1
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Svatunek D. Computational Organic Chemistry: The Frontier for Understanding and Designing Bioorthogonal Cycloadditions. Top Curr Chem (Cham) 2024; 382:17. [PMID: 38727989 PMCID: PMC11087259 DOI: 10.1007/s41061-024-00461-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 04/06/2024] [Indexed: 05/13/2024]
Abstract
Computational organic chemistry has become a valuable tool in the field of bioorthogonal chemistry, offering insights and aiding in the progression of this branch of chemistry. In this review, I present an overview of computational work in this field, including an exploration of both the primary computational analysis methods used and their application in the main areas of bioorthogonal chemistry: (3 + 2) and [4 + 2] cycloadditions. In the context of (3 + 2) cycloadditions, detailed studies of electronic effects have informed the evolution of cycloalkyne/1,3-dipole cycloadditions. Through computational techniques, researchers have found ways to adjust the electronic structure via hyperconjugation to enhance reactions without compromising stability. For [4 + 2] cycloadditions, methods such as distortion/interaction analysis and energy decomposition analysis have been beneficial, leading to the development of bioorthogonal reactants with improved reactivity and the creation of orthogonal reaction pairs. To conclude, I touch upon the emerging fields of cheminformatics and machine learning, which promise to play a role in future reaction discovery and optimization.
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Affiliation(s)
- Dennis Svatunek
- Institute of Applied Synthetic Chemistry, Technische Universität Wien (TU Wien), Getreidemarkt 9, 1060, Vienna, Austria.
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2
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Zhu Q, Chen S, Chen D, Lin L, Xiao K, Zhao L, Solà M, Zhu J. The application of aromaticity and antiaromaticity to reaction mechanisms. FUNDAMENTAL RESEARCH 2023; 3:926-938. [PMID: 38933008 PMCID: PMC11197727 DOI: 10.1016/j.fmre.2023.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/31/2023] [Accepted: 04/24/2023] [Indexed: 06/28/2024] Open
Abstract
Aromaticity, in general, can promote a given reaction by stabilizing a transition state or a product via a mobility of π electrons in a cyclic structure. Similarly, such a promotion could be also achieved by destabilizing an antiaromatic reactant. However, both aromaticity and transition states cannot be directly measured in experiment. Thus, computational chemistry has been becoming a key tool to understand the aromaticity-driven reaction mechanisms. In this review, we will analyze the relationship between aromaticity and reaction mechanism to highlight the importance of density functional theory calculations and present it according to an approach via either aromatizing a transition state/product or destabilizing a reactant by antiaromaticity. Specifically, we will start with a particularly challenging example of dinitrogen activation followed by other small-molecule activation, C-F bond activation, rearrangement, as well as metathesis reactions. In addition, antiaromaticity-promoted dihydrogen activation, CO2 capture, and oxygen reduction reactions will be also briefly discussed. Finally, caution must be cast as the magnitude of the aromaticity in the transition states is not particularly high in most cases. Thus, a proof of an adequate electron delocalization rather than a complete ring current is recommended to support the relatively weak aromaticity in these transition states.
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Affiliation(s)
- Qin Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- Key Laboratory for Organic Electronics & Information Displays (KLOEID) and Institute of Advanced Materials (IAM), SICAM, Nanjing University of Posts & Telecommunications, Nanjing 210023, China
| | - Shuwen Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Dandan Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Lu Lin
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Kui Xiao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Liang Zhao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Miquel Solà
- Institute of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, C/ M. Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen 518172, China
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3
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Levandowski BJ, Abularrage NS, Graham BJ, Raines RT. Computational study of an oxetane 4 H-pyrazole as a Diels-Alder diene. Tetrahedron Lett 2023; 130:154768. [PMID: 37860707 PMCID: PMC10584014 DOI: 10.1016/j.tetlet.2023.154768] [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] [Indexed: 10/21/2023]
Abstract
We combine the effects of spirocyclization and hyperconjugation to increase the Diels-Alder reactivity of the 4H-pyrazole scaffold. A density functional theory (DFT) investigation predicts that 4H-pyrazoles containing an oxetane functionality at the saturated center are extremely reactive despite having a relatively high-lying lowest unoccupied molecular orbital (LUMO) energy.
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Affiliation(s)
- Brian J. Levandowski
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA
| | - Nile S. Abularrage
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA
| | - Brian J. Graham
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA
| | - Ronald T. Raines
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA
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4
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Abularrage NS, Levandowski BJ, Giancola JB, Graham BJ, Raines RT. Bioorthogonal 4 H-pyrazole "click" reagents. Chem Commun (Camb) 2023; 59:4451-4454. [PMID: 36987784 PMCID: PMC10088812 DOI: 10.1039/d3cc00112a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/07/2023] [Indexed: 03/30/2023]
Abstract
4H-Pyrazoles are emerging as useful click reagents. Fluorinating the saturated center enables 4H-pyrazoles to react rapidly as Diels-Alder dienes without a catalyst but compromises the stability of these dienes under physiological conditions. To identify more stable 4H-pyrazoles for bioorthogonal chemistry applications, we investigated the Diels-Alder reactivity and biological stability of three 4-oxo-substituted 4H-pyrazoles. We found that these dienes undergo rapid Diels-Alder reactions with endo-bicyclo[6.1.0]non-4-yne (BCN) while being much more stable to biological nucleophiles than their fluorinated counterparts. We attribute the rapid Diels-Alder reactivity of the optimal oxygen-substituted pyrazole to a combination of antiaromaticity, predistortion, and spirocyclization. Their reactivity and stability suggest that 4-oxo-4H-pyrazoles can be useful bioorthogonal reagents.
