1
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Zeng X. The Strategies Towards Electrochemical Generation of Aryl Radicals. Chemistry 2024; 30:e202402220. [PMID: 39012680 DOI: 10.1002/chem.202402220] [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: 06/09/2024] [Revised: 07/13/2024] [Accepted: 07/15/2024] [Indexed: 07/17/2024]
Abstract
The advancement in electrochemical techniques has unlocked a new path for achieving unprecedented oxidations and reductions of aryl radical precursors in a controlled and selective manner. This approach facilitates the construction of aromatic carbon-carbon and carbon-heteroatom bonds. In light of the green merits and the growing importance of this technique in aryl radical chemistry, this review aims to provide an overview of the recent advance in the electrochemical generation of aryl radicals organized by the aryl radical precursor type, with a focus on the substrate scope, limitation, and underlying mechanism, thereby inspiring future work on electrochemical aryl radical generation.
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Affiliation(s)
- Xiaobao Zeng
- School of Pharmacy and Nantong Key Laboratory of Small Molecular Drug Innovation, Nantong University, Nantong, 226019, People's Republic of China
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2
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Boyd EA, Shin C, Charboneau DJ, Peters JC, Reisman SE. Reductive samarium (electro)catalysis enabled by Sm III-alkoxide protonolysis. Science 2024; 385:847-853. [PMID: 39172824 DOI: 10.1126/science.adp5777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 07/23/2024] [Indexed: 08/24/2024]
Abstract
Samarium diiodide (SmI2) is a privileged, single-electron reductant deployed in diverse synthetic settings. However, generalizable methods for catalytic turnover remain elusive because of the well-known challenge associated with cleaving strong SmIII-O bonds. Prior efforts have focused on the use of highly reactive oxophiles to enable catalyst turnover. However, such approaches give rise to complex catalyst speciation and intrinsically limit the synthetic scope. Herein, we leveraged a mild and selective protonolysis strategy to achieve samarium-catalyzed, intermolecular reductive cross-coupling of ketones and acrylates with broad scope. The modularity of our approach allows rational control of selectivity based on solvent, pKa (where Ka is the acid dissociation constant), and the samarium coordination sphere and provides a basis for future developments in catalytic and electrocatalytic lanthanide chemistry.
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Affiliation(s)
- Emily A Boyd
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Chungkeun Shin
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - David J Charboneau
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jonas C Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Sarah E Reisman
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
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3
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Kuribara T, Kaneki A, Matsuda Y, Nemoto T. Visible-Light-Antenna Ligand-Enabled Samarium-Catalyzed Reductive Transformations. J Am Chem Soc 2024. [PMID: 39031764 DOI: 10.1021/jacs.4c05414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2024]
Abstract
Although divalent Sm reagents are some of the most important single-electron transfer reagents for reductive transformations, their catalytic applications are challenging. In this study, a bidentate phosphine oxide ligand substituted with 9,10-diphenylanthracene as a visible-light antenna was designed for Sm-catalyzed reduction reactions under mild reaction conditions. Pinacol coupling of aryl ketones and aldehydes was developed with 1 mol % of Sm catalyst and organic amine (DIPEA) as a sacrificial mild reductant. Mechanistic studies suggest that the visible-light-antenna ligand coordinates to Sm(III) and reduces Sm(III) to Sm(II) under visible-light irradiation. The catalytic system is also applicable for cross-pinacol coupling and other single-electron reductive transformations, including aza-pinacol coupling, flavone dimerization, C-O bond cleavage, C-C ring-opening of cyclopropane, ketyl-olefin coupling, and cross-coupling of the ketyl radical with the α-amino radical.
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Affiliation(s)
- Takahito Kuribara
- Institute for Advanced Academic Research, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Ayahito Kaneki
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Yu Matsuda
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Tetsuhiro Nemoto
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
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4
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Wang Y, Li SJ, Jiang F, Lan Y, Wang X. Making Full Use of TMSCF 3: Deoxygenative Trifluoromethylation/Silylation of Amides. J Am Chem Soc 2024; 146:19286-19294. [PMID: 38956888 DOI: 10.1021/jacs.4c04760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
As one of the most powerful trifluoromethylation reagents, (trifluoromethyl)trimethylsilane (TMSCF3) has been widely used for the synthesis of fluorine-containing molecules. However, to the best of our knowledge, the simultaneous incorporation of both TMS- and CF3- groups of this reagent onto the same carbon of the products has not been realized. Herein, we report an unprecedented SmI2/Sm promoted deoxygenative difunctionalization of amides with TMSCF3, in which both silyl and trifluoromethyl groups are incorporated into the final product, yielding α-silyl-α-trifluoromethyl amines with high efficiency. Notably, the silyl group could be further transformed into other functional groups, providing a new method for the synthesis of α-quaternary α-CF3-amines.
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Affiliation(s)
- Yuxiao Wang
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Shi-Jun Li
- Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Feng Jiang
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Yu Lan
- Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
- School of Chemistry and Chemical Engineering and Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 400030, China
| | - Xiaoming Wang
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou 310024, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
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5
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Steiner L, Achazi AJ, Kelterer AM, Paulus B, Reissig HU. Diastereoselective Dearomatizing Cyclizations of 5-Arylpentan-2-ones by Samarium Diiodide - A Computational Analysis. Chemistry 2024; 30:e202401120. [PMID: 38512639 DOI: 10.1002/chem.202401120] [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: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 03/23/2024]
Abstract
This study analyzes the samarium diiodide-promoted cyclizations of 5-arylpentan-2-ones to dearomatized bicyclic products utilizing density functional theory. The reaction involves a single electron transfer to the carbonyl group, which occurs synchronously with the rate determining cyclization event, and a second subsequent proton-coupled electron transfer. These redox reactions are accurately computed employing small core pseudo potentials explicitly involving all f-electrons of samarium. Comparison of the energies of the possible final products rules out thermodynamic control of the observed regio- and diastereoselectivities. Kinetic control via appropriate transition states is correctly predicted, but to obtain reasonable energy levels the influence of the co-solvent hexamethylphosphortriamide has to be estimated by using a correction term. The steric effect of the bulky samarium ligands is decisive for the observed stereoselectivity. Carbonyl groups in para-position of the aryl group change the regioselectivity of the cyclization and lead to spiro compounds. The computations suggest again kinetic control of this deviating outcome. However, the standard mechanism has to be modified and the involvement of a complex activated by two SmI2 moieties is proposed in which two electrons are transferred simultaneously to form the new C-C bond. Computation of model intermediates show the feasibility of this alternative+ mechanism.
