1
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Medvedko S, Wagner JP. From Criegee to Breslow: How π-Donors Steer the Route of Olefin Ozonolysis. Chemistry 2024; 30:e202400026. [PMID: 38501221 DOI: 10.1002/chem.202400026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/16/2024] [Accepted: 03/19/2024] [Indexed: 03/20/2024]
Abstract
While π-bonds typically undergo cycloaddition with ozone, resulting in the release of much-noticed carbonyl O-oxide Criegee intermediates, lone-pairs of electrons tend to selectively accept a single oxygen atom from O3, producing singlet dioxygen. We questioned whether the introduction of potent electron-donating groups, akin to N-heterocyclic olefins, could influence the reactivity of double bonds - shifting from cycloaddition to oxygen atom transfer or generating lesser-known, yet stabilized, donor-substituted Criegee intermediates. Consequently, we conducted a comparative computational study using density functional theory on a series of model olefins with increasing polarity due to (asymmetric) π-donor substitution. Reaction path computations indicate that highly polarized double bonds, instead of forming primary ozonides in their reaction with O3, exhibit a preference for accepting a single oxygen atom, resulting in a zwitterionic species formally identified as a carbene-carbonyl adduct. This previously unexplored reactivity potentially introduces aldehyde umpolung chemistry (Breslow intermediate) through olefin ozonolysis. Considering solvent effects implicitly reveals that increased solvent polarity further directs the trajectories toward a single oxygen atom transfer reactivity by stabilizing the zwitterionic character of the transition state. The competing modes of chemical reactivity can be explained by a bifurcation of the reaction valley in the post-transition state region.
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Affiliation(s)
- Serhii Medvedko
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
- Department of Organic Chemistry, National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Peremohy Ave. 37, 03056, Kyiv, Ukraine
| | - J Philipp Wagner
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
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2
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Eitzinger A, Reitz J, Antoni PW, Mayr H, Ofial AR, Hansmann MM. Pushing the Upper Limit of Nucleophilicity Scales by Mesoionic N-Heterocyclic Olefins. Angew Chem Int Ed Engl 2023; 62:e202309790. [PMID: 37540606 DOI: 10.1002/anie.202309790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/06/2023]
Abstract
A series of mesoionic, 1,2,3-triazole-derived N-heterocyclic olefins (mNHOs), which have an extraordinarily electron-rich exocyclic CC-double bond, was synthesized and spectroscopically characterized, in selected cases by X-ray crystallography. The kinetics of their reactions with arylidene malonates, ArCH=C(CO2 Et)2 , which gave zwitterionic adducts, were investigated photometrically in THF at 20 °C. The resulting second-order rate constants k2 (20 °C) correlate linearly with the reported electrophilicity parameters E of the arylidene malonates (reference electrophiles), thus providing the nucleophile-specific N and sN parameters of the mNHOs according to the correlation lg k2 (20 °C)=sN (N+E). With 21
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Affiliation(s)
- Andreas Eitzinger
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 (Haus F), 81377, München, Germany
| | - Justus Reitz
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Patrick W Antoni
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Herbert Mayr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 (Haus F), 81377, München, Germany
| | - Armin R Ofial
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 (Haus F), 81377, München, Germany
| | - Max M Hansmann
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
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3
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G M, Sharma D, Dandela R, Dhayalan V. Synthetic Strategies of N-Heterocyclic Olefin (NHOs) and Their Recent Application of Organocatalytic Reactions and Beyond. Chemistry 2023:e202302106. [PMID: 37605950 DOI: 10.1002/chem.202302106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 08/23/2023]
Abstract
N-heterocyclic olefin (NHO) derivatives have an electron-rich as well as highly polarized carabon-carbon (C=C) double bond because of the electron-donating nature of nitrogen and sulphur atoms. While NHOs have been developing as novel organocatalysts and ligands for transition-metal complexes in various organic compound syntheses, different research groups are currently interested in preparing imidazole and triazolium-based chiral NHO catalysts. Some of them have been used for enantioselective organic transformations, but were still elusive. N-heterocyclic olefins, the alkylidene derivatives of N-heterocyclic carbenes (NHC), have shown promising results as effective promoters for numerous organic syntheses such as asymmetric catalysis, hydroborylation, hydrosilylation, reduction, CO2 sequestration, alkylation, cycloaddition, polymerization and the ring-opening reaction of aziridine and epoxides, esterification, C-F bond functionalization, amine coupling, trifluoromethyl thiolation, amination etc. NHOs catalysts with suitable structures can serve as a novel class of Lewis/Bronsted bases with strong basicity and high nucleophilicity properties.These facts strongly suggest their enormous chemical potential as sustainable catalysts for a wide variety of reactions in synthetic chemistry. The synthesis of NHOs and their properties are briefly reviewed in this article, along with a summary of the imidazole and triazole core of NHOs' most recent catalytic uses.