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Affiliation(s)
- Nile S Abularrage
- Department of Chemistry, Massachusetts institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Brian J Levandowski
- Department of Chemistry, Massachusetts institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - JoLynn B Giancola
- Department of Chemistry, Massachusetts institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Brian J Graham
- Department of Chemistry, Massachusetts institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Ronald T Raines
- Department of Chemistry, Massachusetts institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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5
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Chen S, Zhu J. Probing the Hyperconjugative Aromaticity of Cyclopentadiene and Pyrroliums Containing Group 7 Transition Metal Substituents. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shuwen Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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6
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Sengupta A, Li B, Svatunek D, Liu F, Houk KN. Cycloaddition Reactivities Analyzed by Energy Decomposition Analyses and the Frontier Molecular Orbital Model. Acc Chem Res 2022; 55:2467-2479. [PMID: 36007242 DOI: 10.1021/acs.accounts.2c00343] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
This Account describes our quest to understand and predict organic reactivity, a principal goal of physical and theoretical organic chemistry. The focus is on the development and testing of models for the prediction of cycloaddition reactivities and selectivities. We describe the involvement of the Houk group, and other groups, in the evolution of theoretical models that can achieve ever greater accuracy as well as provide practical heuristic models for understanding and prediction.Is the venerable frontier molecular orbital (FMO) model, the basis of Kenichi Fukui's 1981 Nobel Prize, still useful, or must it be replaced with more advanced models? In particular, models such as Conceptual Density Functional, the Pauli Exclusion Model, and the recent popularity of Electrostatic Potential Plots and Dispersion Energies have not only added to our understanding, but they have also created uncertainty about whether the simple FMO heuristic model has a place in 21st century discussions. This Account addresses this issue and asserts the value of the FMO model.Beginning with brief descriptions of selected models for cycloaddition reactivity starting with early donor-acceptor (nucleophile-electrophile) charge-transfer concepts, this Account reviews Fukui's frontier molecular orbital model, Salem and Klopman's orbital, electrostatic and Pauli repulsion model, the conceptual DFT model by Parr and later by Domingo and others, the recent Houk and Bickelhaupt Distortion/Interaction Activation Strain model, and the Bickelhaupt-Hamlin's Pauli-repulsion lowering model.Computations and analyses of four well-studied Diels-Alder cycloadditions, both normal and inverse electron-demand types, are presented. Most were studied earlier in our published work but are presented here with new insights from calculations with modern methods. Depending on the types of substrates (cycloaddends), the dominant factors controlling reactivity can be orbital interactions, electrostatics and polarization, or Pauli repulsion and dispersion effects, or a combination of all of these.By comparing orbital interactions, especially the frontier molecular orbital interactions, with the other factors that influence reactivity, we show why the FMO model is such a powerful─and theoretically meaningful─heuristic for understanding and predicting reactivity. We also present a method to understand Pauli repulsion effects on activation barriers, ρ(1.1). The use of a new reaction coordinate, the extent of Pauli repulsion along the reaction path, is advocated to emphasize the role of repulsive occupied orbital interactions on reactivity.Fukui's frontier molecular orbital model is effective because FMO interactions parallel all the quantities that influence reactivity. The FMO model continues to provide a practical model to understand and guide experiments.
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Affiliation(s)
- Arkajyoti Sengupta
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90095, California, United States
| | - Bo Li
- Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, China
| | - Dennis Svatunek
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90095, California, United States
| | - Fang Liu
- College of Sciences, Nanjing Agricultural University, Nanjing 210024, Jiangsu, China
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90095, California, United States
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7
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El Bakouri O, Szczepanik DW, Jorner K, Ayub R, Bultinck P, Solà M, Ottosson H. Three-Dimensional Fully π-Conjugated Macrocycles: When 3D-Aromatic and When 2D-Aromatic-in-3D? J Am Chem Soc 2022; 144:8560-8575. [PMID: 35523019 PMCID: PMC9121391 DOI: 10.1021/jacs.1c13478] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
![]()
Several fully π-conjugated
macrocycles with puckered or cage-type
structures were recently found to exhibit aromatic character according
to both experiments and computations. We examine their electronic
structures and put them in relation to 3D-aromatic molecules (e.g., closo-boranes) and to 2D-aromatic
polycyclic aromatic hydrocarbons. Using qualitative theory combined
with quantum chemical calculations, we find that the macrocycles explored
hitherto should be described as 2D-aromatic with three-dimensional
molecular structures (abbr. 2D-aromatic-in-3D) and not as truly 3D-aromatic.
3D-aromatic molecules have highly symmetric structures (or nearly
so), leading to (at least) triply degenerate molecular orbitals, and
for tetrahedral or octahedral molecules, an aromatic closed-shell
electronic structure with 6n + 2 electrons. Conversely,
2D-aromatic-in-3D structures exhibit aromaticity that results from
the fulfillment of Hückel’s 4n + 2
rule for each macrocyclic path, yet their π-electron counts
are coincidentally 6n + 2 numbers for macrocycles
with three tethers of equal lengths. It is notable that 2D-aromatic-in-3D
macrocyclic cages can be aromatic with tethers of different lengths, i.e., with π-electron counts different from 6n + 2, and they are related to naphthalene. Finally, we
identify tetrahedral and cubic π-conjugated molecules that fulfill
the 6n + 2 rule and exhibit significant electron
delocalization. Yet, their properties resemble those of analogous
compounds with electron counts that differ from 6n + 2. Thus, despite the fact that these molecules show substantial
π-electron delocalization, they cannot be classified as true
3D-aromatics.