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Affiliation(s)
- Luca Steiner
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
- Institut für Physikalische und Theoretischen Chemie, Technische Universität Graz, Stremayrgasse 9, 8010, Graz, Austria
| | - Andreas J Achazi
- Physikalisch-Chemisches Institut, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
- Zentrum für Materialforschung, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392, Gießen, Germany
| | - Anne-Marie Kelterer
- Institut für Physikalische und Theoretischen Chemie, Technische Universität Graz, Stremayrgasse 9, 8010, Graz, Austria
| | - Beate Paulus
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
| | - Hans-Ulrich Reissig
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
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6
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Ma F, Li Y, Akkarasereenon K, Qiu H, Cheung YT, Guo Z, Tong R. Aza-Achmatowicz rearrangement coupled with intermolecular aza-Friedel-Crafts enables total syntheses of uleine and aspidosperma alkaloids. Chem Sci 2024; 15:5730-5737. [PMID: 38638226 PMCID: PMC11023026 DOI: 10.1039/d4sc00601a] [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: 01/25/2024] [Accepted: 03/11/2024] [Indexed: 04/20/2024] Open
Abstract
Aspidosperma and uleine alkaloids belong to the large family of monoterpene indole alkaloids with diverse biological activities and thus have attracted extensive synthetic interest. Reported is the development of a new synthetic strategy that allows direct C3-C2' linkage of indoles with functionalized 2-hydroxypiperidines to construct the core common to all aspidoserma and uleine alkaloids. Such indole-piperidine linkage is enabled by coupling aza-Achmatowicz rearrangement (AAR) with indoles via an intermolecular aza-Friedel-Crafts (iAFC) reaction. This AAR-iAFC reaction proceeds under mild acidic conditions with wide tolerance of functional groups (33 examples). The synthetic application of the AAR-iAFC method was demonstrated with collective total syntheses of 3 uleine-type and 6 aspidosperma alkaloids: (+)-3-epi-N-nor-dasycarpidone, (+)-3-epi-dasycarpidone, (+)-3-epi-uleine, 1,2-didehydropseudoaspidospermidine, 1,2-dehydroaspidospermidine, vincadifformine, winchinine B, aspidospermidine, and N-acetylaspidospermidine. We expect that this AAR-iAFC strategy is applicable to other monoterpene indole alkaloids with the C3-C2' linkage of indoles and piperidines.
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Affiliation(s)
- Foqing Ma
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay Kowloon Hong Kong China +86 23581594 +86 23587357
| | - Yunlong Li
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay Kowloon Hong Kong China +86 23581594 +86 23587357
| | - Kornkamon Akkarasereenon
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay Kowloon Hong Kong China +86 23581594 +86 23587357
| | - Huiying Qiu
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay Kowloon Hong Kong China +86 23581594 +86 23587357
| | - Yuen Tsz Cheung
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay Kowloon Hong Kong China +86 23581594 +86 23587357
| | - Zhihong Guo
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay Kowloon Hong Kong China +86 23581594 +86 23587357
| | - Rongbiao Tong
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay Kowloon Hong Kong China +86 23581594 +86 23587357
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7
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Ning Y, Wang Y, Gui J. Bioinspired Two-Phase Synthesis of Gibbosterol A. JACS AU 2024; 4:635-641. [PMID: 38425898 PMCID: PMC10900487 DOI: 10.1021/jacsau.3c00698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/22/2023] [Accepted: 12/26/2023] [Indexed: 03/02/2024]
Abstract
The disecosteroid natural product gibbosterol A-which has a 14/5-bicyclic framework, a high oxidation state, and a twisted trans-9,11-epoxy motif-is the first water-soluble 5,10:8,9-disecosteroid. Herein, we report a bioinspired two-phase synthesis of this natural product in only 15 steps from inexpensive ergosterol. In the first (isomerase) phase, the core bicyclic framework is rapidly installed by the skeletal reorganization of ergosterol endoperoxide via a ruthenium-catalyzed dual C-C bond fragmentation. In the second (oxidase) phase, chemoselective, regioselective, and stereoselective redox transformations precisely introduce the requisite oxygenated functional groups. This work demonstrates that the ingenious two-phase synthesis logic that has been applied to terpenes is also a powerful strategy for steroid synthesis.
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Affiliation(s)
- Yuhan Ning
- State Key Laboratory of Chemical
Biology, Shanghai Institute of Organic Chemistry, University of Chinese
Academy of Sciences, Chinese Academy of
Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Yun Wang
- State Key Laboratory of Chemical
Biology, Shanghai Institute of Organic Chemistry, University of Chinese
Academy of Sciences, Chinese Academy of
Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Jinghan Gui
- State Key Laboratory of Chemical
Biology, Shanghai Institute of Organic Chemistry, University of Chinese
Academy of Sciences, Chinese Academy of
Sciences, 345 Lingling Road, Shanghai 200032, China
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8
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Zhang Z, Qian X, Gu Y, Gui J. Controllable skeletal reorganizations in natural product synthesis. Nat Prod Rep 2024; 41:251-272. [PMID: 38291905 DOI: 10.1039/d3np00066d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Covering: 2016 to 2023The synthetic chemistry community is always in pursuit of efficient routes to natural products. Among the many available general strategies, skeletal reorganization, which involves the formation, cleavage, and migration of C-C and C-heteroatom bonds, stands out as a particularly useful approach for the efficient assembly of molecular skeletons. In addition, it allows for late-stage modification of natural products for quick access to other family members or unnatural derivatives. This review summarizes efficient syntheses of steroid, terpenoid, and alkaloid natural products that have been achieved by means of this strategy in the past eight years. Our goal is to illustrate the strategy's potency and reveal the spectacular human ingenuity demonstrated in its use and development.
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Affiliation(s)
- Zeliang Zhang
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
| | - Xiao Qian
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
| | - Yucheng Gu
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Jinghan Gui
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
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9
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Wang Y, Deng J, Ressler AJ, Lin S. Electroreductive Radical Addition-Polar Cyclization Cascade to Access Cycloalkanes. Org Lett 2024; 26:116-121. [PMID: 38157449 PMCID: PMC11192528 DOI: 10.1021/acs.orglett.3c03722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Compared with flat aromatic scaffolds, three-dimensional aliphatic ring systems feature high structural complexity and topological diversity and, thus, have received increasing attention in drug discovery. Herein, we describe a mild and general electrochemical method for the modular synthesis of structurally distinct cyclic compounds, including monocyclic alkanes, benzo-fused ring systems, and spirocycles, from readily available alkenes and alkyl halides via a radical-polar crossover mechanism.
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Affiliation(s)
- Yi Wang
- Department of Chemistry and Chemical Biology, Cornell University, New York 14853, United States
| | - Jiachen Deng
- Department of Chemistry and Chemical Biology, Cornell University, New York 14853, United States
| | - Andrew J. Ressler
- Department of Chemistry and Chemical Biology, Cornell University, New York 14853, United States
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, New York 14853, United States
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10
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Tomar M, Bhimpuria R, Kocsi D, Thapper A, Borbas KE. Photocatalytic Generation of Divalent Lanthanide Reducing Agents. J Am Chem Soc 2023; 145:22555-22562. [PMID: 37796974 PMCID: PMC10591332 DOI: 10.1021/jacs.3c07508] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 10/07/2023]
Abstract
Divalent lanthanide (Ln) compounds are excellent reducing agents with unique reactivity profiles. These reagents are typically used in superstoichiometric amounts, often in combination with harmful additives. Reactions catalytic in Ln(II) reagents that retain the reactivity and selectivity of the stoichiometric transformations are currently lacking due to the absence of effective and selective methods to form reactive Ln(II) species from stable precursors. Here, active Ln(II) is generated from a Ln(III) precursor through reduction by a photoexcited coumarin or carbostyril chromophore, which, in turn, is regenerated by a sacrificial reductant. The reductant can be metallic (Zn) or organic (amines) and can be used in strictly stoichiometric amounts. A broad range of reactions, including C-halogen, C═C, C═X (X = O, N), P═O, and N═N reductions, as well as C-C, C-X (X = N, S, P), and N-N couplings were readily carried out in yields and selectivities comparable to or better than those afforded by the analogous stoichiometric transformations. The reaction outcomes could be altered by changing the ligand or the lanthanide or through the addition of environmentally benign additives (e.g., water). EPR spectroscopy supported the formation of both Ln(II) and oxidized chromophore intermediates. Taken together, these results establish photochemical Ln(II) generation as a powerful strategy for rendering Ln(II)-mediated reactions catalytic.
