1
|
Jiao Z, Jaunich KT, Tao T, Gottschall O, Hughes MM, Turlik A, Schuppe AW. Unified Approach to Deamination and Deoxygenation Through Isonitrile Hydrodecyanation: A Combined Experimental and Computational Investigation. Angew Chem Int Ed Engl 2024; 63:e202405779. [PMID: 38619535 DOI: 10.1002/anie.202405779] [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: 03/25/2024] [Revised: 04/13/2024] [Accepted: 04/15/2024] [Indexed: 04/16/2024]
Abstract
Herein, we describe a general hydrodefunctionalization protocol of alcohols and amines through a common isonitrile intermediate. To cleave the relatively inert C-NC bond, we leveraged dual hydrogen atom transfer (HAT) and photoredox catalysis to generate a nucleophilic boryl radical, which readily forms an imidoyl radical intermediate from the isonitrile. Rapid β-scission then accomplishes defunctionalization. This method has been applied to the hydrodefunctionalization of both amine and alcohol-containing pharmaceuticals, natural products, and biomolecules. We extended this approach to the reduction of carbonyls and olefins to their saturated counterparts, as well as the hydrodecyanation of alkyl nitriles. Both experimental and computational studies demonstrate a facile β-scission of the imidoyl radical, and reconcile differences in reactivity between nitriles and isonitriles within our protocol.
Collapse
Affiliation(s)
- Ziqi Jiao
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Kyle T Jaunich
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Thomas Tao
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Olivia Gottschall
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Maxwell M Hughes
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Aneta Turlik
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Alexander W Schuppe
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| |
Collapse
|
2
|
Zhang J, Kong WY, Guo W, Tantillo DJ, Tang Y. Combined Computational and Experimental Study Reveals Complex Mechanistic Landscape of Brønsted Acid-Catalyzed Silane-Dependent P═O Reduction. J Am Chem Soc 2024; 146:13983-13999. [PMID: 38736283 DOI: 10.1021/jacs.4c02042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
The reaction mechanism of Brønsted acid-catalyzed silane-dependent P═O reduction has been elucidated through combined computational and experimental methods. Due to its remarkable chemo- and stereoselective nature, the Brønsted acid/silane reduction system has been widely employed in organophosphine-catalyzed transformations involving P(V)/P(III) redox cycle. However, the full mechanistic profile of this type of P═O reduction has yet to be clearly established to date. Supported by both DFT and experimental studies, our research reveals that the reaction likely proceeds through mechanisms other than the widely accepted "dual activation mode by silyl ester" or "acid-mediated direct P═O activation" mechanism. We propose that although the reduction mechanisms may vary with the substitution patterns of silane species, Brønsted acid generally activates the silane rather than the P═O group in transition structures. The proposed activation mode differs significantly from that associated with traditional Brønsted acid-catalyzed C═O reduction. The uniqueness of P═O reduction originates from the dominant Si/O═P orbital interactions in transition structures rather than the P/H-Si interactions. The comprehensive mechanistic landscape provided by us will serve as a guidance for the rational design and development of more efficient P═O reduction systems as well as novel organophosphine-catalyzed reactions involving P(V)/P(III) redox cycle.
Collapse
Affiliation(s)
- Jingyang Zhang
- School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 100084, China
| | - Wang-Yeuk Kong
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Wentao Guo
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Dean J Tantillo
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Yefeng Tang
- School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 100084, China
| |
Collapse
|
3
|
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.
Collapse
Affiliation(s)
- Dennis Svatunek
- Institute of Applied Synthetic Chemistry, Technische Universität Wien (TU Wien), Getreidemarkt 9, 1060, Vienna, Austria.