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Affiliation(s)
- Mahantesh G
- Department of Chemistry, National Institute of Technology Puducherry, Karaikal, 609609, Union Territory Puducherry, India
| | - Deepika Sharma
- Department of Industrial and Engineering Chemistry, Institute of Chemical Technology, Indian oil Odisha Campus, IIT, Kharagpur extension Centre Mouza Samantpuri, Bhubaneswar, 751013, Odisha, India
| | - Rambabu Dandela
- Department of Industrial and Engineering Chemistry, Institute of Chemical Technology, Indian oil Odisha Campus, IIT, Kharagpur extension Centre Mouza Samantpuri, Bhubaneswar, 751013, Odisha, India
| | - Vasudevan Dhayalan
- Department of Chemistry, National Institute of Technology Puducherry, Karaikal, 609609, Union Territory Puducherry, India
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4
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Reilly LT, McGraw ML, Eckstrom FD, Clarke RW, Franklin KA, Chokkapu ER, Cavallo L, Falivene L, Chen EYX. Compounded Interplay of Kinetic and Thermodynamic Control over Comonomer Sequences by Lewis Pair Polymerization. J Am Chem Soc 2022; 144:23572-23584. [PMID: 36521036 DOI: 10.1021/jacs.2c10568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The design of facile synthetic routes to well-defined block copolymers (BCPs) from direct polymerization of one-pot comonomer mixtures, rather than traditional sequential additions, is both fundamentally and technologically important. Such synthetic methodologies often leverage relative monomer reactivity toward propagating species exclusively and therefore are rather limited in monomer scope and control over copolymer structure. The recently developed compounded sequence control (CSC) by Lewis pair polymerization (LPP) utilizes synergistically both thermodynamic (Keq) and kinetic (kp) differentiation to precisely control BCP sequences and suppress tapering and misincorporation errors. Here, we present an in-depth study of CSC by LPP, focusing on the complex interplay of the fundamental Keq and kp parameters, which enable the unique ability of CSC-LPP to precisely control comonomer sequences across a variety of polar vinyl monomer classes. Individual Lewis acid equilibrium and polymerization rate parameters of a range of commercially relevant monomers were experimentally quantified, computationally validated, and rationalized. These values allowed for the judicious design of copolymerizations which probed multiple hypotheses regarding the constructive vs conflicting nature of the relationship between Keq and kp biases, which arise during CSC-LPP of comonomer mixtures. These relationships were thoroughly explored and directly correlated with resultant copolymer microstructures. Several examples of higher-order BCPs are presented, further demonstrating the potential for materials innovation offered by this methodology.
