1
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Watanabe A, Nagatomo M, Hirose A, Hikone Y, Kishimoto N, Miura S, Yasutake T, Abe T, Misumi S, Inoue M. Total Syntheses of Phorbol and 11 Tigliane Diterpenoids and Their Evaluation as HIV Latency-Reversing Agents. J Am Chem Soc 2024; 146:8746-8756. [PMID: 38486375 DOI: 10.1021/jacs.4c01589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Tigliane diterpenoids possess exceptionally complex structures comprising common 5/7/6/3-membered ABCD-rings and disparate oxygen functionalities. While tiglianes display a wide range of biological activities, compounds with HIV latency-reversing activity can eliminate viral reservoirs, thereby serving as promising leads for new anti-HIV agents. Herein, we report collective total syntheses of phorbol (13) and 11 tiglianes 14-24 with various acylation patterns and oxidation states, and their evaluation as HIV latency-reversing agents. The syntheses were strategically divided into five stages to increase the structural complexity. First, our previously established sequence enabled the expeditious preparation of ABC-tricycle 9 in 15 steps. Second, hydroxylation of 9 and ring-contractive D-ring formation furnished phorbol (13). Third, site-selective attachment of two acyl groups to 13 produced four phorbol diesters 14-17. Fourth, the oxygen functionalities were regio- and stereoselectively installed to yield five tiglianes 18-22. Fifth, further oxidation to the most densely oxygenated acerifolin A (23) and tigilanol tiglate (24) was realized through organizing a 3D shape of the B-ring. Assessment of the HIV latency-reversing activities of the 12 tiglianes revealed seven tiglianes (14-17 and 22-24) with 20- to 300-fold improved efficacy compared with prostratin (12), a representative latency-reversing agent. Therefore, the robust synthetic routes to a variety of tiglianes with promising activities devised in this study provide opportunities for advancing HIV eradication strategies.
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Affiliation(s)
- Ayumu Watanabe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masanori Nagatomo
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Akira Hirose
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuto Hikone
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Naoki Kishimoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Satoshi Miura
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Tae Yasutake
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Towa Abe
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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2
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Abuhafez N, Ehlers AW, de Bruin B, Gramage-Doria R. Markovnikov-Selective Cobalt-Catalyzed Wacker-Type Oxidation of Styrenes into Ketones under Ambient Conditions Enabled by Hydrogen Bonding. Angew Chem Int Ed Engl 2024; 63:e202316825. [PMID: 38037901 DOI: 10.1002/anie.202316825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 12/02/2023]
Abstract
The replacement of palladium catalysts for Wacker-type oxidation of olefins into ketones by first-row transition metals is a relevant approach for searching more sustainable protocols. Besides highly sophisticated iron catalysts, all the other first-row transition metal complexes have only led to poor activities and selectivities. Herein, we show that the cobalt-tetraphenylporphyrin complex is a competent catalyst for the aerobic oxidation of styrenes into ketones with silanes as the hydrogen sources. Remarkably, under room temperature and air atmosphere, the reactions were exceedingly fast (up to 10 minutes) with a low catalyst loading (1 mol %) while keeping an excellent chemo- and Markovnikov-selectivity (up to 99 % of ketone). Unprecedently high TOF (864 h-1 ) and TON (5,800) were reached for the oxidation of aromatic olefins under these benign conditions. Mechanistic studies suggest a reaction mechanism similar to the Mukaiyama-type hydration of olefins with a change in the last fundamental step, which controls the chemoselectivity, thanks to a unique hydrogen bonding network between the ethanol solvent and the cobalt peroxo intermediate.