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Affiliation(s)
| | | | - Daniel Kocsi
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
| | - Anders Thapper
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
| | - K. Eszter Borbas
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
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11
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Li R, Wu J. Reductive Aldol Approach to Natural Products: Bioinspired Synthesis of abeo-11(12 → 13)-Oleanane Triterpenoids. Org Lett 2023; 25:6278-6283. [PMID: 37595290 DOI: 10.1021/acs.orglett.3c02076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
A synthesis of alstoscholarinoid B (1) and 3β-acetoxy-11α-hydroxy-11(12 → 13)abeooleanan-12-al (2) has been accomplished in 7-9 steps and 10%-16% overall yield from oleanolic acid. This synthesis featured a bioinspired SmI2-mediated reductive aldol reaction to establish the abeo-11(12 → 13)-oleanane framework of both 1 and 2 and a retro-aldol/aldol/lactonization cascade to fully construct the skeleton of 1. Moreover, the investigation of the bioinspired aldol reaction also sheds light on the potential biogenesis of natural products.
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Affiliation(s)
- Ruoxi Li
- Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, No. 429, Zhangheng Road, Shanghai 200213, P. R. China
| | - Jingjing Wu
- Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, No. 429, Zhangheng Road, Shanghai 200213, P. R. China
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12
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Ware SD, Zhang W, Charboneau DJ, Klein CK, Reisman SE, See KA. Electrochemical Preparation of Sm(II) Reagent Facilitated by Weakly Coordinating Anions. Chemistry 2023; 29:e202301045. [PMID: 37309269 DOI: 10.1002/chem.202301045] [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: 03/31/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 06/14/2023]
Abstract
Samarium diiodide (SmI2 ) is widely used as a strong one-electron reducing agent and is often employed to form C-C bonds in complex systems. Despite their utility, SmI2 and related salts suffer from several drawbacks that render the use of Sm reducing agents in large-scale synthesis impractical. Here, we report factors influencing the electrochemical reduction of Sm(III) to Sm(II), towards the goal of electrocatalytic Sm(III) reduction. We probe the effect of supporting electrolyte, electrode material, and Sm precursor on Sm(II)/(III) redox and on the reducing power of the Sm species. We find that the coordination strength of the counteranion of the Sm salt affects the reversibility and redox potential of the Sm(II)/(III) couple and establish that the counteranion primarily determines the reducibility of Sm(III). Electrochemically generated SmI2 performs similarly to commercial SmI2 solutions in a proof-of-concept reaction. The results will provide fundamental insight to facilitate the development of Sm-electrocatalytic reactions.
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Affiliation(s)
- Skyler D Ware
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, United States
| | - Wendy Zhang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, United States
| | - David J Charboneau
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, United States
| | - Channing K Klein
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, United States
| | - Sarah E Reisman
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, United States
| | - Kimberly A See
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, United States
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13
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Kaur R, Singh RP. Stereoselective Reductive Coupling Reactions Utilizing [1,2]-Phospha-Brook Rearrangement: A Powerful Umpolung Approach. J Org Chem 2023; 88:10325-10338. [PMID: 37460945 DOI: 10.1021/acs.joc.3c01055] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
[1,2]-Phospha-Brook rearrangement entails the generation of α-oxygenated carbanions via the umpolung process. Recently, these anionic species have been widely utilized for several C-C bond forming strategies, providing various useful frameworks that are difficult to access through conventional approaches. However, the application of this powerful methodology in the development of chiral strategies is still at the nascent stage due to challenges involved in controlling chemoselectivity and enantioselectivity. This synopsis provides a detailed summary of diastereo- and/or enantioselective chemical transformations using [1,2]-phospha-Brook rearrangement.
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Affiliation(s)
- Ravneet Kaur
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Ravi P Singh
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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14
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Li Q, Zhang W, Zhu C, Pan H, Shi KY, Zhang Y, Han MY, Tan CH. Organobase-Catalyzed Umpolung of Amides: The Generation and Transfer of Carbamoyl Anion. J Org Chem 2023; 88:1245-1255. [PMID: 36628963 DOI: 10.1021/acs.joc.2c02487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A novel organobase-catalyzed umpolung reaction of amides was disclosed. This method provides an efficient method to generate and transfer carbamoyl anions. In this transformation, some of the inherent disadvantages of carbamoyl metal were avoided. The mechanistic analysis revealed that the reaction proceeds through polarity inversion of amide, and various carbamoyl anions were applied in the reaction. Moreover, a wide range of substrates was achieved with moderate to excellent yield.
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Affiliation(s)
- Qi Li
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huabei Normal University, Huaibei, Anhui 235000, PR China
| | - Wang Zhang
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huabei Normal University, Huaibei, Anhui 235000, PR China
| | - Chen Zhu
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huabei Normal University, Huaibei, Anhui 235000, PR China
| | - Hong Pan
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huabei Normal University, Huaibei, Anhui 235000, PR China
| | - Kang-Yue Shi
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huabei Normal University, Huaibei, Anhui 235000, PR China
| | - Yicheng Zhang
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huabei Normal University, Huaibei, Anhui 235000, PR China
| | - Man-Yi Han
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huabei Normal University, Huaibei, Anhui 235000, PR China
| | - Choon-Hong Tan
- Division of Chemistry and Biological Chemistry, Nanyang Technological University, Singapore 637371
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15
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Steiner L, Achazi AJ, Vlaisavljevich B, Miro P, Paulus B, Kelterer AM. Samarium Diiodide Acting on Acetone-Modeling Single Electron Transfer Energetics in Solution. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248673. [PMID: 36557814 PMCID: PMC9781745 DOI: 10.3390/molecules27248673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/25/2022] [Accepted: 11/27/2022] [Indexed: 12/13/2022]
Abstract
Samarium diiodide is a versatile single electron transfer (SET) agent with various applications in organic chemistry. Lewis structures regularly insinuate the existence of a ketyl radical when samarium diiodide binds a carbonyl group. The study presented here investigates this electron transfer by the means of computational chemistry. All electron CASPT2 calculations with the inclusion of scalar relativistic effects predict an endotherm electron transfer from samarium diiodide to acetone. Energies calculated with the PBE0-D3(BJ) functional and a small core pseudopotential are in good agreement with CASPT2. The calculations confirm the experimentally measured increase of the samarium diiodide reduction potential through the addition of hexamethylphosphoramide also known as HMPA.