| |
Collapse
|
4
|
Herrmann B, Svatunek D. Directionality of Halogen-Bonds: Insights from 2D Energy Decomposition Analysis. Chem Asian J 2024:e202301106. [PMID: 38390759 DOI: 10.1002/asia.202301106] [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: 12/10/2023] [Revised: 01/25/2024] [Indexed: 02/24/2024]
Abstract
Halogen bonds are typically observed to have a linear arrangement with a 180° angle between the nucleophile and the halogen bond acceptor X-R. This linearity is commonly explained using the σ-hole model, although there have been alternative explanations involving exchange repulsion forces. We employ two-dimensional Distortion/Interaction and Energy Decomposition Analysis to examine the archetypal H3 N⋯X2 halogen bond systems. Our results indicate that although halogen bonds are predominantly electrostatic, their directionality is largely due to decreased Pauli repulsion in linear configurations as opposed to angled ones in the I2 and Br2 systems. As we move to the smaller halogens, Cl2 and F2 , the influence of Pauli repulsion diminishes, and the energy surface is shaped by orbital interactions and electrostatic forces. These results support the role of exchange repulsion forces in influencing the directionality of strong halogen bonds. Additionally, we demonstrate that the 2D Energy Decomposition Analysis is a useful tool for enhancing our understanding of the nature of potential energy surfaces in noncovalent interactions.
Collapse
Affiliation(s)
- Barbara Herrmann
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - Dennis Svatunek
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| |
Collapse
|
5
|
Fernández I, Bickelhaupt FM, Svatunek D. Unraveling the Bürgi-Dunitz Angle with Precision: The Power of a Two-Dimensional Energy Decomposition Analysis. J Chem Theory Comput 2023; 19:7300-7306. [PMID: 37791978 PMCID: PMC10601473 DOI: 10.1021/acs.jctc.3c00907] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Indexed: 10/05/2023]
Abstract
Understanding the geometrical preferences in chemical reactions is crucial for advancing the field of organic chemistry and improving synthetic strategies. One such preference, the Bürgi-Dunitz angle, is central to nucleophilic addition reactions involving carbonyl groups. This study successfully employs a novel two-dimensional Distortion-Interaction/Activation-Strain Model in combination with a two-dimensional Energy Decomposition Analysis to investigate the origins of the Bürgi-Dunitz angle in the addition reaction of CN- to (CH3)2C═O. We constructed a 2D potential energy surface defined by the distance between the nucleophile and carbonylic carbon atom and by the attack angle, followed by an in-depth exploration of energy components, including strain and interaction energy. Our analysis reveals that the Bürgi-Dunitz angle emerges from a delicate balance between two key factors: strain energy and interaction energy. High strain energy, as a result of the carbonyl compound distorting to avoid Pauli repulsion, is encountered at high angles, thus setting the upper bound. On the other hand, interaction energy is shaped by a dominant Pauli repulsion when the angles are lower. This work emphasizes the value of the 2D Energy Decomposition Analysis as a refined tool, offering both quantitative and qualitative insights into chemical reactivity and selectivity.
Collapse
Affiliation(s)
- Israel Fernández
- Departamento
de Química Orgánica and Centro de Innovación
en Química Avanzada (ORFEO−CINQA), Facultad de Ciencias
Químicas, Universidad Complutense
de Madrid, 28040-Madrid, Spain
| | - F. Matthias Bickelhaupt
- Department
of Chemistry and Pharmaceutical Sciences, AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
- Institute
for Molecules and Materials (IMM), Radboud
University, Nijmegen 6500 GL, The Netherlands
- Department
of Chemical Sciences, University of Johannesburg, Johannesburg 2006, South Africa
| | - Dennis Svatunek
- Institute
of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| |
Collapse
|
6
|
Parr JM, Crimmin MR. Carbon-carbon bond activation by Mg, Al, and Zn complexes. Chem Sci 2023; 14:11012-11021. [PMID: 37860653 PMCID: PMC10583701 DOI: 10.1039/d3sc03336h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/13/2023] [Indexed: 10/21/2023] Open
Abstract
Examples of carbon-carbon bond activation reactions at Mg, Al, and Zn are described in this review. Several distinct mechanisms for C-C bond activation at these metals have been proposed, with the key C-C bond activation step occurring by (i) α-alkyl elimination, (ii) β-alkyl elimination, (iii) oxidative addition, or (iv) an electrocyclic reaction. Many of the known pathways involve an overall 2-electron redox process. Despite this, the direct oxidative addition of C-C bonds to these metals is relatively rare, instead most reactions occur through initial installation of the metal on a hydrocarbon scaffold (e.g. by a cycloaddition reaction or hydrometallation) followed by an α-alkyl or β-alkyl elimination step. Emerging applications of Mg, Al, and Zn complexes as catalysts for the functionalisation of C-C bonds are also discussed.