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Affiliation(s)
- Ouissam El Bakouri
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden.,Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain
| | - Dariusz W Szczepanik
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain.,K. Guminski Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, Kraków 30-387, Poland
| | - Kjell Jorner
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
| | - Rabia Ayub
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
| | - Patrick Bultinck
- Department of Chemistry, Ghent University, Krijgslaan 281 S3, Gent 9000, Belgium
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain
| | - Henrik Ottosson
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
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8
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Ito S, Ishii Y, Kuwabara T. Inorganic salt-assisted assembly of anionic π-conjugated rings enabling 7Li NMR-based evaluation of antiaromaticity. Dalton Trans 2022; 51:16397-16402. [DOI: 10.1039/d2dt02649j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A cluster composed of three dilithium dibenzosilepinides and two Li2O molecules showed downfield shifted 7Li{1H} NMR signals (δ = 6.3, 4.4) due to the paratropic ring currents of the dianionic dibenzosilepins.
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Affiliation(s)
- Shotaro Ito
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Youichi Ishii
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Takuya Kuwabara
- Department of Chemistry and Biochemistry, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1, Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
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9
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Zhao F, Yu P, Chen Y, Liu F, Houk KN. π-Facial Stereoselectivity in Acyl Nitroso Cycloadditions to 5,5-Unsymmetrically Substituted Cyclopentadienes: Computational Exploration of Origins of Selectivity and the Role of Substituent Conformations on Selectivity. J Org Chem 2021; 86:17082-17089. [PMID: 34783567 DOI: 10.1021/acs.joc.1c02191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The π-facial selectivity of Diels-Alder cycloadditions of 5-monosubstituted cyclopentadienes is known experimentally and has been extensively studied computationally. Previous studies on 5-monosubstituted cyclopentadienes by the Burnell and Houk groups showed that facial selectivity arises principally from hyperconjugative aromaticity or antiaromaticity of polar groups that cause distortion of the cyclopentadiene; steric effects of nonpolar groups can also be important. We have now explored the stereoselective cycloaddition of 5,5-unsymmetrically substituted cyclopentadienes to an acyl nitroso dienophile reported by Kan and co-workers. Computational studies with M06-2X/6-311+G(d,p) indicate that the stereoselectivity in the cycloadditions of 5,5-unsymmetrically substituted cyclopentadienes is not just a simple combination of effects found for monosubstituted counterparts. Substituent conformations and diene-dienophile steric and electronic interaction effects all influence stereoselectivity. Predictions are made about several as-yet-unstudied cyclopentadiene cycloadditions.
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Affiliation(s)
- Fengyue Zhao
- College of Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Peiyuan Yu
- Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Yu Chen
- College of Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Fang Liu
- College of Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
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10
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Ito S, Ishii Y, Ishimura K, Kuwabara T. A new strategy for hyperconjugative antiaromatic compounds utilizing negative charges: a dibenzo[ b, f]silepinyl dianion. Chem Commun (Camb) 2021; 57:11330-11333. [PMID: 34636825 DOI: 10.1039/d1cc04434f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we propose a new strategy for hyperconjugative antiaromatic compounds utilizing negative charges and design the 5,5-diphenyldibenzo[b,f]silepinyl dianion (pseudo 16π-electron system) in which negative hyperconjugation occurs between the anionic π-cloud and the σ*(Si-Ph) orbital. Essentially, reduction of the dibenzo[b,f]silepin with lithium readily generated a dilithium salt of the dibenzosilepinyl dianion, and its hyperconjugative antiaromaticity has been evidenced by the upfield shifts of 1H NMR signals and theoretical calculations, including large NICSzz values and ACID plots.
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Affiliation(s)
- Shotaro Ito
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Youichi Ishii
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Kazuya Ishimura
- X-Ability, Co., Ltd., Ishiwata Building 3rd Floor, 4-1-5 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Takuya Kuwabara
- Department of Chemistry and Biochemistry, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1, Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan.
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11
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Vargas S, Hennefarth MR, Liu Z, Alexandrova AN. Machine Learning to Predict Diels-Alder Reaction Barriers from the Reactant State Electron Density. J Chem Theory Comput 2021; 17:6203-6213. [PMID: 34478623 DOI: 10.1021/acs.jctc.1c00623] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction barriers are key to our understanding of chemical reactivity and catalysis. Certain reactions are so seminal in chemistry that countless variants, with or without catalysts, have been studied, and their barriers have been computed or measured experimentally. This wealth of data represents a perfect opportunity to leverage machine learning models, which could quickly predict barriers without explicit calculations or measurement. Here, we show that the topological descriptors of the quantum mechanical charge density in the reactant state constitute a set that is both rigorous and continuous and can be used effectively for the prediction of reaction barrier energies to a high degree of accuracy. We demonstrate this on the Diels-Alder reaction, highly important in biology and medicinal chemistry, and as such, studied extensively. This reaction exhibits a range of barriers as large as 270 kJ/mol. While we trained our single-objective supervised (labeled) regression algorithms on simpler Diels-Alder reactions in solution, they predict reaction barriers also in significantly more complicated contexts, such a Diels-Alder reaction catalyzed by an artificial enzyme and its evolved variants, in agreement with experimental changes in kcat. We expect this tool to apply broadly to a variety of reactions in solution or in the presence of a catalyst, for screening and circumventing heavily involved computations or experiments.
