskis
- Department of Organic Chemistry, Vilnius University, Naugarduko 24, 03225, Vilnius, Lithuania.,Center for Physical Sciences and Technology, Saulėtekio av. 3, 10257, Vilnius, Lithuania
| | - Ieva Karpavičienė
- Department of Organic Chemistry, Vilnius University, Naugarduko 24, 03225, Vilnius, Lithuania
| | - Arminas Jurys
- Department of Organic Chemistry, Vilnius University, Naugarduko 24, 03225, Vilnius, Lithuania
| | - Gustautas Snarskis
- Center for Physical Sciences and Technology, Saulėtekio av. 3, 10257, Vilnius, Lithuania
| | - Rita Bukšnaitienė
- Department of Organic Chemistry, Vilnius University, Naugarduko 24, 03225, Vilnius, Lithuania
| | - Edvinas Orentas
- Department of Organic Chemistry, Vilnius University, Naugarduko 24, 03225, Vilnius, Lithuania
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12
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Yang F, Zou D, Chen S, Wang H, Zhao Y, Zhao L, Li L, Li J, Walsh PJ. Transition Metal‐Free Aroylation of Diarylmethanes with N‐Bn‐ N‐Boc Arylamides and N‐Acylpyrroles. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000622] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Fan Yang
- Department of PharmacySchool of MedicineZhejiang University City College No. 48, Huzhou Road Hangzhou 310015 People's Republic of China
| | - Dong Zou
- Department of PharmacySchool of MedicineZhejiang University City College No. 48, Huzhou Road Hangzhou 310015 People's Republic of China
| | - Shuguang Chen
- Roy and Diana Vagelos LaboratoriesDepartment of ChemistryUniversity of Pennsylvania 231 South 34th Street Philadelphia Pennsylvania 19104-6323 USA
| | - Huan Wang
- Department of PharmacySchool of MedicineZhejiang University City College No. 48, Huzhou Road Hangzhou 310015 People's Republic of China
| | - Yichen Zhao
- Department of PharmacySchool of MedicineZhejiang University City College No. 48, Huzhou Road Hangzhou 310015 People's Republic of China
| | - Liyi Zhao
- Department of PharmacySchool of MedicineZhejiang University City College No. 48, Huzhou Road Hangzhou 310015 People's Republic of China
| | - Linlin Li
- Department of PharmacySchool of MedicineZhejiang University City College No. 48, Huzhou Road Hangzhou 310015 People's Republic of China
| | - Jie Li
- Department of PharmacySchool of MedicineZhejiang University City College No. 48, Huzhou Road Hangzhou 310015 People's Republic of China
| | - Patrick J. Walsh
- Roy and Diana Vagelos LaboratoriesDepartment of ChemistryUniversity of Pennsylvania 231 South 34th Street Philadelphia Pennsylvania 19104-6323 USA
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13
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Pasturaud K, Rkein B, Sanselme M, Sebban M, Lakhdar S, Durandetti M, Legros J, Chataigner I. The facile dearomatization of nitroaromatic compounds using lithium enolates of unsaturated ketones in conjugate additions and (4+2) formal cycloadditions. Chem Commun (Camb) 2019; 55:7494-7497. [PMID: 31185071 DOI: 10.1039/c9cc02924a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The dearomatization of conventional nitroarenes by lithiated enolates derived from methyl vinyl ketones easily takes place, following a formal (4+2) cycloaddition process. While nitroindoles react readily with in situ generated conjugated enolates, the deaggregation of these latter species using HMPA extends the reaction scope to the more aromatic nitronaphthalenes and pyridines.
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Affiliation(s)
- Karine Pasturaud
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, COBRA, 76000 Rouen, France.
| | - Batoul Rkein
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, COBRA, 76000 Rouen, France.
| | | | - Muriel Sebban
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, COBRA, 76000 Rouen, France.
| | - Sami Lakhdar
- Normandie Univ., LCMT, ENSICAEN, UNICAEN, CNRS, 6, Boulevard Maréchal Juin, Caen 14000, France
| | - Muriel Durandetti
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, COBRA, 76000 Rouen, France.
| | - Julien Legros
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, COBRA, 76000 Rouen, France.
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14
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Namirembe S, Gao C, Wexler RP, Morken JP. Stereoselective Synthesis of Trisubstituted Alkenylboron Reagents by Boron-Wittig Reaction of Ketones. Org Lett 2019; 21:4392-4394. [PMID: 31140815 DOI: 10.1021/acs.orglett.9b01663] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Application of the boron-Wittig reaction to ketone electrophiles provides a straightforward route to trisubstituted alkenylboronic esters. With either a pentamethyldiethylenetriamine or trimethyl-1,4,7-triazacyclononane additive, the olefination can occur with very high levels of stereocontrol and in good chemical yield.