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Affiliation(s)
- Luca Steiner
- Institute of Physical und Theoretical Chemistry, NAWI Graz, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Andreas J. Achazi
- Physikalisch-Chemisches Institut, Justus-Liebig-Universität Giessen, 35392 Giessen, Germany
| | - Bess Vlaisavljevich
- Department of Chemistry, University of South Dakota, 414 E. Clark St., Vermillion, SD 57069, USA
| | - Pere Miro
- Department of Chemistry, University of South Dakota, 414 E. Clark St., Vermillion, SD 57069, USA
| | - Beate Paulus
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Anne-Marie Kelterer
- Institute of Physical und Theoretical Chemistry, NAWI Graz, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
- Correspondence:
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16
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Das S, Maity J, Panda TK. Metal/Non-Metal Catalyzed Activation of Organic Nitriles. CHEM REC 2022; 22:e202200192. [PMID: 36126180 DOI: 10.1002/tcr.202200192] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Indexed: 12/15/2022]
Abstract
Nitrile activation is a prominent topic in recent developments in chemistry, especially in organic, inorganic, biological chemistry, as well as in the natural synthesis of products and in the pharmaceutical industry. The activation of nitriles using both metal and non-metal precursors has attracted several researchers, who are exploring newer ways to synthesize novel compounds. Nitrile activation can be achieved by combining various catalytic double hydroelementation reactions, such as hydrosilylation, hydroboration, and hydrogenation of organonitriles using silanes, pinacolborane, and other sources of hydrogen. These methodologies have garnered considerable attention since they are effective in the reduction of organonitriles, whose end products are extensively applied in synthetic organic chemistry. In this review, we summarize the development of selective hydroborylation, hydrosilylation, dihydroborysilylation, and hydrogenation of organonitriles, as well as their reaction mechanisms and the role of metal complexes in the catalytic cycles. This review article explains various synthetic methodologies applied toward the reduction of organonitriles into corresponding amines.
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Affiliation(s)
- Suman Das
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi - 502 285, Sangareddy, Telangana, India
| | - Jyotirmoy Maity
- Department of Chemistry, St. Stephen's College, University of Delhi, Delhi, 110 007, India
| | - Tarun K Panda
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi - 502 285, Sangareddy, Telangana, India
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17
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Hui C, Craggs L, Antonchick AP. Ring contraction in synthesis of functionalized carbocycles. Chem Soc Rev 2022; 51:8652-8675. [PMID: 36172989 DOI: 10.1039/d1cs01080h] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carbocycles are a key and widely present structural motif in organic compounds. The construction of structurally intriguing carbocycles, such as highly-strained fused rings, spirocycles or highly-functionalized carbocycles with congested stereocenters, remains challenging in organic chemistry. Cyclopropanes, cyclobutanes and cyclopentanes within such carbocycles can be synthesized through ring contraction. These ring contractions involve re-arrangement of and/or small molecule extrusion from a parental ring, which is either a carbocycle or a heterocycle of larger size. This review provides an overview of synthetic methods for ring contractions to form cyclopropanes, cyclobutanes and cyclopentanes en route to structurally intriguing carbocycles.
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Affiliation(s)
- Chunngai Hui
- Max Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany. .,Technical University Dortmund, Faculty of Chemistry and Chemical Biology, Otto-Hahn-Strasse 6, 44221 Dortmund, Germany
| | - Luke Craggs
- Nottingham Trent University, School of Science and Technology, Department of Chemistry and Forensics, Clifton Lane, NG11 8NS Nottingham, UK
| | - Andrey P Antonchick
- Max Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany. .,Technical University Dortmund, Faculty of Chemistry and Chemical Biology, Otto-Hahn-Strasse 6, 44221 Dortmund, Germany.,Nottingham Trent University, School of Science and Technology, Department of Chemistry and Forensics, Clifton Lane, NG11 8NS Nottingham, UK
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18
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Vasilev VH, Spessert L, Yu K, Maimone TJ. Total Synthesis of Resiniferatoxin. J Am Chem Soc 2022; 144:16332-16337. [PMID: 36043948 DOI: 10.1021/jacs.2c08200] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
From both structural and functional perspectives, the large family of daphnane diterpene orthoesters (DDOs) represent a truly remarkable class of natural products. As potent lead compounds for the treatment of pain, neurodegeneration, HIV/AIDS, and cancer, their medicinal potential continues to be heavily investigated, yet synthetic routes to DDO natural products remain rare. Herein we report a distinct approach to this class of complex diterpenes, highlighted by a 15-step total synthesis of the flagship DDO, resiniferatoxin.
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Affiliation(s)
- Vasil H Vasilev
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Lukas Spessert
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Kuan Yu
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Thomas J Maimone
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
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19
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Chen J, Yang Y, Wu C, Huo L, Xie X, Li H, She X. De Novo Diastereoselective Synthesis of 1-Hydroxyl Allogibberic Methyl Ester en Route to Diverse Bioactive Molecules. Org Lett 2022; 24:6402-6406. [PMID: 36017965 DOI: 10.1021/acs.orglett.2c02422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The first de novo synthesis of 1-hydroxyl allogibberic methyl ester, en route to pharbinilic acid and other bioactive molecules, is accomplished in diastereoselective manner. Key reactions of the synthesis include a Pd-catalyzed Suzuki-Miyaura cross-coupling reaction, a Lewis acid-catalyzed reductive Prins cyclization reaction, and a SmI2-mediated transannular pinacol coupling reaction. The synthesis provides a new avenue to access diverse relevant bioactive molecules.
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Affiliation(s)
- Jinyan Chen
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu, P. R. China
| | - Yunxia Yang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu, P. R. China
| | - Chuanhua Wu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu, P. R. China
| | - Liang Huo
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu, P. R. China
| | - Xingang Xie
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu, P. R. China
| | - Huilin Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu, P. R. China
| | - Xuegong She
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu, P. R. China
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20
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Morrill C, Péter Á, Amalina I, Pye E, Crisenza GEM, Kaltsoyannis N, Procter DJ. Diastereoselective Radical 1,4-Ester Migration: Radical Cyclizations of Acyclic Esters with SmI 2. J Am Chem Soc 2022; 144:13946-13952. [PMID: 35858251 PMCID: PMC9377304 DOI: 10.1021/jacs.2c05972] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Reductive cyclizations of carbonyl compounds, mediated
by samarium(II)
diiodide (SmI2, Kagan’s reagent), represent an invaluable
platform to generate molecular complexity in a stereocontrolled manner.
In addition to classical ketone and aldehyde substrates, recent advances
in radical chemistry allow the cyclization of lactone and lactam-type
substrates using SmI2. In contrast, acyclic esters are
considered to be unreactive to SmI2 and their participation
in reductive cyclizations is unprecedented. Here, we report a diastereoselective
radical 1,4-ester migration process, mediated by SmI2,
that delivers stereodefined alkene hydrocarboxylation products via
radical cyclization of acyclic ester groups in α-carbomethoxy
δ-lactones. Isotopic labeling experiments and computational
studies have been used to probe the mechanism of the migration. We
propose that a switch in conformation redirects single electron transfer
from SmI2 to the acyclic ester group, rather than the “more
reactive” lactone carbonyl. Our study paves the way for the
use of elusive ketyl radicals, derived from acyclic esters, in SmI2-mediated reductive cyclizations.
