1
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Wang Y, Huang Y, Bao X, Wei X, Wei S, Qu J, Wang B. Organocatalytic diastereo- and atropo-selective construction of eight-membered bridged (hetero)biaryls via asymmetric intramolecular [3 + 2] cycloaddition. Chem Sci 2024; 15:8880-8887. [PMID: 38873056 PMCID: PMC11168085 DOI: 10.1039/d4sc01892c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 05/07/2024] [Indexed: 06/15/2024] Open
Abstract
An unprecedented and straightforward route for the asymmetric construction of privileged atroposelective bridged (hetero)biaryl eight-membered scaffolds has been accomplished through chiral phosphoric acid catalyzed asymmetric intramolecular [3 + 2] cycloaddition of innovative (hetero)biaryl aldehydes with 3-aminooxindole hydrochlorides. A class of eight-membered bridged (hetero)biaryl lactones fused to spiro[pyrrolidine-oxindole] derivatives, possessing both chiral C-C/C-N axes and multiple contiguous stereocenters, were obtained in good yields with excellent enantioselectivities and diastereoselectivities in one step through this direct strategy. In addition, the good scalability and derivatization of the title compounds demonstrated their synthetic utility.
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Affiliation(s)
- Yue Wang
- Department of Pharmaceutical Engineering, State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Yue Huang
- Department of Pharmaceutical Engineering, State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Xiaoze Bao
- College of Pharmaceutical Science & Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology Hangzhou 310014 P. R. China
| | - Xingfu Wei
- Department of Pharmaceutical Engineering, State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Shiqiang Wei
- Department of Pharmaceutical Engineering, State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Jingping Qu
- Department of Pharmaceutical Engineering, State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Baomin Wang
- Department of Pharmaceutical Engineering, State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
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2
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Kowalska J, Łukasik B, Frankowski S, Albrecht Ł. Hydrazone Activation in the Aminocatalytic Cascade Reaction for the Synthesis of Tetrahydroindolizines. Org Lett 2024; 26:814-818. [PMID: 38266767 PMCID: PMC10845150 DOI: 10.1021/acs.orglett.3c03911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/10/2024] [Accepted: 01/17/2024] [Indexed: 01/26/2024]
Abstract
In this Letter, we demonstrate the usefulness of hydrazone activation for the synthesis of biologically relevant tetrahydroindolizines. A pyrrol-derived hydrazone bearing a Michael acceptor moiety in the N-alkyl side chain has been designed with the aim of participating in the aminocatalytic cascade reaction leading to the annulation of the new six-membered heterocyclic scaffold. The application of (S)-(-)-α,α-diphenyl-2-pyrrolidinemethanol trimethylsilyl ether as the aminocatalyst allows for the iminium ion-enamine-mediated cascade to proceed in a fully stereoselective manner.
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Affiliation(s)
- Justyna Kowalska
- Institute
of Organic Chemistry, Lodz University of
Technology, Żeromskiego 116, 90-924 Łódź, Poland
| | - Beata Łukasik
- Institute
of Organic Chemistry, Lodz University of
Technology, Żeromskiego 116, 90-924 Łódź, Poland
| | - Sebastian Frankowski
- Institute
of Organic Chemistry, Lodz University of
Technology, Żeromskiego 116, 90-924 Łódź, Poland
| | - Łukasz Albrecht
- Institute
of Organic Chemistry, Lodz University of
Technology, Żeromskiego 116, 90-924 Łódź, Poland
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3
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García-Ramírez J, González-Cortés LA, Miranda LD. A Modular Synthesis of the Rhazinilam Family of Alkaloids and Analogs Thereof. Org Lett 2022; 24:8093-8097. [PMID: 36095152 DOI: 10.1021/acs.orglett.2c02446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A short, modular strategy for synthesizing three representative alkaloids of the (±)-rhazinilam family and 10 non-natural analogs is described. The protocol involves a radical addition/cyclization cascade reaction that assembles the tetrahydroindolizine system decorated with appropriate groups for a subsequent Pd-mediated cyclization, which generates the nine-membered lactam.