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Affiliation(s)
- Santiago Vargas
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States
| | - Matthew R Hennefarth
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States
| | - Zhihao Liu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States.,California NanoSystems Institute, University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095-1569, United States
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12
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Levandowski BJ, Abularrage NS, Raines RT. Geminal Repulsion Disrupts Diels-Alder Reactions of Geminally Substituted Cyclopentadienes and 4 H-Pyrazoles. Tetrahedron 2021; 91. [PMID: 34290459 DOI: 10.1016/j.tet.2021.132160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have experimentally and computationally explored the sluggish Diels-Alder reactivities of the geminally substituted 5,5-dimethylcyclopentadiene and 5,5-dimethyl-2,3-diazacyclopentadiene (4,4-dimethyl-4H-pyrazole) scaffolds. We found that geminal dimethylation of 1,2,3,4-tetramethylcyclopentadiene to 1,2,3,4,5,5-hexamethylcyclopentadiene decreases the Diels-Alder reactivity towards maleimide by 954-fold. Quantum mechanical calculations revealed that the decreased Diels-Alder reactivities of gem-dimethyl substituted cyclopentadienes and 2,3-diazacyclopentadienes are not a consequence of unfavorable steric interactions between the diene and dienophile as reported previously, but a consequence of the increased repulsion within the gem-dimethyl group in the transition state. The findings have implications for the use of cyclopentadienes in "click" chemistry.
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Affiliation(s)
- Brian J Levandowski
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Nile S Abularrage
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Ronald T Raines
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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13
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Abstract
Cyclopentadiene is one of the most reactive dienes in normal electron-demand Diels-Alder reactions. The high reactivities and yields of cyclopentadiene cycloadditions make them ideal as click reactions. In this review, we discuss the history of the cyclopentadiene cycloaddition as well as applications of cyclopentadiene click reactions. Our emphasis is on experimental and theoretical studies on the reactivity and stability of cyclopentadiene and cyclopentadiene derivatives.
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Affiliation(s)
- Brian J. Levandowski
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Ronald T. Raines
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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14
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Houk KN, Liu F, Yang Z, Seeman JI. Die Evolution des Diels‐Alder‐Reaktionsmechanismus seit den 1930er Jahren: Woodward, Houk zusammen mit Woodward und der Einfluss der Computerchemie auf das Verständnis von Cycloadditionen. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202001654] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Kendall N. Houk
- Department of Chemistry and Biochemistry University of California Los Angeles California 90005 USA
| | - Fang Liu
- Department of Chemistry and Biochemistry University of California Los Angeles California 90005 USA
- College of Sciences Nanjing Agricultural University Nanjing 210095 China
| | - Zhongyue Yang
- Department of Chemistry and Biochemistry University of California Los Angeles California 90005 USA
| | - Jeffrey I. Seeman
- Department of Chemistry University of Richmond Richmond Virginia 23173 USA
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15
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Houk KN, Liu F, Yang Z, Seeman JI. Evolution of the Diels–Alder Reaction Mechanism since the 1930s: Woodward, Houk with Woodward, and the Influence of Computational Chemistry on Understanding Cycloadditions. Angew Chem Int Ed Engl 2021; 60:12660-12681. [DOI: 10.1002/anie.202001654] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 06/30/2020] [Indexed: 01/16/2023]
Affiliation(s)
- Kendall N. Houk
- Department of Chemistry and Biochemistry University of California Los Angeles CA 90005 USA
| | - Fang Liu
- Department of Chemistry and Biochemistry University of California Los Angeles CA 90005 USA
- College of Sciences Nanjing Agricultural University Nanjing 210095 China
| | - Zhongyue Yang
- Department of Chemistry and Biochemistry University of California Los Angeles CA 90005 USA
| | - Jeffrey I. Seeman
- Department of Chemistry University of Richmond Richmond VA 23173 USA
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16
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Deb T, Tu J, Franzini RM. Mechanisms and Substituent Effects of Metal-Free Bioorthogonal Reactions. Chem Rev 2021; 121:6850-6914. [DOI: 10.1021/acs.chemrev.0c01013] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Titas Deb
- Department of Medicinal Chemistry, University of Utah, 30 S 2000 E, Salt Lake City, Utah 84112, United States
| | - Julian Tu
- Department of Medicinal Chemistry, University of Utah, 30 S 2000 E, Salt Lake City, Utah 84112, United States
| | - Raphael M. Franzini
- Department of Medicinal Chemistry, University of Utah, 30 S 2000 E, Salt Lake City, Utah 84112, United States
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17
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Zhao Y, Zeng J, Zhu J. Tuning the hyperconjugative aromaticity in Au(III)-substituted indoliums. Dalton Trans 2021; 50:8096-8101. [PMID: 34018516 DOI: 10.1039/d1dt00599e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
As a fundamental concept in chemistry, aromaticity has been extended from traditional organics to organometallics. Similarly, hyperconjugative aromaticity (HCA) has also been developed from main group to transition metal systems through the hyperconjugation of the substituents. However, it remains unclear that how the oxidation state of transition metal in the substituents affects the HCA. Herein, we demonstrate via density functional theory calculations that HCA could disappear in indoliums when the Au(i) substituents are changed to the Au(iii) ones. By tuning the ligand or cis-trans isomerization, HCA could be regained or enhanced in indoliums containing Au(iii) substitutents.
