1
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Röder L, Wurst K, Magauer T. Synthesis of the Tetracyclic Spiro-naphthoquinone Chartspiroton. Org Lett 2024; 26:3065-3068. [PMID: 38557044 PMCID: PMC11041114 DOI: 10.1021/acs.orglett.4c00695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/17/2024] [Accepted: 03/28/2024] [Indexed: 04/04/2024]
Abstract
Chartspiroton is a recently discovered naphthoquinone natural product that features a spiro-fused benzofuran lactone. We report its first synthesis via an 11-step linear sequence. The sterically hindered tetra-ortho-substituted biaryl subunit was installed by base-induced ring expansion of a readily available 1,3-indandione. This step also liberated the fully substituted naphthalene core unit at the same time. The unique spiro-fused benzofuran lactone of the natural product was constructed via late-stage oxidation of an advanced naphthoquinone.
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Affiliation(s)
- Liesa Röder
- Department
of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80−82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Department
of General Inorganic and Theoretical Chemistry, University of Innsbruck, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Department
of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80−82, 6020 Innsbruck, Austria
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2
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Röder L, Venegas ST, Wurst K, Magauer T. Synthesis of C3- epi-virenose and anomerically activated derivatives. Tetrahedron Lett 2024; 140:155041. [PMID: 38665383 PMCID: PMC7615872 DOI: 10.1016/j.tetlet.2024.155041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
A 9-step synthetic route to a protected form of the C3-epimer of virenose from D-fucose is described. C3-epi-virenose is the carbohydrate unit of the bioactive polyketide elsamicin B and part of the carbohydrate unit of elsamicin A. The developed route enabled preparation of anomerically activated forms of this unique C6-deoxy sugar, including derivatives with 1-acetyl, 1-acetylthio, 1-trichloroacetimidate, 1-bromo, and 1-fluoro substituents.
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Affiliation(s)
- Liesa Röder
- Department of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80–82, 6020 Innsbruck, Austria
| | - Sofia Torres Venegas
- Department of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80–82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Department of General, Inorganic and Theoretical Chemistry, University of Innsbruck, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Department of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80–82, 6020 Innsbruck, Austria
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3
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Steinborn C, Huber T, Lichtenegger J, Plangger I, Höfler D, Schnell SD, Weisheit L, Mayer P, Wurst K, Magauer T. Synthesis of Waixenicin A: Exploring Strategies for Nine-Membered Ring Formation. Chemistry 2024; 30:e202303489. [PMID: 37942708 PMCID: PMC7615592 DOI: 10.1002/chem.202303489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/10/2023]
Abstract
We present a comprehensive account on our efforts behind the recently published synthesis of waixenicin A. Our approach for constructing the dihydropyran ring relied on an Achmatowicz rearrangement. For the assembly of the nine-membered ring, four distinct strategies were investigated. Our initial attempts using radical-based addition/fragmentation reactions targeting the C7-C11 bond proved unsuitable for accessing the 6/9-bicycle. By employing anionic fragmentation conditions at the furfuryl alcohol stage, we successfully reached a 5/9-bicycle. However, subsequent ring-expansion was unsuccessful. Alternative approaches, such as Nozaki-Hiyama-Kishi or Heck reactions to connect the C6-C7 bond, also encountered difficulties, with no nine-membered ring formation observed. Our first breakthrough came from our attempts to install the C5-C6 bond via an intramolecular alkylation. Surprisingly, subsequent functional group modifications proved unexpectedly challenging, necessitating a redesign of our synthetic route. Drawing from all our investigations, we concluded that construction of the C9-C10 bond would enable efficient nine-membered ring alkylation and would facilitate the installation of the desired substitution pattern along the southern periphery. Exploration of this strategy yielded further surprises but ultimately led to the successful synthesis of waixenicin A and 9-deacetoxy-14,15-deepoxyxeniculin. For the latter compound, a bioinspired one-step rearrangement to xeniafauranol A was achieved.
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Affiliation(s)
- Christian Steinborn
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Tatjana Huber
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Julian Lichtenegger
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Immanuel Plangger
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Denis Höfler
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Simon D Schnell
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Lara Weisheit
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Peter Mayer
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Klaus Wurst
- Institute of General, Inorganic & Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
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4
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Steinborn C, Tancredi A, Habiger C, Diederich C, Kramer J, Reingruber AM, Laber B, Freigang J, Lange G, Schmutzler D, Machettira A, Besong G, Magauer T, Barber DM. Investigations into Simplified Analogues of the Herbicidal Natural Product (+)-Cornexistin. Chemistry 2023; 29:e202300199. [PMID: 36807428 PMCID: PMC7614749 DOI: 10.1002/chem.202300199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 02/22/2023]
Abstract
We report the design, synthesis and biological evaluation of simplified analogues of the herbicidal natural product (+)-cornexistin. Guided by an X-Ray co-crystal structure of cornexistin bound to transketolase from Zea mays, we attempted to identify the key interactions that are necessary for cornexistin to maintain its herbicidal profile. This resulted in the preparation of three novel analogues investigating the importance of substituents that are located on the nine-membered ring of cornexistin. One analogue maintained a good level of biological activity and could provide researchers insights in how to further optimize the structure of cornexistin for commercialization in the future.
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Affiliation(s)
- Christian Steinborn
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Aldo Tancredi
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Christoph Habiger
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Christina Diederich
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Jan Kramer
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Anna M Reingruber
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Bernd Laber
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Jörg Freigang
- Research & Development, Hit Discovery Bayer AG, Crop Science Division, Alfred-Nobel-Straße 50, 40789, Monheim am Rhein, Germany
| | - Gudrun Lange
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Dirk Schmutzler
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Anu Machettira
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Gilbert Besong
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - David M Barber
- Research & Development, Weed Control Bayer AG, Crop Science Division, Industriepark Höchst, 65926, Frankfurt am Main, Germany
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5
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Plangger I, Pinkert T, Wurst K, Magauer T. A Divergent Polyene Cyclization for the Total Synthesis of Greenwayodendrines, Greenwaylactams, Polysin and Polyveoline. Angew Chem Int Ed Engl 2023:e202307719. [PMID: 37318945 PMCID: PMC7614870 DOI: 10.1002/anie.202307719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 06/17/2023]
Abstract
We present a concise (5-8 steps) asymmetric total synthesis of nine sesquiterpenoid alkaloids featuring four different tetra-/pentacyclic scaffolds. To this end, a novel, bioinspired indole N-terminated cationic tricyclization has been developed enabling the divergent syntheses of greenwayodendrines and polysin. Subtle variation of the C2-substituted indole cyclization precursor allowed switching between indole N- and C-termination. For the latter, a subsequent Witkop oxidation enabled conversion of the cyclopentene fused indole to the eight-membered benzolactam directly furnishing the family of greenwaylactams. In addition, a diastereomeric C-termination product has been elaborated to provide access to polyveoline.