Collapse
Affiliation(s)
- Joseph M Parr
- Department of Chemistry, Molecular Science Research Hub, Imperial College London 82 Wood Lane, White City London W12 0BZ UK
| | - Mark R Crimmin
- Department of Chemistry, Molecular Science Research Hub, Imperial College London 82 Wood Lane, White City London W12 0BZ UK
| |
Collapse
|
7
|
Lindeboom W, Deacy AC, Phanopoulos A, Buchard A, Williams CK. Correlating Metal Redox Potentials to Co(III)K(I) Catalyst Performances in Carbon Dioxide and Propene Oxide Ring Opening Copolymerization. Angew Chem Int Ed Engl 2023; 62:e202308378. [PMID: 37409487 PMCID: PMC10952574 DOI: 10.1002/anie.202308378] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/07/2023]
Abstract
Carbon dioxide copolymerization is a front-runner CO2 utilization strategy but its viability depends on improving the catalysis. So far, catalyst structure-performance correlations have not been straightforward, limiting the ability to predict how to improve both catalytic activity and selectivity. Here, a simple measure of a catalyst ground-state parameter, metal reduction potential, directly correlates with both polymerization activity and selectivity. It is applied to compare performances of 6 new heterodinuclear Co(III)K(I) catalysts for propene oxide (PO)/CO2 ring opening copolymerization (ROCOP) producing poly(propene carbonate) (PPC). The best catalyst shows an excellent turnover frequency of 389 h-1 and high PPC selectivity of >99 % (50 °C, 20 bar, 0.025 mol% catalyst). As demonstration of its utility, neither DFT calculations nor ligand Hammett parameter analyses are viable predictors. It is proposed that the cobalt redox potential informs upon the active site electron density with a more electron rich cobalt centre showing better performances. The method may be widely applicable and is recommended to guide future catalyst discovery for other (co)polymerizations and carbon dioxide utilizations.
Collapse
Affiliation(s)
- Wouter Lindeboom
- Department ChemistryUniversity of OxfordChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
| | - Arron C. Deacy
- Department ChemistryUniversity of OxfordChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
| | - Andreas Phanopoulos
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 OBZUK
| | - Antoine Buchard
- Department of ChemistryInstitute for SustainabilityUniversity of BathBathBA2 7AYUK
| | - Charlotte K. Williams
- Department ChemistryUniversity of OxfordChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
| |
Collapse
|
8
|
Svatunek D, Chojnacki K, Deb T, Eckvahl H, Houk KN, Franzini RM. Orthogonal Inverse-Electron-Demand Cycloaddition Reactions Controlled by Frontier Molecular Orbital Interactions. Org Lett 2023; 25:6340-6345. [PMID: 37591496 PMCID: PMC10476241 DOI: 10.1021/acs.orglett.3c02265] [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: 07/12/2023] [Indexed: 08/19/2023]
Abstract
Chemoselective pairs of bioorthogonal reactants enable the simultaneous labeling of several biomolecules. Here, we access orthogonal click reactions by exploiting differences in frontier molecular orbital interaction energies in transition states. We establish that five-membered cyclic dienes are inert to isonitriles but readily react with strained alkynes, while tetrazines with bulky substituents readily react with isonitriles. Strained alkynes show an opposite reactivity pattern. The approach was demonstrated by orthogonally labeling two proteins with different fluorophores.
Collapse
Affiliation(s)
- Dennis Svatunek
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
- Institute
of Applied Synthetic Chemistry, TU Wien, 1060 Vienna, Austria
| | - Konrad Chojnacki
- Department
of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Titas Deb
- Department
of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Hannah Eckvahl
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - K. N. Houk
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Raphael M. Franzini
- Department
of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Huntsman
Cancer Institute, Salt Lake City, Utah 84112, United States
| |
Collapse
|
9
|
Houszka N, Mikula H, Svatunek D. Substituent Effects in Bioorthogonal Diels-Alder Reactions of 1,2,4,5-Tetrazines. Chemistry 2023; 29:e202300345. [PMID: 36853623 PMCID: PMC10946812 DOI: 10.1002/chem.202300345] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/01/2023]
Abstract
1,2,4,5-Tetrazines are increasingly used as reactants in bioorthogonal chemistry due to their high reactivity in Diels-Alder reactions with various dienophiles. Substituents in the 3- and 6-positions of the tetrazine scaffold are known to have a significant impact on the rate of cycloadditions; this is commonly explained on the basis of frontier molecular orbital theory. In contrast, we show that reactivity differences between commonly used classes of tetrazines are not controlled by frontier molecular orbital interactions. In particular, we demonstrate that mono-substituted tetrazines show high reactivity due to decreased Pauli repulsion, which leads to a more asynchronous approach associated with reduced distortion energy. This follows the recent Vermeeren-Hamlin-Bickelhaupt model of reactivity increase in asymmetric Diels-Alder reactions. In addition, we reveal that ethylene is not a good model compound for other alkenes in Diels-Alder reactions.
