1
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Patra SG. Asymmetric catalysis by chiral FLPs: A computational mini-review. Chirality 2024; 36:e23671. [PMID: 38660756 DOI: 10.1002/chir.23671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 03/21/2024] [Accepted: 04/07/2024] [Indexed: 04/26/2024]
Abstract
Steric hindrance in Lewis acid (LA) and Lewis base (LB) obstruct the Lewis acid-base adduct formation, and the pair was termed as frustrated Lewis pair (FLP). In the past 16 years, the field of enantioselective catalysis by chiral FLPs has been slowly growing. It was shown that chiral LAs are significant as they are involved in the hydrogen transfer (HT) step to the imine, resulting in enantioselectivity. After H2 activation, the borohydride can exist in a number of plausible conformations and their stability is governed by the presence of noncovalent interaction through C-H····π and π····π interactions. However, LBs are not ideal for asymmetric induction as they compete with the imine substrate as a counter LB. Further, the proton transfer from chiral LB to the imine does not induce any chirality as chirality develops in the HT step. However, intramolecular FLPs with chiral scaffold are very efficient as they possess an optimum distance between LA and LB, which facilitates the H2 activation but precludes the adduct formation of the small molecules substrate with the LA component. This mini-review summarizes computational investigation involving chiral LA and LB, and discusses intramolecular FLPs in the enantioselective catalysis.
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Affiliation(s)
- Shanti Gopal Patra
- Department of Chemistry, National Institute of Technology Silchar, Silchar, India
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2
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Kótai B, Laczkó G, Hamza A, Pápai I. Stereocontrol via Propeller Chirality in FLP-Catalyzed Asymmetric Hydrogenation. Chemistry 2024; 30:e202400241. [PMID: 38294415 DOI: 10.1002/chem.202400241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 01/31/2024] [Accepted: 01/31/2024] [Indexed: 02/01/2024]
Abstract
Utilization of chiral frustrated Lewis pairs as catalysts in enantioselective hydrogenation of unsaturated molecules represents a promising approach in asymmetric synthesis. In our effort to improve our current understanding of the factors governing the stereoselectivity in these catalytic processes, herein we examined the mechanism of direct hydrogenation of aromatic enamines catalyzed by a binaphthyl-based chiral amino-borane. Our computational analysis reveals that only one particular conformer of the key borohydride reaction intermediate can be regarded as a reactive form of this species. This borohydride conformer has a well-defined chiral propeller shape, which induces facial selectivity in the hydride transfer to pro-chiral iminium intermediates. The propeller chirality of the reactive borohydride conformer is generated by the axially chiral binaphthyl scaffold of the amino-borane catalyst through stabilizing π-π stacking interactions. This new computational insight can be readily used to interpret the high degree of stereoinduction observed for these reactions. We expect that the concept of chirality relay could be further exploited in catalyst design endeavors.
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Affiliation(s)
- B Kótai
- Institute of Organic Chemistry, Research Centre for Natural Sciences, H-1117, Budapest, Magyar tudósok körútja 2
- Hevesy György Ph.D. School of Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518, Budapest, Hungary
| | - G Laczkó
- Institute of Organic Chemistry, Research Centre for Natural Sciences, H-1117, Budapest, Magyar tudósok körútja 2
- Hevesy György Ph.D. School of Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518, Budapest, Hungary
| | - A Hamza
- Institute of Organic Chemistry, Research Centre for Natural Sciences, H-1117, Budapest, Magyar tudósok körútja 2
| | - I Pápai
- Institute of Organic Chemistry, Research Centre for Natural Sciences, H-1117, Budapest, Magyar tudósok körútja 2
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3
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Mondal H, Chattaraj PK. Unraveling Reactivity Pathways: Dihydrogen Activation and Hydrogenation of Multiple Bonds by Pyramidalized Boron-Based Frustrated Lewis Pairs. ChemistryOpen 2024; 13:e202300179. [PMID: 38117941 PMCID: PMC11004477 DOI: 10.1002/open.202300179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/24/2023] [Indexed: 12/22/2023] Open
Abstract
The activation of H2 by pyramidalized boron-based frustrated Lewis Pairs (FLPs) (B/E-FLP systems where "E" refers to N, P, As, Sb, and Bi) have been explored using density functional theory (DFT) based computational study. The activation pathway for the entire process is accurately characterized through the utilization of the activation strain model (ASM) of reactivity, shedding light on the underlying physical factors governing the process. The study also explores the hydrogenation process of multiple bonds with the help of B/N-FLP. The research findings demonstrate that the liberation of activated dihydrogen occurs in a synchronized, albeit noticeably asynchronous, fashion. The transformation is extensively elucidated using the activation strain model and the energy decomposition analysis. This approach suggests a co-operative double hydrogen-transfer mechanism, where the B-H hydride triggers a nucleophilic attack on the carbon atom of the multiple bonds, succeeded by the migration of the protic N-H.