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Affiliation(s)
- Liam T Reilly
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Michael L McGraw
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Francesca D Eckstrom
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Ryan W Clarke
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Kevin A Franklin
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Eswara Rao Chokkapu
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Luigi Cavallo
- Physical Sciences and Engineering Division, KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Laura Falivene
- Dipartimento di Chimica e Biologia, Università di Salerno, Via Papa Paolo Giovanni II, 84100 Fisciano, SA, Italy
| | - Eugene Y-X Chen
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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5
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Wang S, Zhang C, Li D, Zhou Y, Su Z, Feng X, Dong S. New chiral N-heterocyclic olefin bifunctional organocatalysis in α-functionalization of β-ketoesters. Sci China Chem 2022. [DOI: 10.1007/s11426-022-1458-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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6
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Wanjari PJ, Saha N, Dubey G, Bharatam PV. Metal-free methods for the generation of benzimidazoles and 2-aminobenzimidazoles. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.133143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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7
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Watson I, Zhou Y, Ferguson M, Rivard E. Group 4 Transition Metal Complexes with Anionic N‐Heterocyclic Olefin Ligands. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | | | | | - Eric Rivard
- University of Alberta Deptm. of Chemistry 11227 Saskatchewan Dr. T6G 2G2 Edmonton CANADA
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8
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Pirouzi F, Eshghi H, Sabet-Sarvestani H. A theoretical approach to investigating the mechanism of action and efficiency of N-heterocyclic olefins as organic catalysts for transesterification reactions. NEW J CHEM 2022. [DOI: 10.1039/d1nj05589e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For the first time, it is theoretically proved that carbonyl ester reactions with alcohols can be facilitated by activation of fully-planar NHOs via zwitterionic species.
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Affiliation(s)
- Fatemeh Pirouzi
- Computational Chemistry Research Lab., Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hossein Eshghi
- Computational Chemistry Research Lab., Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hossein Sabet-Sarvestani
- Computational Chemistry Research Lab., Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
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9
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Guthardt R, Mellin J, Bruhn C, Siemeling U. 1,1′‐Ferrocenylene‐Bridged Bis(N‐Heterocyclic Olefin) Derivatives. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Robin Guthardt
- Institut für Chemie Universität Kassel Heinrich-Plett-Straße 40 34132 Kassel Germany
| | - Johanna Mellin
- Institut für Chemie Universität Kassel Heinrich-Plett-Straße 40 34132 Kassel Germany
| | - Clemens Bruhn
- Institut für Chemie Universität Kassel Heinrich-Plett-Straße 40 34132 Kassel Germany
| | - Ulrich Siemeling
- Institut für Chemie Universität Kassel Heinrich-Plett-Straße 40 34132 Kassel Germany
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10
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Watson IC, Ferguson MJ, Rivard E. Zinc-Mediated Transmetalation as a Route to Anionic N-Heterocyclic Olefin Complexes in the p-Block. Inorg Chem 2021; 60:18347-18359. [PMID: 34738790 DOI: 10.1021/acs.inorgchem.1c02961] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Anionic N-heterocyclic olefins (aNHOs) are suited well for the stabilization of low-coordinate inorganic complexes, due to their steric tunability and strong σ- and π-electron donating abilities. In this study, the new two-coordinate zinc complex (MeIPrCH)2Zn (MeIPrCH = [(MeCNDipp)2C═CH]-, Dipp = 2,6-diisopropylphenyl) is shown to participate in a broad range of metathesis reactions with main group element-based halides and hydrides. In the case of the group 14 halides, Cl2E·dioxane (E = Ge and Sn), transmetalation occurs to form dinuclear propellane-shaped cations, [(MeIPrCHE)2(μ-Cl)]+, while the aNHO-capped phosphine ligand MeIPrCH-PPh2 is obtained when (MeIPrCH)2Zn is combined with ClPPh2. Lastly, ZnH2 elimination drives transmetalation between (MeIPrCH)2Zn and hydroboranes and hydroalumanes, leading to Lewis acidic aNHO-supported -boryl and -alane products.
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Affiliation(s)
- Ian C Watson
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada, T6G 2G2
| | - Michael J Ferguson
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada, T6G 2G2
| | - Eric Rivard
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada, T6G 2G2
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11
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Liang Q, Hayashi K, Li L, Song D. Dioxygenation of unprotected mesoionic N-heterocyclic olefins. Chem Commun (Camb) 2021; 57:10927-10930. [PMID: 34596194 DOI: 10.1039/d1cc04695k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We report the dioxygenation of mesoionic N-heterocyclic olefins (mNHOs) using molecular dioxygen. For 1,2,3-triazole-derived mNHOs possessing a vinyl proton and at least one acidic C-H group, they are oxidized into the corresponding triazolium benzoate salts, whereas those without vinyl proton or an acidic C-H group are oxidized into triazolium oxide and ketones/aldehydes.