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Affiliation(s)
- Naba Abuhafez
- Univ Rennes, CNRS, ISCR-UMR6226, 35000, Rennes, France
| | - Andreas W Ehlers
- University of Amsterdam, Science Park 904, 1094 XH, Amsterdam, The Netherlands
| | - Bas de Bruin
- University of Amsterdam, Science Park 904, 1094 XH, Amsterdam, The Netherlands
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3
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Kim B, Puthukanoori RK, Martha B, Reddy Muthyala N, Thota S, Thummala V, Rao Paraselli B, Chen DYK. Stereo-Controlled Synthesis of Vicinal Tertiary Carbinols: Application in the Synthesis of a Diol Substructure of Zaragozic Acid, Pactamycin and Ryanodol. Chemistry 2023; 29:e202301938. [PMID: 37395682 DOI: 10.1002/chem.202301938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 07/04/2023]
Abstract
A novel and flexible approach for the stereo-controlled synthesis of vicinal tertiary carbinols is reported. The developed strategy featured a highly diastereoselective singlet-oxygen (O2 1 ) [4+2] cycloaddition of rationally designed cyclohexadienones (derived from oxidative dearomatization of the corresponding carboxylic-acid appended phenol precursors), followed by programmed "O-O" and "C-C" bond cleavage. In doing so, a highly functionalized and versatile intermediate was identified and prepared in synthetically useful quantity as a plausible precursor to access a variety of designed and naturally occurring vicinal tertiary carbinol containing compounds. Most notably, the developed strategy was successfully applied in the stereo-controlled synthesis of advanced core structures of zaragozic acid, pactamycin and ryanodol.
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Affiliation(s)
- Byungjoo Kim
- Department of Chemistry, Seoul National University, Gwanak-1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea
| | | | | | | | - Srinivas Thota
- Chemveda Life Sciences, Pvt. Ltd., Hyderabad, Telangana, 500039, India
| | | | | | - David Y-K Chen
- Department of Chemistry, Seoul National University, Gwanak-1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea
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4
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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: 10] [Impact Index Per Article: 5.0] [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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5
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Puls F, Seewald F, Grinenko V, Klauß HH, Knölker HJ. Mechanistic Studies on the Hexadecafluorophthalocyanine-Iron-Catalyzed Wacker-Type Oxidation of Olefins to Ketones*. Chemistry 2021; 27:16776-16787. [PMID: 34546596 PMCID: PMC9298363 DOI: 10.1002/chem.202102848] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Indexed: 12/15/2022]
Abstract
The hexadecafluorophthalocyanine-iron complex FePcF16 was recently shown to convert olefins into ketones in the presence of stoichiometric amounts of triethylsilane in ethanol at room temperature under an oxygen atmosphere. Herein, we describe an extensive mechanistic investigation for the conversion of 2-vinylnaphthalene into 2-acetylnaphthalene as model reaction. A variety of studies including deuterium- and 18 O2 -labeling experiments, ESI-MS, and 57 Fe Mössbauer spectroscopy were performed to identify the intermediates involved in the catalytic cycle of the oxidation process. Finally, a detailed and well-supported reaction mechanism for the FePcF16 -catalyzed Wacker-type oxidation is proposed.
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Affiliation(s)
- Florian Puls
- Fakultät Chemie, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany
| | - Felix Seewald
- Institute of Solid State and Materials Physics Fakultät Physik, Technische Universität Dresden, Zellescher Weg 16, 01069, Dresden, Germany
| | - Vadim Grinenko
- Institute of Solid State and Materials Physics Fakultät Physik, Technische Universität Dresden, Zellescher Weg 16, 01069, Dresden, Germany
| | - Hans-Henning Klauß
- Institute of Solid State and Materials Physics Fakultät Physik, Technische Universität Dresden, Zellescher Weg 16, 01069, Dresden, Germany
| | - Hans-Joachim Knölker
- Fakultät Chemie, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany
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6
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Hirose A, Watanabe A, Ogino K, Nagatomo M, Inoue M. Unified Total Syntheses of Rhamnofolane, Tigliane, and Daphnane Diterpenoids. J Am Chem Soc 2021; 143:12387-12396. [PMID: 34319739 DOI: 10.1021/jacs.1c06450] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Rhamnofolane, tigliane, and daphnane diterpenoids are structurally complex natural products with multiple oxygen functionalities, making them synthetically challenging. While these diterpenoids share a 5/7/6-trans-fused ring system (ABC-ring), the three-carbon substitutions at the C13- and C14-positions on the C-ring and appending oxygen functional groups differ among them, accounting for the disparate biological activities of these natural products. Here, we developed a new, unified strategy for expeditious total syntheses of five representative members of these three families, crotophorbolone (1), langduin A (2), prostratin (3), resiniferatoxin (4), and tinyatoxin (5). Retrosynthetically, 1-5 were simplified into their common ABC-ring 6 by detaching the three-carbon units and the oxygen-appended groups. Intermediate 6 with six stereocenters was assembled from four achiral fragments in 12 steps by integrating three powerful transformations, as follows: (i) asymmetric Diels-Alder reaction to induce formation of the C-ring; (ii) π-allyl Stille coupling reaction to set the trisubstituted E-olefin of the B-ring; and (iii) Eu(fod)3-promoted 7-endo cyclization of the B-ring via the generation of a bridgehead radical. Then 6 was diversified into 1-5 by selective installation of the different functional groups. Attachment of the C14-β-isopropenyl and isopropyl groups led to 1 and 2, respectively, while oxidative acetoxylation and C13,14-β-dimethylcyclopropane formation gave rise to 3. Finally, formation of an α-oriented caged orthoester by C13-stereochemical inversion and esterification with two different homovanillic acids delivered 4 and 5 with a C13-β-isopropenyl group. This unified synthetic route to 1-5 required only 16-20 total steps, demonstrating the exceptional efficiency of the present strategy.
