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Du JY, Balan T, Claridge TDW, Smith MD. Counterion-Mediated Enantioconvergent Synthesis of Axially Chiral Medium Rings. J Am Chem Soc 2022; 144:14790-14797. [PMID: 35921549 PMCID: PMC9394463 DOI: 10.1021/jacs.2c05485] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There are few enantioconvergent reactions in which racemic substrates bearing multiple stereochemical features are converted into products with high levels of diastereo- and enantiocontrol. Here, we disclose a process for the highly enantio- and diastereoselective syntheses of medium ring lactams via an intramolecular counterion-directed C-alkylation reaction. The treatment of racemic biaryl anilides that exist as a complex mixture of enantiomers and diastereoisomeric conformers by virtue of multiple axes of restricted rotation with a quinidine-derived ammonium salt under basic conditions affords medium ring lactams bearing elements of both axial and point chirality via an enolate-driven configurational relaxation process. Thermal equilibration of the syn- and anti-product diasteroisomers has demonstrated that the barriers to bowl inversion are >124 kJ mol-1. We propose that the chiral ammonium salt differentiates between a complex and rapidly equilibrating mixture of enolate and rotational isomers, ultimately leading to highly enantioselective alkylative ring closure. This dynamic and enantioconvergent process offers an operationally simple approach to the synthesis of valuable chiral medium ring lactams for which there are few catalytic and enantioselective approaches.
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Affiliation(s)
- Ji-Yuan Du
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom.,College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong 252059, China
| | - Tudor Balan
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Tim D W Claridge
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Martin D Smith
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
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2
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Krivdin LB. Computational 1 H and 13 C NMR in structural and stereochemical studies. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:733-828. [PMID: 35182410 DOI: 10.1002/mrc.5260] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Present review outlines the advances and perspectives of computational 1 H and 13 C NMR applied to the stereochemical studies of inorganic, organic, and bioorganic compounds, involving in particular natural products, carbohydrates, and carbonium ions. The first part of the review briefly outlines theoretical background of the modern computational methods applied to the calculation of chemical shifts and spin-spin coupling constants at the DFT and the non-empirical levels. The second part of the review deals with the achievements of the computational 1 H and 13 C NMR in the stereochemical investigation of a variety of inorganic, organic, and bioorganic compounds, providing in an abridged form the material partly discussed by the author in a series of parent reviews. Major attention is focused herewith on the publications of the recent years, which were not reviewed elsewhere.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
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3
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de Ceuninck van Capelle LA, Macdonald JM, Hyland CJT. Stereogenic and conformational properties of medium-ring benzo-fused N-heterocycle atropisomers. Org Biomol Chem 2021; 19:7098-7115. [PMID: 34190302 DOI: 10.1039/d1ob00836f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Medium-ring (7-9-membered) benzo-fused N-heterocycles - a core structure in several important pharmaceuticals - have a diverse range of interesting conformational and stereochemical properties which arise from restricted bond rotation in the non-aromatic ring. The atropisomers of these pharmaceutically relevant N-heterocycles typically exhibit different biological activities, warranting the need to deeply understand the factors controlling the conformation and stereochemistry of the systems. Beginning with a brief introduction to atropisomer classification, this review will detail a number of medium-ring benzo-fused N-heterocycle systems from the recent literature to provide an overview of structural factors which can affect the atropisomeric nature of the systems by altering the overall conformation and rate of stereo-inversion. As well as general factors such as ring-size and sterics, the impact of additional stereocentres in these systems will be addressed. This includes the differences between sulfur, nitrogen and carbon stereocentres, and the consequences of stereocentre placement around the N-heterocycle ring. Further, conformational stabilisation via non-covalent intramolecular bonds will be explored. As such, this review represents a significant resource for aiding in the design, synthesis and study of new and potentially bioactive medium-ring benzo-fused N-heterocycles.
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Affiliation(s)
- Lillian A de Ceuninck van Capelle
- Molecular Horizons Research Institute, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia.
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Vroemans R, Ribone SR, Thomas J, Van Meervelt L, Ollevier T, Dehaen W. Synthesis of homochiral sulfanyl- and sulfoxide-substituted naphthyltriazoles and study of the conformational stability. Org Biomol Chem 2021; 19:6521-6526. [PMID: 34254109 DOI: 10.1039/d1ob00784j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The preparation of a series of novel homochiral atropisomeric sulfanyl- and sulfoxide-substituted naphthyltriazoles is described. The triazolization methodology used presents a new way towards novel and highly stable 1,2,3-triazole-based atropisomers, and introduces a new and complementary synthetic pathway towards 4-sulfanyl substituted 1,2,3-triazoles. Starting from sulfanyl-substituted naphthyl ketones, enantiopure amines, and 4-nitrophenyl azide, a collection of 16 sulfanyl-substituted naphthyltriazoles were obtained via the triazolization reaction in which the homochiral diastereomers are readily isolated. Subsequent monooxidation results in the preparation of several sulfoxide-substituted naphthyltriazoles. The absolute configuration of a set of diastereomeric sulfanyl- and sulfoxide-appended naphthyltriazoles was deduced via X-ray crystallography. Furthermore, the conformational stability of the atropisomers was determined experimentally, and further confirmed and analyzed with the aid of computational DFT calculations.
