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Kee CW. Molecular Understanding and Practical In Silico Catalyst Design in Computational Organocatalysis and Phase Transfer Catalysis-Challenges and Opportunities. Molecules 2023; 28:1715. [PMID: 36838703 PMCID: PMC9966076 DOI: 10.3390/molecules28041715] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/03/2023] [Accepted: 02/05/2023] [Indexed: 02/25/2023] Open
Abstract
Through the lens of organocatalysis and phase transfer catalysis, we will examine the key components to calculate or predict catalysis-performance metrics, such as turnover frequency and measurement of stereoselectivity, via computational chemistry. The state-of-the-art tools available to calculate potential energy and, consequently, free energy, together with their caveats, will be discussed via examples from the literature. Through various examples from organocatalysis and phase transfer catalysis, we will highlight the challenges related to the mechanism, transition state theory, and solvation involved in translating calculated barriers to the turnover frequency or a metric of stereoselectivity. Examples in the literature that validated their theoretical models will be showcased. Lastly, the relevance and opportunity afforded by machine learning will be discussed.
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Affiliation(s)
- Choon Wee Kee
- Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR), 1 Pesek Road, Jurong Island, Singapore 627833, Republic of Singapore
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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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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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Singh T, Bharatam PV. Donor→acceptor coordination interactions in 1,3-bis(NHC)triazenyl Cations: An electronic structure analysis. J Comput Chem 2019; 40:2207-2215. [PMID: 31144352 DOI: 10.1002/jcc.25872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 11/08/2022]
Abstract
Donor→acceptor coordination interactions (L → N) between ligands and nitrogen center as in L → N⊕ ← L were reported in the recent past. This article describes the possibility of L → N coordination interactions in triazenyl cation species L → N3 ⊕ ← L. A few 1,3-bis(NHC)triazenyl cation species were experimentally known, the electronic structure analysis reported in this work reveals the presence of L → N (donor→acceptor) interactions in these species. Molecular orbital analysis, NBO charge analysis, energy decomposition analysis, and so forth, confirm the possibility of L → N coordination bond character. Ten molecules with the general formula L → N3 ⊕ ← L have been designed carrying L → N3 ⊕ ← L interactions. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Tejender Singh
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, Punjab, 160 062, India
| | - Prasad V Bharatam
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, Punjab, 160 062, India
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Abstract
Phase-transfer catalysts (PTCs), currently, are one of the most important tools of chemists for performing organic reactions. PTCs accelerate several types of reactions in biphasic systems, giving excellent yields of the desired product. Most of the PTCs belong to the general formula NR4+X-. In the recent past, several compounds possessing a novel scaffold with the general formula NL2+X- have been reported as PTCs. In the NL2+ species, a nitrogen atom with a formal positive charge accepts electron density from electron-donating ligands. Electronic structure studies reported in the literature confirmed the possibility of L → N coordination (donor-acceptor) interactions in these species, and thus, this class of compounds are known as divalent NI compounds. These species are reported to exhibit better catalytic potential in comparison to the traditional NR4+ systems. Some of the NL2+ systems are found to be useful in asymmetric phase-transfer catalysis. Thus, these systems offer extensive opportunities for exploring the catalytic properties and novel mechanistic aspects associated with their unique electronic structure. In this paper, the synthesis, electronic, and structural properties and the applications in catalysis of the NL2+-based PTCs are reviewed with their bright future scope in catalytic organic chemistry.
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Affiliation(s)
- Neha Patel
- Department of Medicinal Chemistry , National Institute of Pharmaceutical Education and Research (NIPER) , Sector 67, Sahibzada Ajit Singh Nagar 160 062 , Punjab , India
| | - Radhika Sood
- Department of Medicinal Chemistry , National Institute of Pharmaceutical Education and Research (NIPER) , Sector 67, Sahibzada Ajit Singh Nagar 160 062 , Punjab , India
| | - Prasad V Bharatam
- Department of Medicinal Chemistry , National Institute of Pharmaceutical Education and Research (NIPER) , Sector 67, Sahibzada Ajit Singh Nagar 160 062 , Punjab , India
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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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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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Yu CH, Radom L, Wong MW. Seventh Asia-Pacific Conference of Theoretical and Computational Chemistry (APCTCC7). Aust J Chem 2016. [DOI: 10.1071/chv69n9_fo] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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