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Isak D, Schwartz LA, Schulthoff S, Pérez-Moreno G, Bosch-Navarrete C, González-Pacanowska D, Fürstner A. Collective and Diverted Total Synthesis of the Strasseriolides: A Family of Macrolides Endowed with Potent Antiplasmodial and Antitrypanosomal Activity. Angew Chem Int Ed Engl 2024; 63:e202408725. [PMID: 38864359 DOI: 10.1002/anie.202408725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 06/13/2024]
Abstract
The strasseriolide macrolides show promising in vitro and in vivo activities against P. falciparum and T. cruzi, the parasites causing malaria and Chagas disease, respectively. However, the as yet poor understanding of structure/activity relationships and the fact that one family member proved systemically toxic for unknown reasons render a more detailed assessment of these potential lead compounds difficult. To help overcome these issues, a collective total synthesis was devised. The key steps consisted of a ring closing alkyne metathesis (RCAM) reaction to forge a common macrocyclic intermediate followed by a hydroxy-directed ruthenium catalyzed trans-hydrostannation of the propargyl alcohol site thus formed. The resulting alkenyltin derivative served as the central node of the synthesis blueprint, which could be elaborated into the natural products themselves as well as into a set of non-natural analogues according to the concept of diverted total synthesis. The recorded biological data confirmed the potency of the compounds and showed the lack of any noticeable cytotoxicity. The "northern" allylic alcohol subunit was recognized as an integral part of the pharmacophore, yet it provides opportunities for chemical modification.
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Affiliation(s)
- Daniel Isak
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
| | - Leyah A Schwartz
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
| | - Saskia Schulthoff
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
| | - Guiomar Pérez-Moreno
- Instituto de Parasitologia y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas, Avenida del Conocimiento 17 18016, Armilla, Granada, Spain
| | - Cristina Bosch-Navarrete
- Instituto de Parasitologia y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas, Avenida del Conocimiento 17 18016, Armilla, Granada, Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitologia y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas, Avenida del Conocimiento 17 18016, Armilla, Granada, Spain
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
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2
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Hess SN, Fürstner A. An Efficient and Scalable "Second Generation" Total Synthesis of the Marine Polyketide Limaol Endowed with Antiparasitic Activity. Chemistry 2024; 30:e202401429. [PMID: 38716817 DOI: 10.1002/chem.202401429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Indexed: 06/20/2024]
Abstract
The cluster of four skipped exo-methylene substituents on the "northern" wing of limaol renders this dinoflagellate-derived marine natural product unique in structural terms. This arguably non-thermodynamic array gains kinetic stability by virtue of populating local conformations which impede isomerization to a partly or fully conjugated polyene. This analysis suggested that the difficulties encountered during the late stages of our first total synthesis of this polyketide had not been caused by an overly fragile character of this unusual substructure; rather, an unfavorable steric microenvironment about the spirotricyclic core was identified as the likely cause. To remedy the issue, the protecting groups on this central fragment were changed; in effect, this amendment allowed all strategic and practical problems to be addressed. As a result, the overall yield over the longest linear sequence was multiplied by a factor of almost five and the material throughput increased more than eighty-fold per run. Key-to-success was a gold-catalyzed spirocyclization reaction; the reasons why a Brønsted acid cocatalyst is needed and the origin of the excellent levels of selectivity were delineated. The change of the protecting groups also allowed for much improved fragment coupling processes; most notably, the sequence of a substrate-controlled carbonyl addition reaction followed by Mitsunobu inversion that had originally been necessary to affix the southern tail to the core could be replaced by a reagent controlled asymmetric allylation. Finally, a much-improved route to the "northern" sector was established by leveraging the power of asymmetric hydrogenation of a 2-pyrone derivative. Limaol was found to combine appreciable antiparasitic activity with very modest cytotoxicity.
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Affiliation(s)
- Stephan N Hess
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
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3
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Deliaval M, Jayarajan R, Eriksson L, Szabó KJ. Three-Component Approach to Densely Functionalized Trifluoromethyl Allenols by Asymmetric Organocatalysis. J Am Chem Soc 2023; 145:10001-10006. [PMID: 37126044 PMCID: PMC10176480 DOI: 10.1021/jacs.3c02852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We have developed a new three-component catalytic coupling reaction of alkynyl boronates, diazomethanes, and aliphatic/aromatic ketones in the presence of BINOL derivatives. The reaction proceeds with a remarkably high enantio- and diastereoselectivity (up to three contiguous stereocenters) affording tertiary CF3-allenols in a single operational step. The reaction proceeds under mild, neutral, metal-free conditions, which leads to a high level of functional group tolerance.
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Affiliation(s)
- Marie Deliaval
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ramasamy Jayarajan
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Lars Eriksson
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Kálmán J Szabó
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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4
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Zachmann R, Yahata K, Holzheimer M, Jarret M, Wirtz C, Fürstner A. Total Syntheses of Nominal and Actual Prorocentin. J Am Chem Soc 2023; 145:2584-2595. [PMID: 36652728 PMCID: PMC9896551 DOI: 10.1021/jacs.2c12529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The dinoflagellate-derived polyether prorocentin is a co-metabolite of the archetypical serine/threonine phosphatase inhibitor okadaic acid. Whereas a structural relationship cannot be missed and a biosynthetic link was proposed, it is currently unknown whether there is any parallel in the bioactivity profile of these natural products. However, it was insinuated in the past that the structure assigned to prorocentin might need to be revised. Indeed, re-examination of the published spectra cast doubts as to the constitution of the fused/spirotricyclic BCD-ring system in the core. To clarify this issue, a flexible synthesis blueprint was devised that allowed us to obtain the originally proposed structure as well as the most plausible amended structure. The key to success was late-stage gold-catalyzed spirocyclization reactions that furnished the isomeric central segments with excellent selectivity. The lexicon of catalytic transformations used to make the required cyclization precursors comprised a titanium-mediated ester methylenation/metathesis cascade, a rare example of a gold-catalyzed allylic substitution, and chain extensions via organocatalytic asymmetric aldehyde propargylation. A wing sector to be attached to the isomeric cores was obtained by Krische allylation, followed by a superbly selective cobalt-catalyzed oxidative cyclization of the resulting di-unsaturated alcohol with the formation of a 2,5-trans-disubstituted tetrahydrofuran; the remaining terminal alkene was elaborated into an appropriate handle for fragment coupling by platinum-catalyzed asymmetric diboration/oxidation. The assembly of the different building blocks to the envisaged isomeric target compounds proved that the structure of prorocentin needs to be revised as disclosed herein.