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Affiliation(s)
- Jazmín García-Ramírez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior S. N., Ciudad Universitaria, Ciudad de México, 04510, Mexico
| | - Luis A González-Cortés
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior S. N., Ciudad Universitaria, Ciudad de México, 04510, Mexico
| | - Luis D Miranda
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior S. N., Ciudad Universitaria, Ciudad de México, 04510, Mexico
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4
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Sirindil F, Weibel JM, Pale P, Blanc A. Rhazinilam-leuconolam family of natural products: a half century of total synthesis. Nat Prod Rep 2022; 39:1574-1590. [PMID: 35699109 DOI: 10.1039/d2np00026a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: 1972 to 2021The rhazinilam family of natural products exhibits a main structure with a stereogenic quaternary carbon and a tetrahydroindolizine core imbedded within a 9-membered macrocycle, imposing axial chirality. This unique architecture combined with their taxol-like antimitotic activities have attracted various attention, especially from synthetic chemists, notably in the past decade. The present review describes the known total and formal syntheses of the members of the rhazinilam family (rhazinilam, rhazinal, leuconolam and kopsiyunnanines), according to the strategy developed.
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Affiliation(s)
- Fatih Sirindil
- Laboratoire de Synthèse, Réactivité Organiques et Catalyse, Institut de Chimie, UMR 7177 - CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67070 Strasbourg, France.
| | - Jean-Marc Weibel
- Laboratoire de Synthèse, Réactivité Organiques et Catalyse, Institut de Chimie, UMR 7177 - CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67070 Strasbourg, France.
| | - Patrick Pale
- Laboratoire de Synthèse, Réactivité Organiques et Catalyse, Institut de Chimie, UMR 7177 - CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67070 Strasbourg, France.
| | - Aurélien Blanc
- Laboratoire de Synthèse, Réactivité Organiques et Catalyse, Institut de Chimie, UMR 7177 - CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67070 Strasbourg, France.
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5
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Miranda LD, García-Ramírez J. Peroxide-Mediated Oxidative Radical Cyclization to the Quinazolinone System: Efficient Syntheses of Deoxyvasicinone, Mackinazolinone and (±)-Leucomidine C. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/s-0040-1705975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AbstractAn efficient protocol for obtaining fused quinazolinones through an oxidative free-radical cyclization under metal- and tin-free conditions is described. The oxidative cyclization of various N-3-ω-iodoalkyl derivatives to provide tricyclic systems using dicumyl peroxide as the sole reagent is studied. The method then is employed for the syntheses of 5-, 6-, and 7-membered fused quinazolinone analogues, including the natural products deoxyvasicinone and mackinazolinone. A xanthate-based oxidative radical cascade addition/cyclization process that allows the production of new menthol- and testosterone-quinazolinone conjugates, as well as the first total synthesis of leucomidine C, are also reported.
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6
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Phipps EJT, Piou T, Rovis T. Rh(III)-Catalyzed Cyclopropanation of Unactivated Olefins Initiated by C-H Activation. Synlett 2019; 30:1787-1790. [PMID: 32801480 PMCID: PMC7428168 DOI: 10.1055/s-0039-1690130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We have developed a Rh(III)-catalyzed cyclopropanation of unactivated olefins initiated by an alkenyl C-H activation. A variety of 1,1-disubstituted olefins undergo efficient cyclopropanation with a slight excess of alkene stoichiometry. A series of mechanistic interrogations implicate a metal-carbene as an intermediate.
