1
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Álvarez-Núñez A, Sarkar R, Dantignana V, Xiong J, Guo Y, Luis JM, Costas M, Company A. Intramolecular C-H Oxidation in Iron(V)-oxo-carboxylato Species Relevant in the γ-Lactonization of Alkyl Carboxylic Acids. ACS Catal 2024; 14:14183-14194. [PMID: 39324053 PMCID: PMC11420956 DOI: 10.1021/acscatal.4c01258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 08/26/2024] [Accepted: 08/29/2024] [Indexed: 09/27/2024]
Abstract
High-valent oxoiron species have been invoked as oxidizing agents in a variety of iron-dependent oxygenases. Taking inspiration from nature, selected nonheme iron complexes have been developed as catalysts to elicit C-H oxidation through the mediation of putative oxoiron(V) species, akin to those proposed for Rieske oxygenases. The addition of carboxylic acids in these iron-catalyzed C-H oxidations has proved highly beneficial in terms of product yields and selectivities, suggesting the direct involvement of iron(V)-oxo-carboxylato species. When the carboxylic acid functionality is present in the alkane substrate, it acts as a directing group, enabling the selective intramolecular γ-C-H hydroxylation that eventually affords γ-lactones. While this mechanistic frame is solidly supported by previous mechanistic studies, direct spectroscopic detection of the key iron(V)-oxo-carboxylato intermediate and its competence for engaging in the selective γ-C-H oxidation leading to lactonization have not been accomplished. In this work, we generate a series of well-defined iron(V)-oxo-carboxylato species (2c-2f) differing in the nature of the bound carboxylate ligand. Species 2c-2f are characterized by a set of spectroscopic techniques, including UV-vis spectroscopy, cold-spray ionization mass spectrometry (CSI-MS), and, in selected cases, EPR and Mössbauer spectroscopies. We demonstrate that 2c-2f undergo site-selective γ-lactonization of the carboxylate ligand in a stereoretentive manner, thus unequivocally identifying metal-oxo-carboxylato species as the powerful yet selective C-H cleaving species in catalytic γ-lactonization reactions of carboxylic acids. Reactivity experiments confirm that the intramolecular formation of γ-lactones is in competition with the intermolecular oxidation of external alkanes and olefins. Finally, mechanistic studies, together with DFT calculations, support a mechanism involving a site-selective C-H cleavage in the γ-position of the carboxylate ligand by the oxo moiety, followed by a fast carboxylate rebound, eventually leading to the selective formation of γ-lactones.
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Affiliation(s)
- Andrea Álvarez-Núñez
- Institut
de Química Computacional i Catàlisi (IQCC), Departament
de Química, Universitat de Girona, C/Ma Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Rudraditya Sarkar
- Institut
de Química Computacional i Catàlisi (IQCC), Departament
de Química, Universitat de Girona, C/Ma Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
- Department
of Chemistry, School of Science, Gandhi
Institute of Technology and Management (GITAM), Hyderabad502329, India
| | - Valeria Dantignana
- Institut
de Química Computacional i Catàlisi (IQCC), Departament
de Química, Universitat de Girona, C/Ma Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Jin Xiong
- Chemistry
Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yisong Guo
- Chemistry
Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Josep M. Luis
- Institut
de Química Computacional i Catàlisi (IQCC), Departament
de Química, Universitat de Girona, C/Ma Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Miquel Costas
- Institut
de Química Computacional i Catàlisi (IQCC), Departament
de Química, Universitat de Girona, C/Ma Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Anna Company
- Institut
de Química Computacional i Catàlisi (IQCC), Departament
de Química, Universitat de Girona, C/Ma Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
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2
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Wright BA, Sarpong R. Molecular complexity as a driving force for the advancement of organic synthesis. Nat Rev Chem 2024:10.1038/s41570-024-00645-8. [PMID: 39251714 DOI: 10.1038/s41570-024-00645-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2024] [Indexed: 09/11/2024]
Abstract
The generation of molecular complexity is a primary goal in the field of synthetic chemistry. In the context of retrosynthetic analysis, the concept of molecular complexity is central to identifying productive disconnections and the development of efficient total syntheses. However, this field-defining concept is frequently invoked on an intuitive basis without precise definition or appreciation of its subtleties. Methods for quantifying molecular complexity could prove useful for characterizing the state of synthesis in a more rigorous, reliable and reproducible fashion. As a first step to evaluating the importance of these methods to the state of the field, here we present our perspective on the development of molecular complexity quantification and its implications for chemical synthesis. The extension and application of these methods beyond computer-aided synthesis planning and medicinal chemistry to the traditional practice of 'complex molecule' synthesis could have the potential to unearth new opportunities and more efficient approaches for synthesis.
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Affiliation(s)
- Brandon A Wright
- Department of Chemistry, University of California, Berkeley, USA
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, USA.
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3
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Xiao J, Liu ZH, He ZF, Wu P, Wang YW, Li WDZ, Peng Y. Bioinspired Total Synthesis of 3- epi-Junipercedrol. Org Lett 2024; 26:7463-7467. [PMID: 39190923 DOI: 10.1021/acs.orglett.4c02877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
A bioinspired total synthesis of 3-epi-junipercedrol, which contains a strained tricyclo[5.2.2.03,7]undecane allo-cedrane framework and five stereocenters, was accomplished via an effective anionic semipinacol rearrangement of a tricyclic cedrane mesylate. The corresponding cedrane precursor was synthesized efficiently by employing the reductive oxy-Nazarov cyclization and an intramolecular aldol condensation as the key steps. This synthetic approach provided a further evidence for the biogenetic relationship between the typical cedrane and allo-cedrane sesquiterpenoids.
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Affiliation(s)
- Jian Xiao
- School of Chemistry, Key Laboratory of Advanced Technologies of Material, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - Zi-Hao Liu
- School of Chemistry, Key Laboratory of Advanced Technologies of Material, Ministry of Education, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - Zi-Fan He
- School of Chemistry, Key Laboratory of Advanced Technologies of Material, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - Ping Wu
- School of Chemistry, Key Laboratory of Advanced Technologies of Material, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - Ya-Wen Wang
- School of Chemistry, Key Laboratory of Advanced Technologies of Material, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - Wei-Dong Z Li
- School of Chemistry, Key Laboratory of Advanced Technologies of Material, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - Yu Peng
- School of Chemistry, Key Laboratory of Advanced Technologies of Material, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, P. R. China
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4
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Zhao Z, Deng G, Li CC. Synthesis of the [6-6-7-5-5] Pentacyclic Core of Calyciphylline N. Org Lett 2024; 26:2238-2242. [PMID: 38442391 DOI: 10.1021/acs.orglett.4c00437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
A new approach for the concise 11-step synthesis of the [6-6-7-5-5] BCDEF pentacyclic core of calyciphylline N is described. A type II [5 + 2] cycloaddition was employed to construct the strained BCD skeleton, which encompasses the challenging bicyclo[2.2.2] and bicyclo[4.3.1] ring systems. With a regio- and diastereoselective Lu's [3 + 2] cycloaddition, followed by intramolecular aldol cyclization and elimination, the desired [5-5]-fused EF ring system has been successfully installed, resulting in the complete carbocyclic skeleton of calyciphylline N.
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Affiliation(s)
- Zhiwen Zhao
- Shenzhen Grubbs Institute, Department of Chemistry, Guangming Advanced Research Institute, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Guowei Deng
- Shenzhen Grubbs Institute, Department of Chemistry, Guangming Advanced Research Institute, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Chuang-Chuang Li
- Shenzhen Grubbs Institute, Department of Chemistry, Guangming Advanced Research Institute, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
- Shenzhen Bay Laboratory, Shenzhen, Guangdong 518132, People's Republic of China
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5
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Fay N, Kouklovsky C, de la Torre A. Natural Product Synthesis: The Endless Quest for Unreachable Perfection. ACS ORGANIC & INORGANIC AU 2023; 3:350-363. [PMID: 38075446 PMCID: PMC10704578 DOI: 10.1021/acsorginorgau.3c00040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/24/2023] [Accepted: 09/25/2023] [Indexed: 06/13/2024]
Abstract
Total synthesis is a field in constant progress. Its practitioners aim to develop ideal synthetic strategies to build complex molecules. As such, they are both a driving force and a showcase of the progress of organic synthesis. In this Perspective, we discuss recent notable total syntheses. The syntheses selected herein are classified according to the key strategic considerations for each approach.