Collapse
Affiliation(s)
- Nicole Houszka
- Institute of Applied Synthetic ChemistryTU WienGetreidemarkt 91060ViennaAustria
| | - Hannes Mikula
- Institute of Applied Synthetic ChemistryTU WienGetreidemarkt 91060ViennaAustria
| | - Dennis Svatunek
- Institute of Applied Synthetic ChemistryTU WienGetreidemarkt 91060ViennaAustria
| |
Collapse
|
10
|
Theoretical Study on the Origin of Abnormal Regioselectivity in Ring-Opening Reaction of Hexafluoropropylene Oxide. Molecules 2023; 28:molecules28041669. [PMID: 36838653 PMCID: PMC9962681 DOI: 10.3390/molecules28041669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/19/2023] [Accepted: 02/01/2023] [Indexed: 02/12/2023] Open
Abstract
That nucleophiles preferentially attack at the less sterically hindered carbon of epoxides under neutral and basic conditions has been generally accepted as a fundamental rule for predicting the regioselectivity of this type of reaction. However, this rule does not hold for perfluorinated epoxides, such as hexafluoropropylene oxide (HFPO), in which nucleophiles were found to attack at the more hindered CF3 substituted β-C rather than the fluorine substituted α-C. In this contribution, we aim to shed light on the nature of this intriguing regioselectivity by density functional theory methods. Our calculations well reproduced the observed abnormal regioselectivities and revealed that the unusual regiochemical preference for the sterically hindered β-C of HFPO mainly arises from the lower destabilizing distortion energy needed to reach the corresponding ring-opening transition state. The higher distortion energy required for the attack of the less sterically hindered α-C results from a significant strengthening of the C(α)-O bond by the negative hyperconjugation between the lone pair of epoxide O atom and the antibonding C-F orbital.
Collapse
|
11
|
Parr JM, Phanopoulos A, Vickneswaran A, Crimmin MR. Understanding the role of ring strain in β-alkyl migration at Mg and Zn centres. Chem Sci 2023; 14:1590-1597. [PMID: 36794202 PMCID: PMC9906642 DOI: 10.1039/d2sc06288g] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/07/2023] [Indexed: 01/11/2023] Open
Abstract
The activation of C-C σ-bonds within strained three- and four-membered hydrocarbons at electrophilic Mg and Zn centres is reported. This was achieved in a two-step process involving (i) hydrometallation of a methylidene cycloalkane followed by (ii) intramolecular C-C bond activation. While hydrometallation of methylidene cyclopropane, cyclobutane, cyclopentane and cyclohexane occurs for both Mg and Zn reagents, the C-C bond activation step is sensitive to ring size. For Mg, both cyclopropane and cyclobutane rings participate in C-C bond activation. For Zn, only the smallest cyclopropane ring reacts. These findings were used to expand the scope of catalytic hydrosilylation of C-C σ-bonds to include cyclobutane rings. The mechanism of C-C σ-bond activation was investigated through kinetic analysis (Eyring), spectroscopic observation of intermediates, and a comprehensive series of DFT calculations, including activation strain analysis. Based on our current understanding, C-C bond activation is proposed to occur by a β-alkyl migration step. β-Alkyl migration is more facile for more strained rings and occurs with lower barriers for Mg compared to Zn. Relief of ring strain is a key factor in determining the thermodynamics of C-C bond activation, but not in stabilising the transition state for β-alkyl migration. Rather, we ascribe the differences in reactivity to the stabilising interaction between the metal centre and the hydrocarbon ring-system, with the smaller rings and more electropositive metal (Mg) leading to a smaller destabilisation interaction energy as the transition state is approached. Our findings represent the first example of C-C bond activation at Zn and provide detailed new insight into the factors at play in β-alkyl migration at main group centres.
