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Ciber L, Ričko S, Gregorc J, Pozgan F, Svete J, Brodnik H, Štefane B, Grošelj U. Mechanistic Insights into Annulation of Arylidene‐Δ2‐pyrrolin‐4‐ones by Cinchona Squaramide‐Based Organocatalysts. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202101369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Luka Ciber
- University of Ljubljana, Faculty of Chemistry and Chemical Technology SLOVENIA
| | - Sebastijan Ričko
- Univerza v Ljubljani Fakulteta za Kemijo in Kemijsko tehnologijo SLOVENIA
| | - Jure Gregorc
- University of Ljubljana Faculty of Chemistry and Chemical Technology SLOVENIA
| | | | | | | | | | - Uroš Grošelj
- University of Ljubljana Faculty of Chemistry and Chemical Technology SLOVENIA
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2
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Li Y, Li Z, Zhang Z. Mechanism and regio- and stereoselectivity in NHC-catalyzed reaction of 2-bromoenals with β-ketoamides. MOLECULAR CATALYSIS 2021. [DOI: 10.1016/j.mcat.2021.111790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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3
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Li Y, Li Z, Zhang Z. Mechanism and regio- and stereoselectivity in an NHC-catalyzed Mannich/lactamization domino reaction. Phys Chem Chem Phys 2021; 23:6204-6212. [PMID: 33687420 DOI: 10.1039/d1cp00369k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Density functional theory (DFT) calculations (M06-2X) have been employed to disclose the mechanisms and regio- and stereo-selectivities of the N-heterocyclic carbene (NHC)-catalyzed reaction of 2-benzothiazolimines and α-chloroaldehydes. The preferred mechanism is initiated by the nucleophilic attack of NHC on α-chloroaldehyde (first step), followed by 1,2-proton transfer which was assisted by the Brønsted acid DABCO·H+ to generate the Breslow intermediate (second step). The cleavage of the C-Cl bond (third step) and deprotonation (fourth step) form the enolate intermediate. This further reacts with 2-benzothiazolimine which leads to the formation of a new C-C bond (fifth step). Subsequent cyclization takes place via the formation of a new C-N bond (sixth step). Catalyst regeneration completes the whole catalytic cycle and affords the final product (seventh step). The DFT results indicate that the fifth step determines the stereochemistry of the reaction and leads to benzothiazolopyrimidinone with the SS configuration, which agrees well with experimental observations. Intramolecular cyclization is found to be the regioselectivity-determining step, for which the [4+2] annulation pathway is more preferred than that via [2+2] annulation, which again agrees well with experimental observations. Based on the mechanism proposed, the origins of regio- and stereoselectivities have also been investigated by performing distortion/interaction, natural bond orbital (NBO) and non-covalent interaction (NCI) analyses. The mechanistic insights gained in this work should be helpful in the rational design of potential catalysts for analogous reactions.
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Affiliation(s)
- Yan Li
- School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, P. R. China.
| | - Zhilin Li
- School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, P. R. China.
| | - Zhiqiang Zhang
- School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, P. R. China.
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4
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Li Y, Li Z, Zhang Z. Mechanistic study on the NHC-catalyzed [3+4] annulation of enals and thiazolones. NEW J CHEM 2021. [DOI: 10.1039/d1nj01617b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Reaction mechanisms and origins of regio- and stereo-selectivities of NHC catalyzed [3+4] annulation of enals and thiazolones.
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Affiliation(s)
- Yan Li
- School of Chemical Engineering
- University of Science and Technology
- Liaoning
- P. R. China
| | - Zhilin Li
- School of Chemical Engineering
- University of Science and Technology
- Liaoning
- P. R. China
| | - Zhiqiang Zhang
- School of Chemical Engineering
- University of Science and Technology
- Liaoning
- P. R. China
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5
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Kee CW, Wong MW. Bicyclic Guanidine-Catalyzed Asymmetric Cycloaddition Reaction of Anthrones-Bifunctional Binding Modes and Origin of Stereoselectivity. J Org Chem 2020; 85:15139-15153. [PMID: 33175532 DOI: 10.1021/acs.joc.0c02008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We report a computational analysis of the [5,5] bicyclic guanidine-catalyzed asymmetric cycloaddition reaction of anthrones. Based on extensive conformational search of key intermediates and transition states on the potential energy surface and density functional theory calculations, we studied five plausible binding modes between the guanidine catalyst and substrates for this reaction. Our results indicate that the most favorable pathway is a stepwise conjugate addition-Aldol sequence via the dual hydrogen-bond binding mode. The predicted level of enantioselectivity is in good agreement with experimental values. Trends in variation of substrates and catalysts have also been reproduced by our calculations. Decomposition analysis revealed the significance of aromatic interactions in stabilizing the key enantioselectivity-determining transition state structures.