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Affiliation(s)
- Charlotte Morrill
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Áron Péter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Ilma Amalina
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Emma Pye
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Giacomo E M Crisenza
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Nikolas Kaltsoyannis
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - David J Procter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
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21
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Klementyeva SV, Schrenk C, Schnepf A. Oxidation of [Ge 9{Si(SiMe 3) 3} 3] − with LnI 3 (Ln = Eu, Sm, Yb): Isomerism of Metalloid Germanium Clusters. Inorg Chem 2022; 61:11787-11795. [DOI: 10.1021/acs.inorgchem.2c01501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Claudio Schrenk
- Chemistry Department, University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen Germany
| | - Andreas Schnepf
- Chemistry Department, University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen Germany
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22
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Quevedo-Acosta Y, Jurberg ID, Gamba-Sánchez D. Cyclization Strategies Using Imide Derivatives for the Synthesis of Polycyclic Nitrogen‐Containing Compounds. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Igor D. Jurberg
- Universidade Estadual de Campinas Institute of Chemistry 13083 BRAZIL
| | - Diego Gamba-Sánchez
- Universidad de Los Andes Chemistry Department Cra 1 No. 18A-12 Q:305 111711 Bogota COLOMBIA
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23
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Zhou L, Qiu J, Wang C, Zhang F, Yang K, Song Q. Synthesis of α-Aminosilanes by 1,2-Metalate Rearrangement Deoxygenative Silylation of Aromatic Amides. Org Lett 2022; 24:3249-3253. [PMID: 35475726 DOI: 10.1021/acs.orglett.2c01041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
An efficient nickel-catalyzed deoxygenative silylation reaction of aromatic amides with silylboranes in the presence of a Sm/SmI2 system for the construction of α-aminosilanes is described. This strategy provides a direct method for synthesizing α-aminosilanes with high efficiency and good functional group compatibility and includes readily accessible starting materials and valuable products.
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Affiliation(s)
- Lu Zhou
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian 350108, China
| | - Jian Qiu
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian 350108, China
| | - Cece Wang
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian 350108, China
| | - Feng Zhang
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian 350108, China
| | - Kai Yang
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian 350108, China
| | - Qiuling Song
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian 350108, China.,Institute of Next Generation Matter Transformation, College of Materials Science Engineering, Huaqiao University, Xiamen, Fujian 361021, China.,School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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24
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Zhang C, Wang L, Shi H, Lin Z, Wang C. Iron-Catalyzed Allylic Defluorinative Ketone Olefin Coupling. Org Lett 2022; 24:3211-3216. [PMID: 35481351 DOI: 10.1021/acs.orglett.2c00979] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this protocol, we demonstrate our discovery that iron is able to efficiently catalyze the reductive allylic defluorinative ketyl olefin coupling reaction between α-trifluoromethyl alkenes and unactivated ketones. This operationally simple cross-electrophile reaction circumvents the use of pre-generated organometallics and allows for the synthesis of diverse functional-group-rich tertiary gem-difluorohomoallylic alcohols through a polarity-reversed strategy. Preliminary mechanistic studies support a mechanism that proceeds through a ketyl formation/olefin insertion/β-fluoro elimination sequence.
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Affiliation(s)
- Chang Zhang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Lin Wang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Hongzhang Shi
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Zhiyang Lin
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Chuan Wang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.,Center for Excellence in Molecular Synthesis of CAS, Hefei, Anhui 230026, P. R. China
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25
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Stereodivergent total synthesis of rocaglaol initiated by synergistic dual-metal-catalyzed asymmetric allylation of benzofuran-3(2H)-one. Chem 2022. [DOI: 10.1016/j.chempr.2022.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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26
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Derosa J, Garrido-Barros P, Peters JC. Electrocatalytic Ketyl-Olefin Cyclization at a Favorable Applied Bias Enabled by a Concerted Proton-Electron Transfer Mediator. Inorg Chem 2022; 61:6672-6678. [PMID: 35436099 DOI: 10.1021/acs.inorgchem.2c00839] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recent studies showcase reductive concerted proton-electron transfer (CPET) as a powerful strategy for transferring a net hydrogen atom to organic substrates; however, direct application of CPET in the context of C-C bond formation beyond homocoupling is underexplored. We report herein the expansion of electrocatalytic CPET (eCPET) using a Brønsted base-appended cobaltocene mediator ([CpCoCpNMe2][OTf]) with keto-olefin substrates that undergo cyclization subsequent to ketyl radical generation via eCPET. Using acetophenone-derived substrates with tethered acrylates as radical acceptors, in the presence of tosylic acid, we demonstrate that ketyl-olefin cyclization is achieved by characterization of cis-lactone and alkene products. Mechanistic analysis of this 2 H+/2 e- process reveals a mixed order in substrate and acid and a Hammett plot with a modest negative slope, highlighting the contribution of sequential CPET and ET/PT steps involved in the overall rate of the reaction and providing support for initial O-H bond formation. The ability to access ketyl radicals at comparatively mild reduction potentials via controlled potential electrolysis enables functional group tolerance across a range of substrates.
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Affiliation(s)
- Joseph Derosa
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Pablo Garrido-Barros
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jonas C Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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27
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Abstract
![]()
The therapeutic properties of Curcuma (ginger
and turmeric’s family) have long been known in traditional
medicine. However, only recently have guaiane-type sesquiterpenes
extracted from Curcuma phaeocaulis been
submitted to biological testing, and their enhanced bioactivity was
highlighted. Among these compounds, phaeocaulisin A has shown remarkable
anti-inflammatory and anticancer activity, which appears to be tied
to the unique bridged acetal moiety embedded in its tetracyclic framework.
Prompted by the promising biological profile of phaeocaulisin A and
by the absence of a synthetic route for its provision, we have implemented
the first enantioselective total synthesis of phaeocaulisin A in 17
steps with 2% overall yield. Our route design builds on the identification
of an enantioenriched lactone intermediate, tailored with both a ketone
moiety and a conjugated alkene system. Taking advantage of the umpolung
carbonyl-olefin coupling reactivity enabled by the archetypal single-electron
transfer (SET) reductant samarium diiodide (SmI2), the
lactone intermediate was submitted to two sequential SmI2-mediated cyclizations to stereoselectively construct the polycyclic
core of the natural product. Crucially, by exploiting the innate inner-sphere
nature of carbonyl reduction using SmI2, we have used a
steric blocking strategy to render sites SET-unreceptive and thus
achieve chemoselective reduction in a complex substrate. Our asymmetric
route enabled elucidation of the naturally occurring isomer of phaeocaulisin
A and provides a synthetic platform to access other guaiane-type sesquiterpenes
from C. phaeocaulis—as well
as their synthetic derivatives—for medicinal chemistry and
drug design.
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Affiliation(s)
- Áron Péter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Giacomo E M Crisenza
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - David J Procter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
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28
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Hui C, Wang Z, Xie Y, Liu J. Contemporary synthesis of bioactive cyclobutane natural products. GREEN SYNTHESIS AND CATALYSIS 2022. [DOI: 10.1016/j.gresc.2022.04.006] [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] Open
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29
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Heravi MM, Nazari A. Samarium(ii) iodide-mediated reactions applied to natural product total synthesis. RSC Adv 2022; 12:9944-9994. [PMID: 35424959 PMCID: PMC8965710 DOI: 10.1039/d1ra08163b] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 03/12/2022] [Indexed: 12/22/2022] Open
Abstract
Natural product synthesis remains a field in which new synthetic methods and reagents are continually being evaluated. Due to the demanding structures and complex functionality of many natural products, only powerful and selective methods and reagents will be highlighted in this proceeding. Since its introduction by Henri Kagan, samarium(ii) iodide (SmI2, Kagan's reagent) has found increasing use in chemical synthesis. Over the years, many reviews have been published on the application of SmI2 in numerous reductive coupling procedures as well as in natural product total synthesis. This review highlights recent advances in SmI2-mediated synthetic strategies, as applied in the total synthesis of natural products since 2004.