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Affiliation(s)
- Nicolas Fay
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Saclay, CNRS, 17 Avenue des Sciences, 91405 Orsay, France
| | - Cyrille Kouklovsky
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Saclay, CNRS, 17 Avenue des Sciences, 91405 Orsay, France
| | - Aurélien de la Torre
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Saclay, CNRS, 17 Avenue des Sciences, 91405 Orsay, France
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6
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Bakanas I, Lusi RF, Wiesler S, Hayward Cooke J, Sarpong R. Strategic application of C-H oxidation in natural product total synthesis. Nat Rev Chem 2023; 7:783-799. [PMID: 37730908 DOI: 10.1038/s41570-023-00534-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2023] [Indexed: 09/22/2023]
Abstract
The oxidation of unactivated C-H bonds has emerged as an effective tactic in natural product synthesis and has altered how chemists approach the synthesis of complex molecules. The use of C-H oxidation methods has simplified the process of synthesis planning by expanding the choice of starting materials, limiting functional group interconversion and protecting group manipulations, and enabling late-stage diversification. In this Review, we propose classifications for C-H oxidations on the basis of their strategic purpose: type 1, which installs functionality that is used to establish the carbon skeleton of the target; type 2, which is used to construct a heterocyclic ring; and type 3, which installs peripheral functional groups. The reactions are further divided based on whether they are directed or undirected. For each classification, examples from recent literature are analysed. Finally, we provide two case studies of syntheses from our laboratory that were streamlined by the judicious use of C-H oxidation reactions.
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Affiliation(s)
- Ian Bakanas
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Robert F Lusi
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Stefan Wiesler
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Jack Hayward Cooke
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
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7
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Harmange Magnani C, Hernández-Meléndez JR, Tantillo DJ, Maimone TJ. Total Synthesis of Altemicidin: A Surprise Ending for a Monoterpene Alkaloid. JACS AU 2023; 3:2883-2893. [PMID: 37885570 PMCID: PMC10598567 DOI: 10.1021/jacsau.3c00417] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/21/2023] [Accepted: 09/21/2023] [Indexed: 10/28/2023]
Abstract
Monoterpene alkaloids encompass distinct chemical diversity and wide-ranging bioactivity. Their compact complexity has made them popular as synthetic targets and has inspired many distinct strategies and tactics in the field of heterocyclic chemistry. This article documents the evolution of a synthetic program aimed at accessing the unusual sulfonamide-containing natural product altemicidin, which was generally believed to be a monoterpene alkaloid throughout our entire synthetic investigations but has recently been found to originate through an unexpected and quite disparate biosynthetic pathway. By leveraging a pyridine dearomatization/cycloaddition strategy, we developed a concise pathway to the 5,6-fused bicyclic azaindane core and, after significant experimentation, an ultimate synthesis of altemicidin itself. Tactics to productively manipulate the multiple functional groups present on this highly polar scaffold proved challenging but were eventually realized via several carefully orchestrated and chemoselective transformations-investments that paid dividends in the form of significantly shorter chemical synthesis. Surprisingly, the bond-forming logic between our presumed abiotic synthetic strategy to this alkaloid class and its subsequently identified biosynthetic pathway is eerily similar.
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Affiliation(s)
- Claire
S. Harmange Magnani
- Department
of Chemistry, University of California,
Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - José R. Hernández-Meléndez
- Department
of Chemistry, University of California,
Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Dean J. Tantillo
- Department
of Chemistry, University of California−Davis; 1 Shields Avenue, Davis, California 95616, United States
| | - Thomas J. Maimone
- Department
of Chemistry, University of California,
Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
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8
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Yu IF, Wilson JW, Hartwig JF. Transition-Metal-Catalyzed Silylation and Borylation of C-H Bonds for the Synthesis and Functionalization of Complex Molecules. Chem Rev 2023; 123:11619-11663. [PMID: 37751601 DOI: 10.1021/acs.chemrev.3c00207] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
The functionalization of C-H bonds in organic molecules containing functional groups has been one of the holy grails of catalysis. One synthetically important approach to the diverse functionalization of C-H bonds is the catalytic silylation or borylation of C-H bonds, which enables a broad array of downstream transformations to afford diverse structures. Advances in both undirected and directed methods for the transition-metal-catalyzed silylation and borylation of C-H bonds have led to their rapid adoption in early-, mid-, and late-stage of the synthesis of complex molecules. In this Review, we review the application of the transition-metal-catalyzed silylation and borylation of C-H bonds to the synthesis of bioactive molecules, organic materials, and ligands. Overall, we aim to provide a picture of the state of art of the silylation and borylation of C-H bonds as applied to the synthesis and modification of diverse architectures that will spur further application and development of these reactions.
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Affiliation(s)
- Isaac F Yu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jake W Wilson
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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9
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Fu P, Liu T, Shen Y, Lei X, Xiao T, Chen P, Qiu D, Wang Z, Zhang Y. Divergent Total Syntheses of Illicium Sesquiterpenes through Late-Stage Skeletal Reorganization. J Am Chem Soc 2023; 145:18642-18648. [PMID: 37562030 DOI: 10.1021/jacs.3c06442] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
We disclose unified, protecting-group-free, bioinspired divergent total syntheses of eight allo-cedrane and seco-prezizaane Illicium sesquiterpenes and formal syntheses of five anislactone sesquiterpenes. The efficiency of our approach derives from rapid access to the 15-carbon tricyclic carboxylic acid through cationic epoxide-ene cyclization and HAT oxygenation, transformation of this intermediate into three distinct tricyclic precursors via Lewis acid-mediated skeletal reorganizations, subsequent programmed oxidation level enhancement, and a biomimetic oxidation-initiated skeletal rearrangement cascade. Consequently, we created a synthetic correlation map of the three most prevalent Illicium sesquiterpene families.
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Affiliation(s)
- Pengfei Fu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Tao Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Yang Shen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Xin Lei
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Tianjie Xiao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Peng Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Dongsheng Qiu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhen Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Yandong Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iCHEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
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10
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Call A, Capocasa G, Palone A, Vicens L, Aparicio E, Choukairi Afailal N, Siakavaras N, López Saló ME, Bietti M, Costas M. Highly Enantioselective Catalytic Lactonization at Nonactivated Primary and Secondary γ-C-H Bonds. J Am Chem Soc 2023; 145:18094-18103. [PMID: 37540636 PMCID: PMC10507665 DOI: 10.1021/jacs.3c06231] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Indexed: 08/06/2023]
Abstract
Chiral oxygenated aliphatic moieties are recurrent in biological and pharmaceutically relevant molecules and constitute one of the most versatile types of functionalities for further elaboration. Herein we report a protocol for straightforward and general access to chiral γ-lactones via enantioselective oxidation of strong nonactivated primary and secondary C(sp3)-H bonds in readily available carboxylic acids. The key enabling aspect is the use of robust sterically encumbered manganese catalysts that provide outstanding enantioselectivities (up to >99.9%) and yields (up to 96%) employing hydrogen peroxide as the oxidant. The resulting γ-lactones are of immediate interest for the preparation of inter alia natural products and recyclable polymeric materials.
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Affiliation(s)
- Arnau Call
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Giorgio Capocasa
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Andrea Palone
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Laia Vicens
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Eric Aparicio
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Najoua Choukairi Afailal
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Nikos Siakavaras
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Maria Eugènia López Saló
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Massimo Bietti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Miquel Costas
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
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11
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Sun D, Chen R, Tang D, Xia Q, Zhao Y, Liu CH, Ding H. Total Synthesis of (-)-Retigeranic Acid A: A Reductive Skeletal Rearrangement Strategy. J Am Chem Soc 2023. [PMID: 37224289 DOI: 10.1021/jacs.3c03178] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The asymmetric total synthesis of (-)-retigeranic acid A was described, which relies on a crucial reductive skeletal rearrangement cascade for the controllable assembly of diverse angular triquinane subunits. Taken together with an intramolecular Michael/aldol cyclization, an ODI-[5 + 2] cycloaddition/pinacol rearrangement cascade, a Wolff ring contraction and a stereoselective HAT reduction, our synthetic approach has enabled the access to (-)-retigeranic acid A in a concise and practical manner.