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Affiliation(s)
- Yu Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Jie Zeng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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18
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Zeng J, Zhao Y, Xu F, Zhu J. Probing hyperconjugative aromaticity in 2H-pyrrolium and cyclopentadiene containing group 9 transition metal substituents: bridged carbonyl ligands can enhance aromaticity. Phys Chem Chem Phys 2021; 23:2697-2702. [DOI: 10.1039/d0cp06388f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bridged carbonyls can enhance hyperconjugative aromaticity of group 9 transition metal disubstituted 2H-pyrrolium and cyclopentadiene.
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Affiliation(s)
- Jie Zeng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial
- Key Laboratory of Theoretical and Computational Chemistry
- College of Chemistry, and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Yu Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial
- Key Laboratory of Theoretical and Computational Chemistry
- College of Chemistry, and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Fangzhou Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial
- Key Laboratory of Theoretical and Computational Chemistry
- College of Chemistry, and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial
- Key Laboratory of Theoretical and Computational Chemistry
- College of Chemistry, and Chemical Engineering
- Xiamen University
- Xiamen 361005
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19
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Karas LJ, Campbell AT, Alabugin IV, Wu JI. Antiaromaticity Gain Activates Tropone and Nonbenzenoid Aromatics as Normal-Electron-Demand Diels-Alder Dienes. Org Lett 2020; 22:7083-7087. [PMID: 32856925 PMCID: PMC8124018 DOI: 10.1021/acs.orglett.0c02343] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We propose a carbonyl umpolung strategy for activating tropone as a normal-electron-demand Diels-Alder diene. Tropone has low reactivity for Diels-Alder reactions because of its [4n+2] π-aromaticity. Conversion of the carbonyl group into a hydrazone ion (═N-NR-) reverses the polarity of the exocyclic double bond, increases the [4n] ring π-antiaromaticity, and raises the HOMO energy. Computed gas-phase activation free energies for a Diels-Alder reaction with maleimide suggest a billion-fold rate increase when the tropone C═O is replaced by ═N-NR- (R = H or SO2CH3). Other nonbenzenoid aromatics can be activated as normal-electron-demand Diels-Alder dienes in the same way.
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Affiliation(s)
- Lucas J Karas
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Adam T Campbell
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Judy I Wu
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
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20
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Stewart SG, Harfoot GJ, McRae KJ, Teng Y, Yu LJ, Chen B, Cammi R, Coote ML, Banwell MG, Willis AC. High-Pressure-Promoted and Facially Selective Diels–Alder Reactions of Enzymatically Derived cis-1,2-Dihydrocatechols and Their Acetonide Derivatives: Enantiodivergent Routes to Homochiral and Polyfunctionalized Bicyclo[2.2.2]octenes. J Org Chem 2020; 85:13080-13095. [DOI: 10.1021/acs.joc.0c01767] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Scott G. Stewart
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601 Australia
| | - Gwion J. Harfoot
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601 Australia
| | - Kenneth J. McRae
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601 Australia
| | - Yinglai Teng
- Institute for Advanced and Applied Chemical Synthesis, Jinan University, Guangzhou 510632, China
| | - Li-Juan Yu
- Research School of Chemistry, Institute of Advanced Studies and ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, The Australian National University, Canberra, ACT 2601 Australia
| | - Bo Chen
- Donostia International Physics Center, Paseo Manuel de Lardizabal, 4, 20018 Donostia-San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
| | - Roberto Cammi
- Department of Chemical Science, Life Science and Environmental Sustainability, University of Parma, I-43100 Parma, Italy
| | - Michelle L. Coote
- Research School of Chemistry, Institute of Advanced Studies and ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, The Australian National University, Canberra, ACT 2601 Australia
| | - Martin G. Banwell
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601 Australia
- Institute for Advanced and Applied Chemical Synthesis, Jinan University, Guangzhou 510632, China
| | - Anthony C. Willis
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601 Australia
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21
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Zhuang D, Li Y, Zhu J. Antiaromaticity-Promoted Activation of Dihydrogen with Borole Fused Cyclooctatetraene Frustrated Lewis Pairs: A Density Functional Theory Study. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00263] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Danling Zhuang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yuanyuan Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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22
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Levandowski BJ, Abularrage NS, Raines RT. Differential Effects of Nitrogen Substitution in 5- and 6-Membered Aromatic Motifs. Chemistry 2020; 26:8862-8866. [PMID: 32166866 DOI: 10.1002/chem.202000825] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Indexed: 12/30/2022]
Abstract
The replacement of carbon with nitrogen can affect the aromaticity of organic rings. Nucleus-independent chemical shift (NICS) calculations at the center of the aromatic π-systems reveal that incorporating nitrogen into 5-membered heteroaromatic dienes has only a small influence on aromaticity. In contrast, each nitrogen incorporated into benzene results in a sequential and substantial loss of aromaticity. The contrasting effects of nitrogen substitution in 5-membered dienes and benzene are reflected in their Diels-Alder reactivities as dienes. 1,2-Diazine experiences a 1011 -fold increase in reactivity upon nitrogen substitution at the 4- and 5-positions, whereas a 5-membered heteroaromatic diene, furan, experiences a comparatively incidental 102 -fold increase in reactivity upon nitrogen substitution at the 3- and 4-positions.