Collapse
Affiliation(s)
- Joseph M. Parr
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London82 Wood Lane, White City, Shepherds BushLondonW12 0BZUK
| | - Andreas Phanopoulos
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London 82 Wood Lane, White City, Shepherds Bush London W12 0BZ UK
| | - Aaranjah Vickneswaran
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London 82 Wood Lane, White City, Shepherds Bush London W12 0BZ UK
| | - Mark R. Crimmin
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London82 Wood Lane, White City, Shepherds BushLondonW12 0BZUK
| |
Collapse
|
12
|
Labadie N, Pellegrinet SC. Diels–Alder Reactivity of Allenylboronic Acid Pinacol Ester and Related Dienophiles: Mechanistic Studies and Distortion/Interaction-Activation Strain Model Analysis. J Org Chem 2022; 87:16776-16784. [DOI: 10.1021/acs.joc.2c02445] [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)
- Natalia Labadie
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario 2000, Argentina
| | - Silvina C. Pellegrinet
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario 2000, Argentina
| |
Collapse
|
13
|
Hernández-Mancera JP, Rojas-Valencia N, Núñez-Zarur F. Rationalizing the Substituent Effects in Diels-Alder Reactions of Triazolinediones with Anthracene. J Phys Chem A 2022; 126:6657-6667. [PMID: 36122186 DOI: 10.1021/acs.jpca.2c04970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work we tackle the problem of the substituent effects in the Diels-Alder cycloadditions between triazolinediones (TADs) and anthracene. Experiments showed that aryl TADs substituted with electron-withdrawing groups (EWG) are more reactive than those substituted with electron-donating (EDG) or alkyl groups. However, the molecular origin of this preference is not yet understood. By a combination of methods including the activation strain model (ASM), energy decomposition analysis (EDA), molecular orbital (MO) theory, and conceptual density functional theory (CDFT), we disclosed the substituent effects of TADs. First, ASM/EDA analysis revealed that the reactivity of alkyl and aryl-substituted TADs is controlled by interaction energies, ΔEint, which are ultimately defined by orbital interactions between frontier molecular orbitals. Moreover, alkyl-TADs are also controlled by the extent of strain at the transition state. The MO analysis suggested that the rate acceleration for EWG-substituted TADs is due to a more favorable orbital interaction between the HOMO of anthracene and the LUMO of the TADs, which is corroborated by calculations of charge transfer at the transition states. From CDFT, the chemical potential of anthracene is higher than those of TADs, indicating a flow of electron density from anthracene to TADs, in agreement with the results from the electrophilicity index.
Collapse
Affiliation(s)
| | - Natalia Rojas-Valencia
- Facultad de Ciencias Básicas, Universidad de Medellín, Carrera 87 no. 30-65, 050026 Medellín, Colombia
| | - Francisco Núñez-Zarur
- Facultad de Ciencias Básicas, Universidad de Medellín, Carrera 87 no. 30-65, 050026 Medellín, Colombia
| |
Collapse
|
14
|
Svatunek D, Wilkovitsch M, Hartmann L, Houk KN, Mikula H. Uncovering the Key Role of Distortion in Bioorthogonal Tetrazine Tools That Defy the Reactivity/Stability Trade-Off. J Am Chem Soc 2022; 144:8171-8177. [PMID: 35500228 PMCID: PMC9100665 DOI: 10.1021/jacs.2c01056] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
The tetrazine/trans-cyclooctene ligation stands
out from the bioorthogonal toolbox due to its exceptional reaction
kinetics, enabling multiple molecular technologies in vitro and in
living systems. Highly reactive 2-pyridyl-substituted tetrazines have
become state of the art for time-critical processes and selective
reactions at very low concentrations. It is widely accepted that the
enhanced reactivity of these chemical tools is attributed to the electron-withdrawing
effect of the heteroaryl substituent. In contrast, we show that the
observed reaction rates are way too high to be explained on this basis.
Computational investigation of this phenomenon revealed that distortion
of the tetrazine caused by intramolecular repulsive N–N interaction
plays a key role in accelerating the cycloaddition step. We show that
the limited stability of tetrazines in biological media strongly correlates
with the electron-withdrawing effect of the substituent, while intramolecular
repulsion increases the reactivity without reducing the stability.