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Affiliation(s)
- Qiuming Liang
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Kasumi Hayashi
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Longfei Li
- College of Pharmacy, Hebei University, Baoding 071002, Hebei, P. R. China
| | - Datong Song
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
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12
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Liang Q, Hayashi K, Zeng Y, Jimenez-Santiago JL, Song D. Constructing fused N-heterocycles from unprotected mesoionic N-heterocyclic olefins and organic azides via diazo transfer. Chem Commun (Camb) 2021; 57:6137-6140. [PMID: 34042131 DOI: 10.1039/d1cc02245h] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mesoionic N-heterocyclic olefins (mNHOs) were first reported last year and their reactivity remains largely unexplored. Herein we report the reaction of unprotected mNHOs and organic azides as a novel synthetic route to a variety of pyrazolo[3,4-d][1,2,3]triazoles, an important structural motif in drug candidates and energetic materials. The only byproduct aniline can be easily recycled and converted back to the starting organic azide, in compliance with the green chemistry principle. The reaction mechanism has been explored through experimental and computational studies.
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Affiliation(s)
- Qiuming Liang
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Kasumi Hayashi
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Yimin Zeng
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Jose L Jimenez-Santiago
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Datong Song
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
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13
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Li Z, Ji P, Cheng JP. Brönsted Basicities and Nucleophilicities of N-Heterocyclic Olefins in Solution: N-Heterocyclic Carbene versus N-Heterocyclic Olefin. Which Is More Basic, and Which Is More Nucleophilic? J Org Chem 2021; 86:2974-2985. [PMID: 33464082 DOI: 10.1021/acs.joc.0c02838] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A Brönsted basicity scale comprising nine representative N-heterocyclic olefins (NHOs) was established by measuring the equilibrium acidities of their corresponding precursors in DMSO using an ultraviolet-visible spectroscopic method. The basicities (pKaHs) of the investigated NHOs cover a range from 14.7 to 24.1. The basicities of unsaturated NHOs are stronger than those of their N-heterocyclic carbene (NHC) analogues; however, the basicities for the saturated ones are much weaker than those of their NHC analogues, which is largely due to the aromatization effect that intrinsically influences the acidic dissociations of NHC and NHO precursors. The nucleophilicities of four NHOs were measured photometrically by monitoring the kinetics of reactions of these NHOs with common reference electrophiles for quantifying nucleophilic reactivities. In general, the nucleophilicity of the NHOs is much stronger than that of commonly used Lewis bases such as Ph3P or DMAP [4-(dimethylamino)pyridine] but weaker than that of their NHC analogues; however, caution should be taken when generalizing this conclusion to a wide range of electrophiles with distinctively electronic and structural properties.
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Affiliation(s)
- Zhen Li
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Pengju Ji
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jin-Pei Cheng
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China.,State Key Laboratory of Elemento-organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
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14
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Balint A, Naumann S. A comparison of zwitterionic and anionic mechanisms in the dual-catalytic polymerization of lactide. Polym Chem 2021. [DOI: 10.1039/d1py00992c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Two different polymerization mechanisms for lactide are selectivity addressed to illuminate the respective role of organobase and Lewis acid component.
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Affiliation(s)
- Alexander Balint
- University of Stuttgart, Institute of Polymer Chemistry, 70569 Stuttgart, Germany
| | - Stefan Naumann
- University of Stuttgart, Institute of Polymer Chemistry, 70569 Stuttgart, Germany
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15
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Zhou L, Wang Z, Xu G, Lv C, Wang Q. Structure and activity relationship studies of N-heterocyclic olefin and thiourea/urea catalytic systems: application in ring-opening polymerization of lactones. Polym Chem 2021. [DOI: 10.1039/d0py01747g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structure–activity relationship studies of N-heterocyclic olefin and thiourea/urea catalytic systems were performed and applied to ROP of lactones.