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Affiliation(s)
- Sheila Namirembe
- Department of Chemistry, Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - Chenpeng Gao
- Department of Chemistry, Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - Ryan P Wexler
- Department of Chemistry, Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - James P Morken
- Department of Chemistry, Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467 , United States
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15
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Jagtap PR, Císařová I, Jahn U. Bioinspired total synthesis of tetrahydrofuran lignans by tandem nucleophilic addition/redox isomerization/oxidative coupling and cycloetherification reactions as key steps. Org Biomol Chem 2018; 16:750-755. [DOI: 10.1039/c7ob02848b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three steps suffice to complete a bioinspired total synthesis of tetrahydrofuran lignans using tandem addition/isomerization/dimerization and cycloetherification reactions.
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Affiliation(s)
- Pratap R. Jagtap
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences
- 166 10 Prague
- Czech Republic
| | - Ivana Císařová
- Department of Inorganic Chemistry
- Charles University in Prague
- 12843 Prague 2
- Czech Republic
| | - Ullrich Jahn
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences
- 166 10 Prague
- Czech Republic
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16
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Reyes-Rodríguez GJ, Algera RF, Collum DB. Lithium Hexamethyldisilazide-Mediated Enolization of Acylated Oxazolidinones: Solvent, Cosolvent, and Isotope Effects on Competing Monomer- and Dimer-Based Pathways. J Am Chem Soc 2017; 139:1233-1244. [PMID: 28080036 PMCID: PMC6059651 DOI: 10.1021/jacs.6b11354] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Lithium hexamethyldisilazide (LiHMDS)-mediated enolization of (+)-4-benzyl-3-propionyl-2-oxazolidinone in THF-hydrocarbon mixtures shows unusual sensitivity to the choice of hydrocarbon cosolvent (hexane versus toluene) and to isotopic labeling. Four mechanisms corresponding to monosolvated monomers, trisolvated dimers, octasolvated monomers, and octasolvated dimers were identified. Even under conditions in which the LiHMDS monomer was the dominant observable form, dimer-based metalation was significant. The mechanism-dependent isotope and cosolvent effects are discussed in the context of ground-state stabilization and transition-state tunneling.
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Affiliation(s)
- Gabriel J. Reyes-Rodríguez
- 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
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
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17
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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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18
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Affiliation(s)
- Dieter Seebach
- Laboratorium für Organische Chemie; ETH Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
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19
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Roca-López D, Polo V, Tejero T, Merino P. Mechanism Switch in Mannich-Type Reactions: ELF and NCI Topological Analyses of the Reaction between Nitrones and Lithium Enolates. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500447] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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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.
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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
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21
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Guang J, Liu QP, Hopson R, Williard PG. Lithium pinacolone enolate solvated by hexamethylphosphoramide. J Am Chem Soc 2015; 137:7347-56. [PMID: 25933508 DOI: 10.1021/jacs.5b01906] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the crystal structure of a substoichiometric, HMPA-trisolvated lithium pinacolone enolate tetramer (LiOPin)4·HMPA3 abbreviated as T3. In this tetramer one HMPA binds to lithium more strongly than the other two causing a reduction in spatial symmetry with corresponding loss of C3 symmetry. A variety of NMR experiments, including HMPA titration, diffusion coefficient-formula weight (D-FW) analysis, and other multinuclear one- and two-dimensional NMR techniques reveal that T3 is the major species in hydrocarbon solution when more than 0.6 equiv of HMPA is present. Due to a small amount of moisture from HMPA or air leaking into the solution, a minor complex was identified and confirmed by X-ray diffraction analysis as a mixed aggregate containing enolate, lithium hydroxide, and HMPA in a 4:2:4 ratio, [(LiOPin)4·(LiOH)2·HMPA4], that we refer to as pseudo-T4. A tetra-HMPA-solvated lithium cyclopentanone enolate tetramer was also prepared and characterized by X-ray diffraction, leading to the conclusion that steric effects dominate the formation and solvation of the pinacolone aggregates. An unusual mixed aggregate consisting of pinacolone enolate, lithium diisopropyl amide, lithium oxide, and HMPA in the ratio 5:1:1:2 is also described.
