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Foubelo F, Nájera C, Retamosa MG, Sansano JM, Yus M. Catalytic asymmetric synthesis of 1,2-diamines. Chem Soc Rev 2024; 53:7983-8085. [PMID: 38990173 DOI: 10.1039/d3cs00379e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
The asymmetric catalytic synthesis of 1,2-diamines has received considerable interest, especially in the last ten years, due to their presence in biologically active compounds and their applications for the development of synthetic building blocks, chiral ligands and organocatalysts. Synthetic strategies based on C-N bond-forming reactions involve mainly (a) ring opening of aziridines and azabenzonorbornadienes, (b) hydroamination of allylic amines, (c) hydroamination of enamines and (d) diamination of olefins. In the case of C-C bond-forming reactions are included (a) the aza-Mannich reaction of imino esters, imino nitriles, azlactones, isocyano acetates, and isothiocyanates with imines, (b) the aza-Henry reaction of nitroalkanes with imines, (c) imine-imine coupling reactions, and (d) reductive coupling of enamines with imines, and (e) [3+2] cycloaddition with imines. C-H bond forming reactions include hydrogenation of CN bonds and C-H amination reactions. Other catalytic methods include desymmetrization reactions of meso-diamines.
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Affiliation(s)
- Francisco Foubelo
- Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
| | - Carmen Nájera
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
| | - Ma Gracia Retamosa
- Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
| | - José M Sansano
- Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
| | - Miguel Yus
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
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Smajlagic I, Johnston JN, Dudding T. Secondary Orbital Effect Involving Fluorine is Responsible for Substrate-Controlled Diastereodivergence in the Catalyzed syn-aza-Henry Reaction of α-Fluoronitroalkanes. Chemistry 2023; 29:e202204066. [PMID: 36607705 DOI: 10.1002/chem.202204066] [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: 12/29/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 01/07/2023]
Abstract
The fluorine atom is a powerful, yet enigmatic influence on chemical reactions. True to form, fluorine was recently discovered to effect diastereodivergence in an enantioselective aza-Henry reaction, resulting in a very rare case of syn-β-amino nitroalkane products. More bewildering was the observation of an apparent hierarchy of substituents within this substrate-controlled behavior: Ph>F>alkyl. These cases have now been examined comprehensively by computational methods, including both non-fluorinated and α-fluoro nitronate additions to aldimines catalyzed by a chiral bis(amidine) [BAM] proton complex. This study revealed the network of non-covalent interactions that dictate anti- (α-aryl) versus syn-selectivity (α-alkyl) using α-fluoronitronate nucleophiles, and an underlying secondary orbital interaction between fluorine and the activated azomethine.
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Affiliation(s)
- Ivor Smajlagic
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St., Catharines, ON L2S 3A1, Canada
| | - Jeffrey N Johnston
- Department of Chemistry and Institute of Chemical Biology, Vanderbilt University Nashville, Tennessee, 37235, USA
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St., Catharines, ON L2S 3A1, Canada
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Bing JA, Schley ND, Johnston JN. Fluorine-induced diastereodivergence discovered in an equally rare enantioselective syn-aza-Henry reaction. Chem Sci 2022; 13:2614-2623. [PMID: 35356677 PMCID: PMC8890141 DOI: 10.1039/d1sc05910f] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/03/2022] [Indexed: 11/21/2022] Open
Abstract
Attention to the aza-Henry reaction, particularly over the past two decades, has resulted in a wide range of effective catalysts for the enantio- and diastereoselective versions, driven by the versatility of the β-amino nitroalkane products as precursors to secondary amines and vic-diamines. Despite this broad effort, syn-diastereoselective variants are exceedingly rare. We have discovered a subset of α-fluoro nitroalkane additions that are characterized by an unusual crossover in diastereoselection, often delivering the products with high selectivities. We report here a rigorous comparative analysis of non-fluorinated and α-fluoro nitroalkanes in their additions to azomethines. Both homogeneous and heterogeneous catalysis were applied to probe the possibility that this phenomenon might be more widely operative in the enantioselective additions of fluorine-substituted carbon nucleophiles. A complete correlation within four categories is described that uncovered a clear trend, while revealing a dramatic and distinct reversal of diastereoselection that would normally go undetected.