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Affiliation(s)
- Li Zhou
- Key Laboratory of Biobased Materials
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao
- China
| | - Zhenyu Wang
- Key Laboratory of Biobased Materials
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao
- China
| | - Guangqiang Xu
- Key Laboratory of Biobased Materials
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao
- China
| | - Chengdong Lv
- Key Laboratory of Biobased Materials
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao
- China
| | - Qinggang Wang
- Key Laboratory of Biobased Materials
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao
- China
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16
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Vogler C, Naumann S. A simplified approach for the metal-free polymerization of propylene oxide. RSC Adv 2020; 10:43389-43393. [PMID: 35519681 PMCID: PMC9058424 DOI: 10.1039/d0ra08970b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 11/23/2020] [Indexed: 12/05/2022] Open
Abstract
Triethyl borane (Et3B), in combination with phosphazene-type superbases, has recently emerged as a powerful co-catalyst for the anionic polymerization of epoxides. Here, it is demonstrated that the monomer-activating property of Et3B can also compensate for the application of much gentler organobases. This not only results in simpler setups, but also significantly reduces nucleophilicity/basicity-derived side reactions. Notably, this principle applies to such a degree that simple 4-dimethylaminopyridine (DMAP) or 1,4-diazabicyclo[2.2.2]octane (DABCO) can serve to polymerize propylene oxide (PO). With suitable initiators, this results for example in very well-defined block copolyethers (ÐM ≤ 1.03) without requiring work-up to remove side products such as PPO homopolymer. Performance correlates nicely with the corresponding organobase proton affinities (PAs), and a limiting PA of 220–230 kcal mol−1 was identified for successful PO polymerization. Mild organobases and Et3B constitute an operationally simple, user-friendly catalyst setup for polymerizing propylene oxide.![]()
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Affiliation(s)
- Charlotte Vogler
- University of Stuttgart, Institute of Polymer Chemistry 70569 Stuttgart Germany
| | - Stefan Naumann
- University of Stuttgart, Institute of Polymer Chemistry 70569 Stuttgart Germany
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17
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Affiliation(s)
- Qiuming Liang
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Kasumi Hayashi
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Datong Song
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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18
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Zhou L, Wang Z, Xu G, Yang R, Yan H, Hao XQ, Wang Q. N-heterocyclic olefins catalyzed ring-opening polymerization of N-tosyl aziridines. Eur Polym J 2020. [DOI: 10.1016/j.eurpolymj.2020.110046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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19
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Wang Z, Niu QH, Xue XS, Ji P. The Brönsted Basicities of N-Heterocyclic Olefins in DMSO: An Effective Way to Evaluate the Stability of NHO-CO 2 Adducts. J Org Chem 2020; 85:13204-13210. [PMID: 32900190 DOI: 10.1021/acs.joc.0c01987] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A Brönsted basicity scale (∼24 pK units) for 85 commonly seen imidazole-, imidazoline-, triazole-, and thiazole-based N-heterocyclic olefins (NHOs) in DMSO was established using a well-examined computational model. The influence of substituents on the Brönsted basicities of these NHOs was investigated through basicity comparisons and rationalized by geometric analyses. The Gibbs energy (ΔGr) of the reaction between NHO and CO2 was also calculated, which linearly correlates with the basicity of the corresponding NHO, suggesting that the stability of NHO-CO2 adducts can be evaluated by the basicity of NHOs and a stronger basicity leads to a more stable NHO-CO2 adduct.