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Affiliation(s)
- Dongyu Sun
- Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Ruyi Chen
- Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Dongmin Tang
- Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Qidong Xia
- College of Chemistry, Jilin University, Changchun 130012, China
| | - Yifan Zhao
- Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Chun-Hui Liu
- Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Hanfeng Ding
- Department of Chemistry, Zhejiang University, Hangzhou 310058, China
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12
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Etling C, Tedesco G, Di Marco A, Kalesse M. Asymmetric Total Synthesis of Illisimonin A. J Am Chem Soc 2023; 145:7021-7029. [PMID: 36926847 PMCID: PMC10064331 DOI: 10.1021/jacs.3c01262] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The discovery of illisimonin A in 2017 extended the structural repertoire of the Illicium sesquiterpenoids─a class of natural products known for their high oxidation levels and neurotrophic properties─with a new carbon backbone combining the strained trans-pentalene and norbornane substructures. We report an asymmetric total synthesis of (-)-illisimonin A that traces its tricyclic carbon framework back to a spirocyclic precursor, generated by a tandem-Nazarov/ene cyclization. As crucial link between the spirocyclic key intermediate and illisimonin A, a novel approach for the synthesis of tricyclo[5.2.1.01,5]decanes via radical cyclization was explored. This approach was applied in a two-stage strategy consisting of Ti(III)-mediated cyclization and semipinacol rearrangement to access the natural product's carbon backbone. These key steps were combined with carefully orchestrated C-H oxidations to establish the dense oxidation pattern.
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Affiliation(s)
- Christoph Etling
- Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany
| | - Giada Tedesco
- Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany
| | - Anna Di Marco
- Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany
| | - Markus Kalesse
- Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany
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13
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Call A, Cianfanelli M, Besalú-Sala P, Olivo G, Palone A, Vicens L, Ribas X, Luis JM, Bietti M, Costas M. Carboxylic Acid Directed γ-Lactonization of Unactivated Primary C-H Bonds Catalyzed by Mn Complexes: Application to Stereoselective Natural Product Diversification. J Am Chem Soc 2022; 144:19542-19558. [PMID: 36228322 DOI: 10.1021/jacs.2c08620] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reactions that enable selective functionalization of strong aliphatic C-H bonds open new synthetic paths to rapidly increase molecular complexity and expand chemical space. Particularly valuable are reactions where site-selectivity can be directed toward a specific C-H bond by catalyst control. Herein we describe the catalytic site- and stereoselective γ-lactonization of unactivated primary C-H bonds in carboxylic acid substrates. The system relies on a chiral Mn catalyst that activates aqueous hydrogen peroxide to promote intramolecular lactonization under mild conditions, via carboxylate binding to the metal center. The system exhibits high site-selectivity and enables the oxidation of unactivated primary γ-C-H bonds even in the presence of intrinsically weaker and a priori more reactive secondary and tertiary ones at α- and β-carbons. With substrates bearing nonequivalent γ-C-H bonds, the factors governing site-selectivity have been uncovered. Most remarkably, by manipulating the absolute chirality of the catalyst, γ-lactonization at methyl groups in gem-dimethyl structural units of rigid cyclic and bicyclic carboxylic acids can be achieved with unprecedented levels of diastereoselectivity. Such control has been successfully exploited in the late-stage lactonization of natural products such as camphoric, camphanic, ketopinic, and isoketopinic acids. DFT analysis points toward a rebound type mechanism initiated by intramolecular 1,7-HAT from a primary γ-C-H bond of the bound substrate to a highly reactive MnIV-oxyl intermediate, to deliver a carbon radical that rapidly lactonizes through carboxylate transfer. Intramolecular kinetic deuterium isotope effect and 18O labeling experiments provide strong support to this mechanistic picture.
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Affiliation(s)
- Arnau Call
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Marco Cianfanelli
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Pau Besalú-Sala
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Giorgio Olivo
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Andrea Palone
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain.,Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Laia Vicens
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Xavi Ribas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Josep M Luis
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
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14
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Sennari G, Gardner KE, Wiesler S, Haider M, Eggert A, Sarpong R. Unified Total Syntheses of Benzenoid Cephalotane-Type Norditerpenoids: Cephanolides and Ceforalides. J Am Chem Soc 2022; 144:19173-19185. [PMID: 36198090 DOI: 10.1021/jacs.2c08803] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Detailed herein are our synthetic studies toward the preparation of the C18- and C19-benzenoid cephalotane-type norditerpenoids. Guided by chemical network analysis, the core structure of this natural product family was constructed in a concise manner using an iterative cross-coupling, followed by a formal inverse-electron-demand [4 + 2] cycloaddition. Initial efforts to functionalize an alkene group in the [4 + 2] cycloadduct using a Mukaiyama hydration and a subsequent olefination led to the complete C18-carbon framework. While effective, this approach proved lengthy and prompted the development of a direct alkene difunctionalization that relies on borocupration to advance the cycloadduct to the natural products. Late-stage peripheral C-H functionalization facilitated access to all of the known cephanolides in 6-10 steps as well as five recently isolated ceforalides in 8-13 steps.
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Affiliation(s)
- Goh Sennari
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States
| | - Kristen E Gardner
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States
| | - Stefan Wiesler
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States
| | - Maximilian Haider
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States
| | - Alina Eggert
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States
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15
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Georgiev T, Armanino N. Biomimetic Synthesis of Nor‐Cedrene and Nor‐Isozizaene Sesquiterpenoids and Exploration of Their Olfactive Properties. Chemistry 2022; 28:e202201037. [DOI: 10.1002/chem.202201037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Tony Georgiev
- Philochem AG Libernstrasse 3 8112 Otelfingen Switzerland
| | - Nicolas Armanino
- Fragrance Discovery Research Givaudan Suisse SA Kemptpark 50 8310 Kemptthal Switzerland
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16
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Santana VCS, Rocha ECS, Pavan JCS, Heleno VCG, de Lucca EC. Selective Oxidations in the Synthesis of Complex Natural ent-Kauranes and ent-Beyeranes. J Org Chem 2022; 87:10462-10466. [PMID: 35862248 DOI: 10.1021/acs.joc.2c01051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Syntheses of two natural products derived from the ent-kaurene kaurenoic acid are described for the first time using regio- and diastereoselective oxidations. Palladium- and manganese-mediated oxidations were used to accomplish the syntheses of two ent-beyerane metabolites. The use of the White-Gormisky-Zhao catalyst Mn(CF3-PDP) enabled the first application of a nondirected metal-catalyzed oxidation in an unactivated C-H bond in a total synthesis.
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Affiliation(s)
- Victor C S Santana
- Institute of Chemistry, University of Campinas, 13083-970 Campinas, SP, Brazil
| | - Eduardo C S Rocha
- Institute of Chemistry, University of Campinas, 13083-970 Campinas, SP, Brazil
| | - Julian C S Pavan
- Research Center in Exact and Technological Sciences, University of Franca, 14404-600 Franca, SP, Brazil
| | - Vladimir C G Heleno
- Research Center in Exact and Technological Sciences, University of Franca, 14404-600 Franca, SP, Brazil
| | - Emilio C de Lucca
- Institute of Chemistry, University of Campinas, 13083-970 Campinas, SP, Brazil
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17
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Xiao S, Ai L, Liu Q, Yang B, Huang J, Xue W, Chen Y. Total Synthesis of Natural Terpenoids Enabled by Cobalt Catalysis. Front Chem 2022; 10:941184. [PMID: 35783212 PMCID: PMC9241582 DOI: 10.3389/fchem.2022.941184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 05/17/2022] [Indexed: 12/01/2022] Open
Abstract
Transition metal catalysis plays an essential role in the total synthesis of natural products. Cobalt-mediated asymmetric catalysis has successfully been used as a primary or a secondary step in the total synthesis of natural products, especially terpenoids. Terpenoids represent one of the most prominent families among various categories of natural products, attracting immense attention due to their promising physiological activities. This review summarizes the recent advances toward the total synthesis of terpenoids by cobalt-mediated asymmetric catalysis, which may shed some light on their future synthetic efforts toward natural pesticides such as celanguline, azadirachtin, etc.