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5
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Gribble GW. Naturally Occurring Organohalogen Compounds-A Comprehensive Review. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2023; 121:1-546. [PMID: 37488466 DOI: 10.1007/978-3-031-26629-4_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
The present volume is the third in a trilogy that documents naturally occurring organohalogen compounds, bringing the total number-from fewer than 25 in 1968-to approximately 8000 compounds to date. Nearly all of these natural products contain chlorine or bromine, with a few containing iodine and, fewer still, fluorine. Produced by ubiquitous marine (algae, sponges, corals, bryozoa, nudibranchs, fungi, bacteria) and terrestrial organisms (plants, fungi, bacteria, insects, higher animals) and universal abiotic processes (volcanos, forest fires, geothermal events), organohalogens pervade the global ecosystem. Newly identified extraterrestrial sources are also documented. In addition to chemical structures, biological activity, biohalogenation, biodegradation, natural function, and future outlook are presented.
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Affiliation(s)
- Gordon W Gribble
- Department of Chemistry, Dartmouth College, Hanover, NH, 03755, USA.
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6
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Bone Relat RM, Winder PL, Bowden GD, Guzmán EA, Peterson TA, Pomponi SA, Roberts JC, Wright AE, O’Connor RM. High-Throughput Screening of a Marine Compound Library Identifies Anti-Cryptosporidium Activity of Leiodolide A. Mar Drugs 2022; 20:md20040240. [PMID: 35447913 PMCID: PMC9026894 DOI: 10.3390/md20040240] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023] Open
Abstract
Cryptosporidium sp. are apicomplexan parasites that cause significant morbidity and possible mortality in humans and valuable livestock. There are no drugs on the market that are effective in the population most severely affected by this parasite. This study is the first high-throughput screen for potent anti-Cryptosporidium natural products sourced from a unique marine compound library. The Harbor Branch Oceanographic Institute at Florida Atlantic University has a collection of diverse marine organisms some of which have been subjected to medium pressure liquid chromatography to create an enriched fraction library. Numerous active compounds have been discovered from this library, but it has not been tested against Cryptosporidium parvum. A high-throughput in vitro growth inhibition assay was used to test 3764 fractions in the library, leading to the identification of 23 fractions that potently inhibited the growth of Cryptosporidium parvum. Bioassay guided fractionation of active fractions from a deep-sea sponge, Leiodermatium sp., resulted in the purification of leiodolide A, the major active compound in the organism. Leiodolide A displayed specific anti-Cryptosporidium activity at a half maximal effective concentration of 103.5 nM with selectivity indexes (SI) of 45.1, 11.9, 19.6 and 14.3 for human ileocecal colorectal adenocarcinoma cells (HCT-8), human hepatocellular carcinoma cells (Hep G2), human neuroblastoma cells (SH-SY5Y) and green monkey kidney cells (Vero), respectively. The unique structure of leiodolide A provides a valuable drug scaffold on which to develop new anti-Cryptosporidium compounds and supports the importance of screening natural product libraries for new chemical scaffolds.
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Affiliation(s)
- Rachel M. Bone Relat
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, 100 Dairy Rd, Pullman, WA 99164, USA; (R.M.B.R.); (G.D.B.)
| | - Priscilla L. Winder
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Gregory D. Bowden
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, 100 Dairy Rd, Pullman, WA 99164, USA; (R.M.B.R.); (G.D.B.)
| | - Esther A. Guzmán
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Tara A. Peterson
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Shirley A. Pomponi
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Jill C. Roberts
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Amy E. Wright
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
- Correspondence: (A.E.W.); (R.M.O.)
| | - Roberta M. O’Connor
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, 100 Dairy Rd, Pullman, WA 99164, USA; (R.M.B.R.); (G.D.B.)
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, 1971 Commonwealth Ave, St Paul, MN 55108, USA
- Correspondence: (A.E.W.); (R.M.O.)
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7
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Späth G, Fürstner A. Total Synthesis of Mycinamicin IV as Integral Part of a Collective Approach to Macrolide Antibiotics. Chemistry 2022; 28:e202104400. [PMID: 34910333 PMCID: PMC9305142 DOI: 10.1002/chem.202104400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Indexed: 11/09/2022]
Abstract
The total synthesis of the 16-membered macrolide mycinamicin IV is outlined, which complements our previously disclosed, largely catalysis-based route to the aglycone. This work must also be seen in the context of our recent conquest of aldgamycin N, a related antibiotic featuring a similar core but a distinctly different functionalization pattern. Taken together, these projects prove that the underlying blueprint is integrative and hence qualifies for a collective approach to this prominent class of natural products. In both cases, the final glycosylation phase mandated close attention and was accomplished only after robust de novo syntheses of the (di)deoxy sugars of the desosamine, chalcose, mycinose and aldgarose types had been established. Systematic screening of the glycosidation promoter was also critically important for success.