These fundamental insights reveal thus far overlooked mechanistic
aspects that govern the reactivity/stability trade-off for tetrazines
in physiologically relevant environments, thereby providing a new
strategy that may facilitate the rational design of these bioorthogonal
tools.
Collapse
Affiliation(s)
- Dennis Svatunek
- Institute of Applied Synthetic Chemistry, TU Wien 1060 Vienna, Austria
| | | | - Lea Hartmann
- Institute of Applied Synthetic Chemistry, TU Wien 1060 Vienna, Austria
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles 90095, United States
| | - Hannes Mikula
- Institute of Applied Synthetic Chemistry, TU Wien 1060 Vienna, Austria
| |
Collapse
|
15
|
De Castro PP, Batista GMF, Amarante GW, Dos Santos HF. Origin of Enantioselectivity in Chiral Phosphoric-Acid-Catalyzed Azlactone Dynamic Kinetic Resolution. J Org Chem 2021; 86:13169-13174. [PMID: 34464119 DOI: 10.1021/acs.joc.1c01882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Theoretical calculations, associated with control experiments, were carried out to gain insights into the mechanism and origin of enantioselectivity in the phosphoric-acid-catalyzed dynamic kinetic resolution of azlactones. The results revealed a Münchnone intermediate as the key species involved in the isomerization of azlactone rings. The developed model was successfully employed in the comprehension and prediction of enantioselectivity under diverse of reaction conditions, including alcoholysis and aminolysis protocols.
Collapse
Affiliation(s)
- Pedro P De Castro
- Chemistry Department, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Campus Universitário São Pedro, Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Gabriel M F Batista
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center (iNANO), and Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Giovanni W Amarante
- Chemistry Department, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Campus Universitário São Pedro, Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Hélio F Dos Santos
- Chemistry Department, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Campus Universitário São Pedro, Juiz de Fora, Minas Gerais 36036-900, Brazil
| |
Collapse
|
16
|
Mahaut D, Chardon A, Mineur L, Berionni G, Champagne B. Rational Development of a Metal-Free Bifunctional System for the C-H Activation of Methane: A Density Functional Theory Investigation. Chemphyschem 2021; 22:1958-1966. [PMID: 34309144 DOI: 10.1002/cphc.202100527] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Indexed: 11/10/2022]
Abstract
The activation or heterolytic splitting of methane, a challenging substrate usually restricted to transition metals, has so far proven elusive in experimental frustrated Lewis pair (FLP) chemistry. In this article, we demonstrate, using density functional theory (DFT), that 1-aza-9-boratriptycene is a conceptually simple intramolecular FLP for the activation of methane. Systematic comparison with other FLP systems allows to gain insight into their reactivity with methane. The thermodynamics and kinetics of methane activation are interpreted by referring to the analysis of the natural charges and by employing the distortion-interaction/activation strain (DIAS) model. These showed that the nature of the Lewis base influences the selectivity over the reaction pathway, with N Lewis bases favoring the deprotonation mechanism and P bases the hydride abstraction one. The lower barrier of activation for 1-aza-9-boratriptycene and the higher products stability are due to a better interaction energy than its counterparts, itself due to electrostatic interactions with the methane moiety, favorable orbital overlaps allowed by the side-attack, and space proximity between the B and N atoms.
Collapse
Affiliation(s)
- Damien Mahaut
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Aurélien Chardon
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Loïc Mineur
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Guillaume Berionni
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Benoît Champagne
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| |
Collapse
|
17
|
Chen PP, Ma P, He X, Svatunek D, Liu F, Houk KN. Computational Exploration of Ambiphilic Reactivity of Azides and Sustmann's Paradigmatic Parabola. J Org Chem 2021; 86:5792-5804. [PMID: 33769821 PMCID: PMC8154615 DOI: 10.1021/acs.joc.1c00239] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
We
examine the theoretical underpinnings of the seminal discoveries
by Reiner Sustmann about the ambiphilic nature of Huisgen’s
phenyl azide cycloadditions. Density functional calculations with
ωB97X-D and B2PLYP-D3 reproduce the experimental data and provide
insights into ambiphilic control of reactivity. Distortion/interaction-activation
strain and energy decomposition analyses show why Sustmann’s
use of dipolarophile ionization potential is such a powerful predictor
of reactivity. We add to Sustmann’s data set several modern
distortion-accelerated dipolarophiles used in bioorthogonal chemistry
to show how these fit into the orbital energy criteria that are often
used to understand cycloaddition reactivity. We show why such a simple
indicator of reactivity is a powerful predictor of reaction rates
that are actually controlled by a combination of distortion energies,
charge transfer, closed-shell repulsion, polarization, and electrostatic
effects.
