1
|
Deraet X, Desmedt E, Van Lommel R, Van Speybroeck V, De Proft F. The electrophilic aromatic bromination of benzenes: mechanistic and regioselective insights from density functional theory. Phys Chem Chem Phys 2023; 25:28581-28594. [PMID: 37703074 DOI: 10.1039/d3cp03137c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
The HBr-assisted electrophilic aromatic bromination of benzene, anisole and nitrobenzene was investigated using static DFT calculations in gas phase and implicit apolar (CCl4) and polar (acetonitrile) solvent models at the ωB97X-D/cc-pVTZ level of theory. The reaction profiles corresponding to either a direct substitution reaction or an addition-elimination process were constructed and insight into the preferred regioselectivity was provided using a combination of conceptual DFT reactivity indices, aromaticity indices, Wiberg bond indices and the non-covalent interaction index. Our results show that under the considered reaction conditions the bromination reaction preferentially occurs through an addition-elimination mechanism and without formation of a stable charged Wheland intermediate. The ortho/para directing effect of the electron-donating methoxy-group in anisole was ascribed to a synergy between strong electron delocalisation and attractive interactions. In contrast, the preferred meta-addition on nitrobenzene could not be traced back to any of these effects, nor to the intrinsic reactivity property of the reactant. In this case, an electrostatic clash between the ipso-carbon of the ring and the nitrogen atom resulting from the later nature of the rate-determining step, with respect to anisole, appeared to play a crucial role.
Collapse
Affiliation(s)
- Xavier Deraet
- Department of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Elsene, Brussels, Belgium.
| | - Eline Desmedt
- Department of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Elsene, Brussels, Belgium.
| | - Ruben Van Lommel
- Department of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Elsene, Brussels, Belgium.
- Molecular Design and Synthesis, Department of Chemistry, KU Leuven, Celestijnenlaan 200F Leuven Chem&Tech, Box 2404, 3001 Leuven, Belgium
| | | | - Frank De Proft
- Department of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Elsene, Brussels, Belgium.
| |
Collapse
|
2
|
Qiu CS, Qiu NP, Flinn C, Zhao Y. DFT mechanistic studies of boron-silicon exchange reactions between silyl-substituted arenes and boron bromides. Phys Chem Chem Phys 2023; 25:6714-6725. [PMID: 36805579 DOI: 10.1039/d2cp05615a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
C-B bond forming reactions are important methodologies in modern synthetic chemistry, since many borylated organic substrates, ranging from alkanes and alkenes to arenes and heteroarenes, are useful intermediates for the synthesis of natural products, pharmaceuticals, and organic π-conjugated materials. Among numerous borylation methods, C-Si/B-Br exchange reactions have attracted increasing attention in recent years. While experimental exploration has been continually carried out for more than two decades, mechanistic insights into this type of reaction have not yet been clearly established. To address this deficiency of knowledge, we performed density functional theory (DFT) calculations to map out the reaction pathways for a range of boron-silicon exchange reactions between boron tribromide (BBr3) and trimethylsilyl-substituted arenes (TMSAr). Our computational analyses have disclosed the energetic, structural, and electronic properties for key stationary points on the potential energy surfaces (PES) in both the gas and solution (CH2Cl2) phases.
Collapse
Affiliation(s)
- Christopher S Qiu
- Department of Chemistry, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.
| | - Nicholas P Qiu
- Department of Chemistry, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.
| | - Christopher Flinn
- Department of Chemistry, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.
| | - Yuming Zhao
- Department of Chemistry, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.
| |
Collapse
|
3
|
Lichte D, Pirkl N, Heinrich G, Dutta S, Goebel JF, Koley D, Gooßen LJ. Palladium-Catalyzed para-C-H Arylation of Anilines with Aromatic Halides. Angew Chem Int Ed Engl 2022; 61:e202210009. [PMID: 36112053 PMCID: PMC9828783 DOI: 10.1002/anie.202210009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Indexed: 01/12/2023]
Abstract
Controlling regioselectivity in C-H functionalizations is a key challenge in chemical method development. In arenes, functionalizations are most difficult to direct towards the C-H group furthest away from a substituent, in its para position. We herein demonstrate how the para-C-H arylation of anilines with non-activated aryl halides, elusive to date, is achieved by a base-assisted "metalla-tautomerism" approach. A proton is abstracted from the aniline substrate and replaced by an arylpalladium species, generated from the aryl halide coupling partner. In this step, the palladium is directed away from the N- to the tautomeric para-C-H position by a large phosphine ligand combined with a triphenylmethyl shielding group. The triphenylmethyl group is easily installed and removed, and can be recycled.