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Affiliation(s)
- Majid M Heravi
- Department of Chemistry, School of Science, Alzahra University PO Box 1993891176 Vanak Tehran Iran +98 21 88041344 +98 21 88044051
| | - Azadeh Nazari
- Department of Chemistry, School of Science, Alzahra University PO Box 1993891176 Vanak Tehran Iran +98 21 88041344 +98 21 88044051
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30
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Rao CN, Reissig HU. Samarium(II)‐Promoted Cyclizations of Non‐activated Indolyl Sulfinyl Imines to Polycyclic Tertiary Carbinamines. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Chintada Nageswara Rao
- Freie Universität Berlin: Freie Universitat Berlin Institut für Chemie und Biochemie 14195 Berlin GERMANY
| | - Hans-Ulrich Reissig
- Freie Universität Berlin Institut für Chemie und Biochemie Takustr. 3 14195 Berlin GERMANY
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31
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He Y, Wang Y, Li SJ, Lan Y, Wang X. Deoxygenative Cross-Coupling of Aromatic Amides with Polyfluoroarenes. Angew Chem Int Ed Engl 2022; 61:e202115497. [PMID: 35014163 DOI: 10.1002/anie.202115497] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Indexed: 01/17/2023]
Abstract
Considering the ubiquitous nature and ready synthesis of amides, and the great significance of organofluorine-containing species, the cross-coupling of amides and polyfluoroarenes, leading to new carbon-carbon bond-forming methodologies, would find useful applications in synthesis, late-stage functionalization, and rapid generation of molecular diversity. Herein, we present a novel synthesis of α-polyfluoroaryl amines via Sm/SmI2 -mediated deoxygenative cross-coupling of aromatic amides with polyfluoroarenes through direct C-H functionalization. The structural and functional diversity of these readily available precursors provides a versatile and flexible strategy for the streamlined synthesis of α-polyfluoroaryl amines. Combining experimental and theoretical studies, a novel plausible mechanism of the α-aminocarbene-mediated C-H insertion has been revealed, which may stimulate future work for the development of novel methods in amine synthesis.
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Affiliation(s)
- Youliang He
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Yuxiao Wang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Shi-Jun Li
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
| | - Yu Lan
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.,School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing, 400030, China
| | - Xiaoming Wang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China.,School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
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32
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Xiao J, Montgomery J. Nickel-Catalyzed Defluorinative Coupling of Aliphatic Aldehydes with Trifluoromethyl Alkenes. ACS Catal 2022; 12:2463-2471. [PMID: 35992737 PMCID: PMC9390876 DOI: 10.1021/acscatal.1c05801] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A simple procedure is reported for the nickel-catalyzed defluorinative alkylation of unactivated aliphatic aldehydes. The process involves the catalytic reductive union of trifluoromethyl alkenes with aldehydes using a nickel complex of a 6,6'-disubstituted bipyridine ligand with zinc metal as the terminal reductant. The protocol is distinguished by its broad substrate scope, mild conditions, and simple catalytic setup. Reaction outcomes are consistent with the intermediacy of an α-silyloxy(alkyl)nickel intermediate generated by a low-valent nickel catalyst, silyl electrophile, and the aldehyde substrate. Mechanistic findings with cyclopropanecarboxaldehyde provide insights into nature of the reactive intermediates and illustrate fundamental reactivity differences that are governed by subtle changes in ligand and substrate structure.
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Affiliation(s)
| | - John Montgomery
- Corresponding authors: John Montgomery - Department of Chemistry, University of Michigan, 930 N. University Ave. Ann Arbor, MI 48109-1055, USA,
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33
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He Y, Wang Y, Li S, Lan Y, Wang X. Deoxygenative Cross‐Coupling of Aromatic Amides with Polyfluoroarenes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Youliang He
- State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Yuxiao Wang
- State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Shi‐Jun Li
- Green Catalysis Center, and College of Chemistry Zhengzhou University Zhengzhou 450001 China
| | - Yu Lan
- Green Catalysis Center, and College of Chemistry Zhengzhou University Zhengzhou 450001 China
- School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Theoretical and Computational Chemistry Chongqing University Chongqing 400030 China
| | - Xiaoming Wang
- State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Chemistry and Materials Science Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences 1 Sub-lane Xiangshan Hangzhou 310024 China
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34
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Maity S. Tools and techniques for solution‐phase structural understanding of SmI
2
–additive complexes. J PHYS ORG CHEM 2022. [DOI: 10.1002/poc.4318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sandeepan Maity
- Department of Chemistry C. V. Raman Global University Bhubaneswar Odisha India
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35
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Mellah M, Zhang YF. Samarium(II)-Electrocatalyzed Chemoselective Reductive Alkoxylation of Phthalimides. Org Chem Front 2022. [DOI: 10.1039/d1qo01760h] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The unprecedented samarium-eletrocatalyzed reductive alkoxylation of phthalimides in a single step is presented. Under mild conditions, using electrogenerated Sm(II) with TMSCl (trimethyl chlorosilane), N-substituted 3-alkoxyl isoindolin-1-ones are isolated in good...
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36
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Agarwal RG, Coste SC, Groff BD, Heuer AM, Noh H, Parada GA, Wise CF, Nichols EM, Warren JJ, Mayer JM. Free Energies of Proton-Coupled Electron Transfer Reagents and Their Applications. Chem Rev 2021; 122:1-49. [PMID: 34928136 DOI: 10.1021/acs.chemrev.1c00521] [Citation(s) in RCA: 141] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We present an update and revision to our 2010 review on the topic of proton-coupled electron transfer (PCET) reagent thermochemistry. Over the past decade, the data and thermochemical formalisms presented in that review have been of value to multiple fields. Concurrently, there have been advances in the thermochemical cycles and experimental methods used to measure these values. This Review (i) summarizes those advancements, (ii) corrects systematic errors in our prior review that shifted many of the absolute values in the tabulated data, (iii) provides updated tables of thermochemical values, and (iv) discusses new conclusions and opportunities from the assembled data and associated techniques. We advocate for updated thermochemical cycles that provide greater clarity and reduce experimental barriers to the calculation and measurement of Gibbs free energies for the conversion of X to XHn in PCET reactions. In particular, we demonstrate the utility and generality of reporting potentials of hydrogenation, E°(V vs H2), in almost any solvent and how these values are connected to more widely reported bond dissociation free energies (BDFEs). The tabulated data demonstrate that E°(V vs H2) and BDFEs are generally insensitive to the nature of the solvent and, in some cases, even to the phase (gas versus solution). This Review also presents introductions to several emerging fields in PCET thermochemistry to give readers windows into the diversity of research being performed. Some of the next frontiers in this rapidly growing field are coordination-induced bond weakening, PCET in novel solvent environments, and reactions at material interfaces.
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Affiliation(s)
- Rishi G Agarwal
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Scott C Coste
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Benjamin D Groff
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Abigail M Heuer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Hyunho Noh
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Giovanny A Parada
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.,Department of Chemistry, The College of New Jersey, Ewing, New Jersey 08628, United States
| | - Catherine F Wise
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Eva M Nichols
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Jeffrey J Warren
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - James M Mayer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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37
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Mondal A, Satpathi B, Ramasastry SSV. Phosphine-Catalyzed Intramolecular Vinylogous Aldol Reaction of α-Substituted Enones. Org Lett 2021; 24:256-261. [PMID: 34908421 DOI: 10.1021/acs.orglett.1c03913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We demonstrate the first phosphine-catalyzed intramolecular vinylogous aldol reaction (IVAR) of α-substituted enones. This strategy provides access to various pentannulated (hetero)arenes and dibenzocycloheptanones incorporated with two contiguous stereocenters, one of which is an all-carbon quaternary center. The scope of this work is further broadened through elaborations of the IVAR adducts to (i) benzannulated nine-membered carbocyclic systems, (ii) interesting classes of 1,3-dienes, 1,3,5-trienes, and 1-yn-3,5-dienes, and (iii) the analogs of echinolactone D and russujaponol F.