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Affiliation(s)
- Akira Hirose
- Graduate School of Pharmaceutical Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ayumu Watanabe
- Graduate School of Pharmaceutical Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kohei Ogino
- Graduate School of Pharmaceutical Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masanori Nagatomo
- Graduate School of Pharmaceutical Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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7
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Mutoh H, Nakamura S, Hagiwara K, Inoue M. Construction of Pentacyclic Limonoid Skeletons via Radical Cascade Reactions. J Org Chem 2021; 86:6869-6878. [PMID: 33905252 DOI: 10.1021/acs.joc.1c00212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Limonoids 1 and 2 share a 6/6/6/5-membered ABCD-ring system and a six-membered oxacycle and differ in their C9-stereochemistries. A new radical-based strategy was devised to construct the pentacyclic skeletons of 1 and 2. An oxacycle-fused A-ring and enyne fragments were coupled to produce radical precursors 4a-4c with different C7-oxygen functionalities. The bridgehead tertiary bromide of 4a-4c participated in a radical cascade reaction with the three unsaturated bonds to cyclize the C9-diastereomeric BCD-rings.
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Affiliation(s)
- Hiroyuki Mutoh
- Graduate School of Pharmaceutical Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shu Nakamura
- Graduate School of Pharmaceutical Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Koichi Hagiwara
- Graduate School of Pharmaceutical Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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8
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Dibrell SE, Tao Y, Reisman SE. Synthesis of Complex Diterpenes: Strategies Guided by Oxidation Pattern Analysis. Acc Chem Res 2021; 54:1360-1373. [PMID: 33621061 DOI: 10.1021/acs.accounts.0c00858] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
With complex molecular architectures, intriguing oxidation patterns, and wide-ranging biological activities, diterpene natural products have greatly impacted research in organic chemistry and drug discovery. Our laboratory has completed total syntheses of several highly oxidized diterpenes, including the ent-kauranoids maoecrystal Z, trichorabdal A, and longikaurin E; the antibiotic pleuromutilin; and the insecticides ryanodol, ryanodine, and perseanol. In this Account, we show how analysis of oxidation patterns and inherent functional group relationships can inform key C-C bond disconnections that greatly simplify the complexity of polycyclic structures and streamline their total syntheses. In articulating these concepts, we draw heavily from the approaches to synthetic strategy that were codified by Evans, Corey, Seebach, and others, based on the formalism that heteroatoms impose an alternating acceptor and donor reactivity pattern upon a carbon skeleton. We find these ideas particularly useful when considering oxidized diterpenes as synthetic targets.In the first part of the Account, we describe the use of reductive cyclizations as strategic tactics for building polycyclic systems with γ-hydroxyketone motifs. We have leveraged Sm-ketyl radical cyclizations as "reactivity umpolungs" to generate γ-hydroxyketones in our total syntheses of the Isodon ent-kauranoid diterpenes (-)-maoecrystal Z, (-)-longikaurin E, and (-)-trichorabdal A. Following this work, we identified the same γ-hydroxyketone pattern in the diterpene antibiotic (+)-pleuromutilin, which again inspired the use of a SmI2-mediated reductive cyclization, this time to construct a bridging eight-membered ring. This collection of four total syntheses highlights how reductive cyclizations are particularly effective umpolung tactics when used to simultaneously form rings and introduce 1,4-dioxygenation patterns.In the second part of the Account, we detail the syntheses of the complex and highly oxidized ryanodane and isoryanodane diterpenes and present the oxidation pattern analysis that guided our synthetic designs. We first discuss our 15-step total synthesis of (+)-ryanodol, which incorporated five of the eight oxygen atoms in just two transformations: a dihydroxylation of (S)-pulegone and a SeO2-mediated trioxidation of the A-ring cyclopentenone. This latter transformation gave rise to an independent investigation of SeO2-mediated peroxidations of simple bicyclic cyclopent-2-en-1-ones. The syntheses of (+)-ryanodine and (+)-20-deoxyspiganthine are also presented, which required modified end-game strategies to selectively incorporate the key pyrrole-2-carboxylate ester. Finally, we describe our fragment coupling approach to prepare the isoryanodane diterpene (+)-perseanol. Using a similar oxidation pattern analysis to that developed in the synthesis of ryanodol, we again identified a two-stage strategy to install the five hydroxyl groups. This strategy was enabled by a Pd-mediated carbopalladation/carbonylation cascade and leveraged unexpected, emergent reactivity to sequence a series of late-stage oxidations.While each of the diterpene natural products discussed in this Account present unique synthetic questions, we hope that through their collective discussion, we provide a conceptual framework that condenses and summarizes the chemical knowledge we have learned and inspires future discourse and innovations in strategy design and methodology development.