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Affiliation(s)
- Erik J T Phipps
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Tiffany Piou
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Tomislav Rovis
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
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7
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Khan F, Dlugosch M, Liu X, Banwell MG. The Palladium-Catalyzed Ullmann Cross-Coupling Reaction: A Modern Variant on a Time-Honored Process. Acc Chem Res 2018; 51:1784-1795. [PMID: 30010313 DOI: 10.1021/acs.accounts.8b00169] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cross-coupling reactions, especially those that are catalyzed by palladium, have revolutionized the way in which carbon-carbon bonds can be formed. The most commonly deployed variants of such processes are the Suzuki-Miyaura, Mizoroki-Heck, Stille, and Negishi cross-coupling reactions, and these normally involve the linking of an organohalide or pseudohalide (such as a triflate or nonaflate) with an organo-metallic or -metalloid such as an organo-boron, -magnesium, -tin, or -zinc species. Since the latter type of coupling partner is often prepared from the corresponding halide, methods that allow for the direct cross-coupling of two distinct halogen-containing compounds would provide valuable and more atom-economical capacities for the formation of carbon-carbon bonds. While the venerable Ullmann reaction can in principle achieve this, it has a number of drawbacks, the most significant of which is that homocoupling of the reaction partners is a competitive, if not the dominant, process. Furthermore, such reactions normally occur only under forcing conditions (viz., often at temperatures in excess of 250 °C). As such, the Ullmann reaction has seen only limited application in this regard, especially as a mid- to late-stage feature of complex natural product synthesis. This Account details the development of the palladium-catalyzed Ullmann cross-coupling reaction as a useful method for the assembly of a range of heterocyclic systems relevant to medicinal and/or natural products chemistry. These couplings normally proceed under relatively mild conditions (<100 °C) over short periods of time and, usually, to the exclusion of (unwanted) homocoupling events. The keys to success are the appropriate choice of coupling partners, the form of the copper metal employed, and the choice of reaction solvent. At the present time, the cross-coupling partners capable of engaging in the title reaction are confined to halogenated and otherwise electron-deficient arenes and, as complementary reactants, α- or β-halogenated, α,β-unsaturated aldehydes, ketones, esters, lactones, lactams, and cycloimides. Nitro-substituted (and halogenated) arenes, in particular, serve as effective participants in these reactions, and the products of their coupling with the above-mentioned carbonyl-containing systems can be manipulated in a number of different ways. Depending on the positional relationship between the nitro and carbonyl groups in the cross-coupling product, the reduction of the former group, which can be achieved under a range of different conditions, provides, through intramolecular nucleophilic addition reactions, including Schiff base condensations, access to a diverse range of heterocyclic systems. These include indoles, quinolines, quinolones, isoquinolines, carbazoles, and carbolines. Tandem variants of such cyclization processes, in which Raney cobalt is used as a catalyst for the chemoselective reduction (by dihydrogen) of nitro and nitrile groups (but not olefins), allow for the assembly of a range of structurally challenging natural products, including marinoquinoline A, (±)-1-acetylaspidoalbidine, and (±)-gilbertine.
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Affiliation(s)
- Faiyaz Khan
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia
| | - Michael Dlugosch
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia
| | - Xin Liu
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia
| | - Martin G. Banwell
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia
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8
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Affiliation(s)
| | - Giuseppe Zanoni
- Dipartimento di Chimica; Università di Pavia; Viale Taramelli 10 27100 Pavia Italy
| | - Debabrata Maiti
- Department of Chemistry; IIT Bombay; Powai Mumbai 400076 India
- Dipartimento di Chimica; Università di Pavia; Viale Taramelli 10 27100 Pavia Italy
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9
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Shemet A, Carreira EM. Total Synthesis of (−)-Rhazinilam and Formal Synthesis of (+)-Eburenine and (+)-Aspidospermidine: Asymmetric Cu-Catalyzed Propargylic Substitution. Org Lett 2017; 19:5529-5532. [DOI: 10.1021/acs.orglett.7b02619] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrej Shemet
- ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
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10
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Pfaffenbach M, Gaich T. The Rhazinilam-Leuconoxine-Mersicarpine Triad of Monoterpenoid Indole Alkaloids. THE ALKALOIDS: CHEMISTRY AND BIOLOGY 2017; 77:1-84. [DOI: 10.1016/bs.alkal.2016.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Zhao K, Xu S, Pan C, Sui X, Gu Z. Catalytically Asymmetric Pd/Norbornene Catalysis: Enantioselective Synthesis of (+)-Rhazinal, (+)-Rhazinilam, and (+)-Kopsiyunnanine C1–3. Org Lett 2016; 18:3782-5. [DOI: 10.1021/acs.orglett.6b01790] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kun Zhao
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, P. R. China
| | - Shibo Xu
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, P. R. China
| | - Chongqing Pan
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, P. R. China
| | - Xianwei Sui
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, P. R. China
| | - Zhenhua Gu
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, P. R. China
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12