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Affiliation(s)
- Zhen Wang
- Henan Joint International Research Laboratory of Nanocomposite Sensing Materials, School of Chemical and Environmental Engineering, Anyang Institute of Technology, Anyang 455000, China
| | - Qian-Hang Niu
- Henan Joint International Research Laboratory of Nanocomposite Sensing Materials, School of Chemical and Environmental Engineering, Anyang Institute of Technology, Anyang 455000, China
| | - Xiao-Song Xue
- Henan Joint International Research Laboratory of Nanocomposite Sensing Materials, School of Chemical and Environmental Engineering, Anyang Institute of Technology, Anyang 455000, China.,State Key Laboratory on Elemento-Organic Chemistry, Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Pengju Ji
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
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20
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Gulia N, Pigulski B, Szafert S. Base‐Promoted Double Amination of 1‐Haloalkynes: Direct Synthesis of Ene‐1,1‐diamines. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Nurbey Gulia
- Faculty of Chemistry University of Wrocław 14 F. Joliot‐Curie 50‐383 Wrocław Poland
| | - Bartłomiej Pigulski
- Faculty of Chemistry University of Wrocław 14 F. Joliot‐Curie 50‐383 Wrocław Poland
| | - Sławomir Szafert
- Faculty of Chemistry University of Wrocław 14 F. Joliot‐Curie 50‐383 Wrocław Poland
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21
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Delaude L. The Chemistry of Azolium‐Carboxylate Zwitterions and Related Compounds: a Survey of the Years 2009–2020. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000639] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Lionel Delaude
- Laboratory of CatalysisMolSys Research UnitInstitut de Chimie Organique (B6a)Université de Liège Allée du six Août 13 4000 Liège Belgium
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Affiliation(s)
- Michael L. McGraw
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Eugene Y.-X. Chen
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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23
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Hansmann MM, Antoni PW, Pesch H. Stable Mesoionic N-Heterocyclic Olefins (mNHOs). Angew Chem Int Ed Engl 2020; 59:5782-5787. [PMID: 31863704 PMCID: PMC7154647 DOI: 10.1002/anie.201914571] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 12/16/2019] [Indexed: 01/07/2023]
Abstract
We report a new class of stable mesoionic N-heterocyclic olefins, featuring a highly polarized (strongly ylidic) double bond. The ground-state structure cannot be described through an uncharged mesomeric Lewis-structure, thereby structurally distinguishing them from traditional N-heterocyclic olefins (NHOs). mNHOs can easily be obtained through deprotonation of the corresponding methylated N,N'-diaryl-1,2,3-triazolium and N,N'-diaryl-imidazolium salts, respectively. In their reactivity, they represent strong σ-donor ligands as shown by their coordination complexes of rhodium and boron. Their calculated proton affinities, their experimentally derived basicities (competition experiments), as well as donor abilities (Tolman electronic parameter; TEP) exceed the so far reported class of NHOs.
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Affiliation(s)
- Max M. Hansmann
- Fakultät für Chemie und Chemische BiologieTechnische Universität DortmundOtto-Hahn-Str. 644227DortmundGermany
- Georg-August Universität GöttingenInstitut für Organische und Biomolekulare ChemieTammannstr. 237077GöttingenGermany
| | - Patrick W. Antoni
- Georg-August Universität GöttingenInstitut für Organische und Biomolekulare ChemieTammannstr. 237077GöttingenGermany
| | - Henner Pesch
- Georg-August Universität GöttingenInstitut für Organische und Biomolekulare ChemieTammannstr. 237077GöttingenGermany
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24
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de Lima Batista AP, de Oliveira-Filho AGS, Braga AAC. Probing N-heterocyclic olefin as ancillary ligand in scandium-mediated $$\hbox {CO}_2$$ to CO conversion. Theor Chem Acc 2020. [DOI: 10.1007/s00214-019-2528-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Hansmann MM, Antoni PW, Pesch H. Stable Mesoionic N‐Heterocyclic Olefins (mNHOs). Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914571] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Max M. Hansmann
- Fakultät für Chemie und Chemische Biologie Technische Universität Dortmund Otto-Hahn-Str. 6 44227 Dortmund Germany
- Georg-August Universität Göttingen Institut für Organische und Biomolekulare Chemie Tammannstr. 2 37077 Göttingen Germany
| | - Patrick W. Antoni
- Georg-August Universität Göttingen Institut für Organische und Biomolekulare Chemie Tammannstr. 2 37077 Göttingen Germany
| | - Henner Pesch