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Affiliation(s)
- Sara E. Dibrell
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Yujia Tao
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Sarah E. Reisman
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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9
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Shimakawa T, Hagiwara K, Inoue M. Total Synthesis of Talatisamine: Exploration of Convergent Synthetic Strategies. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Tsukasa Shimakawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Koichi Hagiwara
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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10
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Li H, Zhang J, She X. The Total Synthesis of Diquinane-Containing Natural Products. Chemistry 2021; 27:4839-4858. [PMID: 32955141 DOI: 10.1002/chem.202003741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/15/2020] [Indexed: 12/18/2022]
Abstract
Diquinane or bicyclo[3.3.0]octane is a conspicuous structural unit existing in the carbo-frameworks of a wide range of natural products such as alkaloids and terpenoids. These diquinane-containing molecules not merely exhibit intriguing architectures, but also showcase a broad spectrum of significant bioactivities, which draw widespread attention from the global synthetic community. During the past decade, with an aim to accomplish the total syntheses of such specified cornucopias of natural products, a variety of elegant strategies for construction of the diquinane ring system have been disclosed. In this Minireview, the achievements on this subject in the timeline from 2010 to June 2020 are demonstrated and it is discussed how the diquinane unit is strategically forged in the context of the specific target structure. In addition, impacts of the selected works to the field of natural product total synthesis is highlighted and the particular outlook of diquinane-containing natural product synthesis is provided.
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Affiliation(s)
- Huilin Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou, 730000, Gansu, P. R. China
| | - Jing Zhang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou, 730000, Gansu, P. R. China
| | - Xuegong She
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou, 730000, Gansu, P. R. China
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11
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Haider M, Sennari G, Eggert A, Sarpong R. Total Synthesis of the Cephalotaxus Norditerpenoids (±)-Cephanolides A-D. J Am Chem Soc 2021; 143:2710-2715. [PMID: 33577317 DOI: 10.1021/jacs.1c00293] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Concise syntheses of the Cephalotaxus norditerpenoids cephanolides A-D (8-14 steps from commercial material) using a common late-stage synthetic intermediate are described. The success of our approach rested on an early decision to apply chemical network analysis to identify the strategic bonds that needed to be forged, as well as the efficient construction of the carbon framework through iterative Csp2-Csp3 cross-coupling, followed by an intramolecular inverse-demand Diels-Alder cycloaddition. Strategic late-stage oxidations facilitated access to all congeners of the benzenoid cephanolides isolated to date.
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Affiliation(s)
- Maximilian Haider
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Goh Sennari
- 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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12
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Du K, Kier MJ, Stempel ZD, Jeso V, Rheingold AL, Micalizio GC. Synthesis of Anhydroryanodol. J Am Chem Soc 2020; 142:12937-12941. [PMID: 32609506 DOI: 10.1021/jacs.0c05766] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A stereoselective entry to ryanoids is described that culminates in the synthesis of anhydroryanodol and thus the formal total synthesis of ryanodol. The pathway described features an annulation reaction conceived to address the uniquely complex and highly oxygenated polycyclic skeleton common to members of this natural product class. It is demonstrated that metallacycle-mediated intramolecular coupling of an alkyne and a 1,3-diketone can proceed with a highly functionalized enyne and with outstanding levels of stereoselection. Furthermore, the first application of this technology in natural product synthesis is demonstrated here. More broadly, the advances described demonstrate the value that programs in natural product total synthesis have in advancing organic chemistry, here through the design and realization of an annulation reaction that accomplishes what previously established reactions do not.