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Hildebrandt S, Gansäuer A. Synthesis of Dihydropyrrolizine and Tetrahydroindolizine Scaffolds from Pyrroles by Titanocene(III) Catalysis. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603985] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sven Hildebrandt
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard-Domagk-Str. 1 53121 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard-Domagk-Str. 1 53121 Bonn Germany
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13
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Synthesis of Dihydropyrrolizine and Tetrahydroindolizine Scaffolds from Pyrroles by Titanocene(III) Catalysis. Angew Chem Int Ed Engl 2016; 55:9719-22. [DOI: 10.1002/anie.201603985] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/01/2016] [Indexed: 01/02/2023]
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14
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Pfaffenbach M, Gaich T. The Diaza[5.5.6.6]fenestrane Skeleton-Synthesis of Leuconoxine Alkaloids. Chemistry 2015; 22:3600-10. [DOI: 10.1002/chem.201502228] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Magnus Pfaffenbach
- Institute of Organic Chemistry; Leibniz University of Hannover; Schneiderberg 1b 30167 Hannover Germany
| | - Tanja Gaich
- Institute of Organic Chemistry; Leibniz University of Hannover; Schneiderberg 1b 30167 Hannover Germany
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15
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Ballini R, Petrini M. The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500008] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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16
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Crossley SWM, Shenvi RA. A Longitudinal Study of Alkaloid Synthesis Reveals Functional Group Interconversions as Bad Actors. Chem Rev 2015; 115:9465-531. [PMID: 26158529 DOI: 10.1021/acs.chemrev.5b00154] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Steven W M Crossley
- 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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17
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Yamada Y, Ebata S, Hiyama T, Nakao Y. Synthesis of rhazinilam through intramolecular arylcyanation of alkenes catalyzed cooperatively by nickel/aluminum. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.03.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Sugimoto K, Miyakawa Y, Tokuyama H. Total synthesis of (−)-rhazinilam using 1,3-dipolar cycloaddition of optically active münchnone intermediate. Tetrahedron 2015. [DOI: 10.1016/j.tet.2014.12.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Sailu M, Muley SS, Das A, Mainkar PS, Chandrasekhar S. Formal total synthesis of (±)-rhazinal and its B-ring carbamate analogue. Tetrahedron 2015. [DOI: 10.1016/j.tet.2014.12.090] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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20
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21
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Yang Y, Bai Y, Sun S, Dai M. Biosynthetically inspired divergent approach to monoterpene indole alkaloids: total synthesis of mersicarpine, leuconodines B and D, leuconoxine, melodinine E, leuconolam, and rhazinilam. Org Lett 2014; 16:6216-9. [PMID: 25412144 PMCID: PMC4260631 DOI: 10.1021/ol503150c] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Indexed: 01/08/2023]
Abstract
Inspired by their potential biosynthesis, we have developed divergent total syntheses of seven monoterpene indole alkaloids including mersicarpine, leuconodines B and D, leuconoxine, melodinine E, leuconolam, and rhazinilam, and one unnatural analogue with an unprecedented structural skeleton. The key steps involve a Witkop-Winterfeldt oxidative indole cleavage followed by transannular cyclization. The transannular cyclization product was then converted to the corresponding structural skeletons by pairing its functional groups into different reaction modes.
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Affiliation(s)
| | | | - Siyuan Sun
- Department
of Chemistry and
Center for Cancer Research, Purdue University, 720 Clinic Drive, West Lafayette, Indiana 47907, United States
| | - Mingji Dai
- Department
of Chemistry and
Center for Cancer Research, Purdue University, 720 Clinic Drive, West Lafayette, Indiana 47907, United States
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22
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Kholod I, Vallat O, Buciumas AM, Neels A, Neier R. Synthetic Strategies for the Synthesis and Transformation of Substituted Pyrrolinones as Advanced Intermediates for Rhazinilam Analogues. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402903] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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23
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Low YY, Hong FJ, Lim KH, Thomas NF, Kam TS. Transformations of the 2,7-Seco Aspidosperma alkaloid leuconolam, structure revision of epi-leuconolam, and partial syntheses of leuconoxine and leuconodines A and F. JOURNAL OF NATURAL PRODUCTS 2014; 77:327-338. [PMID: 24428198 DOI: 10.1021/np400922x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Several transformations of the seco Aspidosperma alkaloid leuconolam were carried out. The based-induced reaction resulted in cyclization to yield two epimers, the major product corresponding to the optical antipode of a (+)-meloscine derivative. The structures and relative configuration of the products were confirmed by X-ray diffraction analysis. Reaction of leuconolam and epi-leuconolam with various acids, molecular bromine, and hydrogen gave results that indicated that the structure of the alkaloid, previously assigned as epi-leuconolam, was incorrect. This was confirmed by an X-ray diffraction analysis, which revealed that epi-leuconolam is in fact 6,7-dehydroleuconoxine. Short partial syntheses of the diazaspiro indole alkaloid leuconoxine and the new leuconoxine-type alkaloids leuconodines A and F were carried out.