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Affiliation(s)
- Immanuel Plangger
- University of Innsbruck: Universitat Innsbruck, Institute of Organic Chemistry, AUSTRIA
| | - Tobias Pinkert
- University of Innsbruck: Universitat Innsbruck, Institute of Organic Chemistry, AUSTRIA
| | - Klaus Wurst
- University of Innsbruck: Universitat Innsbruck, Institute of General, Inorganic and Theoretical Chemistry, AUSTRIA
| | - Thomas Magauer
- University of Innsbruck: Universitat Innsbruck, Department of Organic Chemistry, Innrain 80/82, 6020, Innsbruck, AUSTRIA
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6
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Steinborn C, Huber T, Lichtenegger J, Plangger I, Wurst K, Magauer T. Total Syntheses of (+)-Waixenicin A, (+)-9-Deacetoxy-14,15-deepoxyxeniculin, and (-)-Xeniafaraunol A. J Am Chem Soc 2023; 145:11811-11817. [PMID: 37192136 DOI: 10.1021/jacs.3c03366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The first asymmetric total synthesis of the Xenia diterpenoid waixenicin A, a potent and highly selective TRPM7 inhibitor, is reported. The characteristic trans-fused oxabicyclo[7.4.0]tridecane ring system was constructed via a diastereoselective conjugate addition/trapping sequence, followed by an intramolecular alkylation to forge the 9-membered ring. While a β-keto sulfone motif enabled efficient ring-closure, the subsequent radical desulfonylation suffered from (E)/(Z)-isomerization of the C7/C8-alkene. Conducting the sequence with a trimethylsilylethyl ester allowed for a fluoride-mediated decarboxylation that proceeded without detectable isomerization. The acid-labile enol acetal of the delicate dihydropyran core was introduced at an early stage and temporarily deactivated by a triflate function. The latter was critical for the introduction of the side chain. Diverting from a common late-stage intermediate provided access to waixenicin A and 9-deacetoxy-14,15-deepoxyxeniculin. A high-yielding base-mediated dihydropyran-cyclohexene rearrangement of 9-deacetoxy-14,15-deepoxyxeniculin led to xeniafaraunol A in one step.
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Affiliation(s)
- Christian Steinborn
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Tatjana Huber
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Julian Lichtenegger
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Immanuel Plangger
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute of General, Inorganic & Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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7
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Paciorek J, Höfler D, Sokol KR, Wurst K, Magauer T. Total Synthesis of the Dihydrooxepine-Spiroisoxazoline Natural Product Psammaplysin A. J Am Chem Soc 2022; 144:19704-19708. [PMID: 36270001 PMCID: PMC9634798 DOI: 10.1021/jacs.2c10010] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Indexed: 11/29/2022]
Abstract
We report a general synthetic entry to dihydrooxepine-spiroisoxazoline (DOSI) natural products that culminated in the first racemic total synthesis of psammaplysin A. For the synthesis of the unique spirocyclic fragment we employed a strategy that features two key transformations: (1) a diastereoselective Henry reaction/cyclization sequence to access the C7 hydroxylated isoxazoline scaffold in one step and (2) a regioselective Baeyer-Villiger ring expansion to install the fully substituted dihydrooxepine and avoid the risk of a previously observed oxepine-arene oxide rearrangement. The overall synthesis proceeds in 13 steps from an inexpensive starting material.
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Affiliation(s)
- Jan Paciorek
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Denis Höfler
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Kevin Rafael Sokol
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute
of General, Inorganic & Theoretical Chemistry, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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8
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Plangger I, Wurst K, Magauer T. Short, Divergent, and Enantioselective Total Synthesis of Bioactive ent-Pimaranes. Org Lett 2022; 24:7151-7156. [PMID: 36170466 PMCID: PMC7613685 DOI: 10.1021/acs.orglett.2c02843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present the first total synthesis of eight ent-pimaranes via a short and enantioselective route (11-16 steps). Key features of the divergent synthesis are a Sharpless asymmetric dihydroxylation, a Brønsted acid catalyzed cationic bicyclization, and a mild Rh-catalyzed arene hydrogenation for rapid access to a late synthetic branching point. From there on, selective functional group manipulations enable the synthesis of ent-pimaranes bearing different modifications in the A- and C-rings.
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Affiliation(s)
- Immanuel Plangger
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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9
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Maier M, Olthoff S, Hill K, Zosel C, Magauer T, Wein LA, Schaefer M. KS0365, a novel activator of the transient receptor potential vanilloid 3 (TRPV3) channel, accelerates keratinocyte migration. Br J Pharmacol 2022; 179:5290-5304. [PMID: 35916168 DOI: 10.1111/bph.15937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 06/09/2022] [Accepted: 07/06/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Ca2+ signalling mediated by the thermosensitive, non-selective, Ca2+ -permeable transient receptor potential channel TRPV3 is assumed to play a critical role in regulating several aspects of skin functions, such as keratinocyte proliferation, differentiation, skin barrier formation and wound healing. Studying the function of TRPV3 in skin homeostasis, however, is still constrained by a lack of potent and selective pharmacological modulators of TRPV3. EXPERIMENTAL APPROACH By screening an in-house compound library using fluorometric intracellular Ca2+ assays, we identified two chemically related hits. The more potent and efficient TRPV3 activator KS0365 was further evaluated in fluo-4-assisted Ca2+ assays, different Ca2+ imaging approaches, electrophysiological studies, cytotoxicity and migration assays. KEY RESULTS KS0365 activated recombinant and native mouse TRPV3 more potently and with a higher efficacy compared to 2-APB and did not activate TRPV1, TRPV2 or TRPV4 channels. The activation of TRPV3 by KS0365 super-additively accelerated the EGF-induced keratinocyte migration, which was inhibited by the TRP channel blocker ruthenium red or by siRNA-mediated TRPV3 knockdown. Moreover, KS0365 induced strong Ca2+ responses in migrating front cells and in leading edges of keratinocytes. CONCLUSIONS AND IMPLICATIONS The selective TRPV3 activator KS0365 triggers increases in [Ca2+ ]i with most prominent signals in the leading edge, and accelerates migration of keratinocytes. TRPV3 activators may promote reepithelialization upon skin wounding.