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Affiliation(s)
- Choon Wee Kee
- Process & Catalysis Research, Institute of Chemical and Engineering Sciences, 1 Pesek Road, Singapore 627899.,Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Ming Wah Wong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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6
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Li Y, Li Z, Zhang Z. A computational study on NHC-Catalyzed [3+4] annulation between isatin-derived enal and aurone-derived azadiene: Insights into mechanism and stereoselectivity. MOLECULAR CATALYSIS 2020. [DOI: 10.1016/j.mcat.2020.111183] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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Mechanisms and origins of stereoselectivity of NHC-catalyzed reaction of aldehyde and butadienoate. MOLECULAR CATALYSIS 2020. [DOI: 10.1016/j.mcat.2020.111030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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8
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Ashraf MA, Li C, Norouzi F, Zhang D. New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivity. CR CHIM 2020. [DOI: 10.5802/crchim.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Yang H, Wong MW. Automatic Conformational Search of Transition States for Catalytic Reactions Using Genetic Algorithm. J Phys Chem A 2019; 123:10303-10314. [DOI: 10.1021/acs.jpca.9b09543] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Hui Yang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Ming Wah Wong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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10
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Ser CT, Yang H, Wong MW. Iodoimidazolinium-Catalyzed Reduction of Quinoline by Hantzsch Ester: Halogen Bond or Brønsted Acid Catalysis. J Org Chem 2019; 84:10338-10348. [DOI: 10.1021/acs.joc.9b01494] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Cher Tian Ser
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Hui Yang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Ming Wah Wong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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11
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Li Y, Zhang Z. Mechanisms and Stereoselectivities of NHC-Catalyzed [3 + 4] Cycloaddition Reaction between Isatin-Derived Enal and N-(ortho
-Chloromethyl)aryl Amide. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900087] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yan Li
- School of Chemical Engineering; University of Science and Technology Liaoning; 114051 Anshan P. R. China
| | - Zhiqiang Zhang
- School of Chemical Engineering; University of Science and Technology Liaoning; 114051 Anshan P. R. China
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12
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Li Y, Zhang Z. Mechanism and stereoselectivity in NHC-catalyzed β-functionalization of saturated carboxylic ester. RSC Adv 2019; 9:7635-7644. [PMID: 35521168 PMCID: PMC9061211 DOI: 10.1039/c8ra10262g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 02/28/2019] [Indexed: 12/18/2022] Open
Abstract
To understand the mechanism and origin of the stereoselectivity of the [3 + 2] annulation reaction between a carboxylic ester and an isatin generating spirooxindole lactone catalyzed by N-heterocyclic carbene (NHC), density functional theory (DFT) calculations have been carried out. DFT results indicate that the catalytic cycle begins with the coupling of the catalyst with benzotriazole ester, followed by α-deprotonation to produce the enolate intermediate. The subsequent 1,4-proton transfer affords the homoenolate intermediate. The next crucial step is the stereoselective C-C bond formation. Then proton transfer takes place leading to the formation of the lactone intermediate. Finally, the elimination of the catalyst furnishes the final product. The presence of 1-hydroxybenzotriazole (HOBt) dramatically accelerates the proton transfer step. More importantly, HOBt has a non-negligible impact on stereoselective C-C bond formation, and the SR-configured product is the major stereoisomer of the annulation product, which is in good agreement with the experimental observations. The differential π⋯π stacking, C-H⋯π, lone pair (LP)⋯π and repulsion interactions are found to be responsible for the stereoselectivity. The obtained mechanistic insights should provide valuable information for understanding the important roles of the NHC catalyst and HOBt additive and be helpful for designing better NHC catalysts for this kind of reaction.