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Affiliation(s)
- Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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24
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Rossi R, Bellina F, Lessi M, Manzini C. Cross-Coupling of Heteroarenes by CH Functionalization: Recent Progress towards Direct Arylation and Heteroarylation Reactions Involving Heteroarenes Containing One Heteroatom. Adv Synth Catal 2014. [DOI: 10.1002/adsc.201300922] [Citation(s) in RCA: 366] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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25
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Sui X, Zhu R, Li G, Ma X, Gu Z. Pd-Catalyzed Chemoselective Catellani Ortho-Arylation of Iodopyrroles: Rapid Total Synthesis of Rhazinal. J Am Chem Soc 2013; 135:9318-21. [DOI: 10.1021/ja404494u] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Xianwei Sui
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui
230026, China
| | - Rui Zhu
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui
230026, China
| | - Gencheng Li
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui
230026, China
| | - Xinna Ma
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui
230026, China
| | - Zhenhua Gu
- Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui
230026, China
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26
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Gopi E, Namboothiri INN. Synthesis of Fused Bromofurans via Mg-Mediated Dibromocyclopropanation of Cycloalkanone-Derived Chalcones and Cloke–Wilson Rearrangement. J Org Chem 2013; 78:910-9. [DOI: 10.1021/jo3022988] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elumalai Gopi
- Department of Chemistry, Indian Institute of Technology, Bombay, Mumbai 400 076, India
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27
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Izgu EC, Hoye TR. Total synthesis of (±)-leuconolam: intramolecular allylic silane addition to a maleimide carbonyl group. Chem Sci 2013; 4:2262-2266. [PMID: 25419448 DOI: 10.1039/c3sc00056g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A concise total synthesis of the plant alkaloid (±)-leuconolam (1) has been achieved. A regio- and diastereoselective Lewis-acid mediated allylative cyclization was used to establish, simultaneously, two adjacent tetrasubstituted carbon centers. Furthermore, an essential arene cross-coupling to a hindered haloalkene was enabled by the use of a novel 2-anilinostannane.
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Affiliation(s)
- Enver Cagri Izgu
- Department of Chemistry, 207 Pleasant St. SE, University of Minnesota, Minneapolis, MN 55455, USA Tel: 612-625-1891
| | - Thomas R Hoye
- Department of Chemistry, 207 Pleasant St. SE, University of Minnesota, Minneapolis, MN 55455, USA Tel: 612-625-1891
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28
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Izgu EC, Hoye TR. o-(Trialkylstannyl)anilines and Their Utility in Stille Cross-Coupling: Direct Introduction of the 2-Aminophenyl Substituent. Tetrahedron Lett 2012; 53:4938-4941. [PMID: 22984300 DOI: 10.1016/j.tetlet.2012.06.138] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have developed shelf- and air-stable ortho-stannylated aniline reagents that can directly be coupled with alkenyl and aryl halides via Stille cross-coupling. We report i) the efficient preparation of o-(tributylstannyl)aniline (2a) and o-(trimethylstannyl)aniline (2b), ii) the comparison of the reactivities of 2a and 2b with those of related organostannanes in cross-coupling reaction with an alkenyl halide, and iii) the cross-coupling of 2a and 2b with a series of arylhalides and triflate.
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Affiliation(s)
- Enver Cagri Izgu
- Department of Chemistry, 207 Pleasant Street, SE, University of Minnesota, Minneapolis, Minnesota 55455
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29
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Chen DYK, Youn SW. C-H activation: a complementary tool in the total synthesis of complex natural products. Chemistry 2012; 18:9452-74. [PMID: 22736530 DOI: 10.1002/chem.201201329] [Citation(s) in RCA: 451] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Indexed: 02/05/2023]
Abstract
The recent advent of transition-metal mediated C-H activation is revolutionizing the synthetic field and gradually infusing a "C-H activation mind-set" in both students and practitioners of organic synthesis. As a powerful testament of this emerging synthetic tool, applications of C-H activation in the context of total synthesis of complex natural products are beginning to blossom. Herein, recently completed total syntheses showcasing creative and ingenious incorporation of C-H activation as a strategic manoeuver are compared with their "non-C-H activation" counterparts, illuminating a new paradigm in strategic synthetic design.