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Affiliation(s)
- Kang Du
- Department of Chemistry, Burke Laboratory, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Matthew J Kier
- Department of Chemistry, Burke Laboratory, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Zachary D Stempel
- Department of Chemistry, Burke Laboratory, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Valer Jeso
- Department of Chemistry, Burke Laboratory, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Arnold L Rheingold
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Glenn C Micalizio
- Department of Chemistry, Burke Laboratory, Dartmouth College, Hanover, New Hampshire 03755, United States
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13
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Nagatomo M. [Development of Synthetic Strategies for Densely Oxygenated Natural Products: Total Synthesis of Lactacystin and Zaragozic Acid C Using Photochemical C(sp 3)-H Functionalization]. YAKUGAKU ZASSHI 2019; 139:651-661. [PMID: 31061332 DOI: 10.1248/yakushi.18-00210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This review describes two novel synthetic routes from (S)-pyroglutaminol to (+)-lactacystin, a potent inhibitor of the 20S proteasome and from d-gluconolactone derivative to zaragozic acid C, a potent squalene synthase inhibitor. In lactacystin synthesis, the photoinduced intermolecular C(sp3)-H alkynylation and intramolecular C(sp3)-H acylation chemoselectively and stereoselectively constructed the tetrasubstituted and trisubstituted carbon centers, respectively. In the synthesis of zaragozic acid C, the stereoselective installation of the two contiguous tetrasubstituted carbons was achieved by the photochemical intramolecular C(sp3)-H acylation of a densely oxygenated intermediate.
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14
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Zhou H, Guoruoluo Y, Tuo Y, Zhou J, Zhang H, Wang W, Xiang M, Aisa HA, Yao G. Cassiabudanols A and B, Immunostimulative Diterpenoids with a Cassiabudane Carbon Skeleton Featuring a 3-Oxatetracyclo[6.6.1.0 2,6.0 10,14]pentadecane Scaffold from Cassia Buds. Org Lett 2019; 21:549-553. [PMID: 30601013 DOI: 10.1021/acs.orglett.8b03883] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Two novel diterpenoids, cassiabudanols A (1) and B (2), were isolated from cassia buds. Their structures were determined by comprehensive spectroscopic analysis and single-crystal X-ray diffraction. Compounds 1 and 2 possess an unprecedented 11,14- cyclo-8,14:12,13-di- seco-isoryanodane (cassiabudane) carbon skeleton featuring a unique 3-oxatetracyclo[6.6.1.02,6.010,14]pentadecane bridged system, and their biosynthetic pathways are proposed. Compounds 1 and 2 exhibited significant immunostimulative activity, and the mode of action of 2 involves upregulating CD4+ and CD8+ T cells and downregulating Tregs.
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Affiliation(s)
- Haofeng Zhou
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , Wuhan 430030 , China
| | - Yindengzhi Guoruoluo
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , Wuhan 430030 , China.,State Key Laboratory of Xinjiang Indigenous Medicinal Plants Resource Utilization, Key Laboratory of Plant Resources and Chemistry of Arid Zone , Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Urumqi 830011 , China
| | - Yali Tuo
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , Wuhan 430030 , China
| | - Junfei Zhou
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , Wuhan 430030 , China
| | - Hanqi Zhang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , Wuhan 430030 , China
| | - Wei Wang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , Wuhan 430030 , China
| | - Ming Xiang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , Wuhan 430030 , China
| | - Haji Akber Aisa
- State Key Laboratory of Xinjiang Indigenous Medicinal Plants Resource Utilization, Key Laboratory of Plant Resources and Chemistry of Arid Zone , Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Urumqi 830011 , China
| | - Guangmin Yao
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , Wuhan 430030 , China
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15
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Zhou RJ, Dai GY, Zhou XH, Zhang MJ, Wu PZ, Zhang D, Song H, Liu XY, Qin Y. Progress towards the synthesis of aconitine: construction of the AE fragment and attempts to access the pentacyclic core. Org Chem Front 2019. [DOI: 10.1039/c8qo01228h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We reported the first successful preparation of fully functionalized aconitine AE fragment and attempts to access the pentacyclic skeleton of aconitine via radical cascade.