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Affiliation(s)
- Jie Guang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Qiyong Peter Liu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Russell Hopson
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Paul G Williard
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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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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Reich HJ. Role of Organolithium Aggregates and Mixed Aggregates in Organolithium Mechanisms. Chem Rev 2013; 113:7130-78. [DOI: 10.1021/cr400187u] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Hans J. Reich
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
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Chakrabarti N, Sattler W, Parkin G. Structural characterization of tris(pyrazolyl)hydroborato and tris(2-pyridylthio)methyl lithium compounds: Lithium in uncommon trigonal pyramidal and trigonal monopyramidal coordination environments. Polyhedron 2013. [DOI: 10.1016/j.poly.2013.02.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Gupta L, Hoepker AC, Ma Y, Viciu MS, Faggin MF, Collum DB. Lithium diisopropylamide-mediated ortholithiation of 2-fluoropyridines: rates, mechanisms, and the role of autocatalysis. J Org Chem 2013; 78:4214-30. [PMID: 23270408 DOI: 10.1021/jo302408r] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Lithium diisopropylamide (LDA)-mediated ortholithiations of 2-fluoropyridine and 2,6-difluoropyridine in tetrahydrofuran at -78 °C were studied using a combination of IR and NMR spectroscopic and computational methods. Rate studies show that a substrate-assisted deaggregation of LDA dimer occurs parallel to an unprecedented tetramer-based pathway. Standard and competitive isotope effects confirm post-rate-limiting proton transfer. Autocatalysis stems from ArLi-catalyzed deaggregation of LDA proceeding via 2:2 LDA-ArLi mixed tetramers. A hypersensitivity of the ortholithiation rates to traces of LiCl derives from LiCl-catalyzed LDA dimer-monomer exchange and a subsequent monomer-based ortholithiation. Fleeting 2:2 LDA-LiCl mixed tetramers are suggested to be key intermediates. The mechanisms of both the uncatalyzed and catalyzed deaggregations are discussed. A general mechanistic paradigm is delineated to explain a number of seemingly disparate LDA-mediated reactions, all of which occur in tetrahydrofuran at -78 °C.
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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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Lazny R, Wolosewicz K. An expedient preparation of amine-free lithium enolates using immobilized amide reagents. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2012.12.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Guino-o MA, Torvisco A, Teng W, Ruhlandt-Senge K. Alkaline earth metal di- and triphenylmethanides: Analysis of ion association modes. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2012.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Affiliation(s)
- Hans J. Reich
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
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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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Lecachey B, Fressigné C, Oulyadi H, Harrison-Marchand A, Maddaluno J. First substoichiometric version of the catalytic enantioselective addition of an alkyllithium to an aldehyde. Chem Commun (Camb) 2011; 47:9915-7. [PMID: 21811732 DOI: 10.1039/c1cc13513a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A substoichiometric enantioselective version of the extremely fast nucleophilic addition of Alk-Li to RCHO is made possible thanks to a thorough analysis of the aggregation phenomena involved in the reaction: calculated quantities of LiCl must be added to the medium at the right time to keep the catalytic cycle running.
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Affiliation(s)
- Baptiste Lecachey
- CNRS UMR 6014 & FR 3038, Université de Rouen and INSA de Rouen, Mont St Aignan, France
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Boileau S, Illy N. Activation in anionic polymerization: Why phosphazene bases are very exciting promoters. Prog Polym Sci 2011. [DOI: 10.1016/j.progpolymsci.2011.05.005] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Casey BM, Flowers RA. On the nature of the oxidative heterocoupling of lithium enolates. J Am Chem Soc 2011; 133:11492-5. [PMID: 21721524 DOI: 10.1021/ja205017e] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The coupling of enolates through single-electron oxidation is one of the most direct routes for generating 1,4-dicarbonyls. Recent work on the intermolecular heterocoupling of equimolar amounts of two different enolates through single-electron oxidation has shown that synthetically useful yields beyond those predicted by statistics can be obtained. To determine the underlying basis for the selective formation of heterocoupled products, kinetic, (7)Li NMR, and synthetic studies were performed. The collection of data obtained from these experiments shows that the selective formation of heterocoupled products is a consequence of heteroaggregation of lithium enolates.
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Affiliation(s)
- Brian M Casey
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA
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Stern D, Finkelmeier N, Meindl K, Henn J, Stalke D. Consecutive donor-base exchange in anthracenyllithium compounds. Angew Chem Int Ed Engl 2010; 49:6869-72. [PMID: 20677300 DOI: 10.1002/anie.201002873] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel Stern
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
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Stern D, Finkelmeier N, Meindl K, Henn J, Stalke D. Schrittweiser Donorbasenaustausch in Anthracenyllithiumverbindungen. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201002873] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Moraleda D, Santelli M. Enantio-differentiating reactions of a racemic γ
-lactone enolate with chiral esters. A DFT investigation. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Skotnicka A, Kolehmainen E, Laihia K, Gawinecki R. NMR studies of benzoannulation in lithium, sodium and potassium ortho-formylphenolates. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2010.04.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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