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Affiliation(s)
- Marion Maier
- Leipzig University, Medical Faculty, Rudolf-Boehm-Institute of Pharmacology and Toxicology, Leipzig, Germany
| | - Stefan Olthoff
- Leipzig University, Medical Faculty, Rudolf-Boehm-Institute of Pharmacology and Toxicology, Leipzig, Germany
| | - Kerstin Hill
- Leipzig University, Medical Faculty, Rudolf-Boehm-Institute of Pharmacology and Toxicology, Leipzig, Germany
| | - Carolin Zosel
- Leipzig University, Medical Faculty, Rudolf-Boehm-Institute of Pharmacology and Toxicology, Leipzig, Germany
| | - Thomas Magauer
- Leopold-Franzens-University Innsbruck, Institute of Organic Chemistry and Center for Molecular Biosciences, Innsbruck, Austria
| | - Lukas Anton Wein
- Leopold-Franzens-University Innsbruck, Institute of Organic Chemistry and Center for Molecular Biosciences, Innsbruck, Austria
| | - Michael Schaefer
- Leipzig University, Medical Faculty, Rudolf-Boehm-Institute of Pharmacology and Toxicology, Leipzig, Germany
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10
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Abstract
Herein, we present our studies to construct seven ent-trachylobane diterpenoids by employing a bioinspired two-phase synthetic strategy. The first phase provided enantioselective and scalable access to five ent-trachylobanes, of which methyl ent-trachyloban-19-oate was produced on a 300 mg scale. During the second phase, chemical C-H oxidation methods were employed to enable selective conversion to two naturally occurring higher functionalized ent-trachylobanes. The formation of regioisomeric analogs, which are currently inaccessible via enzymatic methods, reveals the potential as well as limitations of established chemical C-H oxidation protocols for complex molecule synthesis.
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Affiliation(s)
- Lukas Anton Wein
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Klaus Wurst
- Institute of GeneralInorganic and Theoretical ChemistryLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
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11
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Wein LA, Wurst K, Magauer T. Total Synthesis and Late-Stage C-H Oxidations of ent-Trachylobane Natural Products. Angew Chem Weinheim Bergstr Ger 2022; 134:e202113829. [PMID: 38505342 PMCID: PMC10947344 DOI: 10.1002/ange.202113829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Indexed: 03/21/2024]
Abstract
Herein, we present our studies to construct seven ent-trachylobane diterpenoids by employing a bioinspired two-phase synthetic strategy. The first phase provided enantioselective and scalable access to five ent-trachylobanes, of which methyl ent-trachyloban-19-oate was produced on a 300 mg scale. During the second phase, chemical C-H oxidation methods were employed to enable selective conversion to two naturally occurring higher functionalized ent-trachylobanes. The formation of regioisomeric analogs, which are currently inaccessible via enzymatic methods, reveals the potential as well as limitations of established chemical C-H oxidation protocols for complex molecule synthesis.
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Affiliation(s)
- Lukas Anton Wein
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Klaus Wurst
- Institute of GeneralInorganic and Theoretical ChemistryLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
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12
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Abstract
Herein, we describe a two-step ring expansion of 1-indanones to afford 2-chloro/bromo-1-naphthols (32 examples). The developed method shows broad functional group tolerance, benefits from mild reaction conditions, and enables rapid access to the tetracyclic core of gilvocarcin natural products. The orthogonally functionalized products allow for selective postmodifications as exemplified in the total synthesis of defucogilvocarcin M. For the selective oxidation of the chromene, a mild and regioselective oxidation protocol (DDQ and TBHP) was developed.
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Affiliation(s)
- Ivica Zamarija
- Institute of Organic Chemistry and Center for
Molecular Biosciences, Leopold-Franzens-University Innsbruck,
Innrain 80-82, 6020 Innsbruck, Austria
| | - Benjamin J. Marsh
- Department of Chemistry and Pharmacy,
Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13,
81377 Munich, Germany
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for
Molecular Biosciences, Leopold-Franzens-University Innsbruck,
Innrain 80-82, 6020 Innsbruck, Austria
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13
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Abstract
Polyene cyclizations generate molecular complexity from a linear polyene in a single step. While methods to initiate these cyclizations have been continuously expanded and improved over the years, the majority of polyene substrates are still limited to simple alkyl-substituted alkenes. In this study, we took advantage of the unique reactivity of higher-functionalized bifunctional alkenes. The realization of a polyene tetracyclization of a dual nucleophilic aryl enol ether involving a transannular endo-termination step enabled the total synthesis of the tricyclic diterpenoid pimara-15-en-3α-8α-diol. The highly flexible and modular route allowed for the preparation of a diverse library of cyclization precursors specifically designed for the total synthesis of the tetracyclic nor-diterpenoid norflickinflimiod C. The tetracyclization of three diversely substituted allenes enabled access to complex pentacyclic products and provided a detailed insight into the underlying reaction pathways.