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Affiliation(s)
- Atanu Mondal
- Organic Synthesis and Catalysis Lab, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, S A S Nagar, Manauli PO, Punjab 140 306, India
| | - Bishnupada Satpathi
- Organic Synthesis and Catalysis Lab, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, S A S Nagar, Manauli PO, Punjab 140 306, India
| | - S S V Ramasastry
- Organic Synthesis and Catalysis Lab, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, S A S Nagar, Manauli PO, Punjab 140 306, India
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38
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Ramírez-Solís A, Boekell NG, León-Pimentel CI, Saint-Martin H, Bartulovich CO, Flowers RA. Ammonia Solvation vs Aqueous Solvation of Samarium Diiodide. A Theoretical and Experimental Approach to Understanding Bond Activation Upon Coordination to Sm(II). J Org Chem 2021; 87:1689-1697. [PMID: 34775764 DOI: 10.1021/acs.joc.1c01771] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Coordination-induced desolvation or ligand displacement by cosolvents and additives is a key feature responsible for the reactivity of Sm(II)-based reagent systems. High-affinity proton donor cosolvents such as water and glycols also demonstrate coordination-induced bond weakening of the O-H bond, facilitating reduction of a broad range of substrates. In the present work, the coordination of ammonia to SmI2 was examined using Born-Oppenheimer molecular dynamics simulations and mechanistic studies, and the SmI2-ammonia system is compared to the SmI2-water system. The coordination number and reactivity of the SmI2-ammonia solvent system were found to be similar to those of SmI2-water but exhibited an order of magnitude greater rate of arene reduction by SmI2-ammonia than by SmI2-water at the same concentrations of cosolvent. In addition, upon coordination of ammonia to SmI2, the Sm(II)-ammonia solvate demonstrates one of the largest degrees of N-H bond weakening reported in the literature compared to known low-valent transition metal ammonia complexes.
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Affiliation(s)
- Alejandro Ramírez-Solís
- Depto. de Física, Centro de Investigación en Ciencias-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209, México
| | - Nicholas G Boekell
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | | | | | - Caroline O Bartulovich
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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39
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Komine K, Ninomiya R, Fukuda H, Ishihara J. A Stereoselective Synthesis of Fused Carbocycles with a cis-1,2-Diol Moiety by Desymmetrization: SmI 2-mediated Pinacol Coupling of meso-Cyclic 1,3-Diones. Chem Pharm Bull (Tokyo) 2021; 70:89-93. [PMID: 34732589 DOI: 10.1248/cpb.c21-00837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
SmI2-mediated desymmetrization of a meso-cyclic 1,3-dione pinacol coupling is described. The reaction proceeds with high stereoselectivity to provide fused carbocyclic compounds with three contiguous stereogenic centers featuring an all-carbon quaternary center and a cis-1,2-diol moiety.
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Affiliation(s)
- Keita Komine
- Graduate School of Biomedical Sciences, Nagasaki University
| | - Riki Ninomiya
- Graduate School of Biomedical Sciences, Nagasaki University
| | - Hayato Fukuda
- Graduate School of Biomedical Sciences, Nagasaki University
| | - Jun Ishihara
- Graduate School of Biomedical Sciences, Nagasaki University
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40
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Ji C, Xiao J, Zeng X. Recent Progress in the Stereoselective Synthesis of (−)‐α‐Kainic Acid. ChemistrySelect 2021. [DOI: 10.1002/slct.202102562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Cong‐Bin Ji
- School of Chemistry and Environmental Sciences Shangrao Normal University Shangrao Jiangxi 334001 People's Republic of China
| | - Jie Xiao
- School of Chemistry and Environmental Sciences Shangrao Normal University Shangrao Jiangxi 334001 People's Republic of China
| | - Xing‐Ping Zeng
- Key Laboratory of Small Functional Organic Molecule Ministry of Education Jiangxi Normal University Nanchang Jiangxi 330022 People's Republic of China
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41
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Poe TN, Molinari S, Beltran-Leiva MJ, Celis-Barros C, Ramanantoanina H, Albrecht-Schönzart TE. Influence of Outer-Sphere Anions on the Photoluminescence from Samarium(II) Crown Complexes. Inorg Chem 2021; 60:15196-15207. [PMID: 34590830 DOI: 10.1021/acs.inorgchem.1c01606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three samarium(II) crown ether complexes, [Sm(15-crown-5)2]I2 (1), [Sm(15-crown-5)2]I2·CH3CN (2), and [Sm(benzo-15-crown-5)2]I2 (3), have been prepared via the reaction of SmI2 with the corresponding crown ether in either THF or acetonitrile in good to moderate yields. The compounds have been characterized by single crystal X-ray diffraction and a variety of spectroscopic techniques. In all cases, the Sm(II) centers are sandwiched between two crown ether molecules and are bound by the five etheric oxygen atoms from each crown ether to yield 10-coordinate environments. Despite the higher symmetry crystal class of 1 (R3c), the samarium center resides on a general position, whereas in 2 and 3 (both in P21/c) the metal centers lie upon inversion centers. Moreover, the complexes in 2 and 3 are approximated well by D5d symmetry. The molecule in 1, however, is distorted from idealized D5d symmetry, and the crown ethers are more puckered than observed in 2 and 3. All three complexes luminesce in the NIR at low temperatures. However, the nature of the luminescence differs between the three compounds. 1 exhibits broadband photoluminescence at 20 °C but at low temperatures transitions to narrow peaks. 2 only exhibits nonradiative decay at 20 °C and at low temperatures retains a mixture of broadband and fine transitions. Finally, 3 displays broadband luminescence regardless of temperature. Spin-orbit (SO) CASSCF calculations reveal that the outer-sphere iodide anions influence whether broadband luminescence from 5d → 4f or fine 4f → 4f transitions occur through the alteration of symmetry around the metal centers and the nature of the excited states as a function of temperature.
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Affiliation(s)
- Todd N Poe
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Sarah Molinari
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Maria J Beltran-Leiva
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Cristian Celis-Barros
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Harry Ramanantoanina
- Department of Chemistry, Johannes Gutenberg-University of Mainz, 55128 Mainz, Germany
| | - Thomas E Albrecht-Schönzart
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
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42
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Affiliation(s)
- Sandeepan Maity
- Department of Applied Sciences and Humanities Invertis University Bareilly Uttar Pradesh 243123 India
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43
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Galliher MS, Roldan BJ, Stephenson CRJ. Evolution towards green radical generation in total synthesis. Chem Soc Rev 2021; 50:10044-10057. [PMID: 34350919 PMCID: PMC9074136 DOI: 10.1039/d1cs00411e] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of radicals as intermediates in total synthesis has evolved since their initial use in the latter half of the twentieth century. Radical generation from metal hydride methodologies has shifted to "greener" techniques including catalytic metal-mediated systems, electrochemical and photoredox-mediated processes. This review will focus on these classical and contemporary methods for radical generation and their applications in recent total syntheses.
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Affiliation(s)
- Matthew S Galliher
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109, USA.
| | - Bec J Roldan
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109, USA.
| | - Corey R J Stephenson
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109, USA.