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Affiliation(s)
- Himangshu Mondal
- Department of ChemistryIndian Institute of TechnologyKharagpur721302India
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4
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Csókás D, Mondal B, Đokić M, Gupta R, Lee BJY, Young RD. Stereoselective Synthesis of Fluoroalkanes via FLP Mediated Monoselective C─F Activation of Geminal Difluoroalkanes. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2305768. [PMID: 37907424 PMCID: PMC10754124 DOI: 10.1002/advs.202305768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Indexed: 11/02/2023]
Abstract
A method of desymmetrization of geminal difluoroalkanes using frustrated Lewis pair (FLP) mediated monoselective C-F activation where a chiral sulfide is the Lewis base component is reported. The stereoselective reaction provides generally high yields of diastereomeric sulfonium salts with dr of up to 95:5. The distribution of diastereomers is found to be thermodynamically controlled via facile sulfide exchange. The use of enantiopure chiral sulfides allows for high stereospecificity in nucleophilic substitution reactions and the formation of stereoenriched products.
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Affiliation(s)
- Dániel Csókás
- Department of ChemistryNational University of SingaporeSingapore117543Singapore
- Research Centre for Natural SciencesInstitute of Organic ChemistryBudapest1117Hungary
| | - Bivas Mondal
- Department of ChemistryNational University of SingaporeSingapore117543Singapore
| | - Miloš Đokić
- Department of ChemistryNational University of SingaporeSingapore117543Singapore
| | - Richa Gupta
- Department of ChemistryNational University of SingaporeSingapore117543Singapore
| | - Beatrice J. Y. Lee
- Department of ChemistryNational University of SingaporeSingapore117543Singapore
| | - Rowan D. Young
- School of Chemistry and Molecular BiosciencesThe University of QueenslandSt Lucia4067Australia
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5
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Abstract
Chiral catalysts play a crucial role in the realm of asymmetric catalysis. Since their breakthrough discovery in 2006, chiral frustrated Lewis pairs (FLPs) have risen as a novel catalyst category for a broad range of metal-free asymmetric reactions. This review provides an overview of the remarkable progress made in this field over the past 15 years. The design and synthesis of chiral FLPs and their applications in hydrogenation, hydrosilylation, transfer hydrogenation, and various other reactions are summarized and highlighted.
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Affiliation(s)
- Xiangqing Feng
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Meng
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haifeng Du
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
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6
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Li JF, Luo L, Bai ZH, Yin B. Unveiling the correlation between the catalytic efficiency and acidity of a metal-free catalyst in a hydrogenation reaction. A theoretical case study of the hydrogenation of ethene catalyzed by a superacid arising from a superhalogen. Phys Chem Chem Phys 2023; 25:21684-21698. [PMID: 37551777 DOI: 10.1039/d3cp03147k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
A systematic quantum-chemical study of the hydrogenation of ethene, catalyzed by strong acids HX (X = F, Cl, Br) and superacids HA (A = MgX3, Mg2X5; X = F, Cl, Br) arising from octet superhalogens is explored. Two possible paths are proposed, concerted and stepwise, and the calculated results show that the concerted path is more favorable than the stepwise path. Compared to the hydrogenation reaction without any catalyst, the improvement of the catalytic efficiency of the superacid HA (A = MgX3, Mg2X5) is high, up to 38.8 to 59.4%. Compared to the strong acid HX (X = F, Cl, Br), the barrier energy is significantly reduced and the improvement of the catalytic efficiency of the superacid HA reaches 23.1 to 31.7%. In particular, for HMg2Br5, the barrier energy of the hydrogenation of ethene is only 36 kcal mol-1, which shows that the reaction could proceed under experimental conditions. In addition, the results show that the catalytic efficiency of the superacid HA is related to the acidity of the superacid. In general, the greater the acidity, the lower the barrier energy and the easier the hydrogenation reaction. From the analysis of the bond order, the newly formed C-H bond of the transition state (TS3) in the concerted path, in which the H atom comes from the superacid catalyst, directly affects the barrier energy of the entire reaction. For the more acidic catalyst, this H atom is provided more easily, and then the formed C-H bond in the transition state is stronger. Consequently, this stronger bond leads to a more stable transition state, and hence to a lower energy barrier as well as a higher efficiency of the superacid catalyst. Therefore, a positive correlation between the acidity of the metal-free catalyst and its catalytic efficiency is expected in the hydrogenation reaction.