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Affiliation(s)
- Julian M. Feilner
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Immanuel Plangger
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical ChemistryLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
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14
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Wildermuth RE, Steinborn C, Barber DM, Mühlfenzl KS, Kendlbacher M, Mayer P, Wurst K, Magauer T. Evolution of a Strategy for the Total Synthesis of (+)-Cornexistin. Chemistry 2021; 27:12181-12189. [PMID: 34105834 PMCID: PMC8457225 DOI: 10.1002/chem.202101849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Indexed: 12/13/2022]
Abstract
Herein is given a full account of the evolution of the first total synthesis of (+)-cornexistin. Initial efforts were based on masking the reactive maleic anhydride moiety as a 3,4-substituted furan and on forming the nine-membered carbocycle in an intramolecular Conia-ene or Nozaki-Hiyama-Kishi (NHK) reaction. Those strategies suffered from low yields and were jeopardized by a late-stage installation of the Z-alkene, as well as the stereocenters along the eastern periphery. These issues were addressed by employing a chiral-pool strategy that involved construction of the crucial stereocenters at C2, C3 and C8 at an early stage with installation of the maleic anhydride as late as possible. The successful approach featured an intermolecular NHK coupling to install the Z-alkene, a syn-Evans-aldol reaction to forge the stereocenters along the eastern periphery, an intramolecular allylic alkylation to close the nine-membered carbocycle, and a challenging stepwise hydrolysis of a β-keto nitrile to furnish the maleic anhydride.
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Affiliation(s)
- Raphael E. Wildermuth
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
- Department of Chemistry and PharmacyLudwig-Maximilians-University MunichButenandtstrasse 5–1381377MunichGermany
| | - Christian Steinborn
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - David M. Barber
- Research & DevelopmentWeed Control Chemistry, Bayer AG Crop Science Division Industriepark Höchst65926Frankfurt am MainGermany
| | - Kim S. Mühlfenzl
- Department of Chemistry and PharmacyLudwig-Maximilians-University MunichButenandtstrasse 5–1381377MunichGermany
| | - Mario Kendlbacher
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Peter Mayer
- Department of Chemistry and PharmacyLudwig-Maximilians-University MunichButenandtstrasse 5–1381377MunichGermany
| | - Klaus Wurst
- Institute of GeneralInorganic & Theoretical ChemistryLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
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15
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Abstract
The construction of oxepin and dihydrooxepin containing natural products represents a challenging task in total synthesis. In the last decades, a variety of synthetic methods have been reported for the installation of these structural motifs. Herein, we provide an overview of synthetic methods and strategies to construct these motifs in the context of natural product synthesis and highlight the key steps of each example.
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Affiliation(s)
- Kevin Rafael Sokol
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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16
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Haut FL, Feichtinger NJ, Plangger I, Wein LA, Müller M, Streit TN, Wurst K, Podewitz M, Magauer T. Synthesis of Pyrroles via Consecutive 6π-Electrocyclization/Ring-Contraction of Sulfilimines. J Am Chem Soc 2021; 143:9002-9008. [PMID: 34106724 PMCID: PMC8227482 DOI: 10.1021/jacs.1c04835] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Indexed: 12/20/2022]
Abstract
We present a modular, synthetic entry to polysubstituted pyrroles employing readily available 2,5-dihydrothiophenes. Ring-opening of the heterocycle provides access to a panel of 1,3-dienes which undergo pyrrole formation in the presence of inexpensive chloramine-T trihydrate. The transformation is conducted in an open flask and proceeds at ambient temperatures (23 °C) in nondry solvents. A careful adjustment of the electronics and sterics of the 1,3-diene precursor allows for the isolation of key intermediates. DFT studies identified a reaction mechanism that features a 6π-electrocyclization of a sulfilimine intermediate followed by spontaneous ring-contraction to reveal the pyrrole skeleton.
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Affiliation(s)
- Franz-Lucas Haut
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Niklas J. Feichtinger
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Immanuel Plangger
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Lukas A. Wein
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Mira Müller
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Tim-Niclas Streit
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute
of General, Inorganic and Theoretical Chemistry and Center for Molecular
Biosciences, Leopold-Franzens-University
Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Maren Podewitz
- Institute
of General, Inorganic and Theoretical Chemistry and Center for Molecular
Biosciences, Leopold-Franzens-University
Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Institute
of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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17
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Ciulli A, Hamann L, Jahnke W, Kalgutkar AS, Magauer T, Ritter T, Steadman V, Williams SD, Winter G, Hoegenauer K, Krawinkler KH, Stepan AF. The 2 nd Alpine Winter Conference on Medicinal and Synthetic Chemistry. ChemMedChem 2021; 16:2417-2423. [PMID: 34114371 DOI: 10.1002/cmdc.202100372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Indexed: 11/07/2022]
Abstract
The second biannual Alpine Winter Conference on Medicinal and Synthetic Chemistry (short: Alpine Winter Conference) took place January 19-23, 2020, in St. Anton in western Austria. There were roughly 180 attendees from around the globe, making this mid-sized conference particularly conducive to networking and exchanging ideas over the course of four and a half days. This report summarizes the key events and presentations given by researchers working in both industry and academia.
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Affiliation(s)
- Alessio Ciulli
- Biological Chemistry & Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Lawrence Hamann
- Drug Discovery Sciences, Takeda Pharmaceuticals, 30 Landsdowne Street, Cambridge, MA 02139, USA
| | - Wolfgang Jahnke
- Novartis Institutes for BioMedical Research, 4002, Basel, Switzerland
| | - Amit S Kalgutkar
- Medicine Design, Pfizer, Inc., 1 Portland Street, Cambridge, MA 02139, USA
| | - Thomas Magauer
- Department of Chemistry and Pharmacy, Institute of Organic Chemistry, Leopold-Franzens-University Innsbruck, Innrain 80-82, L02.012, 6020, Innsbruck, Austria
| | - Tobias Ritter
- Max-Planck Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Muelheim an der Ruhr, Germany
| | | | | | - Georg Winter
- Research Center for Molecular Medicine (CeMM), Austrian Academy of Sciences, 1090, Vienna, Austria
| | | | | | - Antonia F Stepan
- F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070, Basel, Switzerland
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18
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Abstract
Polyene cyclizations are capable of producing molecular complexity in a single step. While classical systems are limited to simple alkyl substitution patterns only, bifunctional polyenes take advantage of the unique reactivity of higher‐functionalized alkenes. Here, we highlight the potential of these variants for the synthesis of structurally complex polycycles involving unprecedented termination steps. We also want to provide a stimulus for the development of novel modes of cyclization that involve bifunctional units to enable efficient synthesis of yet inaccessible natural products.