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Affiliation(s)
- Georg Späth
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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8
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Melot R, Saiegh TJ, Fürstner A. Regioselective trans-Hydrostannation of Boron-Capped Alkynes. Chemistry 2021; 27:17002-17011. [PMID: 34240757 PMCID: PMC9291331 DOI: 10.1002/chem.202101901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Indexed: 01/16/2023]
Abstract
Alkynyl-B(aam) (aam=anthranilamidato) derivatives are readily available bench-stable compounds that undergo remarkably selective reactions with Bu3 SnH in the presence of [Cp*RuCl]4 as the catalyst. The addition follows a stereochemically unorthodox trans-selective course; in terms of regioselectivity, the Bu3 Sn- unit is delivered with high fidelity to the C-atom of the triple bond adjacent to the boracyclic head group ("alpha,trans-addition"). This outcome is deemed to reflect a hydrogen bonding interaction between the protic -NH groups of the benzo-1,3,2-diazaborininone ring system and the polarized [Ru-Cl] bond in the loaded catalyst, which locks the substrate in place in a favorable orientation relative to the incoming reagent. The resulting isomerically (almost) pure gem-dimetalated building blocks are amenable to numerous downstream functionalizations; most remarkable is the ability to subject the -B(aam) moiety to Suzuki-Miyaura cross coupling without need for prior hydrolysis while keeping the adjacent Bu3 Sn- group intact. Alternatively, the tin residue can be engaged in selective tin/halogen exchange without touching the boron substituent; the fact that the two -NH entities of -B(aam) do not protonate organozinc reagents and hence do not interfere with Negishi reactions of the alkenyl halides thus formed is another virtue of this so far underutilized boracycle. Overall, the ruthenium catalyzed trans-hydrostannation of alkynyl-B(aam) derivatives opens a practical gateway to isomerically pure trisubstituted alkenes of many different substitution patterns by sequential functionalization of the 1-alkenyl-1,1-heterobimetallic adducts primarily formed.
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Affiliation(s)
- Romain Melot
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Tomas J. Saiegh
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
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9
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Alonso JM, Almendros P. Deciphering the Chameleonic Chemistry of Allenols: Breaking the Taboo of a Onetime Esoteric Functionality. Chem Rev 2021; 121:4193-4252. [PMID: 33630581 PMCID: PMC8479864 DOI: 10.1021/acs.chemrev.0c00986] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Indexed: 12/19/2022]
Abstract
The allene functionality has participated in one of the most exciting voyages in organic chemistry, from chemical curiosities to a recurring building block in modern organic chemistry. In the last decades, a special kind of allene, namely, allenol, has emerged. Allenols, formed by an allene moiety and a hydroxyl functional group with diverse connectivity, have become common building blocks for the synthesis of a wide range of structures and frequent motif in naturally occurring systems. The synergistic effect of the allene and hydroxyl functional groups enables allenols to be considered as a unique and sole functionality exhibiting a special reactivity. This Review summarizes the most significant contributions to the chemistry of allenols that appeared during the past decade, with emphasis on their synthesis, reactivity, and occurrence in natural products.
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Affiliation(s)
- José M. Alonso
- Grupo
de Lactamas y Heterociclos Bioactivos, Departamento de Química
Orgánica, Unidad Asociada al CSIC, Facultad de Química, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Pedro Almendros
- Instituto
de Química Orgánica General, IQOG-CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
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10
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Herlé B, Späth G, Schreyer L, Fürstner A. Total Synthesis of Mycinolide IV and Path‐Scouting for Aldgamycin N. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Bart Herlé
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Georg Späth
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Lucas Schreyer
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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Späth G, Fürstner A. Scalable De Novo Synthesis of Aldgarose and Total Synthesis of Aldgamycin N. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Georg Späth
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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12
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Herlé B, Späth G, Schreyer L, Fürstner A. Total Synthesis of Mycinolide IV and Path-Scouting for Aldgamycin N. Angew Chem Int Ed Engl 2021; 60:7893-7899. [PMID: 33448619 PMCID: PMC8048839 DOI: 10.1002/anie.202016475] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/13/2021] [Indexed: 12/19/2022]
Abstract
Proof-of-concept is provided that a large estate of 16-membered macrolide antibiotics can be reached by a "unified" approach. The key building block was formed on scale by an asymmetric vinylogous Mukaiyama aldol reaction; its alkene terminus was then converted either into the corresponding methyl ketone by Wacker oxidation or into a chain-extended aldehyde by catalyst-controlled branch-selective asymmetric hydroformylation. These transformations ultimately opened access to two structurally distinct series of macrolide targets. Notable late-stage maneuvers comprise a rare example of a ruthenium-catalyzed redox isomerization of an 1,3-enyne-5-ol into a 1,3-diene-5-one derivative, as well as the elaboration of a tertiary propargylic alcohol into an acyloin by trans-hydrostannation/Chan-Lam-type coupling. Moreover, this case study illustrates the underutilized possibility of forging complex macrolactone rings by transesterification under essentially neutral conditions.
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Affiliation(s)
- Bart Herlé
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Georg Späth
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Lucas Schreyer
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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13
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Späth G, Fürstner A. Scalable De Novo Synthesis of Aldgarose and Total Synthesis of Aldgamycin N. Angew Chem Int Ed Engl 2021; 60:7900-7905. [PMID: 33448589 PMCID: PMC8048874 DOI: 10.1002/anie.202016477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/13/2021] [Indexed: 12/25/2022]
Abstract
Since the accompanying study had shown that the introduction of the eponymous aldgarose sugar to the C5-OH group of the macrocyclic aglycone of aldgamycin N is most difficult, if not even impossible, the synthesis route was revised and the glycosidation performed at an earlier stage. To mitigate the "cost" of this strategic amendment, a practical and scalable de novo synthesis of this branched octose was developed. The glycoside formation required mild conditions; it commenced with the reaction of the aglycone with the trichloroacetimidate donor to give a transient orthoester, which slowly rearranged to the desired aldgaropyranoside. The presence of the polar peripheral groups in the product did not impede the selective late-stage functionalization of the macrolide ring itself: the contained propargylic alcohol entity was readily transformed into the characteristic acyloin motif of the target by a ruthenium-catalyzed trans-hydrostannation followed by a modified Chan-Lam-type coupling.