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Affiliation(s)
- Jin-Feng Li
- College of Chemistry & Chemical Engineering, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan'an University, Yan'an, 716000, P. R. China.
| | - Lan Luo
- Lab of Theoretical Molecular Magnetism (LTMM), College of Chemistry and Materials Science, Northwest University, 710127, China.
| | - Zhi-Hui Bai
- College of Chemistry & Chemical Engineering, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan'an University, Yan'an, 716000, P. R. China.
| | - Bing Yin
- Lab of Theoretical Molecular Magnetism (LTMM), College of Chemistry and Materials Science, Northwest University, 710127, China.
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Nakanishi T, Terada M. Computational molecular refinement to enhance enantioselectivity by reinforcing hydrogen bonding interactions in major reaction pathway. Chem Sci 2023; 14:5712-5721. [PMID: 37265716 PMCID: PMC10231322 DOI: 10.1039/d3sc01637d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 04/29/2023] [Indexed: 06/03/2023] Open
Abstract
Computational analyses have revealed that the distortion of a catalyst and the substrates and their interactions are key to determining the stability of the transition state. Hence, two strategies "distortion strategy" and "interaction strategy" can be proposed for improving enantiomeric excess in enantioselective reactions. The "distortion strategy" is used as a conventional approach that destabilizes the TS (transition state) of the minor pathway. On the other hand, the "interaction strategy" focuses on the stabilization of the TS of the major pathway in which an enhancement of the reaction rate is expected. To realize this strategy, we envisioned the TS stabilization of the major reaction pathway by reinforcing hydrogen bonding and adopted the chiral phosphoric acid-catalysed enantioselective Diels-Alder reaction of 2-vinylquinolines with dienylcarbamates. The intended "interaction strategy" led to remarkable improvements in the enantioselectivity and reaction rate.
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Affiliation(s)
- Taishi Nakanishi
- Department of Chemistry, Graduate School of Science, Tohoku University 6-3 Aramaki Aza Aoba, Aoba-ku Sendai Miyagi 980-8578 Japan
| | - Masahiro Terada
- Department of Chemistry, Graduate School of Science, Tohoku University 6-3 Aramaki Aza Aoba, Aoba-ku Sendai Miyagi 980-8578 Japan
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8
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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:molecules28041715. [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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9
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Zhang Y, Chen S, Al-Enizi AM, Nafady A, Tang Z, Ma S. Chiral Frustrated Lewis Pair@Metal-Organic Framework as a New Platform for Heterogeneous Asymmetric Hydrogenation. Angew Chem Int Ed Engl 2023; 62:e202213399. [PMID: 36347776 DOI: 10.1002/anie.202213399] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Indexed: 11/11/2022]
Abstract
Asymmetric hydrogenation, a seminal strategy for the synthesis of chiral molecules, remains largely unmet in terms of activation by non-metal sites of heterogeneous catalysts. Herein, as demonstrated by combined computational and experimental studies, we present a general strategy for integrating rationally designed molecular chiral frustrated Lewis pair (CFLP) with porous metal-organic framework (MOF) to construct the catalyst CFLP@MOF that can efficiently promote the asymmetric hydrogenation in a heterogeneous manner, which for the first time extends the concept of chiral frustrated Lewis pair from homogeneous system to heterogeneous catalysis. Significantly, the developed CFLP@MOF, inherits the merits of both homogeneous and heterogeneous catalysts, with high activity/enantio-selectivity and excellent recyclability/regenerability. Our work not only advances CFLP@MOF as a new platform for heterogeneous asymmetric hydrogenation, but also opens a new avenue for the design and preparation of advanced catalysts for asymmetric catalysis.