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Affiliation(s)
- Julian M Feilner
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Franz-Lucas Haut
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
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19
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Haut FL, Habiger C, Wein LA, Wurst K, Podewitz M, Magauer T. Rapid Assembly of Tetrasubstituted Furans via Pummerer-Type Rearrangement. J Am Chem Soc 2021; 143:1216-1223. [PMID: 33399454 PMCID: PMC7884018 DOI: 10.1021/jacs.0c12194] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
![]()
Despite
the many methods available for the synthesis of furans,
few methods remain that allow for the custom-made assembly of fully
substituted furans. Here we report a powerful protocol to rapidly
construct tetrasubstituted, orthogonally functionalized furans under
mild reaction conditions. The developed method involves the regioselective
ring-opening of readily available 2,5-dihydrothiophenes followed by
an oxidative cyclization to provide the heterocycle. The selective
oxidation at sulfur is promoted by N-chlorosuccinimide
as an inexpensive reagent and proceeds at ambient temperature in high
yield within 30 min. The obtained furans serve as exceptionally versatile
intermediates and were shown to participate in a series of valuable
postmodifications. The fate of the initial sulfonium intermediate
was investigated by mechanistic experiments, and computational studies
revealed the existence of an unprecedented Pummerer-type rearrangement.
The potential for organic synthesis is highlighted by the total synthesis
of bisabolene sesquiterpenoids (pleurotins A, B, and D).
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20
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Abstract
Herein, we describe the first total synthesis of (+)-cornexistin as well as its 8-epi-isomer starting from malic acid. The robust and scalable route features a Nozaki-Hiyama-Kishi reaction, an auxiliary-controlled syn-Evans-aldol reaction, and a highly efficient intramolecular alkylation to form the nine-membered carbocycle. The delicate maleic anhydride moiety of the nonadride skeleton was constructed from a β-keto nitrile. The developed route enabled the synthesis of 165 mg (+)-cornexistin.
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Affiliation(s)
- Christian Steinborn
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Raphael E. Wildermuth
- Research and Early Development, Respiratory & ImmunologyAstraZeneca43183MölndalSweden
| | - David M. Barber
- Research & Development, Weed Control ChemistryBayer AG, Crop Science DivisionIndustriepark Höchst65926Frankfurt am MainGermany
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
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21
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Affiliation(s)
- Christian Steinborn
- Institute of Organic Chemistry and Center for Molecular Biosciences Leopold-Franzens-University Innsbruck Innrain 80–82 6020 Innsbruck Austria
| | - Raphael E. Wildermuth
- Research and Early Development, Respiratory & Immunology AstraZeneca 43183 Mölndal Sweden
| | - David M. Barber
- Research & Development, Weed Control Chemistry Bayer AG, Crop Science Division Industriepark Höchst 65926 Frankfurt am Main Germany
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences Leopold-Franzens-University Innsbruck Innrain 80–82 6020 Innsbruck Austria
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22
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Schmid M, Sokol KR, Wein LA, Torres Venegas S, Meisenbichler C, Wurst K, Podewitz M, Magauer T. Synthesis of Vicinal Quaternary All-Carbon Centers via Acid-catalyzed Cycloisomerization of Neopentylic Epoxides. Org Lett 2020; 22:6526-6531. [PMID: 32806198 PMCID: PMC7115968 DOI: 10.1021/acs.orglett.0c02296] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
We
report our studies on the development of a catalytic cycloisomerization
of 2,2-disubstituted neopentylic epoxides to produce highly substituted
tetralins and chromanes. Termination of the sequence occurs via Friedel–Crafts-type
alkylation of the remote (hetero)arene linker. The transformation
is efficiently promoted by sulfuric acid and proceeds best in 1,1,1,3,3,3-hexafluoroisopropanol
(HFIP) as the solvent. Variation of the substitution pattern provided
detailed insights into the migration tendencies and revealed a competing
disproportionation pathway of dihydronaphthalenes.
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Affiliation(s)
- Matthias Schmid
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Kevin R Sokol
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Lukas A Wein
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Sofia Torres Venegas
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Christina Meisenbichler
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Maren Podewitz
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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23
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Feilner JM, Wurst K, Magauer T. A Transannular Polyene Tetracyclization for Rapid Construction of the Pimarane Framework. Angew Chem Int Ed Engl 2020; 59:12436-12439. [PMID: 32167649 PMCID: PMC7383491 DOI: 10.1002/anie.202003127] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Indexed: 01/27/2023]
Abstract
Polyene cyclizations are one of the most powerful and fascinating chemical transformations to rapidly generate molecular complexity. However, cyclizations employing heteroatom-substituted polyenes are rare. Described here is the tetracyclization of a dual nucleophilic aryl enol ether involving an unprecedented transannular endo-termination step. In this transformation, five stereocenters, two of which are quaternary, four carbon-carbon bonds, and four six-membered rings are formed from a readily available cyclization precursor. The realization of this cyclization enabled short synthetic access to the tricyclic diterpenoid pimara-15-en-3α-8α-diol.
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Affiliation(s)
- Julian M. Feilner
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical ChemistryLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular BiosciencesLeopold-Franzens-University InnsbruckInnrain 80–826020InnsbruckAustria
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24
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Affiliation(s)
- Julian M. Feilner
- Institute of Organic Chemistry and Center for Molecular Biosciences Leopold-Franzens-University Innsbruck Innrain 80–82 6020 Innsbruck Austria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry Leopold-Franzens-University Innsbruck Innrain 80–82 6020 Innsbruck Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences Leopold-Franzens-University Innsbruck Innrain 80–82 6020 Innsbruck Austria
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25
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Wein LA, Wurst K, Angyal P, Weisheit L, Magauer T. Synthesis of (-)-Mitrephorone A via a Bioinspired Late Stage C-H Oxidation of (-)-Mitrephorone B. J Am Chem Soc 2019; 141:19589-19593. [PMID: 31770485 DOI: 10.1021/jacs.9b11646] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We present a bioinspired late-stage C-H oxidation of the ent-trachylobane natural product mitrephorone B to mitrephorone A. The realization of this unprecedented transformation was accomplished by either an iron-catalyzed or electrochemical oxidation and enabled access to the densely substituted oxetane in one step. Formation of mitrephorone C, which is lacking the central oxetane unit but features a keto-function at C2, was not formed under these conditions.