Collapse
Affiliation(s)
- Dominik Lichte
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| | - Nico Pirkl
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| | - Gregor Heinrich
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| | - Sayan Dutta
- Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)Kolkata, Mohanpur 741 246India
| | - Jonas F. Goebel
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| | - Debasis Koley
- Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)Kolkata, Mohanpur 741 246India
| | - Lukas J. Gooßen
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| |
Collapse
|
4
|
Shernyukov AV, Salnikov GE, Krasnov VI, Genaev AM. Cluster halogenation of adamantane and its derivatives with bromine and iodine monochloride. Org Biomol Chem 2022; 20:8515-8527. [DOI: 10.1039/d2ob01455f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Noncatalytic halogenation of adamantane with Br2 or ICl proceeds according to the cluster mechanism featuring high kinetic order in halogen and a sharp decrease in DFT energy barrier when additional halogen molecules are involved in the system.
Collapse
Affiliation(s)
- Andrey V. Shernyukov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - George E. Salnikov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - Vyacheslav I. Krasnov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - Alexander M. Genaev
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| |
Collapse
|
5
|
Nesterov ID, Belen’kii LI, Pivina TS. Quantum chemical simulation for the mechanism of benzene bromination. Russ Chem Bull 2021. [DOI: 10.1007/s11172-021-3187-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
6
|
Li B, Li Y, Dang Y, Houk KN. Post-Transition State Bifurcation in Iron-Catalyzed Arene Aminations. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Bo Li
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, China
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Yuli Li
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, China
| | - Yanfeng Dang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, China
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| |
Collapse
|
7
|
Pliego JR. Diradical character of the bond breaking in the reaction of Br2 with benzene: Reliable barriers using the CR-CC(2,3) method. COMPUT THEOR CHEM 2021. [DOI: 10.1016/j.comptc.2021.113171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
8
|
Shernyukov AV, Salnikov GE, Rudakov DA, Genaev AM. Noncatalytic Bromination of Icosahedral Dicarboranes: The Key Role of Anionic Bromine Clusters Facilitating Br Atom Insertion into the B-H σ-Bond. Inorg Chem 2021; 60:3106-3116. [PMID: 33595316 DOI: 10.1021/acs.inorgchem.0c03392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanism of the noncatalytic bromination of carboranes was studied experimentally and theoretically. We found that the reactions of o- and m-carboranes 1 and 2 with elemental bromine are first order in the substrate but unusually high (approximately fifth) order in bromine. The calculated energy barriers of these reactions decrease sharply as more bromine molecules are added to the quantum-chemical system. A considerable primary deuterium kinetic isotope effect for the bromination of 2 indicates that the rate-limiting stage is B-H bond breakage. According to quantum-chemical reaction path calculations, the bond breakage proceeds after the intrusion of a bromine atom into the B-H σ-bond. The 9-Br and 9-OH substituents in carborane 1 strongly retard the bromination of the corresponding derivatives. The bromination mechanism of 9-OH-1 is complex and includes neutral, deprotonated, and protonated forms of the carborane. The high experimental kinetic reaction order in bromine, together with quantum chemical modeling, points to a specific mechanism of bromination facilitated by anionic bromine clusters which significantly stabilize the transition state.
Collapse
Affiliation(s)
- Andrey V Shernyukov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - George E Salnikov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - Dmitry A Rudakov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - Alexander M Genaev
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| |
Collapse
|
9
|
Munárriz J, Gallegos M, Contreras-García J, Martín Pendás Á. Energetics of Electron Pairs in Electrophilic Aromatic Substitutions. Molecules 2021; 26:513. [PMID: 33478091 PMCID: PMC7835785 DOI: 10.3390/molecules26020513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 11/16/2022] Open
Abstract
The interacting quantum atoms approach (IQA) as applied to the electron-pair exhaustive partition of real space induced by the electron localization function (ELF) is used to examine candidate energetic descriptors to rationalize substituent effects in simple electrophilic aromatic substitutions. It is first shown that inductive and mesomeric effects can be recognized from the decay mode of the aromatic valence bond basin populations with the distance to the substituent, and that the fluctuation of the population of adjacent bonds holds also regioselectivity information. With this, the kinetic energy of the electrons in these aromatic basins, as well as their mutual exchange-correlation energies are proposed as suitable energetic indices containing relevant information about substituent effects. We suggest that these descriptors could be used to build future reactive force fields.