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Affiliation(s)
- David Y-K Chen
- Department of Chemistry, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul 151-742, South Korea.
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30
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Gu Z, Zakarian A. Total synthesis of rhazinilam: axial to point chirality transfer in an enantiospecific Pd-catalyzed transannular cyclization. Org Lett 2011; 12:4224-7. [PMID: 20795730 DOI: 10.1021/ol101523z] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A total synthesis of rhazinilam based on a transannular cyclization strategy is described. Using a Heck reaction, the axial chirality of a halogenated 13-membered lactam can be exploited to create the quaternary chiral stereogenic center in the target molecule with high enantiospecificity.
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Affiliation(s)
- Zhenhua Gu
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, USA
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31
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Chen J, Chen JJ, Yao X, Gao K. Kopsihainanines A and B, two unusual alkaloids from Kopsia hainanensis. Org Biomol Chem 2011; 9:5334-6. [DOI: 10.1039/c1ob05724c] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Synthetic Studies on Amaryllidaceae and Other Terrestrially Derived Alkaloids. Top Curr Chem (Cham) 2011; 309:163-202. [DOI: 10.1007/128_2011_217] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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33
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Paleo E, Osornio YM, Miranda LD. Synthesis of (±)-desethylrhazinal using a tandem radical addition-cyclization process. Org Biomol Chem 2011; 9:361-2. [DOI: 10.1039/c0ob00572j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Bringmann G, Gulder T, Gulder TAM, Breuning M. Atroposelective Total Synthesis of Axially Chiral Biaryl Natural Products. Chem Rev 2010; 111:563-639. [DOI: 10.1021/cr100155e] [Citation(s) in RCA: 909] [Impact Index Per Article: 64.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Gerhard Bringmann
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Tanja Gulder
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Tobias A. M. Gulder
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Matthias Breuning
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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35
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Neier R, Kholod I, Vallat O, Buciumas AM. Synthesis of Rhazinilam: A Comparative Review of Forty Years of Synthetic Endeavors. HETEROCYCLES 2010. [DOI: 10.3987/rev-10-sr(e)2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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36
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Bowie AL, Trauner D. Total synthesis of (+/-)-rhazinal using novel palladium-catalyzed cyclizations. J Org Chem 2009; 74:1581-6. [PMID: 19170539 DOI: 10.1021/jo801791j] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A concise synthesis of (+/-)-rhazinal that hinges on novel oxidative Heck cyclizations and palladium-catalyzed direct couplings is described. An X-ray structure of N-MOM-rhazinal, which provides insight into the conformation of the strained 9-membered lactam ring, is described.
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Affiliation(s)
- Alfred L Bowie
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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37
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Wu Y, Suehiro M, Kitajima M, Matsuzaki T, Hashimoto S, Nagaoka M, Zhang R, Takayama H. Rhazinilam and quebrachamine derivatives from Yunnan Kopsia arborea. JOURNAL OF NATURAL PRODUCTS 2009; 72:204-209. [PMID: 19133778 DOI: 10.1021/np800489e] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Three new rhazinilam-derived alkaloids, kopsiyunnanines C1, C2, and C3, and a new quebrachamine-type alkaloid, kopsiyunnanine D, which possess an unusual methoxymethyl or ethoxymethyl function, were isolated from the aerial parts of Yunnan Kopsia arborea. This is the first report of the presence of these functions in natural alkaloids. The structures and absolute configurations of the alkaloids were determined by spectroscopic methods and confirmed by semisynthesis.