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Affiliation(s)
- Robby Vroemans
- Molecular Design and Synthesis, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
| | - Sergio R Ribone
- Unidad de Investigación y Desarrollo en Tecnología Farmacéutica (UNITEFA, CONICET), Dpto. Ciencias Farmacéuticas, Fac. Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba X5000HUA, Argentina
| | - Joice Thomas
- Molecular Design and Synthesis, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
| | - Luc Van Meervelt
- Biochemistry, Molecular and Structural Biology, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Thierry Ollevier
- Département de chimie, Pavillon Alexandre-Vachon, Université Laval, 1045 avenue de la Médecine, Québec, QC G1V 0A6, Canada
| | - Wim Dehaen
- Molecular Design and Synthesis, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
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5
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Zhang X, Ponce V, Galvez-Aranda DE, Zhou G, Zhou H, Seminario JM. CS 2 Removal from C 5 Distillates by Reactive Molecular Dynamics Simulations. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c00530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiance Zhang
- College of New Energy and Materials, China University of Petroleum-Beijing, Beijing 102249, China
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Victor Ponce
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Diego E. Galvez-Aranda
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Guanglin Zhou
- College of New Energy and Materials, China University of Petroleum-Beijing, Beijing 102249, China
| | - Hongjun Zhou
- College of New Energy and Materials, China University of Petroleum-Beijing, Beijing 102249, China
| | - Jorge M. Seminario
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
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Semenov VA, Samultsev DO, Krivdin LB. The 1 H and 13 C NMR chemical shifts of Strychnos alkaloids revisited at the DFT level. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:532-539. [PMID: 31663170 DOI: 10.1002/mrc.4948] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 06/10/2023]
Abstract
The density functional theory calculation of 1 H and 13 C NMR chemical shifts in a series of ten 10 classically known Strychnos alkaloids with a strychnine skeleton was performed at the PBE0/pcSseg-2//pcseg-2 level. It was found that calculated 1 H and 13 C NMR chemical shifts provided a markedly good correlation with experiment characterized by a mean absolute error of 0.08 ppm in the range of 7 ppm for protons and 1.67 ppm in the range of 150 ppm for carbons, so that a mean absolute percentage error was as small as ~1% in both cases.
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Affiliation(s)
- Valentin A Semenov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| | - Dmitry O Samultsev
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| | - Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
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Krivdin LB. Computational 1 H NMR: Part 3. Biochemical studies. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:15-30. [PMID: 31286566 DOI: 10.1002/mrc.4895] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/14/2019] [Accepted: 05/18/2019] [Indexed: 06/09/2023]
Abstract
This is the third and the last part of three closely interrelated reviews dealing with computation of 1 H nuclear magnetic resonance chemical shifts and 1 H-1 H spin-spin coupling constants. Present review deals with the computation of these parameters in biologically active natural products, carbohydrates, and other molecules of biological origin focusing on stereochemical applications of computational 1 H nuclear magnetic resonance to these objects.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
- Department of Chemistry, Angarsk State Technical University, Angarsk, Russia
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Krivdin LB. Computational protocols for calculating 13C NMR chemical shifts. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 112-113:103-156. [PMID: 31481156 DOI: 10.1016/j.pnmrs.2019.05.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/19/2019] [Accepted: 05/20/2019] [Indexed: 06/10/2023]
Abstract
The most recent results dealing with the computation of 13C NMR chemical shifts in chemistry (small molecules, saturated, unsaturated and aromatic compounds, heterocycles, functional derivatives, coordination complexes, carbocations, and natural products) are reviewed, paying special attention to theoretical background and accuracy, the latter involving solvent effects, vibrational corrections, and relativistic effects.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russia.
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Buevich AV, Elyashberg ME. Synergistic Combination of CASE Algorithms and DFT Chemical Shift Predictions: A Powerful Approach for Structure Elucidation, Verification, and Revision. JOURNAL OF NATURAL PRODUCTS 2016; 79:3105-3116. [PMID: 28006916 DOI: 10.1021/acs.jnatprod.6b00799] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Structure elucidation of complex natural products and new organic compounds remains a challenging problem. To support this endeavor, CASE (computer-assisted structure elucidation) expert systems were developed. These systems are capable of generating a set of all possible structures consistent with an ensemble of 2D NMR data followed by selection of the most probable structure on the basis of empirical NMR chemical shift prediction. However, in some cases, empirical chemical shift prediction is incapable of distinguishing the correct structure. Herein, we demonstrate for the first time that the combination of CASE and density functional theory (DFT) methods for NMR chemical shift prediction allows the determination of the correct structure even in difficult situations. An expert system, ACD/Structure Elucidator, was used for the CASE analysis. This approach has been tested on three challenging natural products: aquatolide, coniothyrione, and chiral epoxyroussoenone. This work has demonstrated that the proposed synergistic approach is an unbiased, reliable, and very efficient structure verification and de novo structure elucidation method that can be applied to difficult structural problems when other experimental methods would be difficult or impossible to use.
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Affiliation(s)
- Alexei V Buevich
- Department of Discovery and Preclinical Sciences, Process Research and Development, NMR Structure Elucidation, Merck & Co., Inc. , Kenilworth, New Jersey 07033, United States
| | - Mikhail E Elyashberg
- Advanced Chemistry Development (ACD/Laboratories) , Akademik Bakulev Street 6, 117513 Moscow, Russian Federation
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