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Affiliation(s)
- Brian J Levandowski
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Nile S Abularrage
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Ronald T Raines
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
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23
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Abularrage NS, Levandowski BJ, Raines RT. Synthesis and Diels-Alder Reactivity of 4-Fluoro-4-Methyl-4 H-Pyrazoles. Int J Mol Sci 2020; 21:ijms21113964. [PMID: 32486503 PMCID: PMC7312747 DOI: 10.3390/ijms21113964] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 02/01/2023] Open
Abstract
4H-Pyrazoles are emerging scaffolds for “click” chemistry. Late-stage fluorination with Selectfluor® is found to provide a reliable route to 4-fluoro-4-methyl-4H-pyrazoles. 4-Fluoro-4-methyl-3,5-diphenyl-4H-pyrazole (MFP) manifested 7-fold lower Diels–Alder reactivity than did 4,4-difluoro-3,5-diphenyl-4H-pyrazole (DFP), but higher stability in the presence of biological nucleophiles. Calculations indicate that a large decrease in the hyperconjugative antiaromaticity in MFP relative to DFP does not lead to a large loss in Diels–Alder reactivity because the ground-state structure of MFP avoids hyperconjugative antiaromaticity by distorting into an envelope-like conformation like that in the Diels–Alder transition state. This predistortion enhances the reactivity of MFP and offsets the decrease in reactivity from the diminished hyperconjugative antiaromaticity.
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24
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Noland WE, Kumar HV, Reddi Y, Cramer CJ, Novikov AV, Kim H, Zhu Y, Chin YC, Zhou Y, Radakovic P, Uprety A, Xie J, Flick GC. Diels–Alder/Ene Reactivities of 2-(1′-Cycloalkenyl)thiophenes and 2-(1′-Cycloalkenyl)benzo[b]thiophenes with N-Phenylmaleimides: Role of Cycloalkene Ring Size on Benzothiophene and Dibenzothiophene Product Distributions. J Org Chem 2020; 85:5265-5287. [DOI: 10.1021/acs.joc.9b03363] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Wayland E. Noland
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Honnaiah Vijay Kumar
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Yernaidu Reddi
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Christopher J. Cramer
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Alexei V. Novikov
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Hyejin Kim
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Yumeng Zhu
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Yoke Ching Chin
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Yuqi Zhou
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Predrag Radakovic
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Anjola Uprety
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Jun Xie
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Grant C. Flick
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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25
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Zhuang D, Rouf AM, Li Y, Dai C, Zhu J. Aromaticity‐promoted CO
2
Capture by P/N‐Based Frustrated Lewis Pairs: A Theoretical Study. Chem Asian J 2019; 15:266-272. [DOI: 10.1002/asia.201901415] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/24/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Danling Zhuang
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy Materials (iChem)Fujian Provincial Key Laboratory of Theoretical Computational ChemistryDepartment of ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P. R. China
| | - Alvi Muhammad Rouf
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy Materials (iChem)Fujian Provincial Key Laboratory of Theoretical Computational ChemistryDepartment of ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P. R. China
| | - Yuanyuan Li
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy Materials (iChem)Fujian Provincial Key Laboratory of Theoretical Computational ChemistryDepartment of ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P. R. China
| | - Chenshu Dai
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy Materials (iChem)Fujian Provincial Key Laboratory of Theoretical Computational ChemistryDepartment of ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P. R. China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy Materials (iChem)Fujian Provincial Key Laboratory of Theoretical Computational ChemistryDepartment of ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P. R. China
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26
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Xiao K, Zhao Y, Zhu J, Zhao L. Hyperconjugative aromaticity and protodeauration reactivity of polyaurated indoliums. Nat Commun 2019; 10:5639. [PMID: 31822673 PMCID: PMC6904676 DOI: 10.1038/s41467-019-13663-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/14/2019] [Indexed: 12/16/2022] Open
Abstract
Aromaticity generally describes a cyclic structure composed of sp2-hybridized carbon or hetero atoms with remarkable stability and unique reactivity. The doping of even one sp3-hybridized atom often damages the aromaticity due to the interrupted electron conjugation. Here we demonstrate the occurrence of an extended hyperconjugative aromaticity (EHA) in a metalated indole ring which contains two gem-diaurated tetrahedral carbon atoms. The EHA-involved penta-aurated indolium shows extended electron conjugation because of dual hyperconjugation. Furthermore, the EHA-induced low electron density on the indolyl nitrogen atom enables a facile protodeauration reaction for the labile Au-N bond. In contrast, the degraded tetra-aurated indolium with a single gem-dimetalated carbon atom exhibits poor bond averaging and inertness in the protodeauration reaction. The aromaticity difference in such two polyaurated indoliums is discussed in the geometrical and electronic perspectives. This work highlights the significant effect of metalation on the aromaticity of polymetalated species. Hyperconjugative aromaticity combines the concepts of hyperconjugation and aromaticity and explains cyclopentadiene stability. Here, the authors demonstrate extended hyperconjugative aromaticity in a metallated indole ring, which shows extended electron conjugation due to the dual hyperconjugation.
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Affiliation(s)
- Kui Xiao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, 100084, Beijing, China
| | - Yu Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China.
| | - Liang Zhao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, 100084, Beijing, China.