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44
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Ma F, He C, Wang E, Tong R. Collective Asymmetric Total Syntheses of Marine Decahydroquinoline Alkaloid Lepadins A-E, H, and ent-I. Org Lett 2021; 23:6583-6588. [PMID: 34374548 DOI: 10.1021/acs.orglett.1c02435] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lepadins are cis-fused decahydroquinoline (DHQ) marine alkaloids that have shown diverse biological activities and have attracted extensive synthetic interest. A new collective synthetic strategy is reported that features a green chemistry approach for constructing the common cis-fused DHQ core, which is achieved through green oxone-halide oxidation for both the aza-Achmatowicz rearrangement and the intramolecular [3 + 2] cycloaddition of nitrile oxide-alkene. Collective total syntheses of lepadins A-E and H are accomplished from the common DHQ core within 10 steps.
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Affiliation(s)
- Foqing Ma
- Department of Chemistry and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Chenxi He
- Department of Chemistry and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Eryu Wang
- Department of Chemistry and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Rongbiao Tong
- Department of Chemistry and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China
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45
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Trost BM, Zhang G, Gholami H, Zell D. Total Synthesis of Kadcoccinic Acid A Trimethyl Ester. J Am Chem Soc 2021; 143:12286-12293. [PMID: 34324806 DOI: 10.1021/jacs.1c05521] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first total synthesis of the trimethyl ester of kadcoccinic acid A is described. The central structural element of our synthesis is a cyclopentenone motif that allows the assembly of the natural product skeleton. A gold(I)-catalyzed cyclization of an enynyl acetate led to efficient construction of the cyclopentenone scaffold. In this step, optimization studies revealed that the stereochemistry of the enynyl acetate dictates regioisomeric cyclopentenone formation. The synthesis further highlights an efficient copper-mediated conjugate addition, merged with a gold(I)-catalyzed Conia-ene reaction to connect the two fragments, thereby forging the D-ring of the natural product. The synthetic strategy reported herein can provide a general platform to access the skeleton of other members of this family of natural products.
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Affiliation(s)
- Barry M Trost
- Department of Chemistry, Stanford University, Stanford, California 94305-5580, United States
| | - Guoting Zhang
- Department of Chemistry, Stanford University, Stanford, California 94305-5580, United States
| | - Hadi Gholami
- Department of Chemistry, Stanford University, Stanford, California 94305-5580, United States
| | - Daniel Zell
- Department of Chemistry, Stanford University, Stanford, California 94305-5580, United States
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46
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De S, Hoz S. Quantitation of the Interactions of Alcohols and Amines with SmI 2: Pros and Cons of VIS and NMR Spectroscopies. J Org Chem 2021; 86:10861-10865. [PMID: 34318663 DOI: 10.1021/acs.joc.1c01183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
While additives play an important role in the reactions of samarium iodide, ligand-SmI2 complexation constants are scarce. Here, VIS spectroscopy was harnessed along with NMR to determine the first complexation constant for most of the alcohols and amines used in SmI2 reactions. The second equilibrium constant was determined for selected ligands. In cases where both methods could be applied, in general, a good correlation between the equilibrium constants was obtained.
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Affiliation(s)
- Suranjan De
- Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Shmaryahu Hoz
- Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
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47
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Jiao J, Wang X. Merging Electron Transfer with 1,2-Metalate Rearrangement: Deoxygenative Arylation of Aromatic Amides with Arylboronic Esters. Angew Chem Int Ed Engl 2021; 60:17088-17093. [PMID: 33988285 DOI: 10.1002/anie.202104359] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/28/2021] [Indexed: 12/15/2022]
Abstract
Amides are essentially inert carboxyl derivatives in many types of chemical transformations. In particular, deoxygenative C-C bond formation of amides to synthetically important amines is a long-standing challenge for synthetic chemists due to the inertness of the resonance-stabilized amide C=O bond. Herein, it is disclosed that by merging electron-transfer-induced activation with 1,2-metalate rearrangement, a wide range of aromatic amides react smoothly with arylboron reagents, affording a series of biologically relevant diarylmethylamines as deoxygenative C-C bond cross-coupling products. With its simplicity and versatility, this reaction shows great promise in the synthesis of amines from amides, which may open up new avenues in retrosynthetic planning and find widespread use in academia and industry.
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Affiliation(s)
- Jiwen Jiao
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Xiaoming Wang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China.,School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
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48
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Jiao J, Wang X. Merging Electron Transfer with 1,2‐Metalate Rearrangement: Deoxygenative Arylation of Aromatic Amides with Arylboronic Esters. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jiwen Jiao
- State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Xiaoming Wang
- State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Chemistry and Materials Science Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences 1 Sub-lane Xiangshan Hangzhou 310024 China
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49
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Classen MJ, Böcker MNA, Roth R, Amberg WM, Carreira EM. Enantioselective Total Synthesis of (+)-Euphorikanin A. J Am Chem Soc 2021; 143:8261-8265. [PMID: 34043906 DOI: 10.1021/jacs.1c04210] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We disclose the first total synthesis of (+)-euphorikanin A, an ingenane-derived natural product featuring an unprecedented 5/6/7/3-fused tetracyclic skeleton. Key to the approach is a SmI2-mediated ketyl-enoate reaction that leads to the formation of two rings in a single step. The polarity-reversed cyclization proceeds in excellent yield and high diastereoselectivity. Access to ring B is effected late in the synthesis by implementation of a number of chemoselective transformations, including in situ generation of a vinyl lithium species and subsequent intramolecular attack onto an α-ketolactone.
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Affiliation(s)
- Moritz J Classen
- ETH Zürich, Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, Vladimir Prelog Weg 3, 8093 Zürich, Switzerland
| | - Markus N A Böcker
- ETH Zürich, Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, Vladimir Prelog Weg 3, 8093 Zürich, Switzerland
| | - Remo Roth
- ETH Zürich, Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, Vladimir Prelog Weg 3, 8093 Zürich, Switzerland
| | - Willi M Amberg
- ETH Zürich, Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, Vladimir Prelog Weg 3, 8093 Zürich, Switzerland
| | - Erick M Carreira
- ETH Zürich, Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, Vladimir Prelog Weg 3, 8093 Zürich, Switzerland
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50
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Zhang Q, Yang Z, Wang Q, Liu S, Zhou T, Zhao Y, Zhang M. Asymmetric Total Synthesis of Hetidine-Type C 20-Diterpenoid Alkaloids: (+)-Talassimidine and (+)-Talassamine. J Am Chem Soc 2021; 143:7088-7095. [PMID: 33938219 DOI: 10.1021/jacs.1c01865] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Here, we report the first asymmetric total synthesis of (+)-talassimidine and (+)-talassamine, two hetidine-type C20-diterpenoid alkaloids. A highly regio- and diastereoselective 1,3-dipolar cycloaddition of an azomethine ylide yielded a chiral tetracyclic intermediate in high enantiopurity, thus providing the structural basis for asymmetric assembly of the hexacyclic hetidine skeleton. In this key step, the introduction of a single chiral center induces four new continuous chiral centers. Another key transformation is the dearomative cyclopropanation of the benzene ring and subsequent SN2-like ring opening of the resultant cyclopropane ring with water as a nucleophile, which not only establishes the B ring but also precisely installs the difficult-to-achieve equatorial C7-OH group.
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Affiliation(s)
- Quanzheng Zhang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Zhao Yang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Qi Wang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Shuangwei Liu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Tao Zhou
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Yankun Zhao
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Min Zhang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
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