Collapse
Affiliation(s)
- Pan-Pan Chen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Pengchen Ma
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Xue He
- College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Dennis Svatunek
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Fang Liu
- College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| |
Collapse
|
18
|
Svatunek D, Hansen T, Houk KN, Hamlin TA. How the Lewis Base F - Catalyzes the 1,3-Dipolar Cycloaddition between Carbon Dioxide and Nitrilimines. J Org Chem 2021; 86:4320-4325. [PMID: 33577314 PMCID: PMC8023701 DOI: 10.1021/acs.joc.0c02963] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Indexed: 12/11/2022]
Abstract
The mechanism of the Lewis base F- catalyzed 1,3-dipolar cycloaddition between CO2 and nitrilimines is interrogated using DFT calculations. F- activates the nitrilimine, not CO2 as proposed in the literature, and imparts a significant rate enhancement for the cycloaddition. The origin of this catalysis is in the strength of the primary orbital interactions between the reactants. The Lewis base activated nitrilimine-F- has high-lying filled FMOs. The smaller FMO-LUMO gap promotes a rapid nucleophilic attack and overall cycloaddition with CO2.
Collapse
Affiliation(s)
- Dennis Svatunek
- Department
of Theoretical Chemistry, Amsterdam Institute of Molecular and Life
Sciences (AIMSS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
- Institute
of Applied Synthetic Chemistry, TU Wien
(Vienna University of Technology), A-1060, Vienna, Austria
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California 90095, Los Angeles, United States
| | - Thomas Hansen
- Department
of Theoretical Chemistry, Amsterdam Institute of Molecular and Life
Sciences (AIMSS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Kendall N. Houk
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California 90095, Los Angeles, United States
| | - Trevor A. Hamlin
- Department
of Theoretical Chemistry, Amsterdam Institute of Molecular and Life
Sciences (AIMSS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
| |
Collapse
|
19
|
Joshi K, Krishnamurty S, Dar MA. Surface functionalization: an efficient alternative for promoting the catalytic activity of closed shell gold clusters. Phys Chem Chem Phys 2020; 22:23351-23359. [PMID: 33043944 DOI: 10.1039/d0cp01918f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Surface functionalization through adsorption of ligands or non-metal atoms is considered to be an interesting and viable approach for tuning the physicochemical properties of gold clusters. Highly stable and magic numbered electronic configurations of thiolate protected gold clusters such as Au25(SR)18, Au38(SR)24etc. with intriguing properties are the direct manifestation of the rich chemistry of the Au-S interface. The present investigation discerns the CO oxidation activity of structurally well characterized sulphur functionalized gold cluster anions AumS4-, m = 6-10. To establish an in-depth understanding, their activities are analyzed and compared with the corresponding pristine gold clusters. It is seen that sulphur functionalization irrespective of a closed or open shell nature leads to a significant decrease in the O2 adsorption energies on the anionic gold clusters. However, in sharp contrast to O2 adsorption, surface functionalization gives rise to multifarious catalytic behavior in AumS4- clusters with catalytic activity ranging from low (for Au6S4-, Au8S4-) to moderate (for Au9S4-, Au10S4-) to very high (for Au7S4-) for CO oxidation. It is interesting to note that the closed shell Au7S4- and Au9S4- clusters with poor O2 adsorption show remarkably low activation barriers and enhanced catalytic activity as compared to the open shell AumS4- clusters with an odd number of electrons. In particular, in the case of Au7S4- the lowest activation energy barriers of 0.01 and 0.21 eV are obtained, making the CO oxidation reaction facile. Moreover, ab initio molecular dynamics are performed to confirm the enhanced catalytic behaviour of Au7S4- and its dynamical stability during the desorption of CO2 molecule from its surface.