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27
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Qin P, Holland RL, Bunker KD, O'Connor JM, Baldridge KK, Rheingold AL. Acid-Induced Liberation of Polysubstituted Cyclopentadiene Ligands from Cyclopentadienyl Cobalt: A [2 + 2 + 1] Cycloaddition Route toward 1,2,4-Trisubstituted Cyclopentadienes. J Org Chem 2019; 84:13992-14004. [PMID: 31549512 DOI: 10.1021/acs.joc.9b02182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Here, we report that trifluoroacetic acid (TFAH) induces demetallation and protodesilylation of the cyclopentadiene ligand in cobalt-η4-cyclopentadiene complexes of general formula [(η5-C5H5)Co(η4-exo-C(TMS)═C(SO2Ph)CH═CRCH(CO2Et))] (1-Ph, R = Ph; 1-ArtBu, R = p-C6H4tBu; 1-ArNMe2, R = p-C6H4NMe2; and 1-Me, R = Me). The trisubstituted cyclopentadiene products are isolated as a mixture of two tautomers, [(CH2C(SO2Ph)═CHC(CO2Et)═CR)] (8-R-A) and [(CH═C(SO2Ph)CH2C(CO2Et)═CR)] (8-R-B). The endo isomer, [(η5-C5H5)Co(η4-endo-C(TMS)═C(SO2Ph)CH═CPhCH(CO2Et))] (1-Ph-endo), also undergoes demetallation and protodesilylation to give 8-Ph-A and 8-Ph-B in excellent yield. The cobalt-cyclopentadiene complex, [(η5-C5H5)Co(η4-exo-C(TMS)═C(SO2Ph)CH═C(CO2Me)CH(CO2Et))] (1-CO2Me), undergoes demetallation and protodesilylation upon treatment with TFAH to give a hydrogen-bonded fulvenol (8-CO2Me). Liberation of the ethoxy-substituted cyclopentadiene ligand of [(η5-C5H5)Co(η4-exo-C(TMS)═C(SO2Ph)CH═C(OEt)CH(CO2Et))] (1-OEt) leads to formation of a cyclopentenone derivative (11). Thermolysis of 8-Ph-A/8-Ph-B in the presence of maleimide leads to a highly functionalized Diels-Alder adduct, whereas 8-Ph-A/8-Ph-B serves as precursors to trisubstituted ruthenocenes by in situ deprotonation and reaction with [(η5-C5R5)Ru(NCMe)3]PF6 (16-H, R = H; 16-Me, R = Me).
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Affiliation(s)
- Pengjin Qin
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla, San Diego , California 92093-0358 , United States
| | - Ryan L Holland
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla, San Diego , California 92093-0358 , United States
| | - Kevin D Bunker
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla, San Diego , California 92093-0358 , United States
| | - Joseph M O'Connor
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla, San Diego , California 92093-0358 , United States
| | - Kim K Baldridge
- School of Pharmaceutical Science and Technology , Tianjin University , 92 Weijin Road , Nankai District, Tianjin 300072 , P. R. of China
| | - Arnold L Rheingold
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla, San Diego , California 92093-0358 , United States
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28
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Levandowski BJ, Abularrage NS, Houk KN, Raines RT. Hyperconjugative Antiaromaticity Activates 4 H-Pyrazoles as Inverse-Electron-Demand Diels-Alder Dienes. Org Lett 2019; 21:8492-8495. [PMID: 31589054 DOI: 10.1021/acs.orglett.9b03351] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Diels-Alder reactivity of 4,4-difluoro-3,5-diphenyl-4H-pyrazole was investigated experimentally and computationally with endo-bicyclo[6.1.0]non-4-yne. The computationally predicted rate enhancement from hyperconjugative antiaromaticity induced by fluorination of cyclopentadienes at the 5-position extends to five-membered heterocyclic dienes containing a saturated center. 4,4-Difluoro-4H-pyrazoles are new electron-deficient dienes with rapid reactivities toward strained alkynes.