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Affiliation(s)
- Lukas Anton Wein
- Institute of Organic Chemistry and Center for Molecular Biosciences , Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry , Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Peter Angyal
- Institute of Organic Chemistry , Research Centre for Natural Sciences , Magyar tudósok körútja 2 , 1117 Budapest , Hungary
| | - Lara Weisheit
- Institute of Organic Chemistry and Center for Molecular Biosciences , Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences , Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
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26
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Haut FL, Habiger C, Speck K, Wurst K, Mayer P, Korber JN, Müller T, Magauer T. Synthetic Entry to Polyfunctionalized Molecules through the [3+2]-Cycloaddition of Thiocarbonyl Ylides. J Am Chem Soc 2019; 141:13352-13357. [PMID: 31408334 DOI: 10.1021/jacs.9b07729] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Here we present a comprehensive study on the [3+2]-cycloaddition of thiocarbonyl ylides with a wide variety of alkenes and alkynes. The obtained dihydro- and tetrahydrothiophene products serve as exceptionally versatile intermediates providing access to thiophenes, dienes, dendralenes, and vic-quarternary carbon centers. The use of high-pressure conditions enables thermally unstable, sterically encumbered or moderately reactive substrates to undergo the cycloaddition under mild conditions, thereby increasing the yield by up to 58%. In addition, we showcase its utility by the formal syntheses of the pharmaceuticals NGB 4420 and tenilapine.
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Affiliation(s)
- Franz-Lucas Haut
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Christoph Habiger
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Klaus Speck
- Department of Chemistry and Pharmacy , Ludwig-Maximilians-University Munich , Butenandtstrasse 5-13 , 81377 Munich , Germany
| | - Klaus Wurst
- Institute of General, Inorganic & Theoretical Chemistry, Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Peter Mayer
- Department of Chemistry and Pharmacy , Ludwig-Maximilians-University Munich , Butenandtstrasse 5-13 , 81377 Munich , Germany
| | - Johannes Nepomuk Korber
- Department of Chemistry and Pharmacy , Ludwig-Maximilians-University Munich , Butenandtstrasse 5-13 , 81377 Munich , Germany
| | - Thomas Müller
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
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27
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Abstract
We describe the evolution of a synthetic strategy for the construction of the marine polyketide salimabromide. Combining a bicyclo[3.1.0]hexan-2-one ring-expansion to build up a functionalized naphthalene and an unprecedented rearrangement/cyclization cascade, enabled synthesis of a dearomatized tricyclic subunit of the target compound. Alternatively, an intramolecular ketiminium [2+2]-cycloaddition and subsequent Baeyer-Villiger ring-expansion gave access to the sterically encumbered architecture of salimabromide. Sequential oxidation of the carbon framework finally enabled the total synthesis of this unusual natural product.
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Affiliation(s)
- Matthias Schmid
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstraße 5-13, Munich 81377, Germany
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Adriana S Grossmann
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstraße 5-13, Munich 81377, Germany
| | - Peter Mayer
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstraße 5-13, Munich 81377, Germany
| | - Thomas Müller
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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28
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Huber T, Wildermuth RE, Magauer T. Frontispiece: 9-Membered Carbocycles: Strategies and Tactics for their Synthesis. Chemistry 2018. [DOI: 10.1002/chem.201884761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tatjana Huber
- Department of Chemistry and Pharmacy; Ludwig-Maximillians University Munich; Butenandtstrasse 5-13 81377 Munich Germany
| | - Raphael E. Wildermuth
- Institute of Organic Chemistry and Center for Molecular Biosciences; University of Innsbruck; Innrain 80-82 6020 Innsbruck Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences; University of Innsbruck; Innrain 80-82 6020 Innsbruck Austria
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29
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Abstract
![]()
Salimabromide
is an antibiotic polyketide that was previously isolated
from the obligate marine myxobacterium Enhygromyxa
salina, and its densely functionalized and conformationally
rigid tetracyclic framework is unprecedented in nature. Herein we
report the first chemical synthesis of the target structure by employing
a series of well-orchestrated, robust transformations, highlighted
by an acid-promoted, powerful Wagner–Meerwein rearrangement/Friedel–Crafts
cyclization sequence to forge the two adjacent quaternary carbon centers
embedded in the tetrahydronaphthalene. A high-yielding ketiminium
mediated [2+2]-cycloaddition was also utilized for the simultaneous
construction of the remaining three stereocenters.
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Affiliation(s)
- Matthias Schmid
- Department of Chemistry , Ludwig-Maximilians-University Munich , Butenandtstrasse 5-13 , 81377 Munich , Germany.,Institute of Organic Chemistry and Center for Molecular Biosciences , University of Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Adriana S Grossmann
- Department of Chemistry , Ludwig-Maximilians-University Munich , Butenandtstrasse 5-13 , 81377 Munich , Germany
| | - Klaus Wurst
- Institute of General, Inorganic & Theoretical Chemistry , University of Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences , University of Innsbruck , Innrain 80-82 , 6020 Innsbruck , Austria
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30
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Haut FL, Speck K, Wildermuth R, Möller K, Mayer P, Magauer T. A Negishi cross-coupling reaction enables the total synthesis of (+)-stachyflin. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.02.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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31
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Abstract
Many natural products comprising a nine-membered carbocyclic core structure exhibit interesting biological effects. However, only a minority have succumbed to their synthesis in the past. The synthesis of functionalized nine-membered carbocycles still remains a challenging goal for synthetic chemists, mainly due to their high ring strain. Different strategies to overcome the unfavorable enthalpic and entropic factors associated with their formation are highlighted in this Concept article. The presented methods are classified into two different categories: (1) the ring-expansion of smaller rings or the ring-contraction of larger rings and (2) the direct cyclization of acyclic precursors.