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Affiliation(s)
- Jade A Bing
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University Nashville Tennessee 37235-1822 USA
| | - Nathan D Schley
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University Nashville Tennessee 37235-1822 USA
| | - Jeffrey N Johnston
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University Nashville Tennessee 37235-1822 USA
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Struble TJ, Smajlagic I, Foy H, Dudding T, Johnston JN. DFT-Based Stereochemical Rationales for the Bifunctional Brønsted Acid/Base-Catalyzed Diastereodivergent and Enantioselective aza-Henry Reactions of α-Nitro Esters. J Org Chem 2021; 86:15606-15617. [PMID: 34669416 DOI: 10.1021/acs.joc.1c02112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A pair of chiral bis(amidine) [BAM] proton complexes provide reagent (catalyst)-controlled, highly diastereo- and enantioselective direct aza-Henry reactions leading to α-alkyl-substituted α,β-diamino esters. A C2-symmetric ligand provides high anti-selectivity, while a nonsymmetric congener exhibits syn-selectivity in this example of diastereodivergent, enantioselective catalysis. A detailed computational analysis is reported for the first time, one that supports distinct models for selectivity resulting from the more hindered binding cavity of the C1-symmetric ligand. Binding in this congested pocket accommodates four hydrogen bond contacts among ligands and substrates, ultimately favoring a pre-syn arrangement highlighted by pyridinium-azomethine activation and quinolinium-nitronate activation. The complementary transition states reveal a wide range of alternatives. Comparing the C1- and C2-symmetric catalysts highlights distinct electrophile binding orientations despite their common hydrogen bond donor-acceptor features. Among the factors driving unusual high syn-diastereoselection are favorable dispersion forces that leverage the anthracenyl substituent of the C1-symmetric ligand.
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Affiliation(s)
- Thomas J Struble
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Ivor Smajlagic
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Hayden Foy
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
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Guanidine-Amide-Catalyzed Aza-Henry Reaction of Isatin-Derived Ketimines: Origin of Selectivity and New Catalyst Design. Molecules 2021; 26:molecules26071965. [PMID: 33807341 PMCID: PMC8037019 DOI: 10.3390/molecules26071965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/29/2021] [Accepted: 03/29/2021] [Indexed: 12/05/2022] Open
Abstract
Density functional theory (DFT) calculations were performed to investigate the mechanism and the enantioselectivity of the aza-Henry reaction of isatin-derived ketimine catalyzed by chiral guanidine–amide catalysts at the M06-2X-D3/6-311+G(d,p)//M06-2X-D3/6-31G(d,p) (toluene, SMD) theoretical level. The catalytic reaction occurred via a three-step mechanism: (i) the deprotonation of nitromethane by a chiral guanidine–amide catalyst; (ii) formation of C–C bonds; (iii) H-transfer from guanidine to ketimine, accompanied with the regeneration of the catalyst. A dual activation model was proposed, in which the protonated guanidine activated the nitronate, and the amide moiety simultaneously interacted with the ketimine substrate by intermolecular hydrogen bonding. The repulsion of CPh3 group in guanidine as well as N-Boc group in ketimine raised the Pauli repulsion energy (∆EPauli) and the strain energy (∆Estrain) of reacting species in the unfavorable si-face pathway, contributing to a high level of stereoselectivity. A new catalyst with cyclopropenimine and 1,2-diphenylethylcarbamoyl as well as sulfonamide substituent was designed. The strong basicity of cyclopropenimine moiety accelerated the activation of CH3NO2 by decreasing the energy barrier in the deprotonation step. The repulsion between the N-Boc group in ketimine and cyclohexyl group as well as chiral backbone in the new catalyst raised the energy barrier in C–C bond formation along the si-face attack pathway, leading to the formation of R-configuration product. A possible synthetic route for the new catalyst is also suggested.