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Affiliation(s)
- Brian J Levandowski
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States.,Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Nile S Abularrage
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - K N Houk
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Ronald T Raines
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
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29
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Marques A, Duhail T, Marrot J, Chataigner I, Coeffard V, Vincent G, Moreau X. A Fused Hexacyclic Ring System: Diastereoselective Polycyclization of 2,4‐Dienals through an Interrupted iso‐Nazarov Reaction. Angew Chem Int Ed Engl 2019; 58:9969-9973. [DOI: 10.1002/anie.201903860] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/06/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Anne‐Sophie Marques
- Institut Lavoisier VersaillesUniversité de Versailles-St-Quentin-en-YvelinesUniversité Paris Saclay, UMR CNRS 8180 78035 Versailles cedex France
| | - Thibaut Duhail
- Institut Lavoisier VersaillesUniversité de Versailles-St-Quentin-en-YvelinesUniversité Paris Saclay, UMR CNRS 8180 78035 Versailles cedex France
| | - Jérome Marrot
- Institut Lavoisier VersaillesUniversité de Versailles-St-Quentin-en-YvelinesUniversité Paris Saclay, UMR CNRS 8180 78035 Versailles cedex France
| | - Isabelle Chataigner
- Normandie UnivUNIROUENINSA Rouen, CNRS, COBRA (UMR 6014) 76000 Rouen France
- Present address: Sorbonne UniversitéUPMC Univ. Paris 6, CNRS UMR 7616Laboratoire de Chimie Théorique 75005 Paris France
| | - Vincent Coeffard
- Université de Nantes, CNRSChimie Et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR CNRS 6230Faculté des Sciences et des Techniques 2, rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
| | - Guillaume Vincent
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO)Univ. Paris-Sud, Université Paris-Saclay, CNRS UMR 8182 91405 Orsay cedex France
| | - Xavier Moreau
- Institut Lavoisier VersaillesUniversité de Versailles-St-Quentin-en-YvelinesUniversité Paris Saclay, UMR CNRS 8180 78035 Versailles cedex France
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30
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Xie Q, Zhao Y, Chen D, Zhu J. Probing Reaction Mechanism of [1,5]‐Migration in Pyrrolium and Pyrrole Derivatives: Activation of a Stronger Bond in Electropositive Groups Becomes Easier. Chem Asian J 2019; 14:2604-2610. [DOI: 10.1002/asia.201900440] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/12/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Qiong Xie
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy, Materials (iChEM)Fujian Provincial Key Laboratory of, Theoretical and Computational Chemistry and Department of, ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P.R. China
| | - Yu Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy, Materials (iChEM)Fujian Provincial Key Laboratory of, Theoretical and Computational Chemistry and Department of, ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P.R. China
| | - Dandan Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy, Materials (iChEM)Fujian Provincial Key Laboratory of, Theoretical and Computational Chemistry and Department of, ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P.R. China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy, Materials (iChEM)Fujian Provincial Key Laboratory of, Theoretical and Computational Chemistry and Department of, ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P.R. China
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31
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Marques A, Duhail T, Marrot J, Chataigner I, Coeffard V, Vincent G, Moreau X. A Fused Hexacyclic Ring System: Diastereoselective Polycyclization of 2,4‐Dienals through an Interrupted iso‐Nazarov Reaction. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201903860] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Anne‐Sophie Marques
- Institut Lavoisier VersaillesUniversité de Versailles-St-Quentin-en-YvelinesUniversité Paris Saclay, UMR CNRS 8180 78035 Versailles cedex France
| | - Thibaut Duhail
- Institut Lavoisier VersaillesUniversité de Versailles-St-Quentin-en-YvelinesUniversité Paris Saclay, UMR CNRS 8180 78035 Versailles cedex France
| | - Jérome Marrot
- Institut Lavoisier VersaillesUniversité de Versailles-St-Quentin-en-YvelinesUniversité Paris Saclay, UMR CNRS 8180 78035 Versailles cedex France
| | - Isabelle Chataigner
- Normandie UnivUNIROUENINSA Rouen, CNRS, COBRA (UMR 6014) 76000 Rouen France
- Present address: Sorbonne UniversitéUPMC Univ. Paris 6, CNRS UMR 7616Laboratoire de Chimie Théorique 75005 Paris France
| | - Vincent Coeffard
- Université de Nantes, CNRSChimie Et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR CNRS 6230Faculté des Sciences et des Techniques 2, rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
| | - Guillaume Vincent
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO)Univ. Paris-Sud, Université Paris-Saclay, CNRS UMR 8182 91405 Orsay cedex France
| | - Xavier Moreau
- Institut Lavoisier VersaillesUniversité de Versailles-St-Quentin-en-YvelinesUniversité Paris Saclay, UMR CNRS 8180 78035 Versailles cedex France
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32
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Sun T, Guo P, Xie Q, Zhao L, Zhu J. Bonded to Carbon or Nitrogen? This is a Question on the Regioselectivity in Hyperconjugative Aromaticity. J Org Chem 2019; 84:3881-3886. [PMID: 30821452 DOI: 10.1021/acs.joc.8b02996] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In chemistry, regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions. Although it has been extensively investigated in various reactions, the regioselectivity of hyperconjugative aromaticity on either main group systems or transition metal ones remains elusive due to the challenge of synthesizing the target products. Here we report a joint theoretical and experimental study on this issue. Theoretical calculations predicted that electron-withdrawing groups prefer an attachment to the sp3-hybridized carbon atom rather than the nitrogen atom in indoliums. For the electron-donating groups, the two isomers bonded to the sp3-hybridized carbon or nitrogen atom are almost isoenergetic. When both sp2- and sp3-hybridized carbon and nitrogen atoms in the five-membered ring of indoliums are considered, the isomer with the polyaurated substituents bonded to the sp3-hybridized carbon atom is thermodynamically more stable than that with the polyaurated substituents bonded to the sp3-hybridized nitrogen atom. This prediction is reasonably verified by experimental observation. Bond dissociation energy is found to be more important than aromaticity in rationalizing such a preference. Our findings could help experimentalists to design and realize more novel hyperconjugative aromatics.
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Affiliation(s)
- Tingting Sun
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Ping Guo
- Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry , Tsinghua University , Beijing 100084 , China
| | - Qiong Xie
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Liang Zhao
- Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry , Tsinghua University , Beijing 100084 , China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
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33
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Chen D, Zhuang D, Zhao Y, Xie Q, Zhu J. Reaction mechanisms of iron(iii) catalyzed carbonyl–olefin metatheses in 2,5- and 3,5-hexadienals: significant substituent and aromaticity effects. Org Chem Front 2019. [DOI: 10.1039/c9qo01008d] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Theoretical calculations reveal significant substituent and aromaticity effects on Fe(iii)-catalyzed carbonyl–olefin metatheses of hexadienals.
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Affiliation(s)
- Dandan Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Danling Zhuang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Yu Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Qiong Xie
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
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