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Affiliation(s)
- Yuqiu Wu
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
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38
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Beck E, Hatley R, Gaunt M. Synthesis of Rhazinicine by a Metal-Catalyzed CH Bond Functionalization Strategy. Angew Chem Int Ed Engl 2008; 47:3004-7. [DOI: 10.1002/anie.200705005] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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39
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Beck E, Hatley R, Gaunt M. Synthesis of Rhazinicine by a Metal-Catalyzed CH Bond Functionalization Strategy. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705005] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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40
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Affiliation(s)
- Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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41
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Subramaniam G, Hiraku O, Hayashi M, Koyano T, Komiyama K, Kam TS. Biologically active aspidofractinine, rhazinilam, akuammiline, and vincorine alkaloids from Kopsia. JOURNAL OF NATURAL PRODUCTS 2007; 70:1783-1789. [PMID: 17939738 DOI: 10.1021/np0703747] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Eleven new indole alkaloids, in addition to the previously reported rhazinal (1), and 14 other known alkaloids, were obtained from the Malayan Kopsia singapurensis, viz., kopsiloscines A-F (2-7), 16-epikopsinine (8), kopsilongine- N-oxide (9), 16-epiakuammiline (10), aspidophylline A (11), and vincophylline (12). The structures of these alkaloids were determined using NMR and MS analyses. Rhazinal (1), rhazinilam (17), and rhazinicine (18) showed appreciable cytotoxicity toward drug-sensitive as well as vincristine-resistant KB cells, while kopsiloscines A (2), B (3), and D (5) and aspidophylline A (11) were found to reverse drug-resistance in drug-resistant KB cells.
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Affiliation(s)
- G Subramaniam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
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42
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Stanislawski PC, Willis AC, Banwell MG. gem-Dihalocyclopropanes as Building Blocks in Natural-Product Synthesis: Enantioselective Total Syntheses ofent-Erythramine and 3-epi-Erythramine. Chem Asian J 2007; 2:1127-36. [PMID: 17694511 DOI: 10.1002/asia.200700155] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
ent-Erythramine ((-)-1), the enantiomer of the alkaloid erythramine, was prepared in 15 steps from known compounds. The first of three pivotal bond-forming steps in the synthesis was a Suzuki-Miyaura cross-coupling reaction of the starting materials to give a bis-silyl ether. The second involved silver(I)-induced electrocyclic ring opening of the gem-dichlorocyclopropane formed in the next step and trapping of the ensuing pi-allyl cation by the tethered nitrogen atom to give, following cleavage of the allyloxycarbonyl protecting group, an approximately 5:6 mixture of the chromatographically separable diastereoisomeric spirocyclic products. In the third critical bond-forming reaction, the iodide formed from one of the diastereoisomers underwent a radical-addition/elimination reaction sequence that led to (-)-1 in 89 % yield. The application of the same sequence of transformations to the other diastereoisomer afforded 3-epi-(+)-erythramine (3-epi-(+)-1).
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Affiliation(s)
- Pauline C Stanislawski
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 0200, Australia
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43
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Some S, Ray JK, Banwell MG, Jones MT. New protocols for the synthesis of 3,4-annulated and 4-substituted quinolines from β-bromo-α,β-unsaturated aldehydes and 1-bromo-2-nitrobenzene or 2-bromoacetanilide. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.03.078] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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44
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Hájíček J. A Review on Recent Developments in Syntheses of the post-Secodine Indole Alkaloids. Part II: Modified Alkaloid Types. ACTA ACUST UNITED AC 2007. [DOI: 10.1135/cccc20070821] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The second part of the planned review on developments in the field of total and formal total synthesis of the post-secodine indole alkaloids concentrates on modified alkaloid types, i.e. those skeletons derived from primary types by formation of additional and/or rupture of existing bonds, while connectivities next to indol(e)ine moiety remain intact. It thus reviews the synthesis of alkaloids of quebrachamine/cleavamine type including VLB-bis-indoles, rhazinilam type, aspidofractinine/kopsane and kopsifoline type, as well as kopsijasminilam alkaloids, lapidilectine B and danuphylline. It covers the literature of from 1991-1992 up to approximately end 2006. A review with 174 references.
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45
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Banwell MG, Ma X, Taylor RM, Willis AC. Concise Assembly of the Polycyclic Frameworks Associated with the Hapalindole and Fischerindole Alkaloids. Org Lett 2006; 8:4959-61. [PMID: 17020346 DOI: 10.1021/ol062020x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Reaction of N-methylindole (4) with 6,6-dibromobicyclo[3.1.0]hexane (5) in the presence of silver tetrafluoroborate affords conjugate 7 in 67% yield. This product can be readily elaborated to compounds 12b and 13b which embody the polycyclic frameworks associated with members of the hapalindole and fischerindole classes of alkaloids. The chiral-auxiliary-substituted 6,6-dibromobicyclo[3.1.0]hexanes 21 and 22 react with indole to give adducts likely to be useful in the enantioselective total synthesis of the title alkaloids.
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Affiliation(s)
- Martin G Banwell
- Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia.