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Affiliation(s)
- Rui-Jie Zhou
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Gui-Ying Dai
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Xiao-Han Zhou
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Min-Jie Zhang
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Ping-Zhou Wu
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Dan Zhang
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Hao Song
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Xiao-Yu Liu
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Yong Qin
- Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education
- Sichuan Research Center of Precision Engineering Technology for Small Molecule Drugs
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
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16
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Xu C, Han A, Reisman SE. An Oxidative Dearomatization Approach To Prepare the Pentacyclic Core of Ryanodol. Org Lett 2018; 20:3793-3796. [PMID: 29897247 PMCID: PMC6103443 DOI: 10.1021/acs.orglett.8b01387] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An approach to synthesize the pentacyclic framework of the polyol diterpenoid ryanodol is reported. The ABC tricycle was constructed by a Co-mediated Pauson-Khand reaction, and both radical and anionic cyclization pathways were developed to form the E-ring. In addition, a reaction sequence involving SeO2-mediated enone oxidation and hydroxyl-directed oxy-Michael addition was developed to introduce the A-ring oxidation. The feasibility of forming the bridging D-ring by an oxidative dearomatization was established.
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Affiliation(s)
- Chen Xu
- Shenzhen Grubbs Institute, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Arthur Han
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Sarah E. Reisman
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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17
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Construction of a pentacyclic ring system of isoryanodane diterpenoids by SmI2-mediated transannular cyclization. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.03.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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18
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Nagatomo M. Discontent is the First Step in Progress—Learning from the Total Synthesis of Ryanodine. J SYN ORG CHEM JPN 2018. [DOI: 10.5059/yukigoseikyokaishi.76.494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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19
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Hashimoto S, Katoh SI, Kato T, Urabe D, Inoue M. Total Synthesis of Resiniferatoxin Enabled by Radical-Mediated Three-Component Coupling and 7-endo Cyclization. J Am Chem Soc 2017; 139:16420-16429. [DOI: 10.1021/jacs.7b10177] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Satoshi Hashimoto
- Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shun-ichiro Katoh
- Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takehiro Kato
- Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Daisuke Urabe
- Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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20
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Brill ZG, Condakes ML, Ting CP, Maimone TJ. Navigating the Chiral Pool in the Total Synthesis of Complex Terpene Natural Products. Chem Rev 2017; 117:11753-11795. [PMID: 28293944 PMCID: PMC5638449 DOI: 10.1021/acs.chemrev.6b00834] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The pool of abundant chiral terpene building blocks (i.e., "chiral pool terpenes") has long served as a starting point for the chemical synthesis of complex natural products, including many terpenes themselves. As inexpensive and versatile starting materials, such compounds continue to influence modern synthetic chemistry. This review highlights 21st century terpene total syntheses which themselves use small, terpene-derived materials as building blocks. An outlook to the future of research in this area is highlighted as well.
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Affiliation(s)
- Zachary G. Brill
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720
| | - Matthew L. Condakes
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720
| | - Chi P. Ting
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720
| | - Thomas J. Maimone
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720
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21
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Xu C, Han A, Virgil SC, Reisman SE. Chemical Synthesis of (+)-Ryanodine and (+)-20-Deoxyspiganthine. ACS CENTRAL SCIENCE 2017; 3:278-282. [PMID: 28470044 PMCID: PMC5409222 DOI: 10.1021/acscentsci.6b00361] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Indexed: 06/07/2023]
Abstract
(+)-Ryanodine is a natural product modulator of ryanodine receptors, important intracellular calcium ion channels that play a critical role in signal transduction leading to muscle movement and synaptic transmission. Chemical derivatization of (+)-ryanodine has demonstrated that certain peripheral structural modifications can alter its pharmacology, and that the pyrrole-2-carboxylate ester is critical for high affinity binding to ryanodine receptors. However, the structural variation of available ryanodine analogues has been limited by the challenge of site-specific functionalization of semisynthetic intermediates, such as (+)-ryanodol. Here we report a synthetic strategy that provides access to (+)-ryanodine and the related natural product (+)-20-deoxyspiganthine in 18 and 19 steps, respectively. A key feature of this strategy is the reductive cyclization of an epoxide intermediate that possesses the critical pyrrole-2-carboxylate ester. This approach allows for the direct introduction of this ester in the final stage of the synthesis and provides a framework for the synthesis of previously inaccessible synthetic ryanoids.