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Affiliation(s)
- Georg Späth
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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14
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Abstract
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A nonthermodynamic array of four skipped methylene substituents on the hydrophobic tail
renders limaol, a C40-polyketide of marine origin, unique in structural terms. This
conspicuous segment was assembled by a two-directional approach and finally coupled to
the polyether domain by an allyl/alkenyl Stille reaction under neutral conditions. The
core region itself was prepared via a 3,3′-dibromo-BINOL-catalyzed asymmetric
propargylation, a gold-catalyzed spirocyclization, and introduction of the southern
sector via substrate-controlled allylation as the key steps.
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Affiliation(s)
- Stephan N Hess
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Xiaobin Mo
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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15
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Schulthoff S, Hamilton JY, Heinrich M, Kwon Y, Wirtz C, Fürstner A. The Formosalides: Structure Determination by Total Synthesis. Angew Chem Int Ed Engl 2021; 60:446-454. [PMID: 32946141 PMCID: PMC7821135 DOI: 10.1002/anie.202011472] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Indexed: 01/08/2023]
Abstract
Total synthesis allowed the constitution of the cytotoxic marine macrolides of the formosalide family to be confirmed and their previously unknown stereostructure to be assigned with confidence. The underlying blueprint was inherently modular to ensure that each conceivable isomer could be reached. This flexibility derived from the use of strictly catalyst controlled transformations to set the stereocenters, except for the anomeric position, which is under thermodynamic control; as an extra safety measure, all stereogenic centers were set prior to ring closure to preclude any interference of the conformation adopted by the macrolactone rings of the different diastereomers. Late-stage macrocyclization by ring-closing alkyne metathesis was followed by a platinum-catalyzed transannular 6-exo-dig hydroalkoxylation/ketalization to craft the polycyclic frame. The side chain featuring a very labile unsaturation pattern was finally attached to the core by Stille coupling.
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Affiliation(s)
| | | | - Marc Heinrich
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Yonghoon Kwon
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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16
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Schulthoff S, Hamilton JY, Heinrich M, Kwon Y, Wirtz C, Fürstner A. The Formosalides: Structure Determination by Total Synthesis. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202011472] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
| | | | - Marc Heinrich
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Yonghoon Kwon
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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17
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Heinrich M, Murphy JJ, Ilg MK, Letort A, Flasz JT, Philipps P, Fürstner A. Chagosensine: A Riddle Wrapped in a Mystery Inside an Enigma. J Am Chem Soc 2020; 142:6409-6422. [PMID: 32142305 PMCID: PMC7307910 DOI: 10.1021/jacs.0c01700] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Indexed: 01/02/2023]
Abstract
The marine macrolide chagosensine is supposedly distinguished by a (Z,Z)-configured 1,3-chlorodiene contained within a highly strained 16-membered lactone ring, which also incorporates two trans-2,5-disubstituted tetrahydrofuran (THF) rings; this array is unique. After our initial synthesis campaign had shown that the originally proposed structure is incorrect, the published data set was critically revisited to identify potential mis-assignments. The "northern" THF ring and the anti-configured diol in the "southern" sector both seemed to be sites of concern, thus making it plausible that a panel of eight diastereomeric chagosensine-like compounds would allow the puzzle to be solved. To meet the challenge, the preparation of the required building blocks was optimized, and a convergent strategy for their assembly was developed. A key role was played by the cobalt-catalyzed oxidative cyclization of alken-5-ol derivatives ("Mukaiyama cyclization"), which is shown to be exquisitely chemoselective for terminal alkenes, leaving even terminal alkynes (and other sites of unsaturation) untouched. Likewise, a palladium-catalyzed alkyne alkoxycarbonylation reaction with formation of an α-methylene-γ-lactone proved instrumental, which had not found application in natural product synthesis before. Further enabling steps were a nickel-catalyzed "Tamaru-type" homocrotylation, stereodivergent aldehyde homologations, radical hydroindation, and palladium-catalyzed alkyne-1,2-bis-stannation. The different building blocks were assembled in a serial fashion to give the idiosyncratic chlorodienes by an unprecedented site-selective Stille coupling followed by copper-mediated tin/chlorine exchange. The macrolactones were closed under forcing Yamaguchi conditions, and the resulting products were elaborated into the targeted compound library. Yet, only one of the eight diastereomers turned out to be stable in the solvent mixture that had been used to analyze the natural product; all other isomers were prone to ring opening and/or ring expansion. In addition to this stability issue, our self-consistent data set suggests that chagosensine has almost certainly little to do with the structure originally proposed by the isolation team.
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Affiliation(s)
| | | | - Marina K. Ilg
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Aurélien Letort
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Jakub T. Flasz
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Petra Philipps
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
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18
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Abstract
The synthesis of the macrocyclic core of the cytotoxic natural product salarin C from the sponge Fascaplysinopsis sp. is described, with the two epoxides being replaced by alkene moieties. In the key step, ring-closing metathesis exclusively afforded the ( E)-product. NOESY-based conformational analysis of the macrolactone showed that the oxazole ring and its unsaturated side chains are located in a common plane. Mimicking the conversion of salarin C to salarin A, the trisubstituted oxazole unit embedded in the 17-membered ring underwent photooxidation on treatment with singlet oxygen, affording macrocyclic trisacylamines.