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Affiliation(s)
- Yan Li
- School of Chemical Engineering, University of Science and Technology Liaoning Anshan 114051 P. R. China +86-412-5929627 +86-18741219506
| | - Zhiqiang Zhang
- School of Chemical Engineering, University of Science and Technology Liaoning Anshan 114051 P. R. China +86-412-5929627 +86-18741219506
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13
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Li Y, Zhang Z, Liang C. Understanding the mechanism and stereoselectivity of NHC-catalyzed [3 + 2] cycloaddition of 3-bromoenals and isatin N-Boc ketimines. Org Biomol Chem 2019; 16:9251-9258. [PMID: 30483682 DOI: 10.1039/c8ob02804d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism and origin of stereoselectivities in N-heterocyclic carbine (NHC)-catalyzed [3 + 2] cycloaddition of 3-bromoenals and isatin N-Boc ketimines have been studied using density functional theory (DFT) calculations. Various possible reaction pathways were examined and analyzed. Our calculation results reveal that the catalytic cycle can be characterized by six steps: nucleophilic attack of a catalyst on 3-bromoenal (step I); [1,2]-proton transfer (step II); addition to the other reactant isatin N-Boc ketimine (step III); debromination (step IV); intramolecular cycloaddition concerted with hydrogen-elimination (step V) and elimination of the NHC catalyst (step VI). For step II, besides the direct [1,2]-proton transfer, the mediator (base and water)-assisted proton transfer has been investigated, and the DFT results show that the 2H2O cluster-mediated proton transfer is most energy favorable. The carbon-carbon bond formation step (step III) is calculated to be the stereoselectivity-determining step and the S-configuration product is the predominant product, which are in good agreement with the experimental observations. The mechanistic insights gained in this work should be helpful for other NHC-catalyzed reactions.
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Affiliation(s)
- Yan Li
- School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China.
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14
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Li Y, Zhang Z. Mechanisms of phosphine-catalyzed [3+3] cycloaddition of ynones and azomethine imines: a DFT study. NEW J CHEM 2019. [DOI: 10.1039/c9nj01943j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mechanisms of PPh3-catalyzed [3+3] cycloaddition between a ynone and an azomethine imine.
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Affiliation(s)
- Yan Li
- School of Chemical Engineering
- University of Science and Technology Liaoning
- Anshan 114051
- P. R. China
| | - Zhiqiang Zhang
- School of Chemical Engineering
- University of Science and Technology Liaoning
- Anshan 114051
- P. R. China
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15
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See JY, Yang H, Zhao Y, Wong MW, Ke Z, Yeung YY. Desymmetrizing Enantio- and Diastereoselective Selenoetherification through Supramolecular Catalysis. ACS Catal 2018. [DOI: 10.1021/acscatal.7b03510] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Jie Yang See
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Hui Yang
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Yu Zhao
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Ming Wah Wong
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Zhihai Ke
- Department
of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People’s Republic of China
| | - Ying-Yeung Yeung
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
- Department
of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People’s Republic of China
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16
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Li Y, Liu T, Liang C. Mechanisms and stereoselectivities of NHC-catalyzed [4 + 2] cycloaddition reaction between phenylacetic acid and o-quinone methide: A computational investigation. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.mcat.2017.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Kee CW, Peh KQE, Wong MW. Coupling Reactions of Alkynyl Indoles and CO 2 by Bicyclic Guanidine: Origin of Catalytic Activity? Chem Asian J 2017; 12:1780-1789. [PMID: 28582609 DOI: 10.1002/asia.201700338] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/11/2017] [Indexed: 01/05/2023]
Abstract
Density functional theory calculations were used to investigate the three possible modes of activation for the coupling of CO2 with alkynyl indoles in the presence of a guanidine base. The first of these mechanisms, involving electrophilic activation, was originally proposed by Skrydstrup et al. (Angew. Chem. Int. Ed. 2015, 54, 6682). The second mechanism involves the nucleophilic activation of CO2 . Both of these electrophilic and nucleophilic activation processes involve the formation of a guanidine-CO2 zwitterion adduct. We have proposed a third mechanism involving the bifunctional activation of the bicyclic guanidine catalyst, allowing for the simultaneous activation of the indole and CO2 by the catalyst. We demonstrated that a second molecule of catalyst is required to facilitate the final cyclization step. Based on the calculated turnover frequencies, our newly proposed bifunctional activation mechanism is the most plausible pathway for this reaction under these experimental conditions. Furthermore, we have shown that this bifunctional mode of activation is consistent with the experimental results. Thus, this guanidine-catalyzed reaction favors a specific-base catalyzed mechanism rather than the CO2 activation mechanism. We therefore believe that this bifunctional mechanism for the activation of bicyclic guanidine is typical of most CO2 coupling reactions.