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Sonsona IG, Alegre-Requena JV, Marqués-López E, Gimeno MC, Herrera RP. Asymmetric Organocatalyzed Aza-Henry Reaction of Hydrazones: Experimental and Computational Studies. Chemistry 2020; 26:5469-5478. [PMID: 32012361 DOI: 10.1002/chem.202000232] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Indexed: 12/13/2022]
Abstract
The first asymmetric catalyzed aza-Henry reaction of hydrazones is presented. In this process, quinine was used as the catalyst to synthesize different alkyl substituted β-nitrohydrazides with ee up to 77 %. This ee was improved up to 94 % by a further recrystallization and the opposite enantiomer can be obtained by using quinidine as the catalyst, opening exciting possibilities in fields in which the control of chirality is vital, such as the pharmaceutical industry. Additionally, experimental and ab initio studies were performed to understand the reaction mechanism. The experimental results revealed an unexpected secondary kinetic isotope effect (KIE) that is explained by the calculated reaction pathway, which shows that the protonation of the initial hydrazone and the C-C bond forming reaction occur during a concerted process. This concerted mechanism makes the catalysis conceptually different to traditional base-promoted Henry and aza-Henry reactions.
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Affiliation(s)
- Isaac G Sonsona
- Laboratorio de Organocatálisis Asimétrica, Departamento de, Química Orgánica, Instituto de Síntesis Química y, Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, C/ Pedro Cerbuna, No. 12., 50009, Zaragoza, Spain
| | - Juan V Alegre-Requena
- Laboratorio de Organocatálisis Asimétrica, Departamento de, Química Orgánica, Instituto de Síntesis Química y, Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, C/ Pedro Cerbuna, No. 12., 50009, Zaragoza, Spain
| | - Eugenia Marqués-López
- Laboratorio de Organocatálisis Asimétrica, Departamento de, Química Orgánica, Instituto de Síntesis Química y, Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, C/ Pedro Cerbuna, No. 12., 50009, Zaragoza, Spain
| | - M Concepción Gimeno
- Departamento de Química Inorgánica, Instituto de, Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de, Zaragoza, C/ Pedro Cerbuna, No. 12., 50009, Zaragoza, Spain
| | - Raquel P Herrera
- Laboratorio de Organocatálisis Asimétrica, Departamento de, Química Orgánica, Instituto de Síntesis Química y, Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, C/ Pedro Cerbuna, No. 12., 50009, Zaragoza, Spain
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Saá JM, Lillo VJ, Mansilla J. Catalysis by Networks of Cooperative Hydrogen Bonds. NONCOVALENT INTERACTIONS IN CATALYSIS 2019. [DOI: 10.1039/9781788016490-00066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The main paradigm of today's chemistry is sustainability. In pursuing sustainability, we need to learn from chemical processes carried out by Nature and realize that Nature does not use either strong acids, or strong bases or fancy reagents to achieve outstanding chemical processes. Instead, enzyme activity leans on the cooperation of several chemical entities to avoid strong acids or bases or to achieve such an apparently simple goal as transferring a proton from an NuH unit to an E unit (NuH + E → Nu–EH). Hydrogen bond catalysis emerged strongly two decades ago in trying to imitate Nature and avoid metal catalysis. Now to mount another step in pursuing the goal of sustainability, the focus is upon cooperativity between the different players involved in catalysis. This chapter looks at the concept of cooperativity and, more specifically, (a) examines the role of cooperative hydrogen bonded arrays of the general type NuH⋯(NuH)n⋯NuH (i.e. intermolecular cooperativity) to facilitate general acid–base catalysis, not only in the solution phase but also under solvent-free and catalyst-free conditions, and, most important, (b) analyzes the capacity of designer chiral organocatalysts displaying intramolecular networks of cooperative hydrogen bonds (NCHBs) to facilitate enantioselective synthesis by bringing conformational rigidity to the catalyst in addition to simultaneously increasing the acidity of key hydrogen atoms so to achieve better complementarity in the highly polarized transition states.