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Affiliation(s)
- Jan-Niklas Schäckermann
- TU Braunschweig , Institute of Organic Chemistry , Hagenring 30 , 38106 Braunschweig , Germany
| | - Thomas Lindel
- TU Braunschweig , Institute of Organic Chemistry , Hagenring 30 , 38106 Braunschweig , Germany
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19
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Dachavaram SS, Penthala NR, Calahan JL, Munson EJ, Crooks PA. Highly sulphated cellulose: a versatile, reusable and selective desilylating agent for deprotection of alcoholic TBDMS ethers. Org Biomol Chem 2018; 16:6057-6062. [PMID: 30090907 DOI: 10.1039/c8ob01438h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A mild, efficient and rapid protocol was developed for the deprotection of alcoholic TBDMS ethers using a recyclable, eco-friendly highly sulphated cellulose sulphate acid catalyst in methanol. This acid catalyst selectively cleaves alcoholic TBDMS ethers in bis-TBDMS ethers containing both alcoholic and phenolic TBDMS ether moieties.
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Affiliation(s)
- Soma Shekar Dachavaram
- Department of Pharmaceutical Sciences College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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20
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Zhuo CX, Fürstner A. Catalysis-Based Total Syntheses of Pateamine A and DMDA-Pat A. J Am Chem Soc 2018; 140:10514-10523. [PMID: 30056701 DOI: 10.1021/jacs.8b05094] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The marine natural product pateamine A (1) and its somewhat simplified designer analogue DMDA-Pat A (2) (DMDA = desmethyl-desamino) are potently cytotoxic compounds; most notably, 2 had previously been found to exhibit a promising differential in vivo activity in xenograft melanoma models, even though the ubiquitous eukaryotic initiation factor 4A (eIF4A) constitutes its primary biological target. In addition, 1 had also been identified as a possible lead in the quest for medication against cachexia, an often lethal muscle wasting syndrome affecting many immunocompromised or cancer patients. The short supply of these macrodiolides, however, rendered a more detailed biological assessment difficult. Therefore, a new synthetic approach to 1 and 2 has been devised, which centers on an unorthodox strategy for the formation of the highly isomerization-prone but essential Z, E-configured dienoate substructure embedded into the macrocyclic core. This motif was encoded in the form of a 2-pyrone ring and unveiled only immediately before macrocyclization by an unconventional iron-catalyzed ring opening/cross-coupling reaction, in which the enol ester entity of the pyrone gains the role of a leaving group. Since the required precursor was readily available by gold catalysis, this strategy rendered the overall sequence short, robust, and scalable. A surprisingly easy protecting group management together with a much improved end game for the formation of the trienyl side chain via a modern Stille coupling protocol also helped to make the chosen route practical. Change of a single building block allowed the synthesis to be redirected from the natural lead compound 1 toward its almost equipotent analogue 2. Isolation and reactivity profiling of pyrone tricarbonyliron complexes provide mechanistic information as well as insights into the likely origins of the observed chemoselectivity.
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Affiliation(s)
- Chun-Xiang Zhuo
- Max-Planck-Institut für Kohlenforschung , D-45470 Mülheim/Ruhr , Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung , D-45470 Mülheim/Ruhr , Germany
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21
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Fürstner A. Gold-Katalyse für die Heterocyclenchemie: eine repräsentative Fallstudie zu Naturstoffen der Pyron-Reihe. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201707260] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alois Fürstner
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Deutschland
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22
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Fürstner A. Gold Catalysis for Heterocyclic Chemistry: A Representative Case Study on Pyrone Natural Products. Angew Chem Int Ed Engl 2017; 57:4215-4233. [PMID: 28862364 DOI: 10.1002/anie.201707260] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Indexed: 11/06/2022]
Abstract
2-Pyrones and 4-pyrones are common structural motifs in bioactive natural products. However, traditional methods for their synthesis, which try to emulate the biosynthetic pathway of cyclization of a 1,3,5-tricarbonyl precursor, are often harsh and, therefore, not particularly suitable for applications to polyfunctionalized and/or sensitive target compounds. π-Acid catalysis, in contrast, has proved to be better for a systematic exploration of the pyrone estate. To this end, alkynes are used as stable ketone surrogates, which can be activated under exceedingly mild conditions due to the pronounced carbophilicity of [LAu]+ fragments (L=two electron donor ligand); attack of a tethered ester carbonyl group onto the transient alkyne-gold complex then forges the pyrone ring in a fully regiocontrolled manner.
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Affiliation(s)
- Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
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23
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Huwyler N, Radkowski K, Rummelt SM, Fürstner A. Two Enabling Strategies for the Stereoselective Conversion of Internal Alkynes into Trisubstituted Alkenes. Chemistry 2017; 23:12412-12419. [DOI: 10.1002/chem.201702470] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Nikolas Huwyler
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Karin Radkowski
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | | | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
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24
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Polyunsaturated C-Glycosidic 4-Hydroxy-2-pyrone Derivatives: Total Synthesis Shows that Putative Orevactaene Is Likely Identical with Epipyrone A. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201702189] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Preindl J, Schulthoff S, Wirtz C, Lingnau J, Fürstner A. Polyunsaturated C-Glycosidic 4-Hydroxy-2-pyrone Derivatives: Total Synthesis Shows that Putative Orevactaene Is Likely Identical with Epipyrone A. Angew Chem Int Ed Engl 2017; 56:7525-7530. [DOI: 10.1002/anie.201702189] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/03/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Johannes Preindl
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | | | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Julia Lingnau
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
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26
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Schäckermann JN, Lindel T. Synthesis and Photooxidation of the Trisubstituted Oxazole Fragment of the Marine Natural Product Salarin C. Org Lett 2017; 19:2306-2309. [PMID: 28425712 DOI: 10.1021/acs.orglett.7b00845] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The eastern section of the macrocyclic marine natural product salarin C from the sponge Fascaplysinopsis sp. was synthesized employing a halogen dance reaction to assemble the trisubstituted oxazole moiety. The synthesis was inspired by Kashman's hypothesis on the biomimetic oxidation of salarin C to salarin A. Clean conversion to the triacylamine partial structure of salarin A occurred on treatment with photochemically generated singlet oxygen. Thus, a Wasserman-type oxidative rearrangement is chemically possible in this case.