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46
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Magolan J, Kerr MA. Expanding the Scope of Mn(OAc)3-Mediated Cyclizations: Synthesis of the Tetracyclic Core of Tronocarpine. Org Lett 2006; 8:4561-4. [PMID: 16986950 DOI: 10.1021/ol061698+] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyrroles, indoles, and surprisingly, indolines, when equipped with a pendant malonyl group on the nitrogen atom, were effective substrates in a Mn(III)-mediated oxidative cyclization reaction, yielding the 1,2-annulated products in good to excellent yields. When indole acetonitrile was used as a substrate this method provided a rapid synthesis of a tetracyclic tronocarpine subunit.
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Affiliation(s)
- Jakob Magolan
- Department of Chemistry, University of Western Ontario, London, Ontario, Canada N6A 5B7
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47
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Banwell MG, Goodwin TE, Ng S, Smith JA, Wong DJ. Palladium‐Catalysed Cross‐Coupling and Related Reactions Involving Pyrroles. European J Org Chem 2006. [DOI: 10.1002/ejoc.200500911] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Martin G. Banwell
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia, Fax: +61‐2‐6125‐8114
| | - Thomas E. Goodwin
- Department of Chemistry, Hendrix College, 1600 Washington Ave, Conway, AR 72032, USA
| | - Sarah Ng
- School of Chemistry, University of Tasmania, Hobart, TAS 7000, Australia
| | - Jason A. Smith
- School of Chemistry, University of Tasmania, Hobart, TAS 7000, Australia
| | - David J. Wong
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia, Fax: +61‐2‐6125‐8114
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48
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Abstract
Pyrrole is a unique aromatic molecule as it can readily undergo substitution at all five positions but obtaining the desired regioisomer can prove difficult to control. We now report our results on the regioselective arylation of pyrrole, utilizing selective halogenation and the Suzuki-Miyaura reaction to prepare C4-, C5- and C3-aryl derivatives. We have applied this methodology to the synthesis of lamellarin O dimethyl ether, an intermediate in the synthesis of lukinol A.
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Affiliation(s)
- Jason A Smith
- School of Chemistry, University of Tasmania, Hobart, Australia.
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49
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Stanislawski PC, Willis AC, Banwell MG. New Protocols for the Assembly of the Tetracyclic Framework Associated with the Aromatic Erythrina Alkaloids. Org Lett 2006; 8:2143-6. [PMID: 16671802 DOI: 10.1021/ol060642c] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Treatment of the anion derived from the ring-fused gem-dichlorocyclopropane 4c with silver tetrafluoroborate afforded the spirocyclic compound 17 in 74% yield. Product 17 was readily converted, over three steps, into the beta-iodoethyl derivative 20 and treatment of this latter compound with n-Bu(3)SnH then afforded, in 93% yield and via a radical addition/elimination sequence, compound 2 incorporating the ABCD framework of the aromatic erythrina alkaloids.
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Affiliation(s)
- Pauline C Stanislawski
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra
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50
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Décor A, Monse B, Martin MT, Chiaroni A, Thoret S, Guénard D, Guéritte F, Baudoin O. Synthesis and biological evaluation of B-ring analogues of (−)-rhazinilam. Bioorg Med Chem 2006; 14:2314-32. [PMID: 16314101 DOI: 10.1016/j.bmc.2005.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 11/03/2005] [Accepted: 11/08/2005] [Indexed: 10/25/2022]
Abstract
Three macrocyclic analogues of rhazinilam 1 having a 11- or 12-membered B-ring with an endocyclic carbamate group or an amino-acid residue were synthesized from the natural product. These analogues 3 and 4 displayed a very low activity on tubulin. Thirty N-1 and C-16 substituted analogues of rhazinilam were also synthesized regioselectively from rhazinilam. Stereochemical analyses showed that N-1 and C-16alpha analogues have the same conformation as rhazinilam, whereas C-16beta analogues adopt a different conformation for rings B and D. All N-1 and C-16 analogues were less active than rhazinilam on tubulin, though analogues 5a, 6aalpha, 6balpha, and 6f having the less bulky substituents retained close affinities. A few analogues either active (like 6f) or inactive (like 5o) on tubulin showed significant inhibition of the growth of KB cancer cells.
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Affiliation(s)
- Anne Décor
- Institut de Chimie des Substances Naturelles, CNRS, avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
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