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Affiliation(s)
| | | | | | | | | | - Wei Xue
- *Correspondence: Yang Chen, ; Wei Xue,
| | - Yang Chen
- *Correspondence: Yang Chen, ; Wei Xue,
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18
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Chen B, Wu Q, Xu D, Zhang X, Ding Y, Bao S, Zhang X, Wang L, Chen Y. A Two-Phase Approach to Fusicoccane Synthesis To Uncover a Compound That Reduces Tumourigenesis in Pancreatic Cancer Cells. Angew Chem Int Ed Engl 2022; 61:e202117476. [PMID: 35166433 DOI: 10.1002/anie.202117476] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Indexed: 12/19/2022]
Abstract
Alterbrassicicene D (1) and 3(11)-epoxyhypoestenone (2) were synthesised via a two-phase approach featuring concise construction of the 5-8-5 tricyclic intermediate and a tandem base-mediated epoxide opening-transannular oxa-Michael addition cascade to forge the complex skeleton of 2. The route is scalable and we generated 15 g of the tricyclic intermediate in 8 steps from (R)-limonene and 720 mg of the penultimate bioactive intermediate in a protecting-group-free manner. Our synthesis enabled the structural determination of 2 and provided materials for preliminary anticancer evaluation. The penultimate intermediate showed therapeutic potential in terms of its ability to dramatically reduce the tumourigenic potential of PANC-1 pancreatic cancer cells according to a limiting dilution tumour-initiating assay. Our synthetic approach will facilitate unified access to naturally occurring fusicoccanes and their derivatives for anticancer evaluation.
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Affiliation(s)
- Bolin Chen
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, 38 Tongyan Road, Tianjin, 300353, P. R. China
| | - Qianwei Wu
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, 38 Tongyan Road, Tianjin, 300353, P. R. China
| | - Dongdong Xu
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, 38 Tongyan Road, Tianjin, 300353, P. R. China
| | - Xijing Zhang
- College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, P. R. China
| | - Yahui Ding
- College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, P. R. China
| | - Shiqi Bao
- Accendatech Company, Ltd, 7 Fengze Road, Tianjin, 300384, P. R. China
| | - Xuemei Zhang
- Accendatech Company, Ltd, 7 Fengze Road, Tianjin, 300384, P. R. China
| | - Liang Wang
- College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, P. R. China
| | - Yue Chen
- College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, P. R. China
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19
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Dooley CJ, Rychnovsky SD. Asymmetric Total Synthesis of (2 R)-Hydroxynorneomajucin, a Norsesquiterpene from Illicium jiadifengpi. Org Lett 2022; 24:3411-3415. [DOI: 10.1021/acs.orglett.2c01207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Charles J. Dooley
- Department of Chemistry, University of California at Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Scott D. Rychnovsky
- Department of Chemistry, University of California at Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
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20
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Fukuyama Y. [Synthetic Studies on Small Molecule Natural Products with Neurotrophic Activity]. YAKUGAKU ZASSHI 2022; 142:241-277. [PMID: 35228379 DOI: 10.1248/yakushi.21-00201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurotrophic factors have been shown to potentially be beneficial for the treatment of neurodegenerative diseases such as Alzheimer's disease, because endogenous neurotrophic factors (NGF, BDNF) have been recognized to play critical roles in the promotion of neurogenesis, differentiation, and neuroprotection throughout the development of the central nervous system. However, high-molecular-weight proteins are unable to cross the blood-brain barrier and are easily decomposed under physiological conditions. Thus, small molecules that can mimic the functions of neurotrophic factors are promising alternatives for the treatment of neurodegenerative disease. Since 1990, the author has been involved in searching for natural products with typical neurotrophic properties that can cause neurogenesis, enhance neurite outgrowth, and protect against neuronal death by using three cellular systems (PC12, rat cortical neurons, and MEB5 cells). Through these research activities on neurotrophic natural products, the author has tried to induce a paradigm shift from the discipline of natural products chemistry to science disciplines. This review focuses on our independent synthetic studies of the neurotrophic natural products discovered in the plants. The following synthetic elaborations are described: syntheses of dimeric isocuparane-type sesquiterpenes mastigophorenes A and B, macrocyclic bis-bibenzyls plagiochins A-D and cavicularin through a Pd-catalyzed Stille-Kelly reaction; the formal synthesis of merrilactone A and jiadifenin, which are seco-prezizaane-type sesquiterpenes, through intramolecular Pd-catalyzed Mizoroki-Heck and Tsuji-Trost reactions; and finally the first enantioselective synthesis of neovibsanin B, a vibsane-type diterpene, through a Pd-catalyzed cyclic carbopalladation-carbonyl tandem reaction.
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21
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Chen B, Wu Q, Xu D, Zhang X, Ding Y, Bao S, Zhang X, Wang L, Chen Y. A Two‐Phase Approach to Fusicoccane Synthesis To Uncover a Compound That Reduces Tumourigenesis in Pancreatic Cancer Cells. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202117476] [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)
- Bolin Chen
- State Key Laboratory of Medicinal Chemical Biology College of Pharmacy Nankai University 38 Tongyan Road Tianjin 300353 P. R. China
| | - Qianwei Wu
- State Key Laboratory of Medicinal Chemical Biology College of Pharmacy Nankai University 38 Tongyan Road Tianjin 300353 P. R. China
| | - Dongdong Xu
- State Key Laboratory of Medicinal Chemical Biology College of Pharmacy Nankai University 38 Tongyan Road Tianjin 300353 P. R. China
| | - Xijing Zhang
- College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 P. R. China
| | - Yahui Ding
- College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 P. R. China
| | - Shiqi Bao
- Accendatech Company, Ltd 7 Fengze Road Tianjin 300384 P. R. China
| | - Xuemei Zhang
- Accendatech Company, Ltd 7 Fengze Road Tianjin 300384 P. R. China
| | - Liang Wang
- College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 P. R. China
| | - Yue Chen
- College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 P. R. China
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22
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Semisynthesis and neurotrophic activity studies of novel neomajucin/majucin derivatives as neurotrophin small molecule mimetics. Bioorg Med Chem Lett 2022; 60:128580. [PMID: 35066142 DOI: 10.1016/j.bmcl.2022.128580] [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: 09/30/2021] [Revised: 01/02/2022] [Accepted: 01/16/2022] [Indexed: 11/20/2022]
Abstract
Majucin-type Illicium sesquiterpenes with potent neurotrophic activity are considered to be promising candidates for the treatment of various neurodegenerative disease. Owing to the low-abundance metabolites in Illicium genus, there are few studies on their structural modifications, structure-activity relationships, and pharmacophoric motif. Herein, structural modifications were conducted on the hydroxyl groups at C-3 and C-6 positions of two majucin-type compounds neomajucin (1) and majucin (2), and 39 neomajucin/majucin based esters were synthesized and evaluated for their neurite outgrowth-promoting activities. Among all the target derivatives, compounds 1a, 1j, 1r, 2b, 2d, 3a, 3b, 3d and 3h displayed more potent neurite outgrowth-promoting activity than their precursors. Some interesting structure-activity relationships (SARs) were also observed. Moreover, compound 1a showed good neuroprotective effect on MPP+-induced PC12 cell damage. Finally, compounds 1a and 3a exhibited relatively no cytotoxicity to normal human H9C2 cardiac cells. This work will shed light on the development of neomajucin/majucin derivatives as potential neurotrophic agents.
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23
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Martin T, Galeotti M, Salamone M, Liu F, Yu Y, Duan M, Houk KN, Bietti M. Deciphering Reactivity and Selectivity Patterns in Aliphatic C-H Bond Oxygenation of Cyclopentane and Cyclohexane Derivatives. J Org Chem 2021; 86:9925-9937. [PMID: 34115516 DOI: 10.1021/acs.joc.1c00902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A kinetic, product, and computational study on the reactions of the cumyloxyl radical with monosubstituted cyclopentanes and cyclohexanes has been carried out. HAT rates, site-selectivities for C-H bond oxidation, and DFT computations provide quantitative information and theoretical models to explain the observed patterns. Cyclopentanes functionalize predominantly at C-1, and tertiary C-H bond activation barriers decrease on going from methyl- and tert-butylcyclopentane to phenylcyclopentane, in line with the computed C-H BDEs. With cyclohexanes, the relative importance of HAT from C-1 decreases on going from methyl- and phenylcyclohexane to ethyl-, isopropyl-, and tert-butylcyclohexane. Deactivation is also observed at C-2 with site-selectivity that progressively shifts to C-3 and C-4 with increasing substituent steric bulk. The site-selectivities observed in the corresponding oxidations promoted by ethyl(trifluoromethyl)dioxirane support this mechanistic picture. Comparison of these results with those obtained previously for C-H bond azidation and functionalizations promoted by the PINO radical of phenyl and tert-butylcyclohexane, together with new calculations, provides a mechanistic framework for understanding C-H bond functionalization of cycloalkanes. The nature of the HAT reagent, C-H bond strengths, and torsional effects are important determinants of site-selectivity, with the latter effects that play a major role in the reactions of oxygen-centered HAT reagents with monosubstituted cyclohexanes.