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Affiliation(s)
- Yin Zhang
- Department of Chemistry, University of North Texas, 1508 W Mulberry St, Denton, TX 76201, USA
| | - Songbo Chen
- School of Physical Science and Technology, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, P.R. China
| | - Abdullah M Al-Enizi
- Department of Chemistry, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Ayman Nafady
- Department of Chemistry, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Zhiyong Tang
- National Center for Nanoscience and Nanotechnology, No.11 ZhongGuanCun BeiYiTiao, 100190, Beijing, P.R. China
| | - Shengqian Ma
- Department of Chemistry, University of North Texas, 1508 W Mulberry St, Denton, TX 76201, USA
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10
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Aranda B, Valdebenito G, Parra-Melipán S, López V, Moya S, Vega A, Aguirre P. Hydrogenation of imines catalyzed by ruthenium(II) complexes containing phosphorus-nitrogen ligands via hydrogen transfer reaction. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2022.112374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Zou W, Gao L, Cao J, Li Z, Li G, Wang G, Li S. Mechanistic Insight into Hydroboration of Imines from Combined Computational and Experimental Studies. Chemistry 2022; 28:e202104004. [PMID: 35018677 DOI: 10.1002/chem.202104004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Indexed: 12/15/2022]
Abstract
Boron Lewis acid-catalyzed and catalyst-free hydroboration reactions of imines are attractive due to the mild reaction conditions. In this work, the mechanistic details of the hydroboration reactions of two different kinds of imines with pinacolborane (HBpin) are investigated by combining density functional theory calculations and some experimental studies. For the hydroboration reaction of N-(α-methylbenzylidene)aniline catalyzed by tris[3,5-bis(trifluoromethyl)phenyl]borane (BArF 3 ), our calculations show that the reaction proceeds through a boron Lewis acid-promoted hydride transfer mechanism rather than the classical Lewis acid activation mechanism. For the catalyst- and solvent-free hydroboration reaction of imine, N-benzylideneaniline, our calculations and experimental studies indicate that this reaction is difficult to occur under the reaction conditions reported previously. With a combination of computational and experimental studies, we have established that the commercially available BH3 ⋅ SMe2 can serve as an efficient catalyst for the hydroboration reactions of N-benzylideneaniline and similar imines. The hydroboration reactions catalyzed by BH3 ⋅ SMe2 are most likely to proceed through a hydroboration/B-H/B-N σ-bond metathesis pathway, which is very different from that of the reaction catalyzed by BArF 3 .
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Affiliation(s)
- Wentian Zou
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Liuzhou Gao
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Jia Cao
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Zhenxing Li
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Guoao Li
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Guoqiang Wang
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Shuhua Li
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
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12
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Hamza A, Moock D, Schlepphorst C, Schneidewind J, Baumann W, Glorius F. Unveiling a key catalytic pocket for the ruthenium NHC-catalysed asymmetric heteroarene hydrogenation. Chem Sci 2022; 13:985-995. [PMID: 35211263 PMCID: PMC8790799 DOI: 10.1039/d1sc06409f] [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: 11/18/2021] [Accepted: 12/20/2021] [Indexed: 11/21/2022] Open
Abstract
The chiral ruthenium(ii)bis-SINpEt complex is a versatile and powerful catalyst for the hydrogenation of a broad range of heteroarenes. This study aims to provide understanding of the active form of this privileged catalyst as well as the reaction mechanism, and to identify the factors which control enantioselectivity. To this end we used computational methods and in situ NMR spectroscopy to study the hydrogenation of 2-methylbenzofuran promoted by this system. The high flexibility and conformational freedom of the carbene ligands in this complex lead to the formation of a chiral pocket interacting with the substrate in a "lock-and-key" fashion. The non-covalent stabilization of the substrate in this particular pocket is an exclusive feature of the major enantiomeric pathway and is preserved throughout the mechanism. Substrate coordination leading to the minor enantiomer inside this pocket is inhibited by steric repulsion. Rather, the catalyst exhibits a "flat" interaction surface with the substrate in the minor enantiomer pathway. We probe this concept by computing transition states of the rate determining step of this reaction for a series of different substrates. Our findings open up a new approach for the rational design of chiral catalysts.