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Affiliation(s)
| | - Thomas Lindel
- TU Braunschweig, Institute of Organic Chemistry , Hagenring 30, 38106 Braunschweig, Germany
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27
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Zhang YY, Wei Y, Tang XY, Shi M. Dual-role of PtCl2 catalysis in the intramolecular cyclization of (hetero)aryl-allenes for the facile construction of substituted 2,3-dihydropyrroles and polyheterocyclic skeletons. Chem Commun (Camb) 2017; 53:5966-5969. [DOI: 10.1039/c7cc01684k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel PtCl2-catalyzed cyclization of (hetero)aryl-allenes has been developed, providing controllable and facile synthesis of substituted 2,3-dihydropyrroles and polyheterocyclic skeletons in moderate to good yields.
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Affiliation(s)
- Yan-Yan Zhang
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- University of Chinese Academy of Sciences
- Shanghai
- P. R. China
| | - Yin Wei
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- University of Chinese Academy of Sciences
- Shanghai
- P. R. China
| | - Xiang-Ying Tang
- School of Chemistry and Chemical Engineering
- Huazhong University of Science and Technology
- Wuhan
- China
| | - Min Shi
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- University of Chinese Academy of Sciences
- Shanghai
- P. R. China
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28
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Sommer H, Fürstner A. Stereospecific Synthesis of Fluoroalkenes by Silver-Mediated Fluorination of Functionalized Alkenylstannanes. Chemistry 2016; 23:558-562. [PMID: 27883234 DOI: 10.1002/chem.201605444] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Indexed: 12/21/2022]
Abstract
The known procedures for the conversion of alkenylstannanes into the corresponding fluoroalkenes suffer from largely variable yields and a limited compatibility with functional groups; most notably, protodestannation becomes a serious issue whenever protic sites are present in the substrate. Outlined in this paper is a convenient alternative with a much improved application profile, which is largely unperturbed by free alcohols and amides of all sorts. Key to success is the use of F-TEDA-PF6 in combination with non-hygroscopic and bench-stable silver phosphinate (AgOP(O)Ph2 ) that acts as an essentially neutral, non-nucleophilic promotor and effective tin-scavenger at the same time. This new method opens many opportunities for late-stage fluorination of elaborate compounds far beyond the scope of the literature procedures, as witnessed by the preparation of a fluorinated macrolide antibiotic, a fluorinated prostaglandin derivative, and a set of fluorinated amino acid surrogates and peptide isosteres.
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Affiliation(s)
- Heiko Sommer
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
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29
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Zhuo C, Fürstner A. Concise Synthesis of a Pateamine A Analogue with In Vivo Anticancer Activity Based on an Iron‐Catalyzed Pyrone Ring Opening/Cross‐Coupling. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201602125] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Chun‐Xiang Zhuo
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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30
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Zhuo C, Fürstner A. Concise Synthesis of a Pateamine A Analogue with In Vivo Anticancer Activity Based on an Iron‐Catalyzed Pyrone Ring Opening/Cross‐Coupling. Angew Chem Int Ed Engl 2016; 55:6051-6. [DOI: 10.1002/anie.201602125] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Chun‐Xiang Zhuo
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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31
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Watanabe K, Li J, Veerasamy N, Ghosh A, Carter RG. Stereoselective, Ag-Catalyzed Cyclizations To Access Polysubstituted Pyran Ring Systems: Synthesis of C1-C12 Subunit of Madeirolide A. Org Lett 2016; 18:1744-7. [PMID: 27031993 DOI: 10.1021/acs.orglett.6b00414] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The exploration into the scope of a silver-catalyzed cyclization (AgCC) of propargyl benzoates for accessing pyran ring systems has been reported. The impact of the degree of substitution, nature of the substitution on the carbon backbone/benzoate moiety, and stereochemistry has been evaluated. The application of this methodology to the synthesis of the C1-C12 southern fragment of madeirolide A is disclosed.