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Affiliation(s)
- Teo Martin
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Marco Galeotti
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Fengjiao Liu
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China.,Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Yanmin Yu
- Beijing Key Laboratory for Green Catalysis and Separation, Department of Environmental Chemical Engineering, Beijing University of Technology, Beijing 100124, China.,Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Meng Duan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
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24
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Gayraud O, Laroche B, Casaretto N, Nay B. Synthesis of a Biomimetic Tetracyclic Precursor of Aspochalasins and Formal Synthesis of Trichoderone A. Org Lett 2021; 23:5755-5760. [PMID: 34291937 DOI: 10.1021/acs.orglett.1c01922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aspochalasins are leucine-derived cytochalasins. Their complexity is associated with a high degree of biosynthetic oxidation, herein inspiring a two-phase strategy in total synthesis. We thus describe the synthesis of a putative biomimetic tetracyclic intermediate. The constructive steps are an intramolecular Diels-Alder reaction to install the isoindolone core of cytochalasins, whose branched precursor was obtained from a stereoselective Ireland-Claisen rearrangement performed from a highly unsaturated substrate. This also constitutes a formal synthesis of trichoderone A.
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Affiliation(s)
- Oscar Gayraud
- Laboratoire de Synthèse Organique, Ecole Polytechnique, CNRS, ENSTA, Institut Polytechnique de Paris, Palaiseau 91128, France
| | - Benjamin Laroche
- Unité Molécules de Communication et Adaptation des Microorganismes, Muséum National d'Histoire Naturelle, CNRS, Paris 75005, France
| | - Nicolas Casaretto
- Laboratoire de Chimie Moléculaire, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, Palaiseau 91128, France
| | - Bastien Nay
- Laboratoire de Synthèse Organique, Ecole Polytechnique, CNRS, ENSTA, Institut Polytechnique de Paris, Palaiseau 91128, France.,Unité Molécules de Communication et Adaptation des Microorganismes, Muséum National d'Histoire Naturelle, CNRS, Paris 75005, France
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25
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Tong G, Baker MA, Shenvi RA. Change the channel: CysLoop receptor antagonists from nature. PEST MANAGEMENT SCIENCE 2021; 77:3650-3662. [PMID: 33135373 PMCID: PMC8087819 DOI: 10.1002/ps.6166] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/27/2020] [Accepted: 11/01/2020] [Indexed: 05/04/2023]
Abstract
Vertebrate and invertebrate ligand-gated ion channels (LGICs) exhibit significant structural homology and often share ligands. As a result, ligands with activity against one class can be brought to bear against another, including for development as insecticides. Receptor selectivity, metabolism and distribution must then be optimized using chemical synthesis. Here we review natural products (NPs) that ligate and inhibit the Cys-loop family of LGICs, which benefit from the unique physicochemical properties of natural product space but often present a high synthetic burden. Recent advances in chemical synthesis, however, have opened practical entries into these complex structures, several of which are highlighted. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Guanghu Tong
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | - Meghan A Baker
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | - Ryan A Shenvi
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
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26
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Radical philicity and its role in selective organic transformations. Nat Rev Chem 2021; 5:486-499. [PMID: 37118440 DOI: 10.1038/s41570-021-00284-3] [Citation(s) in RCA: 140] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2021] [Indexed: 12/11/2022]
Abstract
Radical intermediates in organic chemistry lack a full octet of electrons and, thus, are commonly said to be electron deficient. By denotation, such a statement is technically correct; however, in modern literature, the term 'electron deficient' carries a connotation of electrophilicity. This lexical quirk leads one to predict that all radicals should behave as electrophiles, when this is not the case. Indeed, practitioners of radical chemistry have known for decades that many radicals behave as nucleophiles, sometimes strongly so. This Review aims to establish guidelines for understanding radical philicity by highlighting examples from recent literature as a demonstration of general reactivity paradigms across a series of different carbon-based and heteroatom-based radicals. We present strategies for predicting the philicity of a given radical on the basis of qualitative features of the radical's structure. Finally, we discuss the implications of radical philicity to selective hydrogen atom transfer.
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27
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Harmange Magnani CS, Maimone TJ. Dearomative Synthetic Entry into the Altemicidin Alkaloids. J Am Chem Soc 2021; 143:7935-7939. [PMID: 34018391 DOI: 10.1021/jacs.1c04147] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Altemicidin and related Streptomyces-derived monoterpene alkaloids possess dense, highly polar azaindane cores as well as potent cytotoxic and tRNA synthetase inhibitory properties. The congested α-amino acid motif decorating their presumed iridoid-like core structure has proven to be both a synthetic challenge and a biosynthetic mystery to date. Herein, we report a distinct, abiotic strategy to these alkaloids resulting in a concise synthesis of altemicidin from simple chemical feedstocks. Key chemical findings include the exploitation of a dearomative pyridinium addition and dipolar cycloaddition sequence to stereospecifically install the quaternary amine moiety, and a chemoselective molybdenum-mediated double reduction to establish the fully functionalized azaindane nucleus with minimal redox manipulations.
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Affiliation(s)
- Claire S Harmange Magnani
- 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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28
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Wang Z, Hui C. Contemporary advancements in the semi-synthesis of bioactive terpenoids and steroids. Org Biomol Chem 2021; 19:3791-3812. [PMID: 33949606 DOI: 10.1039/d1ob00448d] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Many natural products have intriguing biological properties that arise from their fascinating chemical structures. However, the intrinsic complexity of the structural skeleton and the reactive functional groups on natural products pose tremendous challenges to chemical syntheses. Semi-synthesis uses chemical compounds isolated from natural sources as the starting materials to produce other novel compounds with distinct chemical and medicinal properties. In particular, advancements in various types of sp3 C-H bond functionalization reactions and skeletal rearrangement methods have contributed to the re-emergence of semi-synthesis as an efficient approach for the synthesis of structurally complex bioactive natural products. Here, we begin with a brief discussion of several bioactive natural products that were obtained via a semi-synthetic approach between 2008 and 2015 and we then discuss in-depth contemporary advancements in the semi-synthesis of bioactive terpenoids and steroids reported during 2016-2020.
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Affiliation(s)
- Zhuo Wang
- Southern University of Science and Technology, School of Medicine, Shenzhen, 518055, People's Republic of China.
| | - Chunngai Hui
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
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Nie W, Ding LF, Lei T, Pan ZH, Song LD, Wu XD, Zhao QS. Illilanceolide A, a unique seco-prezizaane sesquiterpenoid with 5/5/6 tricyclic scaffold from the fruits of Illicium lanceolatum A. C. Smith. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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30
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Abstract
Retrosynthetic analysis emerged in the 1960s as a teaching tool with profound implications. Its educational value can be appreciated by a glance at total synthesis manuscripts over 50 years later, most of which contain a retrosynthesis on page one. Its vision extended to computer language-a pioneering idea in the 20th century that continues to expand the frontiers today. The same principles that guide a student to evaluate, expand, and refine a series of bond dissections can be programmed, so that computer assistance can perform the same tasks but at faster speeds.The slow step in the synthesis of complex structures, however, is seldom route design. Compression of molecular information into close proximity (Cm/Å3) requires exploration and empiricism, a close connection between theory and experiment. Here, retrosynthetic analysis guides the choice of experiment, so that the most simplifying-but often least assured-disconnection is prioritized: a high-risk, high reward strategy. The reimagining of total synthesis in a future era of retrosynthetic software may involve, counterintuitively, target design, as discussed here.Compared to the 1960s, retrosynthetic analysis in the 21st century finds itself among computers of unimaginable power and a biology that is increasingly molecular. Put together, the logic of retrosynthesis, the insight of structural biology, and the predictions of computation have inspired us to imagine an integration of the three. The synthetic target is treated as dynamic-a constellation of related structures-in order to find the nearest congener with the closest affinity but the shortest synthetic route. Such an approach merges synthetic design with structural design toward the goal of improved access for improved function.In this Account, we detail the evolution of our program from its inception in traditional natural product (NP) total synthesis to its current expression through the lens of chemical informatics: a view of NPs as aggregates of molecular parameters that define single points in a chemical space. Early work on synthesis and biological annotation of apparent metal pool binders and nonselective covalent electrophiles (asmarine alkaloids, isocyanoterpenes, Nuphar dimers) gave way to NPs with well-defined protein targets. The plant metabolite salvinorin A (SalA) potently and selectively agonizes the κ-opioid receptor (KOR), rapidly penetrates the brain, and represents an important lead for next-generation analgesics and antipruritics. To synthesize and diversify this lead, we adopted what we now call a dynamic approach. Deletion of a central methyl group stabilized the SalA scaffold, opened quick synthetic access, and retained high potency and selectivity. The generality of this idea was then tested against another neuroactive class. As an alternative hypothesis to TrkB channels, we proposed that the so-called "neurotrophic" Illicium terpenes may bind to γ-aminobutyric acid (GABA)-gated ion channels to cause weak, chronic excitation. Syntheses of (-)-jiadifenolide, 3,6-dideoxy-10-hydroxypseudoanisatin, (-)-11-O-debenzoyltashironin, (-)-bilobalide, and (-)-picrotoxinin (PXN) allowed this hypothesis to be probed more broadly. Feedback from protein structure and synthetic reconnaissance led to a dynamic retrosynthesis of PXN and the identification of 5MePXN, a moderate GABAAR antagonist with greater aqueous stability available in eight steps from dimethylcarvone. We expect this dynamic approach to synthetic target analysis to become more feasible in the coming years and hope the next generation of scientists finds this approach helpful to address problems at the frontier of chemistry and biology.