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Affiliation(s)
- Choon Wee Kee
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore.,Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Kai Qi Elizabeth Peh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Ming Wah Wong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
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18
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Mechanisms and stereoselectivities of phosphine-catalyzed Rauhut-Currier reaction between N -phenylmaleimide and 2-benzoyl acrylate: A computational investigation. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.mcat.2017.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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19
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Guo J, Wong MW. Cinchona Alkaloid-Squaramide Catalyzed Sulfa-Michael Addition Reaction: Mode of Bifunctional Activation and Origin of Stereoinduction. J Org Chem 2017; 82:4362-4368. [DOI: 10.1021/acs.joc.7b00388] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Jinlong Guo
- NUS
Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 28 Medical Drive, Singapore 117456
| | - Ming Wah Wong
- NUS
Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 28 Medical Drive, Singapore 117456
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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Yuan H, Zhang J. Mechanistic insights on DBU catalyzedβ-amination of nbs to chalcone driving by water: Multiple roles of water. J Comput Chem 2017; 38:438-445. [DOI: 10.1002/jcc.24700] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 12/01/2016] [Accepted: 12/01/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Haiyan Yuan
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Advanced Energy Materials Research Center, Faculty of Chemistry; Northeast Normal University; Renmin Street 5268# Changchun 130024 China
| | - Jingping Zhang
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Advanced Energy Materials Research Center, Faculty of Chemistry; Northeast Normal University; Renmin Street 5268# Changchun 130024 China
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Li Y, Tian R, Du S. Mechanisms and stereoselectivities of the DABCO-catalyzed Rauhut–Currier reaction of α,β-unsaturated ketones and aryl acrylates: a computational investigation. RSC Adv 2017. [DOI: 10.1039/c6ra25311c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Mechanism of the RC reaction in the absence and presence of PhOH.
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Affiliation(s)
- Yan Li
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin
- China
| | - Ruixue Tian
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin
- China
| | - Shiwen Du
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin
- China
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Xue H, Tan CH, Wong MW. Guanidine-catalyzed asymmetric Strecker reaction: modes of activation and origin of stereoselectivity. CAN J CHEM 2016. [DOI: 10.1139/cjc-2016-0307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Density functional theory calculations were employed to study the catalytic mechanism, modes of activation, and origin of enantioselectivity of guanidine-catalyzed asymmetric Strecker reaction of N-benzhydryl imine with hydrogen cyanide. Two types of bifunctional activation mode were identified, namely conventional bifunctional Brønsted acid activation and unconventional bifunctional Brønsted–Lewis acid activation. The lowest-energy transition states correspond to the conventional bifunctional mode of activation. The calculated enantiomeric excess, based on eight lowest-energy C–C bond forming transition states, is in good accord with observed enantioselectivity. NCI (noncovalent interaction) analysis of the key transition states reveals extensive noncovalent interactions, including aromatic interactions and hydrogen bonds, between the guanidinium catalyst and substrates. Multiple aryl–aryl interactions between the phenyl groups of guanidine catalyst and the phenyl rings of N-benzhydryl imine are the key stabilizations in the most stable (R)-inducing transition state. Differential attractive aryl–aryl stabilization is the major factor for stereoinduction.
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Affiliation(s)
- Hansong Xue
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Choon-Hong Tan
- Department of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Ming Wah Wong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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Kee CW, Wong MW. In Silico Design of Halogen-Bonding-Based Organocatalyst for Diels–Alder Reaction, Claisen Rearrangement, and Cope-Type Hydroamination. J Org Chem 2016; 81:7459-70. [DOI: 10.1021/acs.joc.6b01147] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Choon Wee Kee
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, Singapore 117543
| | - Ming Wah Wong
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, Singapore 117543
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Yuan H, Zheng Y, Zhang J. Understanding the Mechanism of the Lewis Acid Promoted [3 + 2] Cycloaddition of Propargylic Alcohol and α-Oxo Ketene Dithioacetals. J Org Chem 2016; 81:1989-97. [DOI: 10.1021/acs.joc.5b02826] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Haiyan Yuan
- Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, China
| | - Yiying Zheng
- Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, China
| | - Jingping Zhang
- Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, China
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25
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Li Y, Du S. Understanding the mechanisms, regioselectivies and enantioselectivities of the DMAP-catalyzed [2 + 4] cycloaddition of γ-methyl allenoate and phenyl(phenyldiazenyl)methanone. RSC Adv 2016. [DOI: 10.1039/c6ra16321a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
DMAP-catalyzed [2 + 4] cycloaddition reaction.