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Affiliation(s)
- Kazuhiro Watanabe
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Jinming Li
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Nagarathanam Veerasamy
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Ankan Ghosh
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Rich G Carter
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
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32
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Frihed TG, Fürstner A. Progress in the trans-Reduction and trans-Hydrometalation of Internal Alkynes. Applications to Natural Product Synthesis. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2016. [DOI: 10.1246/bcsj.20150317] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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33
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Lee J, Panek JS. Synthesis of the C13–C29 fragment of leiodolide A: allylic asymmetric induction on the stereochemical course of iodolactonization. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.10.087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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34
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Kim JH, Kim SW, Jung MS, Ahn KH, Kang EJ. Regioselectivities in Fe(III)-catalyzed Cycloisomerization Reactions of γ-Allenyl Alcohols. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10581] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Jae Hyung Kim
- Department of Applied Chemistry; Kyung Hee University; Yongin 449-701 Korea
| | - Seung Wook Kim
- Department of Applied Chemistry; Kyung Hee University; Yongin 449-701 Korea
| | - Min Seok Jung
- Department of Applied Chemistry; Kyung Hee University; Yongin 449-701 Korea
| | - Kwang-Hyun Ahn
- Department of Applied Chemistry; Kyung Hee University; Yongin 449-701 Korea
| | - Eun Joo Kang
- Department of Applied Chemistry; Kyung Hee University; Yongin 449-701 Korea
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35
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Irie R, Uchida T, Matsumoto K. Katsuki Catalysts for Asymmetric Oxidation: Design Concepts, Serendipities for Breakthroughs, and Applications. CHEM LETT 2015. [DOI: 10.1246/cl.150747] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ryo Irie
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University
| | - Tatsuya Uchida
- Faculty of Arts and Science, Kyushu University, and International Institute of Carbon-Neutral Energy Research (I2CNER)
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36
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Willwacher J, Heggen B, Wirtz C, Thiel W, Fürstner A. Total Synthesis, Stereochemical Revision, and Biological Reassessment of Mandelalide A: Chemical Mimicry of Intrafamily Relationships. Chemistry 2015; 21:10416-30. [PMID: 26094957 DOI: 10.1002/chem.201501491] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 11/06/2022]
Abstract
Mandelalide A and three congeners had recently been isolated as the supposedly highly cytotoxic principles of an ascidian collected off the South African coastline. Since these compounds are hardly available from the natural source, a concise synthesis route was developed, targeting structure 1 as the purported representation of mandelalide A. The sequence involves an iridium-catalyzed two-directional Krische allylation and a cobalt-catalyzed carbonylative epoxide opening as entry points for the preparation of the major building blocks. The final stages feature the first implementation of terminal acetylene metathesis into natural product total synthesis, which is remarkable in that this class of substrates had been beyond the reach of alkyne metathesis for decades. Synthetic 1, however, proved not to be identical with the natural product. In an attempt to clarify this issue, NMR spectra were simulated for 20 conceivable diastereomers by using DFT followed by DP4 analysis; however, this did not provide a reliable assignment either. The puzzle was ultimately solved by the preparation of three diastereomers, of which compound 6 proved identical with mandelalide A in all analytical and spectroscopic regards. As the entire "northern sector" about the tetrahydrofuran ring in 6 shows the opposite configuration of what had originally been assigned, it is highly likely that the stereostructures of the sister compounds mandelalides B-D must be corrected analogously; we propose that these natural products are accurately represented by structures 68-70. In an attempt to prove this reassignment, an entry into mandelalides C and D was sought by subjecting an advanced intermediate of the synthesis of 6 to a largely unprecedented intramolecular Morita-Baylis-Hillman reaction, which furnished the γ-lactone derivative 74 as a mixture of diastereomers. Whereas (24R)-74 was amenable to a hydroxyl-directed dihydroxylation by using OsO4 /TMEDA as the reagent, the sister compound (24S)-74 did not follow a directed path but simply obeyed Kishi's rule; only this unexpected escape precluded the preparation of mandelalides C and D by this route. A combined spectroscopic and computational (DFT) study showed that the reasons for this strikingly different behavior of the two diastereomers of 74 are rooted in their conformational peculiarities. This aspect apart, our results show that the OsO4 /TMEDA complex reacts preferentially with electron deficient double bonds even if other alkenes are present that are more electron rich and less encumbered. Finally, in a brief biological survey authentic mandelalide A (6) was found to exhibit appreciable cytotoxicity only against one out of three tested human cancer cell lines and all synthetic congeners were hardly active. No significant fungicidal properties were observed.
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Affiliation(s)
- Jens Willwacher
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr (Germany)
| | - Berit Heggen
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr (Germany)
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr (Germany)
| | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr (Germany)
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr (Germany).
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37
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Rummelt SM, Preindl J, Sommer H, Fürstner A. Selective Formation of a Trisubstituted Alkene Motif bytrans-Hydrostannation/Stille Coupling: Application to the Total Synthesis and Late-Stage Modification of 5,6-Dihydrocineromycin B. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201501608] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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38
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Rummelt SM, Preindl J, Sommer H, Fürstner A. Selective Formation of a Trisubstituted Alkene Motif bytrans-Hydrostannation/Stille Coupling: Application to the Total Synthesis and Late-Stage Modification of 5,6-Dihydrocineromycin B. Angew Chem Int Ed Engl 2015; 54:6241-5. [DOI: 10.1002/anie.201501608] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 03/10/2015] [Indexed: 12/20/2022]
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39
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Valot G, Mailhol D, Regens CS, O'Malley DP, Godineau E, Takikawa H, Philipps P, Fürstner A. Concise Total Syntheses of Amphidinolides C and F. Chemistry 2014; 21:2398-408. [DOI: 10.1002/chem.201405790] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Indexed: 01/23/2023]
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40
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41
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Mailhol D, Willwacher J, Kausch-Busies N, Rubitski EE, Sobol Z, Schuler M, Lam MH, Musto S, Loganzo F, Maderna A, Fürstner A. Synthesis, Molecular Editing, and Biological Assessment of the Potent Cytotoxin Leiodermatolide. J Am Chem Soc 2014; 136:15719-29. [DOI: 10.1021/ja508846g] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Damien Mailhol
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Jens Willwacher
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | | | - Elizabeth E. Rubitski
- Pfizer Drug Safety Research and Development, 445 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Zhanna Sobol
- Pfizer Drug Safety Research and Development, 445 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Maik Schuler
- Pfizer Drug Safety Research and Development, 445 Eastern Point Road, Groton, Connecticut 06340, United States
| | - My-Hanh Lam
- Pfizer Oncology, 401 North Middletown
Road, Pearl River, New York 10965, United States
| | - Sylvia Musto
- Pfizer Oncology, 401 North Middletown
Road, Pearl River, New York 10965, United States
| | - Frank Loganzo
- Pfizer Oncology, 401 North Middletown
Road, Pearl River, New York 10965, United States
| | - Andreas Maderna
- Pfizer Oncology Medicinal Chemistry, 445 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
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Voronova K, Homolya L, Udvardy A, Bényei AC, Joó F. Pd-tetrahydrosalan-type complexes as catalysts for sonogashira couplings in water: efficient greening of the procedure. CHEMSUSCHEM 2014; 7:2230-2239. [PMID: 24995656 DOI: 10.1002/cssc.201402147] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Indexed: 06/03/2023]
Abstract
New sulfonated tetrahydrosalen-type ligands and their water-soluble palladium(II) complexes have been synthesized. The palladium(II) complexes catalyze the Sonogashira coupling (23 examples) of various aryl halides (including chloroarenes) with terminal alkynes, with good to excellent conversions under mild conditions (80°C, air, no Cu(I) cocatalyst) in aqueous-organic mixtures and turnover frequencies of up to 2790 h(-1) . Under optimized reaction conditions to minimize environmental contamination, diphenylacetylenes can be isolated in 76-98% yield. The aqueous catalyst solution can be recycled four times with decreasing activity; however, yields between 93 and 98% can still be achieved with extended reaction times. Several water-insoluble products can be isolated in excellent yield by simple filtration and purification by washing with water; this method is used, for the first time, for this type of C-C coupling procedure.