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Affiliation(s)
- Chen Xu
- The Warren and Katharine Schlinger Laboratory
for Chemistry and Chemical Engineering, Division of Chemistry and
Chemical Engineering, California Institute
of Technology, Pasadena, California 91125, United States
| | - Arthur Han
- The Warren and Katharine Schlinger Laboratory
for Chemistry and Chemical Engineering, Division of Chemistry and
Chemical Engineering, California Institute
of Technology, Pasadena, California 91125, United States
| | - Scott C. Virgil
- The Warren and Katharine Schlinger Laboratory
for Chemistry and Chemical Engineering, Division of Chemistry and
Chemical Engineering, California Institute
of Technology, Pasadena, California 91125, United States
| | - Sarah E. Reisman
- The Warren and Katharine Schlinger Laboratory
for Chemistry and Chemical Engineering, Division of Chemistry and
Chemical Engineering, California Institute
of Technology, Pasadena, California 91125, United States
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22
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Inoue M. Evolution of Radical-Based Convergent Strategies for Total Syntheses of Densely Oxygenated Natural Products. Acc Chem Res 2017; 50:460-464. [PMID: 28945405 DOI: 10.1021/acs.accounts.6b00475] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Densely oxygenated natural products often exhibit potent bioactivities and are expected to function as selective cellular probes and novel drug leads. Here we describe our efforts to perfect radical-based convergent strategies for generic total syntheses of these exceedingly challenging structures.
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Affiliation(s)
- Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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23
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Blise K, Cvitkovic MW, Gibbs NJ, Roberts SF, Whitaker RM, Hofmeister GE, Kohen D. A Theoretical Mechanistic Study of the Asymmetric Desymmetrization of a Cyclic meso-Anhydride by a Bifunctional Quinine Sulfonamide Organocatalyst. J Org Chem 2017; 82:1347-1355. [DOI: 10.1021/acs.joc.6b02320] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katie Blise
- Department of Chemistry, Carleton College, Northfield, Minnesota 55057, United States
| | - Milan W. Cvitkovic
- Department of Chemistry, Carleton College, Northfield, Minnesota 55057, United States
| | - Nolly J. Gibbs
- Department of Chemistry, Carleton College, Northfield, Minnesota 55057, United States
| | - Sean F. Roberts
- Department of Chemistry, Carleton College, Northfield, Minnesota 55057, United States
| | - Reid M. Whitaker
- Department of Chemistry, Carleton College, Northfield, Minnesota 55057, United States
| | | | - Daniela Kohen
- Department of Chemistry, Carleton College, Northfield, Minnesota 55057, United States
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24
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Wakamori S. The Construction of a Complex Carbon Skeleton. J SYN ORG CHEM JPN 2017. [DOI: 10.5059/yukigoseikyokaishi.75.770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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25
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26
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Chuang KV, Xu C, Reisman SE. A 15-step synthesis of (+)-ryanodol. Science 2016; 353:912-5. [PMID: 27563092 PMCID: PMC5505075 DOI: 10.1126/science.aag1028] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/25/2016] [Indexed: 11/02/2022]
Abstract
(+)-Ryanodine and (+)-ryanodol are complex diterpenoids that modulate intracellular calcium-ion release at ryanodine receptors, ion channels critical for skeletal and cardiac muscle excitation-contraction coupling and synaptic transmission. Chemical derivatization of these diterpenoids has demonstrated that certain peripheral structural modifications can alter binding affinity and selectivity among ryanodine receptor isoforms. Here, we report a short chemical synthesis of (+)-ryanodol that proceeds in only 15 steps from the commercially available terpene (S)-pulegone. The efficiency of the synthesis derives from the use of a Pauson-Khand reaction to rapidly build the carbon framework and a SeO2-mediated oxidation to install three oxygen atoms in a single step. This work highlights how strategic C-O bond constructions can streamline the synthesis of polyhydroxylated terpenes by minimizing protecting group and redox adjustments.
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Affiliation(s)
- Kangway V Chuang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Chen Xu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sarah E Reisman
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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27
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Crossley SWM, Obradors C, Martinez RM, Shenvi RA. Mn-, Fe-, and Co-Catalyzed Radical Hydrofunctionalizations of Olefins. Chem Rev 2016; 116:8912-9000. [PMID: 27461578 PMCID: PMC5872827 DOI: 10.1021/acs.chemrev.6b00334] [Citation(s) in RCA: 608] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cofactor-mimetic aerobic oxidation has conceptually merged with catalysis of syngas reactions to form a wide range of Markovnikov-selective olefin radical hydrofunctionalizations. We cover the development of the field and review contributions to reaction invention, mechanism, and application to complex molecule synthesis. We also provide a mechanistic framework for understanding this compendium of radical reactions.