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Affiliation(s)
- Yan Li
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin
- China
| | - Shiwen Du
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin
- China
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26
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Li Y, Du S, Du Z, Chen C. A theoretical study of DABCO and PPh3 catalyzed annulations of allenoates with azodicarboxylate. RSC Adv 2016. [DOI: 10.1039/c6ra19308k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous experiments have shown that DABCO-catalyzed annulation of 2,3-butadienoate and diethylazodicarboxylate leads to 1,2-diazetidine (reaction (1)), whereas PPh3-catalyzed 2-benzyl-2,3-butadienoate and diethylazodicarboxylate gives pyrazoline (reaction (2)).
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Affiliation(s)
- Yan Li
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin
- China
| | - Shiwen Du
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin
- China
| | - Zheng Du
- National Supercomputing Center in Shenzhen (Shenzhen Cloud Computing Center)
- Shenzhen
- China
| | - Congmei Chen
- National Supercomputing Center in Shenzhen (Shenzhen Cloud Computing Center)
- Shenzhen
- China
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27
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Kee CW, Wong MW. Pentanidium-Catalyzed Asymmetric Phase-Transfer Conjugate Addition: Prediction of Stereoselectivity via DFT Calculations and Docking Sampling of Transition States, and Origin of Stereoselectivity. Aust J Chem 2016. [DOI: 10.1071/ch16225] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Density functional theory (DFT) study, at the M06–2X/6–311+G(d,p)//M06–2X/6–31G(d,p) level, was carried out to examine the catalytic mechanism and origin of stereoselectivity of pentanidium-catalyzed asymmetric phase-transfer conjugate addition. We employed a hybrid approach by combining automated conformation generation through molecular docking followed by subsequent DFT calculation to locate various possible transition states for the enantioselective conjugate addition. The calculated enantioselectivity (enantiomeric excess), based on the key diastereomeric C–C bond-forming transition states, is in good accord with experimental result. Non-covalent interaction analysis of the key transition states reveals extensive non-covalent interactions, including aromatic interactions, hydrogen bonds, and non-classical C–H⋯O interactions between the pentanidium catalyst and substrates. The origin of stereoselectivity was analysed using a strain-interaction model.
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Cho B, Wong MW. Unconventional Bifunctional Lewis-Brønsted Acid Activation Mode in Bicyclic Guanidine-Catalyzed Conjugate Addition Reactions. Molecules 2015; 20:15108-21. [PMID: 26295222 PMCID: PMC6331857 DOI: 10.3390/molecules200815108] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 06/03/2015] [Accepted: 08/10/2015] [Indexed: 01/26/2023] Open
Abstract
DFT calculations have demonstrated that the unconventional bifunctional Brønsted-Lewis acid activation mode is generally applicable to a range of nucleophilic conjugate additions catalyzed by bicyclic guanidine catalysts. It competes readily with the conventional bifunctional Brønsted acid mode of activation. The optimal pro-nucleophiles for this unconventional bifunctional activation are acidic substrates with low pKa, while the best electrophiles are flexible 1,4-diamide and 1,4-diester conjugated systems.
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Affiliation(s)
- Bokun Cho
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
| | - Ming Wah Wong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
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Xue H, Jiang D, Jiang H, Kee CW, Hirao H, Nishimura T, Wong MW, Tan CH. Mechanistic Insights into Bicyclic Guanidine-Catalyzed Reactions from Microscopic and Macroscopic Perspectives. J Org Chem 2015; 80:5745-52. [DOI: 10.1021/acs.joc.5b00709] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hansong Xue
- Department
of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Danfeng Jiang
- Department
of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Huan Jiang
- Department
of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Choon Wee Kee
- Department
of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Hajime Hirao
- Department
of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Takahiro Nishimura
- Department
of Chemistry, Kyoto University, Sakyo-ku, Kyoto 6068502, Japan
| | - Ming Wah Wong
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Choon-Hong Tan
- Department
of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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