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Affiliation(s)
- Tatjana Huber
- Department of Chemistry and Pharmacy, Ludwig-Maximillians University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Raphael E Wildermuth
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
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32
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Abstract
Benzannelated heterocycles such as indoles and indazoles are prominent structural motifs found in natural products, pharmaceuticals and agrochemicals. For their synthesis, chemists traditionally either functionalize commercially available heterocycles or resort to transformations that make use of benzene-derived building blocks. Here, we report a powerful cascade reaction that enables the de novo construction of variously substituted indoles, indazoles, benzofurans and benzothiophenes from readily available bicyclo[3.1.0]hexan-2-ones. The transformation can be conducted under mild, non-anhydrous conditions. For the synthesis of indoles, mechanistic studies revealed that the electrocyclic ring-opening of the bicyclic ring-system and aromatization precedes the 3,3-sigmatropic rearrangement.
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Affiliation(s)
- Johannes Feierfeil
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Thomas Magauer
- Institute of Organic Chemistry, Leopold-Franzens University, Innrain 80-82, 6020, Innsbruck, Austria
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33
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Affiliation(s)
- Tatjana Huber
- Department
of Chemistry and Pharmacy, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Teresa A. Preuhs
- Department
of Chemistry and Pharmacy, Ludwig-Maximilians-University, 81377 Munich, Germany
| | | | - Thomas Magauer
- Department
of Chemistry and Pharmacy, Ludwig-Maximilians-University, 81377 Munich, Germany
- Institute
of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
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34
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Abstract
Some recent examples of dyotropic rearrangements involved in complex natural product total synthesis and biosynthesis are highlighted.
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Affiliation(s)
| | - Thomas Magauer
- Department of Chemistry and Pharmacy
- Ludwig-Maximilians-Univeristy Munich
- 81377 Munich
- Germany
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35
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Abstract
Some recent examples of conceptually different bioinspired total syntheses of complex terpenoids are presented that highlight the numerous benefits of pursuing bioinspired strategies.
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Affiliation(s)
- Cedric L. Hugelshofer
- Department of Chemistry and Pharmacy
- Ludwig-Maximilians-University Munich
- 81377 Munich
- Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy
- Ludwig-Maximilians-University Munich
- 81377 Munich
- Germany
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36
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Abstract
We report a full account on the development of a unique cationic polyene cyclization for the total synthesis of the tetracyclic meroterpenoid (-)-cyclosmenospongine. A highly convergent three-component coupling strategy enabled rapid access to individual cyclization precursors that were tested for their reactivity. The successful transformation generates three rings and sets four consecutive stereocenters in a single operation proceeding in a highly efficient manner to give exclusively the trans-decalin framework. In addition, we found that the enol ether geometry and the relative configuration of C3 and C8 are crucial for the success of the polyene cyclization.
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Affiliation(s)
- Klaus Speck
- Department of Chemistry and Pharmacy, Ludwig Maximillians University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy, Ludwig Maximillians University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
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37
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Speck K, Wildermuth R, Magauer T. Convergent Assembly of the Tetracyclic Meroterpenoid (−)-Cyclosmenospongine by a Non-Biomimetic Polyene Cyclization. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608040] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Klaus Speck
- Department of Chemistry and Pharmacy; Ludwig Maximilians University Munich; Butenandtstrasse 5-13 81377 Munich Germany
| | - Raphael Wildermuth
- Department of Chemistry and Pharmacy; Ludwig Maximilians University Munich; Butenandtstrasse 5-13 81377 Munich Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy; Ludwig Maximilians University Munich; Butenandtstrasse 5-13 81377 Munich Germany
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38
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Speck K, Wildermuth R, Magauer T. Convergent Assembly of the Tetracyclic Meroterpenoid (-)-Cyclosmenospongine by a Non-Biomimetic Polyene Cyclization. Angew Chem Int Ed Engl 2016; 55:14131-14135. [PMID: 27730742 DOI: 10.1002/anie.201608040] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Indexed: 11/12/2022]
Abstract
The cationic cyclization of polyenes constitutes a powerful and elegant transformation, which has been utilized by nature's biosynthetic machinery for the construction of complex polycyclic terpenoids. Previous studies by chemists to mimic this cyclization in the laboratory were limited to different modes of activation using biosynthetic-like precursors, which accommodate only simple methyl-derived substituents. Here we describe the development of an unprecedented and highly efficient polyene cyclization of an aryl enol ether containing substrate. The cyclization was shown to proceed in a stepwise manner to generate three rings and three consecutive stereocenters, two of which are tetrasubstituted, in a single flask. The developed transformation is of great synthetic value and has enabled the convergent assembly of the tetracyclic meroterpenoid (-)-cyclosmenospongine.
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Affiliation(s)
- Klaus Speck
- Department of Chemistry and Pharmacy, Ludwig Maximilians University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Raphael Wildermuth
- Department of Chemistry and Pharmacy, Ludwig Maximilians University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy, Ludwig Maximilians University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany.
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39
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Hugelshofer CL, Magauer T. A Divergent Approach to the Marine Diterpenoids (+)-Dictyoxetane and (+)-Dolabellane V. Chemistry 2016; 22:15125-15136. [DOI: 10.1002/chem.201603061] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Cedric L. Hugelshofer
- Department of Chemistry and Pharmacy; Ludwig-Maximilians-University Munich; Butenandtstrasse 5-13 81377 Munich Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy; Ludwig-Maximilians-University Munich; Butenandtstrasse 5-13 81377 Munich Germany
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40
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Unzner TA, Grossmann AS, Magauer T. Rapid Access to Orthogonally Functionalized Naphthalenes: Application to the Total Synthesis of the Anticancer Agent Chartarin. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Teresa A. Unzner
- Department of Chemistry and Pharmacy; Ludwig-Maximilians-University Munich; Butenandtstrasse 5-13 81377 Munich Germany
| | - Adriana S. Grossmann
- Department of Chemistry and Pharmacy; Ludwig-Maximilians-University Munich; Butenandtstrasse 5-13 81377 Munich Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy; Ludwig-Maximilians-University Munich; Butenandtstrasse 5-13 81377 Munich Germany
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41
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Unzner TA, Grossmann AS, Magauer T. Rapid Access to Orthogonally Functionalized Naphthalenes: Application to the Total Synthesis of the Anticancer Agent Chartarin. Angew Chem Int Ed Engl 2016; 55:9763-7. [PMID: 27355517 DOI: 10.1002/anie.201605071] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Indexed: 12/14/2022]
Abstract
We report the synthesis of orthogonally functionalized naphthalenes from simple, commercially available indanones in four steps. The developed method proceeds through a two-step process that features a thermally induced fragmentation of a cyclopropane indanone with simultaneous 1,2-chloride shift. Migration of the chloride substituent occurs in a regioselective manner to preferentially afford the para-chloronaphthol substitution pattern. The obtained naphthols are versatile building blocks that can be selectively modified and used for the efficient construction of biologically active molecules. This has enabled the total synthesis of the potent anticancer natural product chartarin through a highly convergent retrosynthetic bond disconnection.