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Affiliation(s)
- José M. Saá
- Department de Química, Universitat de les Illes Balears Crta. de Valldemossa km 7.5 07122 Palma de Mallorca Illes Balears Spain
| | - Victor J. Lillo
- Department de Química, Universitat de les Illes Balears Crta. de Valldemossa km 7.5 07122 Palma de Mallorca Illes Balears Spain
| | - Javier Mansilla
- Department de Química, Universitat de les Illes Balears Crta. de Valldemossa km 7.5 07122 Palma de Mallorca Illes Balears Spain
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Maji R, Ugale H, Wheeler SE. Understanding the Reactivity and Selectivity of Fluxional Chiral DMAP-Catalyzed Kinetic Resolutions of Axially Chiral Biaryls. Chemistry 2019; 25:4452-4459. [PMID: 30657217 DOI: 10.1002/chem.201806068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/17/2019] [Indexed: 12/17/2022]
Abstract
Fluxional chiral DMAP-catalyzed kinetic resolutions of axially chiral biaryls were examined using density functional theory. Computational analyses lead to a revised understanding of this reaction in which the interplay of numerous non-covalent interactions control the conformation and flexibility of the active catalyst, the preferred mechanism, and the stereoselectivity. Notably, while the DMAP catalyst itself is confirmed to be highly fluxional, electrostatically driven π⋅⋅⋅π+ interactions render the active, acylated form of the catalyst highly rigid, explaining its pronounced stereoselectivity.
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Affiliation(s)
- Rajat Maji
- Department of Chemistry, Texas A&M University, College Station, TX, 77842, USA
| | - Heena Ugale
- Department of Chemistry, Texas A&M University, College Station, TX, 77842, USA
| | - Steven E Wheeler
- Department of Chemistry, Texas A&M University, College Station, TX, 77842, USA.,Center for Computational Quantum Chemistry, Department of Chemistry, University of Georgia, Athens, GA, 30602, USA
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Xue Y, Wang Y, Cao Z, Zhou J, Chen ZX. Computational insight into the cooperative role of non-covalent interactions in the aza-Henry reaction catalyzed by quinine derivatives: mechanism and enantioselectivity. Org Biomol Chem 2018; 14:9588-9597. [PMID: 27714327 DOI: 10.1039/c6ob01611a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Density functional theory (DFT) calculations were performed to elucidate the mechanism and the origin of the high enantioselectivity of the aza-Henry reaction of isatin-derived N-Boc ketimine catalyzed by a quinine-derived catalyst (QN). The C-C bond formation step is found to be both the rate-determining and the stereo-controlled step. The results revealed the important role of the phenolic OH group in pre-organizing the complex of nitromethane and QN and stabilizing the in situ-generated nitronate and protonated QN. Three possible activation modes for C-C bond formation involving different coordination patterns of catalyst and substrates were studied, and it was found that both the ion pair-hydrogen bonding mode and the Brønsted acid-hydrogen bonding mode are viable, with the latter slightly preferred for the real catalytic system. The calculated enantiomeric excess (ee) favouring the S enantiomer is in good agreement with the experimental result. The high reactivity and enantioselectivity can be ascribed to the cooperative role of the multiple non-covalent interactions, including classical and non-classical H bonding as well as anionπ interactions. These results also highlight the importance of the inclusion of dispersion correction for achieving a reasonable agreement between theory and experiment for the current reaction.
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Affiliation(s)
- Yunsheng Xue
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China. and School of Pharmacy, Xuzhou Medical University, No. 209, Tongshan Road, Xuzhou, 221004, P. R. China
| | - Yuhui Wang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N. Zhongshan Road, Shanghai, 200062, P. R. China
| | - Zhongyan Cao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N. Zhongshan Road, Shanghai, 200062, P. R. China
| | - Jian Zhou
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N. Zhongshan Road, Shanghai, 200062, P. R. China
| | - Zhao-Xu Chen
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China.