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Affiliation(s)
- Andrea Hamza
- Institute of Organic Chemistry, Research Centre for Natural Sciences Magyar Tudósok Körútja 2 H-1117 Budapest Hungary
| | - Daniel Moock
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Christoph Schlepphorst
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Jacob Schneidewind
- Leibniz-Institut für Katalyse e.V. Albert-Einstein-Straße 29a 18059 Rostock Germany
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University Worringerweg 2 52074 Aachen Germany
| | - Wolfgang Baumann
- Leibniz-Institut für Katalyse e.V. Albert-Einstein-Straße 29a 18059 Rostock Germany
| | - Frank Glorius
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
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13
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Zhao J, Liu S, Liu S, Ding W, Liu S, Chen Y, Du P. A Theoretical Study on the Borane-Catalyzed Reductive Amination of Aniline and Benzaldehyde with Dihydrogen: The Origins of Chemoselectivity. J Org Chem 2022; 87:1194-1207. [PMID: 35016504 DOI: 10.1021/acs.joc.1c02491] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Density functional theory calculations are used in this study to investigate the product selectivity and mechanism of borane-catalyzed reductive aldehyde amination by a H2 reducing agent. Knowing that different boranes yield different products, two typical boranes, (B(2,6-Cl2C6H3)(p-HC6F4)2 and B(C6F5)3), are studied. Of the seven possible pathways of B(2,6-Cl2C6H3)(p-HC6F4)2-catalyzed aldehyde amination analyzed herein, four are favorable. Three of the four favorable pathways involve imine intermediates, and the fourth is a Lewis acid-base synergistic pathway that involves amine-alcohol condensation. As for the B(C6F5)3 catalyst, it forms a highly stable Lewis adduct with aniline, which impedes the hydrogenation of imine. Therefore, the product of B(C6F5)3-catalyzed reductive amination of benzaldehyde and aniline is an imine. The linear relationship between the charge on the boron atom in the Lewis acid and the relative energies of the Lewis adduct and H2 splitting transition state indicates that this parameter determines product selectivity. Indeed, when the natural charge on boron is larger than 1, an amine is produced, whereas when the charge is less than 1, an imine is produced. Hence, the selectivity of products can be controlled by adjusting the natural charge of the boron atom in the Lewis acid catalyst.
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Affiliation(s)
- Jiyang Zhao
- School of Environmental Science, Nanjing Xiaozhuang University, Nanjing, Jiangsu 211171, China
| | - Shaoxian Liu
- School of Environmental Science, Nanjing Xiaozhuang University, Nanjing, Jiangsu 211171, China
| | - Shanshan Liu
- School of Environmental Science, Nanjing Xiaozhuang University, Nanjing, Jiangsu 211171, China
| | - Wenwen Ding
- School of Environmental Science, Nanjing Xiaozhuang University, Nanjing, Jiangsu 211171, China
| | - Sijia Liu
- School of Environmental Science, Nanjing Xiaozhuang University, Nanjing, Jiangsu 211171, China
| | - Yao Chen
- School of Life Science and Chemistry, Jiangsu Second Normal University, Nanjing, Jiangsu 210013, China
| | - Pan Du
- School of Life Science and Chemistry, Jiangsu Second Normal University, Nanjing, Jiangsu 210013, China
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14
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Boron compounds for catalytic applications. ADVANCES IN CATALYSIS 2022. [DOI: 10.1016/bs.acat.2022.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Li J, Daniliuc CG, Kehr G, Erker G. Three‐Component Reaction to 1,4,2‐Diazaborole‐Type Heteroarene Systems. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202111946] [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)
- Jun Li
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraβe 40 48149 Münster Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraβe 40 48149 Münster Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraβe 40 48149 Münster Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraβe 40 48149 Münster Germany
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16
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Li J, Daniliuc CG, Kehr G, Erker G. Three-Component Reaction to 1,4,2-Diazaborole-Type Heteroarene Systems. Angew Chem Int Ed Engl 2021; 60:27053-27061. [PMID: 34597449 DOI: 10.1002/anie.202111946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Indexed: 12/14/2022]
Abstract
The borane FmesBH2 reacts in a three-component reaction with an isonitrile and a small series of organonitriles to give rare examples of the class of dihydro-1,4,2-diazaborole derivatives. In a related way, annulated BN-indolizine derivatives became conveniently available, as were dihydro-1,4,2-oxaza- or thiazaborole derivatives. The nucleophilic framework of a dihydro-1,4,2-diazaborole example allowed for an uncatalyzed acylation reaction. It also served as a 1,3-dipolar reagent and underwent a [3+2] cycloaddition/[4+2] cycloreversion sequence when treated with methyl propiolate to give the respective pyrrole product. The [3+2] cycloaddition product of a dihydro-1,4,2-diazaborole derivative with N-phenylmaleimide was isolated and its heterobicyclo[2.2.1]heptane derived structure characterized by X-ray diffraction.