- Georg-August Universität Göttingen Institut für Organische und Biomolekulare Chemie Tammannstr. 2 37077 Göttingen Germany
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26
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Markus F, Bruckner JR, Naumann S. Controlled Synthesis of “Reverse Pluronic”‐Type Block Copolyethers with High Molar Masses for the Preparation of Hydrogels with Improved Mechanical Properties. MACROMOL CHEM PHYS 2020. [DOI: 10.1002/macp.201900437] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Felix Markus
- Institute of Polymer ChemistryUniversity of Stuttgart 70569 Stuttgart Germany
| | - Johanna R. Bruckner
- Institute of Physical ChemistryUniversity of Stuttgart 70569 Stuttgart Germany
| | - Stefan Naumann
- Institute of Polymer ChemistryUniversity of Stuttgart 70569 Stuttgart Germany
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27
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Naumann S. Synthesis, properties & applications of N-heterocyclic olefins in catalysis. Chem Commun (Camb) 2019; 55:11658-11670. [PMID: 31517349 DOI: 10.1039/c9cc06316a] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
N-Heterocyclic olefins (NHOs), a recently (re-)discovered type of electron-rich, polar alkene, are comprehensively presented. Along with synthetic aspects and chemical properties, special emphasis is put on the multi-faceted impact NHOs already have had on catalysis. This is discussed along the lines of small molecule organocatalysis, organo- and metal-assisted polymerization and of the understanding and application of NHO-ligated organometallic complexes. Highlighted are the strong basicity of NHOs ("superbases"), their high nucleophilicity and the design principles to tailor NHO (organo-)catalysts. It is demonstrated that NHOs can complement, and in many cases out-perform, the much better established N-heterocyclic carbene-based systems. Examples include among others CO2-sequestration, the polymerization of lactones and epoxides or the transfer hydrogenation of carbonyls. Further, the unique ability to selectively address basic or nucleophilic reaction pathways via NHO-mediation is detailed, as is the bonding situation in NHO-metal complexes and the ability of the olefin to act as an electronically flexible ligand.
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Affiliation(s)
- Stefan Naumann
- University of Stuttgart, Institute of Polymer Chemistry, 70569 Stuttgart, Germany.
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28
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Zhang X, Wang L, Wang Q, Ge F, Wang X. Synthesis, Characterization of Pyridyl Heterocyclic Olefins (PHOs) and Activation of Heterocumulenes. ChemistrySelect 2019. [DOI: 10.1002/slct.201902563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Xianhui Zhang
- Key Laboratory of Biobased MaterialsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of Sciences 189 Songling Road Qingdao 266101 China
- Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Sciences Beijing 10049 China
| | - Liang Wang
- Key Laboratory of Biobased MaterialsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of Sciences 189 Songling Road Qingdao 266101 China
| | - Qinggang Wang
- Key Laboratory of Biobased MaterialsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of Sciences 189 Songling Road Qingdao 266101 China
| | - Fang Ge
- College of Chemistry and Chemical EngineeringQingdao University Shandong 266071 China
| | - Xiaowu Wang
- Key Laboratory of Biobased MaterialsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of Sciences 189 Songling Road Qingdao 266101 China
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29
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Walther P, Krauß A, Naumann S. Lewis Pair Polymerization of Epoxides via Zwitterionic Species as a Route to High-Molar-Mass Polyethers. Angew Chem Int Ed Engl 2019; 58:10737-10741. [PMID: 31099454 DOI: 10.1002/anie.201904806] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Indexed: 11/08/2022]
Abstract
A dual catalytic setup based on N-heterocyclic olefins (NHOs) and magnesium bis(hexamethyldisilazide) (Mg(HMDS)2 ) was used to prepare poly(propylene oxide) with a molar mass (Mn ) >500 000 g mol-1 , in some cases even >106 g mol-1 , as determined by GPC/light scattering. This is achieved by combining the rapid polymerization characteristics of a zwitterionic, Lewis pair type mechanism with the efficient epoxide activation by the MgII species. Transfer-to-monomer, traditionally frustrating attempts at synthesizing polyethers with a high degree of polymerization, is practically removed as a limiting factor by this approach. NMR and MALDI-ToF MS experiments reveal key aspects of the proposed mechanism, whereby the polymerization is initiated via nucleophilic attack by the NHO on the activated monomer, generating a zwitterionic species. This strategy can also be extended to other epoxides, including functionalized monomers.