Collapse
Affiliation(s)
- Julen Munárriz
- Departamento de Química Física y Analítica, Universidad de Oviedo, 33006 Oviedo, Spain;
| | - Miguel Gallegos
- Departamento de Química Física y Analítica, Universidad de Oviedo, 33006 Oviedo, Spain;
| | | | - Ángel Martín Pendás
- Departamento de Química Física y Analítica, Universidad de Oviedo, 33006 Oviedo, Spain;
| |
Collapse
|
10
|
Stuyver T, Danovich D, De Proft F, Shaik S. Electrophilic Aromatic Substitution Reactions: Mechanistic Landscape, Electrostatic and Electric-Field Control of Reaction Rates, and Mechanistic Crossovers. J Am Chem Soc 2019; 141:9719-9730. [PMID: 31140274 DOI: 10.1021/jacs.9b04982] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study investigates the rich mechanistic landscape of the iconic electrophilic aromatic substitution (EAS) reaction class, in the gas phase, in solvents, and under stimulation by oriented external electric fields. The study uses DFT calculations, complemented by a qualitative valence bond (VB) perspective. We construct a comprehensive and unifying framework that elucidates the many surprising mechanistic features, uncovered in recent years, of this class of reactions. For example, one of the puzzling issues which have attracted significant interest recently is the finding of a variety of concerted mechanisms that do not involve the formation of σ-complex intermediates, in apparent contradiction to the generally accepted textbook mechanism. Our VB modeling elucidates the existence of both the concerted and stepwise mechanisms and uncovers the root causes and necessary conditions for the appearance of these intermediates. Furthermore, our VB analysis offers insight into the potential applications of external electric fields as smart, green, and selective catalysts, which can control at will reaction rates, as well as mechanistic crossovers, for this class of reactions. Finally, we highlight how understanding of the electric fields effect on the EAS reaction could lead to the formulation of guiding principles for the design of improved heterogeneous catalysts. Overall, our analysis underscores the powerful synergy offered by combining molecular orbital and VB theory to tackle interesting and challenging mechanistic questions in chemistry.
Collapse
Affiliation(s)
- Thijs Stuyver
- Department of Organic Chemistry and the Lise Meitner-Minerva Centre for Computational Quantum Chemistry , The Hebrew University , Jerusalem 91904 , Israel.,Algemene Chemie , Vrije Universiteit Brussel , Pleinlaan 2 , 1050 Brussels , Belgium
| | - David Danovich
- Department of Organic Chemistry and the Lise Meitner-Minerva Centre for Computational Quantum Chemistry , The Hebrew University , Jerusalem 91904 , Israel
| | - Frank De Proft
- Algemene Chemie , Vrije Universiteit Brussel , Pleinlaan 2 , 1050 Brussels , Belgium
| | - Sason Shaik
- Department of Organic Chemistry and the Lise Meitner-Minerva Centre for Computational Quantum Chemistry , The Hebrew University , Jerusalem 91904 , Israel
| |
Collapse
|
11
|
Krivdin LB. Computational protocols for calculating 13C NMR chemical shifts. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 112-113:103-156. [PMID: 31481156 DOI: 10.1016/j.pnmrs.2019.05.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/19/2019] [Accepted: 05/20/2019] [Indexed: 06/10/2023]
Abstract
The most recent results dealing with the computation of 13C NMR chemical shifts in chemistry (small molecules, saturated, unsaturated and aromatic compounds, heterocycles, functional derivatives, coordination complexes, carbocations, and natural products) are reviewed, paying special attention to theoretical background and accuracy, the latter involving solvent effects, vibrational corrections, and relativistic effects.