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Affiliation(s)
- Stone Woo
- Department of Chemistry, Scripps Research, 10550 North Torrey Lines Road, La Jolla, California 92037, United States
| | - Ryan A Shenvi
- Department of Chemistry, Scripps Research, 10550 North Torrey Lines Road, La Jolla, California 92037, United States
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31
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Schuppe AW, Liu Y, Newhouse TR. An invocation for computational evaluation of isomerization transforms: cationic skeletal reorganizations as a case study. Nat Prod Rep 2021; 38:510-527. [PMID: 32931541 PMCID: PMC7956923 DOI: 10.1039/d0np00005a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Covering: 2010 to 2020This review article describes how cationic rearrangement reactions have been used in natural product total synthesis over the last decade as a case study for the many productive ways by which isomerization reactions are enabling for synthesis. This review argues that isomerization reactions in particular are well suited for computational evaluation, as relatively simple calculations can provide significant insight.
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Affiliation(s)
- Alexander W Schuppe
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511-8107, USA.
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32
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Vrubliauskas D, Gross BM, Vanderwal CD. Stereocontrolled Radical Bicyclizations of Oxygenated Precursors Enable Short Syntheses of Oxidized Abietane Diterpenoids. J Am Chem Soc 2021; 143:2944-2952. [PMID: 33555176 DOI: 10.1021/jacs.0c13300] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The power of cation-initiated cyclizations of polyenes for the synthesis of polycyclic terpenoids cannot be overstated. However, a major limitation is the intolerance of many relevant reaction conditions toward the inclusion in the substrate of polar functionality, particularly in unprotected form. Radical polycyclizations are important alternatives to bioinspired cationic variants, in part owing to the range of possible initiation strategies, and in part for the functional group tolerance of radical reactions. In this article, we demonstrate that Co-catalyzed MHAT-initiated radical bicyclizations are not only tolerant of oxidation at virtually every position in the substrate, oftentimes in unprotected form, but these functional groups can also contribute to high levels of stereochemical control in these complexity-generating transformations. Specifically, we show the effects of protected or unprotected hydroxy groups at six different positions and their impact on stereoselectivity. Further, we show how multiply oxidized substrates perform in these reactions, and finally, we document the utility of these reactions in the synthesis of three aromatic abietane diterpenoids.
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Affiliation(s)
- Darius Vrubliauskas
- 1102 Natural Sciences II, Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Benjamin M Gross
- 1102 Natural Sciences II, Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Christopher D Vanderwal
- 1102 Natural Sciences II, Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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Shen Y, Li L, Xiao X, Yang S, Hua Y, Wang Y, Zhang YW, Zhang Y. Site-Specific Photochemical Desaturation Enables Divergent Syntheses of Illicium Sesquiterpenes. J Am Chem Soc 2021; 143:3256-3263. [DOI: 10.1021/jacs.1c00525] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yang Shen
- Department of Chemistry and Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Linbin Li
- Department of Chemistry and Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Xiaoxia Xiao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Sihan Yang
- Department of Chemistry and Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Yuhui Hua
- Department of Chemistry and Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Yinglu Wang
- Department of Chemistry and Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Yun-wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Yandong Zhang
- Department of Chemistry and Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
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Xuan J, Haelsig KT, Sheremet M, Machicao PA, Maimone TJ. Evolution of a Synthetic Strategy for Complex Polypyrrole Alkaloids: Total Syntheses of Curvulamine and Curindolizine. J Am Chem Soc 2021; 143:2970-2983. [PMID: 33570388 DOI: 10.1021/jacs.0c13465] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Structurally unprecedented antibacterial alkaloids containing multiple electron-rich pyrrole units have recently been isolated from Curvularia sp. and Bipolaris maydis fungi. This article documents the evolution of a synthetic program aimed at accessing the flagship metabolites curvulamine and curindolizine which are presumably a dimer and trimer of a C10N biosynthetic building block, respectively. Starting with curvulamine, we detail several strategies to merge two simple, bioinspired fragments, which while ultimately unsuccessful, led us toward a pyrroloazepinone building block-based strategy and an improved synthesis of this 10π-aromatic heterocycle. A two-step annulation process was then designed to forge a conserved tetracyclic bis-pyrrole architecture and advanced into a variety of late-stage intermediates; unfortunately, however, a failed decarboxylation thwarted the total synthesis of curvulamine. By tailoring our annulation precursors, success was ultimately found through the use of a cyanohydrin nucleophile which enabled a 10-step total synthesis of curvulamine. Attempts were then made to realize a biomimetic coupling of curvulamine with an additional C10N fragment to arrive at curindolizine, the most complex family member. Although unproductive, we developed a 14-step total synthesis of this alkaloid through an abiotic coupling approach. Throughout this work, effort was made to harness and exploit the innate reactivity of the pyrrole nucleus, an objective which has uncovered many interesting findings in the chemistry of this reactive heterocycle.
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Affiliation(s)
| | | | | | | | - Thomas J Maimone
- Department of Chemistry, University of California, Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
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35
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Tomanik M, Hsu IT, Herzon SB. Fragment Coupling Reactions in Total Synthesis That Form Carbon-Carbon Bonds via Carbanionic or Free Radical Intermediates. Angew Chem Int Ed Engl 2021; 60:1116-1150. [PMID: 31869476 DOI: 10.1002/anie.201913645] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Indexed: 12/21/2022]
Abstract
Fragment coupling reactions that form carbon-carbon bonds are valuable transformations in synthetic design. Advances in metal-catalyzed cross-coupling reactions in the early 2000s brought a high level of predictability and reliability to carbon-carbon bond constructions involving the union of unsaturated fragments. By comparison, recent years have witnessed an increase in fragment couplings proceeding via carbanionic and open-shell (free radical) intermediates. The latter has been driven by advances in methods to generate and utilize carbon-centered radicals under mild conditions. In this Review, we survey a selection of recent syntheses that have implemented carbanion- or radical-based fragment couplings to form carbon-carbon bonds. We aim to highlight the strategic value of these disconnections in their respective settings and to identify extensible lessons from each example that might be instructive to students.
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Affiliation(s)
- Martin Tomanik
- Department of Chemistry, Yale University, 225 Prospect St, New Haven, CT, USA
| | - Ian Tingyung Hsu
- Department of Chemistry, Yale University, 225 Prospect St, New Haven, CT, USA
| | - Seth B Herzon
- Department of Chemistry, Yale University, 225 Prospect St, New Haven, CT, USA.,Department of Pharmacology, Yale University, 333 Cedar St, New Haven, CT, USA
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36
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Tomanik M, Hsu IT, Herzon SB. Fragmentverknüpfungen in der Totalsynthese – Bildung von C‐C‐Bindungen über intermediäre Carbanionen oder freie Radikale. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.201913645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Martin Tomanik
- Department of Chemistry Yale University 225 Prospect St New Haven CT USA
| | - Ian Tingyung Hsu
- Department of Chemistry Yale University 225 Prospect St New Haven CT USA
| | - Seth B. Herzon
- Department of Chemistry Yale University 225 Prospect St New Haven CT USA
- Department of Pharmacology Yale University 333 Cedar St New Haven CT USA
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Varenikov A, Shapiro E, Gandelman M. Decarboxylative Halogenation of Organic Compounds. Chem Rev 2021; 121:412-484. [PMID: 33200917 PMCID: PMC7884003 DOI: 10.1021/acs.chemrev.0c00813] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Indexed: 12/13/2022]
Abstract
Decarboxylative halogenation, or halodecarboxylation, represents one of the fundamental key methods for the synthesis of ubiquitous organic halides. The method is based on conversion of carboxylic acids to the corresponding organic halides via selective cleavage of a carbon-carbon bond between the skeleton of the molecule and the carboxylic group and the liberation of carbon dioxide. In this review, we discuss and analyze major approaches for the conversion of alkanoic, alkenoic, acetylenic, and (hetero)aromatic acids to the corresponding alkyl, alkenyl, alkynyl, and (hetero)aryl halides. These methods include the preparation of families of valuable organic iodides, bromides, chlorides, and fluorides. The historic and modern methods for halodecarboxylation reactions are broadly discussed, including analysis of their advantages and drawbacks. We critically address the features, reaction selectivity, substrate scopes, and limitations of the approaches. In the available cases, mechanistic details of the reactions are presented, and the generality and uniqueness of the different mechanistic pathways are highlighted. The challenges, opportunities, and future directions in the field of decarboxylative halogenation are provided.