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Affiliation(s)
- Steven W M Crossley
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Carla Obradors
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Ruben M Martinez
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Ryan A Shenvi
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
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28
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Hagiwara K, Tabuchi T, Urabe D, Inoue M. Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process. Chem Sci 2016; 7:4372-4378. [PMID: 30155084 PMCID: PMC6014077 DOI: 10.1039/c6sc00671j] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 03/11/2016] [Indexed: 11/21/2022] Open
Abstract
The fused 6/7/5/6/6/6-hexacyclic ring system of puberuline C was assembled in 18 steps from 2-(ethoxycarbonyl)cyclohexanone. After the azabicyclo[3.3.1]nonane derivative was sequentially coupled with propargyl magnesium bromide, 2-iodo cyclopentenone and allyl bromide, the pentacycle was constructed in a single step via a radical-based cyclization/translocation/cyclization process. The C11-bridgehead radical generated via C-Br homolysis participated in a 7-endo cyclization, and the 1,5-hydrogen translocation of the resultant radical was followed by transannular 6-exo cyclization to simultaneously realize the construction of the two rings and the introduction of the five contiguous stereocenters. The last 6-exo cyclization was induced by the Mukaiyama aldol reaction, and the C16-ketone was stereoselectively reduced by the action of SmI2/t-BuOH, leading for the first time to the synthesis of the entire hexacycle of puberuline C.
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Affiliation(s)
- Koichi Hagiwara
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-0033 , Japan .
| | - Toshiki Tabuchi
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-0033 , Japan .
| | - Daisuke Urabe
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-0033 , Japan .
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-0033 , Japan .
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29
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Masuda K, Nagatomo M, Inoue M. Chemical Conversion of Ryanodol to Ryanodine. Chem Pharm Bull (Tokyo) 2016; 64:874-9. [PMID: 27010543 DOI: 10.1248/cpb.c16-00214] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ryanodine (1) is a plant-derived natural product with powerful pharmacological and insecticidal action, and is a potent modulator of intracellular calcium release channels. Compound 1 possesses a 1H-pyrrole-2-carboxylate ester at the C3-position of heptahydroxylated terpenoid ryanodol (2). Whereas 2 was readily obtained from 1 by basic hydrolysis, 1 has never been synthesized from 2, due to the extreme difficulty in selectively introducing the bulky pyrrole moiety at the severely hindered C3-hydroxyl group of heptaol 2. Here we report chemical conversion of 2 to 1 for the first time. The derivatization was realized through the use of a new protective group strategy and the application of on-site construction of the pyrrole-2-carboxylate ester from the glycine ester and 1,3-bis(dimethylamino)allylium tetrafluoroborate.
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Affiliation(s)
- Kengo Masuda
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
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30
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Tabuchi T, Urabe D, Inoue M. Construction of the Fused Pentacycle of Talatisamine via a Combination of Radical and Cationic Cyclizations. J Org Chem 2016; 81:10204-10213. [DOI: 10.1021/acs.joc.6b01011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Toshiki Tabuchi
- Graduate School of Pharmaceutical
Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Daisuke Urabe
- Graduate School of Pharmaceutical
Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical
Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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31
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Koshimizu M, Nagatomo M, Inoue M. Unified Total Synthesis of 3-epi
-Ryanodol, Cinnzeylanol, Cinncassiols A and B, and Structural Revision of Natural Ryanodol and Cinnacasol. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201511116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Masaki Koshimizu
- Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Masanori Nagatomo
- Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo, Bunkyo-ku Tokyo 113-0033 Japan
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32
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Koshimizu M, Nagatomo M, Inoue M. Unified Total Synthesis of 3-epi
-Ryanodol, Cinnzeylanol, Cinncassiols A and B, and Structural Revision of Natural Ryanodol and Cinnacasol. Angew Chem Int Ed Engl 2016; 55:2493-7. [DOI: 10.1002/anie.201511116] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Masaki Koshimizu
- Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Masanori Nagatomo
- Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo, Bunkyo-ku Tokyo 113-0033 Japan
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