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Dong M, Gao J, Liu C, Zhang D. DFT Study on the Formation Mechanism of Normal and Abnormal N-Heterocyclic Carbene–Carbon Dioxide Adducts from the Reaction of an Imidazolium-Based Ionic Liquid with CO2. J Phys Chem B 2017; 121:10276-10284. [DOI: 10.1021/acs.jpcb.7b07191] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mengmeng Dong
- Institute
of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Jun Gao
- Hubei
Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Chengbu Liu
- Institute
of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Dongju Zhang
- Institute
of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
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Maji R, Wheeler SE. Importance of Electrostatic Effects in the Stereoselectivity of NHC-Catalyzed Kinetic Resolutions. J Am Chem Soc 2017; 139:12441-12449. [DOI: 10.1021/jacs.7b01796] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Rajat Maji
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Steven E. Wheeler
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
- Center
for Computational Quantum Chemistry, Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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12
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Copper(II) arylhydrazone complexes as catalysts for C H activation in the Henry reaction in water. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.molcata.2016.05.030] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Taimoory SM, Dudding T. An Evolving Insight into Chiral H-Bond Catalyzed Aza-Henry Reactions: A Cooperative Role for Noncovalent Attractive Interactions Unveiled by Density Functional Theory. J Org Chem 2016; 81:3286-95. [PMID: 27008440 DOI: 10.1021/acs.joc.6b00248] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The role of cooperative effects arising from noncovalent attractive interactions as a vital factor governing stereoinduction in chiral H-bond catalyzed aza-Henry reactions is reported. Supporting this finding were density functional theory (DFT) calculations which revealed a shape and size dependency existed between the catalyst and substrates that when matched lead to high enantioselectivity, as reflected by favorable activation parameters. Associated with optimal catalyst and substrate pairing were a closed catalytic binding pocket and a synclinal orientation of the substrates that reinforced favorable stereoelectronic effects and dispersive type forces. Meanwhile, unfavorable steric interactions were found to be a dominant effect controlling diastereoselection.
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Affiliation(s)
| | - Travis Dudding
- Brock University , 1812 Sir Isaac Brock Way, St. Catharines, ON, L2S 3A1 Canada
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Belding L, Stoyanov P, Dudding T. Phase-Transfer Catalysis via a Proton Sponge: A Bifunctional Role for Biscyclopropenimine. J Org Chem 2015; 81:553-8. [DOI: 10.1021/acs.joc.5b02395] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Lee Belding
- Brock University, 500 Glenridge
Avenue, St. Catharines, ON L2S 3A1 Canada
| | - Peter Stoyanov
- Brock University, 500 Glenridge
Avenue, St. Catharines, ON L2S 3A1 Canada
| | - Travis Dudding
- Brock University, 500 Glenridge
Avenue, St. Catharines, ON L2S 3A1 Canada
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Computational Mechanism Study of Catalyst-Dependent Competitive 1,2-C→C, −O→C, and −N→C Migrations from β-Methylene-β-silyloxy-β-amido-α-diazoacetate: Insight into the Origins of Chemoselectivity. ACS Catal 2015. [DOI: 10.1021/acscatal.5b02103] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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16
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Zlotin SG, Kochetkov SV. C2-Symmetric diamines and their derivatives as promising organocatalysts for asymmetric synthesis. RUSSIAN CHEMICAL REVIEWS 2015. [DOI: 10.1070/rcr4562] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Qi ZH, Zhang Y, Ruan GY, Zhang Y, Wang Y, Wang XW. Theoretical studies on the activation mechanism involving bifunctional tertiary amine–thioureas and isatylidene malononitriles. RSC Adv 2015. [DOI: 10.1039/c5ra01821h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
DFT studies on the activation mechanism of the Michael addition reactions containing bifunctional tertiary amine–thioureas and isatylidene malononitriles have been performed at the B3LYP/6-311++G(d,p)//B3LYP/6-31G(d) level of theory.
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Affiliation(s)
- Zheng-Hang Qi
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
| | - Ye Zhang
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
| | - Gui-Yu Ruan
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
| | - Yi Zhang
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
| | - Yong Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
| | - Xing-Wang Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
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