Collapse
Affiliation(s)
- Krati Joshi
- Functional Materials Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630 006, India
| | | | | |
Collapse
|
20
|
Sengupta T, Chung JS, Kang SG. A mechanistic insight into rhodium-doped gold clusters as a better hydrogenation catalyst. NANOSCALE 2020; 12:5125-5138. [PMID: 32073083 DOI: 10.1039/c9nr10258b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The reaction mechanism of the hydrogenation of ethylene on pristine (Aun, n = 8 and 20) and rhodium-doped (AunRh) gold clusters was unveiled by theoretical calculations. All reaction pathways are predicted and the thermodynamic and kinetic parameters are computed and compared. Doping a rhodium atom on the magic gold cluster surface is effective in reducing the activation barriers for hydrogenation and in creating two competitive pathways with significantly higher turnover frequencies. The lower barriers of hydrogenation on the AunRh clusters were analyzed and explained based on distortion/interaction activation strain (DIAS) analysis. Further insights into the reaction mechanism on both types of clusters are provided by intrinsic bond orbital (IBO) calculations. This theoretical study provides an idea to elucidate the hydrogenation mechanism on Au clusters and the effect of the rhodium dopant on the catalytic process.
Collapse
Affiliation(s)
- Turbasu Sengupta
- School of Chemical Engineering, University of Ulsan, 93 Daehakro, Nam-Gu, Ulsan 44610, South Korea.
| | - Jin Suk Chung
- School of Chemical Engineering, University of Ulsan, 93 Daehakro, Nam-Gu, Ulsan 44610, South Korea.
| | - Sung Gu Kang
- School of Chemical Engineering, University of Ulsan, 93 Daehakro, Nam-Gu, Ulsan 44610, South Korea.
| |
Collapse
|
21
|
Svatunek D, Pemberton RP, Mackey JL, Liu P, Houk KN. Concerted [4 + 2] and Stepwise (2 + 2) Cycloadditions of Tetrafluoroethylene with Butadiene: DFT and DLPNO-UCCSD(T) Explorations. J Org Chem 2020; 85:3858-3864. [PMID: 32031811 PMCID: PMC7063576 DOI: 10.1021/acs.joc.0c00222] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
Tetrafluoroethylene and butadiene
form the 2 + 2 cycloadduct under
kinetic control, but the Diels–Alder cycloadduct is formed
under thermodynamic control. Borden and Getty showed that the preference
for 2 + 2 cycloaddition is due to the necessity for syn-pyramidalization of the two CF2 groups in the 4 + 2 transition
state. We have explored the full potential energy surface for the
concerted and stepwise reactions of tetrafluoroethylene and butadiene
with density functional theory, DFT (B3LYP and M06-2X), DLPNO-UCCSD(T),
and CASSCF-NEVPT2 methods and with the distortion/interaction–activation
strain model to explain the energetics of different pathways. The
2 + 2 cycloadduct is formed by an anti-transition state followed by
two rotations and a final bond formation transition state. Energetics
are compared to the reaction of maleic anhydride and ethylene.
Collapse
Affiliation(s)
- Dennis Svatunek
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Ryan P Pemberton
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Joel L Mackey
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| |
Collapse
|
22
|
Understanding chemical reactivity using the activation strain model. Nat Protoc 2020; 15:649-667. [PMID: 31925400 DOI: 10.1038/s41596-019-0265-0] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/29/2019] [Indexed: 12/20/2022]
Abstract
Understanding chemical reactivity through the use of state-of-the-art computational techniques enables chemists to both predict reactivity and rationally design novel reactions. This protocol aims to provide chemists with the tools to implement a powerful and robust method for analyzing and understanding any chemical reaction using PyFrag 2019. The approach is based on the so-called activation strain model (ASM) of reactivity, which relates the relative energy of a molecular system to the sum of the energies required to distort the reactants into the geometries required to react plus the strength of their mutual interactions. Other available methods analyze only a stationary point on the potential energy surface, but our methodology analyzes the change in energy along a reaction coordinate. The use of this methodology has been proven to be critical to the understanding of reactions, spanning the realms of the inorganic and organic, as well as the supramolecular and biochemical, fields. This protocol provides step-by-step instructions-starting from the optimization of the stationary points and extending through calculation of the potential energy surface and analysis of the trend-decisive energy terms-that can serve as a guide for carrying out the analysis of any given reaction of interest within hours to days, depending on the size of the molecular system.
Collapse
|