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Affiliation(s)
- Andrii Varenikov
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Evgeny Shapiro
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Mark Gandelman
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
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38
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Matsuoka K, Komami N, Kojima M, Mita T, Suzuki K, Maeda S, Yoshino T, Matsunaga S. Chemoselective Cleavage of Si-C(sp 3) Bonds in Unactivated Tetraalkylsilanes Using Iodine Tris(trifluoroacetate). J Am Chem Soc 2021; 143:103-108. [PMID: 33356223 DOI: 10.1021/jacs.0c11645] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Organosilanes are synthetically useful reagents and precursors in organic chemistry. However, the typical inertness of unactivated Si-C(sp3) bonds under conventional reaction conditions has hampered the application of simple tetraalkylsilanes in organic synthesis. Herein we report the chemoselective cleavage of Si-C(sp3) bonds of unactivated tetraalkylsilanes using iodine tris(trifluoroacetate). The reaction proceeds smoothly under mild conditions (-50 °C to room temperature) and tolerates various polar functional groups, thus enabling subsequent Tamao-Fleming oxidation to provide the corresponding alcohols. NMR experiments and density functional theory calculations on the reaction indicate that the transfer of alkyl groups from Si to the I(III) center and the formation of the Si-O bond proceed concertedly to afford an alkyl-λ3-iodane and silyl trifluoroacetate. The developed method enables the use of unactivated tetraalkylsilanes as highly stable synthetic precursors.
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Affiliation(s)
- Keitaro Matsuoka
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Narumi Komami
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Masahiro Kojima
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Tsuyoshi Mita
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan.,JST, ERATO Maeda Artificial Intelligence for Chemical Reaction Design and Discovery Project, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Kimichi Suzuki
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan.,JST, ERATO Maeda Artificial Intelligence for Chemical Reaction Design and Discovery Project, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.,Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Satoshi Maeda
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan.,JST, ERATO Maeda Artificial Intelligence for Chemical Reaction Design and Discovery Project, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.,Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Tatsuhiko Yoshino
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Shigeki Matsunaga
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.,Global Station for Biosurfaces and Drug Discovery, Hokkaido University, Sapporo 060-0812, Japan
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39
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Wu J, Ma Z. Metal-hydride hydrogen atom transfer (MHAT) reactions in natural product synthesis. Org Chem Front 2021. [DOI: 10.1039/d1qo01139a] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Functionalization of olefins has been an important transformation in synthetic chemistry. This review will focus on the natural product synthesis employing the MHAT reaction as the key strategy.
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Affiliation(s)
- Jinghua Wu
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou 510641, People's Republic of China
| | - Zhiqiang Ma
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou 510641, People's Republic of China
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40
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Holmstedt S, George L, Koivuporras A, Valkonen A, Candeias NR. Deoxygenative Divergent Synthesis: En Route to Quinic Acid Chirons. Org Lett 2020; 22:8370-8375. [PMID: 33002357 DOI: 10.1021/acs.orglett.0c02995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The installation of vicinal mesylate and silyl ether groups in a quinic acid derivative generates a system prone for stereoselective borane-catalyzed hydrosilylation through a siloxonium intermediate. The diversification of the reaction conditions allowed the construction of different defunctionalized fragments foreseen as useful synthetic fragments. The selectivity of the hydrosilylation was rationalized on the basis of deuteration experiments and computational studies.
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Affiliation(s)
- Suvi Holmstedt
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33101 Tampere, Finland
| | - Lijo George
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33101 Tampere, Finland
| | - Alisa Koivuporras
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33101 Tampere, Finland
| | - Arto Valkonen
- Department of Chemistry, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Nuno R Candeias
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33101 Tampere, Finland.,LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
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41
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Zhang X, King-Smith E, Dong LB, Yang LC, Rudolf JD, Shen B, Renata H. Divergent synthesis of complex diterpenes through a hybrid oxidative approach. Science 2020; 369:799-806. [PMID: 32792393 DOI: 10.1126/science.abb8271] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022]
Abstract
Polycyclic diterpenes exhibit many important biological activities, but de novo synthetic access to these molecules is highly challenging because of their structural complexity. Semisynthetic access has also been limited by the lack of chemical tools for scaffold modifications. We report a chemoenzymatic platform to access highly oxidized diterpenes by a hybrid oxidative approach that strategically combines chemical and enzymatic oxidation methods. This approach allows for selective oxidations of previously inaccessible sites on the parent carbocycles and enables abiotic skeletal rearrangements to additional underlying architectures. We synthesized a total of nine complex natural products with rich oxygenation patterns and skeletal diversity in 10 steps or less from ent-steviol.
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Affiliation(s)
- Xiao Zhang
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Emma King-Smith
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Liao-Bin Dong
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Li-Cheng Yang
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Jeffrey D Rudolf
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Ben Shen
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA.,Department of Molecular Medicine, Natural Products Discovery Center at Scripps Research, Jupiter, FL 33458, USA
| | - Hans Renata
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA.
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42
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Kanda Y, Ishihara Y, Wilde NC, Baran PS. Two-Phase Total Synthesis of Taxanes: Tactics and Strategies. J Org Chem 2020; 85:10293-10320. [DOI: 10.1021/acs.joc.0c01287] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Yuzuru Kanda
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Yoshihiro Ishihara
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Nathan C. Wilde
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Phil S. Baran
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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43
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Fukuyama Y, Kubo M, Harada K. The search for, and chemistry and mechanism of, neurotrophic natural products. J Nat Med 2020; 74:648-671. [PMID: 32643028 PMCID: PMC7456418 DOI: 10.1007/s11418-020-01431-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 06/28/2020] [Indexed: 12/13/2022]
Abstract
Abstract Neurotrophic factors, now termed neurotrophins, which belong to a class of polypeptidyl agents, have been shown to potentially be beneficial for the treatment of neurodegenerative diseases such as Alzheimer’s disease, because endogenous neurotrophic factors (NGF, BDNF, NT3, NT4) have been recognized to play critical roles in the promotion of neurogenesis, differentiation, and neuroprotection throughout the development of the central nervous system. However, high-molecular weight proteins are unable to cross the blood–brain barrier and are easily decomposed by peptidase under physiological conditions. To address this issue, small molecules that can mimic the functions of neurotrophic factors would be promising alternatives for the treatment of neurodegenerative disease. We have continued to search for natural products having typical neurotrophic properties, which can cause neurogenesis, enhance neurite outgrowth, and protect neuronal death using three cellular systems (PC12, rat cortical neurons, and MEB5 cells). In this review, we summarize the neurotrophic activities and synthesis of dimeric isocuparane-type sesquiterpenes from the liverwort, Mastigophora diclados, the mechanism of neurotrophic neolignans, magnolol, honokiol and their sesquiterpene derivatives, and introduce unique neurotrophin-mimic natural products, including seco-prezizaane-type sesquiterpenes from the Illicium species, vibsane-type diterpenes from Viburnum awabuki, and miscellaneous natural products with neurotrophic effects discovered by us. Graphic abstract ![]()
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Affiliation(s)
- Yoshiyasu Fukuyama
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan.