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Affiliation(s)
- Jun Li
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149, Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149, Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149, Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149, Münster, Germany
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17
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Yolsal U, Horton TAR, Wang M, Shaver MP. Cyclic Ether Triggers for Polymeric Frustrated Lewis Pair Gels. J Am Chem Soc 2021; 143:12980-12984. [PMID: 34387464 PMCID: PMC8397318 DOI: 10.1021/jacs.1c06408] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
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Sterically hindered
Lewis acid and base centers are unable to form
Lewis adducts, instead forming frustrated Lewis pairs (FLPs), where
latent reactivity can be utilized for the activation of small molecules.
Applying FLP chemistry into polymeric frameworks transforms this chemistry
into responsive and functional materials. Here, we report a versatile
synthesis strategy for the preparation of macromolecular FLPs and
explore its potential with the ring-opening reactions of cyclic ethers.
Addition of the cyclic substrates triggered polymer network formation,
where the extent of cross-linking, strength of network, and reactivity
are tuned by the steric and electronic properties of the ethers. The
resultant networks behave like covalently cross-linked polymers, demonstrating
the versatility of FLPs to simultaneously tune both small-molecule
capture and mechanical properties of materials.
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Affiliation(s)
- Utku Yolsal
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M1 3BB, United Kingdom
| | - Thomas A R Horton
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M1 3BB, United Kingdom
| | - Meng Wang
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M1 3BB, United Kingdom
| | - Michael P Shaver
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M1 3BB, United Kingdom.,Sustainable Materials Innovation Hub, Henry Royce Institute, University of Manchester, Oxford Road, Manchester, M13 9BL, United Kingdom
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18
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Heshmat M. Lewis Acidity of Carbon in Activated Carbonyl Group vs. B(C 6 F 5 ) 3 for Metal-Free Catalysis of Hydrogenation of Carbonyl Compounds. Chemphyschem 2021; 22:1535-1542. [PMID: 33655637 DOI: 10.1002/cphc.202100003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/21/2021] [Indexed: 01/19/2023]
Abstract
In this work, using DFT calculations, we investigated Lewis acidities of carbon (in activated carbonyl group) in comparison to the B(C6 F5 )3 in combination with dioxane as the Lewis base (LB) for metal-free catalysis of heterolytic H2 splitting and hydrogenation of carbonyl compounds. We found that in case of carbon as the Lewis acid (LA) the reaction is controlled by frontier molecular orbital interactions between the H2 and LA-LB fragments at shorter distances. The steric effects can be reduced by electrophilic substitutions on the carbonyl carbon. Synergic combination between stronger orbital interactions and reduced steric effects can lower the barrier of the H2 splitting below 10 kcal/mol. With the B(C6 F5 )3 , the H2 splitting is controlled by electrostatic interactions, which cause to form an early transition state. An advantage of employing Lewis acidity of the activated carbonyl carbon for hydrogenation is that the hydride-type attack and hydrogenation of the C=O bond occur in a single step throughout H2 splitting. Hence, stronger Lewis acidity of the C(C=O) reinforces hydrogenation without prohibition of the hydride delivery.
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Affiliation(s)
- Mojgan Heshmat
- Van't Hoff Institute for Molecular Sciences, Universiteit van Amsterdam, Science Park 904, 1098 XH, Amsterdam, The, Netherlands
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