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Affiliation(s)
- Krisztina Voronova
- Department of Physical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen (Hungary); Current address: Department of Chemistry, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211 (USA).
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43
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Fürstner A. From understanding to prediction: gold- and platinum-based π-acid catalysis for target oriented synthesis. Acc Chem Res 2014; 47:925-38. [PMID: 24279341 DOI: 10.1021/ar4001789] [Citation(s) in RCA: 301] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
During the last century, conceptual advances in organometallic chemistry were often rapidly embraced by target oriented synthesis. Feedback provided by such preparative scrutiny has greatly benefitted method development; particularly prominent are examples from the entire cross coupling arena, as well as olefin metathesis. Seen against this backdrop, it is somewhat surprising that the explosive growth of research into π-acid catalysis has not yet yielded a matching number of implementations into the synthesis of structurally complex targets of biological significance. In contrast to the massive output of methodological and mechanistic investigations, few studies illustrate the strategic use of gold, silver, or platinum catalysis in late stages of such multistep endeavors. These elaborate and highly precious compounds demand utmost confidence in the reliability and robustness of the method to be applied. In this Account, we analyze the possible reasons for this imbalance, after a short summary of the conceptual basis of carbophilic activation of π-bonds with the aid of soft transition metal cations or complexes. We pinpoint mechanistic subtleties, which, at least in part, produce a great deal of structural diversity but can jeopardize predictive power. With the advances in the understanding of π-acid catalyzed processes in general, however, this uncertainty is gradually vanishing and the entire field is transitioning from comprehension to prediction. This is expected to foster advanced applications, while recent progress in asymmetric gold catalysis further improves the preparative significance. The presented work in this Account illustrates our own commitment to the field as well as our growing confidence in the maturity of platinum and gold catalysis. The carbophilic activation of π-bonds, particularly of alkynes, provides a method to manipulate functional groups that is orthogonal to traditional carbonyl chemistry. We illustrate this notion by presenting a new approach to hydroxypyrone derivatives that has enabled the total synthesis of the fragile polyunsaturated cyclophane derivative neurymenolide A. The synthesis of the pyrrole alkaloid streptorubin by an enyne cycloisomerization is equally instructive. In addition, different manifestations of transannular hydroxyl addition reactions across alkyne partners mark the late stages of our conquests of amphidinolide F, polycavernoside A, and spirastrellolide F. Together with a few model studies and a personal selection of recent highlights from other groups, these examples augur well for future applications of π-acid catalysts in the realm of target oriented synthesis.
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Affiliation(s)
- Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
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44
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Willwacher J, Fürstner A. Catalysis-Based Total Synthesis of Putative Mandelalide A. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400605] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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45
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Willwacher J, Fürstner A. Catalysis-Based Total Synthesis of Putative Mandelalide A. Angew Chem Int Ed Engl 2014; 53:4217-21. [DOI: 10.1002/anie.201400605] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Indexed: 12/26/2022]
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46
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Muñoz MP. Silver and platinum-catalysed addition of O–H and N–H bonds to allenes. Chem Soc Rev 2014; 43:3164-83. [DOI: 10.1039/c3cs60408j] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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47
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Peng L, Zhang FM, Yang BM, Zhang XB, Liu WX, Zhang SY, Tu YQ. Toward the natural didemnaketal A: total synthesis of the isomer of didemnaketal A. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.09.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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48
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49
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Abstract
This review covers the literature published in 2011 for marine natural products, with 870 citations (558 for the period January to December 2011) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1152 for 2011), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.
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Affiliation(s)
- John W Blunt
- Department of Chemistry, University of Canterbury, Christchurch, New Zealand.
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50
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Kondoh A, Arlt A, Gabor B, Fürstner A. Total synthesis of nominal gobienine A. Chemistry 2013; 19:7731-8. [PMID: 23589394 DOI: 10.1002/chem.201300827] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Indexed: 11/10/2022]
Abstract
The lichen-derived glycoconjugate gobienine A is structurally more complex than most glycolipids isolated from higher plants by virtue of the all-cis substituted γ-lactone substructure embedded into its macrocyclic frame. A concise entry into this very epimerization-prone and hence challenging structural motif is presented, which relies on an enantioselective cyanohydrin formation, an intramolecular Blaise reaction, a palladium-catalyzed alkoxycarbonylation, and a diastereoselective hydrogenation of the tetrasubstituted alkene in the resulting butenolide. This strategy, in combination with ring-closing olefin metathesis for the formation of the macrocyclic perimeter, allowed the proposed structure of gobienine A (1) to be formed in high overall yield. The recorded spectral data show that the structure originally attributed to gobienine A is incorrect and that it is not the epimerization-prone ester site on the butanolide ring that is the locus of misassignment; rather, the discrepancy must be more profound.
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Affiliation(s)
- Azusa Kondoh
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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