| | - Miwa Kubo
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
| | - Kenichi Harada
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
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44
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Vicens L, Olivo G, Costas M. Rational Design of Bioinspired Catalysts for Selective Oxidations. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02073] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Laia Vicens
- Institut de Quı́mica Computacional i Catàlisi (IQCC) and Departament de Quı́mica, Universitat de Girona, Campus de Montilivi, 17071 Girona, Spain
| | - Giorgio Olivo
- Institut de Quı́mica Computacional i Catàlisi (IQCC) and Departament de Quı́mica, Universitat de Girona, Campus de Montilivi, 17071 Girona, Spain
| | - Miquel Costas
- Institut de Quı́mica Computacional i Catàlisi (IQCC) and Departament de Quı́mica, Universitat de Girona, Campus de Montilivi, 17071 Girona, Spain
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Doering NA, Sarpong R, Hoffmann RW. A Case for Bond-Network Analysis in the Synthesis of Bridged Polycyclic Complex Molecules: Hetidine and Hetisine Diterpenoid Alkaloids. Angew Chem Int Ed Engl 2020; 59:10722-10731. [PMID: 31808282 PMCID: PMC7317470 DOI: 10.1002/anie.201909656] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/29/2019] [Indexed: 01/28/2023]
Abstract
A key challenge in the synthesis of diterpenoid alkaloids lies in identifying strategies that rapidly construct their multiply bridged polycyclic skeletons. Existing approaches to these structurally intricate secondary metabolites are discussed in the context of a "bond-network analysis" of molecular frameworks, which was originally devised by Corey some 40 years ago. The retrosynthesis plans that emerge from a topological analysis of the highly bridged frameworks of the diterpenoid alkaloids are discussed in the context of eight recent syntheses of hetidine and hetisine natural products and their derivatives. This Minireview highlights the extent to which network analyses of the type described here sufficed for designing synthesis plans, as well as areas where they had to be amalgamated with functional group oriented synthetic planning considerations.
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Affiliation(s)
- Nicolle A. Doering
- Latimer HallDepartment of ChemistryUniversity of California, BerkeleyBerkeleyCA94720USA
| | - Richmond Sarpong
- Latimer HallDepartment of ChemistryUniversity of California, BerkeleyBerkeleyCA94720USA
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Karmel C, Hartwig JF. Mechanism of the Iridium-Catalyzed Silylation of Aromatic C-H Bonds. J Am Chem Soc 2020; 142:10494-10505. [PMID: 32375477 DOI: 10.1021/jacs.0c03301] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Phenanthroline ligands and [Ir(cod)(OMe)]2 form complexes that catalyze the silylation of aromatic and aliphatic C-H bonds. However, no experimental data on the identity of complexes related to the mechanism of this process or the mechanisms by which they react to functionalize C-H bonds have been reported. Herein, we describe our studies on the mechanism of the iridium-catalyzed silylation of aryl C-H bonds. The resting state of the catalyst is an iridium disilyl hydride complex (phenanthroline)Ir(SiMe(OTMS)2)2(H)(L), in which L varies with the arene and additives. An iridium disilyl hydride complex was isolated, characterized, and allowed to react with arenes to form aryl silanes. The kinetics of the reactions of electron-rich and electron-poor arenes showed that the rate-limiting step varies with the electronic properties of the arene. Computational studies on related iridium silyl complexes revealed that the high activity of iridium complexes containing sterically encumbered phenanthroline ligands is due to a change in the number of silyl groups bound to iridium between the resting state of the catalyst containing the hindered phenanthroline and that containing less-hindered phenanthroline.
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Affiliation(s)
- Caleb Karmel
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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Harmange Magnani CS, Thach DQ, Haelsig KT, Maimone TJ. Syntheses of Complex Terpenes from Simple Polyprenyl Precursors. Acc Chem Res 2020; 53:949-961. [PMID: 32202757 DOI: 10.1021/acs.accounts.0c00055] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
From structure elucidation and biogenesis to synthetic methodology and total synthesis, terpene natural products have profoundly influenced the development of organic chemistry. Moreover, their myriad functional attributes range from fragrance to pharmaceuticals and have had great societal impact. Ruzicka's formulation of the "biogenetic isoprene rule," a Nobel Prize winning discovery now over 80 years old, allowed for identification of higher order terpene (aka "isoprenoid") structures from simple five-carbon isoprene fragments. Notably, the isoprene rule still holds pedagogical value to students of organic chemistry today. Our laboratory has completed syntheses of over two dozen terpene and meroterpene structures to date, and the isoprene rule has served as a key pattern recognition tool for our synthetic planning purposes. At the strategic level, great opportunity exists in finding unique and synthetically simplifying ways to connect the formal C5 isoprene fragments embedded in terpenes. Biomimetic cationic polyene cyclizations represent the earliest incarnation of this idea, which has facilitated expedient routes to certain terpene polycycle classes. Nonetheless, a large swath of terpene chemical space remains inaccessible using this approach.In this Account, we describe strategic insight into our endeavors in terpene synthesis published over the last five years. We show how biosynthetic understanding, combined with a desire to utilize abundant and inexpensive [C5]n building blocks, has led to efficient, abiotic syntheses of multiple complex terpenes with disparate ring systems. Informed by nature, but unconstrained by its processes, our synthetic assembly exploits chemical reactivity across diverse reaction types-including radical, anionic, pericyclic, and metal-mediated transformations.First, we detail an eight-step synthesis of the cembrane diterpene chatancin from dihydrofarnesal using a bioinspired-but not -mimetic-cycloaddition. Next, we describe the assembly of the antimalarial cardamom peroxide using a polyoxygenation cascade to fuse multiple units of molecular oxygen onto a dimeric skeleton. This three-to-four-step synthesis arises from (-)-myrtenal, an inexpensive pinene oxidation product. We then show how a radical cyclization cascade can forge the hallmark cyclooctane ring system of the complex sesterterpene 6-epi-ophiobolin N from two simple polyprenyl precursors, (-)-linalool and farnesol. To access the related, more complex metabolite 6-epi-ophiobolin A, we exploited the plasticity of our synthetic route and found that use of geraniol (C10) rather than farnesol (C15) gave us the flexibility needed to address the additional oxidation found in this congener. Following this work, we describe two strategies to access several guaianolide sesquiterpenes. Retrosynthetic disconnection to monoterpenes, carvone or (-)-linalool, coupled with a powerful allylation strategy allowed us to address guaianolides with disparate stereochemical motifs. Finally, we examine a semisynthetic approach to the illicium sesquiterpenes from the abundant 15-carbon feedstock terpene (+)-cedrol using an abiotic ring shift and multiple C-H oxidation reactions inspired by a postulated biosynthesis of this natural product class.
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Affiliation(s)
| | - Danny Q. Thach
- Department of Chemistry, University of California—Berkeley, Berkeley, California 94720, United States
| | - Karl T. Haelsig
- Department of Chemistry, University of California—Berkeley, Berkeley, California 94720, United States
| | - Thomas J. Maimone
- Department of Chemistry, University of California—Berkeley, Berkeley, California 94720, United States
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Doering NA, Sarpong R, Hoffmann RW. Ein Fall für die Bindungs‐Netzwerk‐Analyse bei der Synthese verbrückter polycyclischer komplexer Moleküle: Hetidin‐ und Hetisin‐Diterpen‐Alkaloide. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201909656] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Nicolle A. Doering
- Latimer Hall Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
| | - Richmond Sarpong
- Latimer Hall Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
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McCulley CH, Tantillo DJ. Predicting Rearrangement-Competent Terpenoid Oxidation Levels. J Am Chem Soc 2020; 142:6060-6065. [PMID: 32157874 DOI: 10.1021/jacs.9b12398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Results of density functional theory calculations on rearrangements of potential biosynthetic precursors to the sesquiterpenoid illisimonin A reveal that only some possible precursors, those with certain specific oxidation patterns, are rearrangement-competent.
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Affiliation(s)
- Christina H McCulley
- Department of Chemistry, University of California - Davis, Davis, California 95616, United States
| | - Dean J Tantillo
- Department of Chemistry, University of California - Davis, Davis, California 95616, United States
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Borrell M, Gil-Caballero S, Bietti M, Costas M. Site-Selective and Product Chemoselective Aliphatic C–H Bond Hydroxylation of Polyhydroxylated Substrates. ACS Catal 2020. [DOI: 10.1021/acscatal.9b05423] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Margarida Borrell
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia Spain
| | - Sergio Gil-Caballero
- Serveis Tècnics de Recerca (NMR), Universitat de Girona, Parc científic i tecnològic de la UdG, Pic de Peguera 15, Girona E-17003, Catalonia, Spain
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia Spain
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