Collapse
Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russia.
| |
Collapse
|
12
|
Shernyukov AV, Genaev AM, Salnikov GE, Shubin VG, Rzepa HS. Elevated reaction order of 1,3,5-tri-tert-butylbenzene bromination as evidence of a clustered polybromide transition state: a combined kinetic and computational study. Org Biomol Chem 2019; 17:3781-3789. [DOI: 10.1039/c9ob00607a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The kinetics and mechanism of concurrent bromo-de-protonation and bromo-de-tert-butylation of 1,3,5-tri-tert-butylbenzene at different bromine concentrations were studied experimentally and theoretically.
Collapse
Affiliation(s)
- Andrey V. Shernyukov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry
- Siberian Branch of the Russian Academy of Sciences
- Russian Federation
- Novosibirsk State University
- Russian Federation
| | - Alexander M. Genaev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry
- Siberian Branch of the Russian Academy of Sciences
- Russian Federation
| | - George E. Salnikov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry
- Siberian Branch of the Russian Academy of Sciences
- Russian Federation
- Novosibirsk State University
- Russian Federation
| | - Vyacheslav G. Shubin
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry
- Siberian Branch of the Russian Academy of Sciences
- Russian Federation
| | | |
Collapse
|
13
|
Galabov B, Nalbantova D, Schleyer PVR, Schaefer HF. Electrophilic Aromatic Substitution: New Insights into an Old Class of Reactions. Acc Chem Res 2016; 49:1191-9. [PMID: 27268321 DOI: 10.1021/acs.accounts.6b00120] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The classic SEAr mechanism of electrophilic aromatic substitution (EAS) reactions described in textbooks, monographs, and reviews comprises the obligatory formation of arenium ion intermediates (σ complexes) in a two-stage process. Our findings from several studies of EAS reactions challenge the generality of this mechanistic paradigm. This Account focuses on recent computational and experimental results for three types of EAS reactions: halogenation with molecular chlorine and bromine, nitration by mixed acid (mixture of nitric and sulfuric acids), and sulfonation with SO3. Our combined computational and experimental investigation of the chlorination of anisole with molecular chlorine in CCl4 found that addition-elimination pathways compete with the direct substitution processes. Detailed NMR investigation of the course of experimental anisole chlorination at varying temperatures revealed the formation of addition byproducts. Moreover, in the absence of Lewis acid catalysis, the direct halogenation processes do not involve arenium ion intermediates but instead proceed via concerted single transition states. We also obtained analogous results for the chlorination and bromination of several arenes in nonpolar solvents. We explored by theoretical computations and experimental spectroscopic studies the classic reaction of benzene nitration by mixed acid. The structure of the first intermediate in this process has been a subject of contradicting views. We have reported clear experimental UV/vis spectroscopic evidence for the formation of the first intermediate in this reaction. Our broader theoretical modeling of the process considers the effects of the medium as a bulk solvent but also the specific interactions of a H2SO4 solvent molecule with intermediates and transition states along the reaction path. In harmony with the obtained spectroscopic data, our computational results reveal that the structure of the initial π complex precludes the possibility of electronic charge transfer from the benzene π system to the nitronium unit. In contrast to usual interpretations, our computational results provide compelling evidence that in nonpolar, noncomplexing media and in the absence of catalysts, the mechanism of aromatic sulfonation with sulfur trioxide is concerted and does not involve the conventional σ-complex (Wheland) intermediates. Stable under such conditions, (SO3)2 dimers react with benzene much more readily than monomeric sulfur trioxide. In polar (complexing) media, the reaction follows the classic two-stage SEAr mechanism. Still, the rate-controlling transition state involves two SO3 molecules. The reactivity and regioselectivity in EAS reactions that follow the classic mechanistic scheme are quantified using a theoretically evaluated quantity, the electrophile affinity (Eα), which measures the stabilization energy associated with the formation of arenium ions. Examples of applications are provided.
Collapse
Affiliation(s)
- Boris Galabov
- Department
of Chemistry and Pharmacy, University of Sofia, Sofia 1164, Bulgaria
| | - Didi Nalbantova
- Department
of Chemistry and Pharmacy, University of Sofia, Sofia 1164, Bulgaria
| | - Paul von R. Schleyer
- Center
for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Henry F. Schaefer
- Center
for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| |
Collapse
|