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Affiliation(s)
- Patrick Walther
- Institute of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Annabelle Krauß
- Institute of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Stefan Naumann
- Institute of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
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30
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Walther P, Krauß A, Naumann S. Darstellung von hochmolekularen Polyethern durch die zwitterionische Lewis‐Paar‐Polymerisation von Epoxiden. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201904806] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Patrick Walther
- Institut für PolymerchemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Annabelle Krauß
- Institut für PolymerchemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Stefan Naumann
- Institut für PolymerchemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
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31
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Watson IC, Schumann A, Yu H, Davy EC, McDonald R, Ferguson MJ, Hering‐Junghans C, Rivard E. N‐Heterocyclic Olefin‐Ligated Palladium(II) Complexes as Pre‐Catalysts for Buchwald–Hartwig Aminations. Chemistry 2019; 25:9678-9690. [DOI: 10.1002/chem.201901376] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Ian C. Watson
- Department of ChemistryUniversity of Alberta 11227 Saskatchewan Drive Edmonton Alberta T6G 2G2 Canada
| | - André Schumann
- Leibniz Institute for CatalysisUniversity of Rostock Albert Einstein Strasse 29a 18059 Rostock Germany
| | - Haoyang Yu
- Department of ChemistryUniversity of Alberta 11227 Saskatchewan Drive Edmonton Alberta T6G 2G2 Canada
| | - Emma C. Davy
- Department of Physical SciencesQuest University 3200 University Boulevard Squamish British Columbia V8B 0N8 Canada
| | - Robert McDonald
- Department of ChemistryUniversity of Alberta 11227 Saskatchewan Drive Edmonton Alberta T6G 2G2 Canada
| | - Michael J. Ferguson
- Department of ChemistryUniversity of Alberta 11227 Saskatchewan Drive Edmonton Alberta T6G 2G2 Canada
| | - Christian Hering‐Junghans
- Leibniz Institute for CatalysisUniversity of Rostock Albert Einstein Strasse 29a 18059 Rostock Germany
| | - Eric Rivard
- Department of ChemistryUniversity of Alberta 11227 Saskatchewan Drive Edmonton Alberta T6G 2G2 Canada
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32
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Kim Y, Liu LL, Stephan DW. N-Heterocyclic Carbene Derived 3-Azabutadiene as a π-Base in Classic and Frustrated Lewis Pair Chemistry. Chemistry 2019; 25:7110-7113. [PMID: 30968983 DOI: 10.1002/chem.201901609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Indexed: 11/05/2022]
Abstract
N-Heterocyclic carbene (NHC) derived 3-azabutadienes 1 and 2 have been prepared by a single-step reaction of the corresponding NHC with cyclohexyl isocyanide. Compound 1 features π-basic, delocalized nucleophilic sites over the 3-azabutadiene moiety, therefore allowing for coordinating with small Lewis acids, such as AlCl3 , GaCl3 , and Me2 SAuCl, to form diverse classic Lewis adducts 3-5. Combination of 1 with B(C6 F5 )3 or [Ph3 C][B(C6 F5 )4 ] resulted in single-electron transfer and the obtained radical cation was detected by EPR. In addition, a frustrated Lewis pair comprised of the π-basic 1 and BPh3 effects the splitting of the O-H bond of phenol and the N-H bond of imidazole to give 7 and 8, respectively. An intrinsic bond orbital (IBO) analysis of the pathway leading to 8 showcases the transformation of the delocalized π-electrons of 1 to a newly formed C-H localized σ-bond.
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Affiliation(s)
- Youngsuk Kim
- Department of Chemistry, University of Toronto, 80 St. George St. Toronto, Ontario, M5S3H6, Canada.,Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Liu Leo Liu
- Department of Chemistry, University of Toronto, 80 St. George St. Toronto, Ontario, M5S3H6, Canada
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto, 80 St. George St. Toronto, Ontario, M5S3H6, Canada
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33
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de Lima Batista AP, S. de Oliveira-Filho AG, Braga AAC. Unveiling the potential of scandium complexes for methane C–H bond activation: a computational study. NEW J CHEM 2019. [DOI: 10.1039/c9nj02760b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Sc(i) complexes activate methane C–H bonds under mild conditions.
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Affiliation(s)
| | | | - Ataualpa A. C. Braga
- Departamento de Química Fundamental
- Instituto de Química
- Universidade de São Paulo
- São Paulo-SP
- Brazil
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