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Affiliation(s)
- Teresa A Unzner
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Adriana S Grossmann
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377, Munich, Germany.
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42
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Abstract
We have developed the first synthesis of the unique oxetane containing diterpene (+)-dictyoxetane. Our retrosynthetic planning was guided by the putative biosynthesis of the unprecedented 2,7-dioxatricyclo[4.2.1.0(3,8)]nonane ring system. A bioinspired 4-exo-tet, 5-exo-trig cyclization sequence enabled the construction of the synthetically challenging dioxatricyclic framework. The overall synthesis proceeds in 15 linear steps from a known and readily available trans-hydrindane fragment. In addition, we were able to realize the first dyotropic rearrangement of an epoxide-oxetane substrate.
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Affiliation(s)
- Cedric L Hugelshofer
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich , Butenandtstrasse 5-13, 81377, Munich, Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich , Butenandtstrasse 5-13, 81377, Munich, Germany
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43
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Magauer T, Wildermuth R, Speck K. Gold(I)-Catalyzed Enyne Cyclizations: Studies Toward the Total Synthesis of (+)-Aureol. SYNTHESIS-STUTTGART 2016. [DOI: 10.1055/s-0035-1561589] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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44
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Abstract
Trihaloethenes are versatile C2-building blocks that can be simply modified via addition, elimination and transition metal-catalyzed reactions.
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Affiliation(s)
- Adriana S. Grossmann
- Department of Chemistry
- Ludwig-Maximilians-Universität München
- 81377 München
- Germany
| | - Thomas Magauer
- Department of Chemistry
- Ludwig-Maximilians-Universität München
- 81377 München
- Germany
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45
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Huber T, Weisheit L, Magauer T. Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms. Beilstein J Org Chem 2015; 11:2521-2539. [PMID: 26734099 PMCID: PMC4685919 DOI: 10.3762/bjoc.11.273] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 11/27/2015] [Indexed: 11/29/2022] Open
Abstract
This review describes strategies for the chemical synthesis of xenicane diterpenoids and structurally related metabolites. Selected members from the four different subclasses of the Xenia diterpenoid family, the xenicins, xeniolides, xeniaphyllanes and xeniaethers, are presented. The synthetic strategies are discussed with an emphasis on the individual key reactions for the construction of the uncommon nine-membered carbocycle which is the characteristic structural feature of these natural products. Additionally, the putative biosynthetic pathway of xenicanes is illustrated.
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Affiliation(s)
- Tatjana Huber
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstraße 5-13, 81377 Munich, Germany
| | - Lara Weisheit
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstraße 5-13, 81377 Munich, Germany
| | - Thomas Magauer
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstraße 5-13, 81377 Munich, Germany
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46
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Adibekian A, Magauer T. The 50th EUCHEM Conference on Stereochemistry (Bürgenstock Conference 2015), Brunnen, April 26th–Mai 1st, 2015. Chimia (Aarau) 2015; 69:485-487. [DOI: 10.2533/chimia.2015.485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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47
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Feierfeil J, Grossmann A, Magauer T. Ring Opening of Bicyclo[3.1.0]hexan-2-ones: A Versatile Synthetic Platform for the Construction of Substituted Benzoates. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201506232] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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48
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Feierfeil J, Grossmann A, Magauer T. Ring Opening of Bicyclo[3.1.0]hexan-2-ones: A Versatile Synthetic Platform for the Construction of Substituted Benzoates. Angew Chem Int Ed Engl 2015; 54:11835-8. [PMID: 26255867 DOI: 10.1002/anie.201506232] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Indexed: 11/06/2022]
Abstract
Described is the development of a highly efficient 2π disrotatory ring-opening aromatization sequence using bicyclo[3.1.0]hexan-2-ones. This unprecedented transformation efficiently proceeds under thermal conditions and allows facile construction of uniquely substituted and polyfunctionalized benzoates. In the presence of either amines or alcohols formation of substituted anilines or ethers, respectively, is achieved. Additionally, the utility of this method was demonstrated in a short synthesis of sekikaic acid methyl ester.
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Affiliation(s)
- Johannes Feierfeil
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377 Munich
| | - Adriana Grossmann
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377 Munich
| | - Thomas Magauer
- Department of Chemistry and Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, 81377 Munich.
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49
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Speck K, Karaghiosoff K, Magauer T. Sequential O–H/C–H Bond Insertion of Phenols Initiated by the Gold(I)-Catalyzed Cyclization of 1-Bromo-1,5-enynes. Org Lett 2015; 17:1982-5. [DOI: 10.1021/acs.orglett.5b00738] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Klaus Speck
- Department
of Chemistry and
Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse
5-13, 81377 Munich, Germany
| | - Konstantin Karaghiosoff
- Department
of Chemistry and
Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse
5-13, 81377 Munich, Germany
| | - Thomas Magauer
- Department
of Chemistry and
Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse
5-13, 81377 Munich, Germany
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50
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Affiliation(s)
- Cedric L. Hugelshofer
- Department
of Chemistry and
Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse
5-13, 81377 Munich, Germany
| | - Thomas Magauer
- Department
of Chemistry and
Pharmacy, Ludwig-Maximilians-University Munich, Butenandtstrasse
5-13, 81377 Munich, Germany
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