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Yotsu-Yamashita M, Umeda K, Iwasaki A, Suenaga K. Toxicity of the marine glycosidic macrolides, polycavernoside E and akunolides, from Okinawan cyanobacterium Okeania sp. in mice. Toxicon 2024; 250:108122. [PMID: 39393538 DOI: 10.1016/j.toxicon.2024.108122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 10/04/2024] [Accepted: 10/08/2024] [Indexed: 10/13/2024]
Abstract
The toxicity of polycavernoside E and its structurally related macrolides, akunolides A, B, and C, was evaluated in mice. These compounds were recently isolated from the marine cyanobacterium Okeania sp. collected in Okinawa, Japan. The minimal toxicity of polycavernoside E was estimated as 0.81 mg/kg by intraperitoneal injection, whereas those of akunolides A-C were >13 mg/kg. Owing to the considerable toxicity of polycavernoside E, the occurrence of this cyanobacterium should be considered in seaweed production environments.
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Affiliation(s)
- Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan.
| | - Kairi Umeda
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
| | - Arihiro Iwasaki
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, Tokyo, 112-8551, Japan
| | - Kiyotake Suenaga
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
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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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Sutro JL, Fürstner A. Total Synthesis of the Allenic Macrolide (+)-Archangiumide. J Am Chem Soc 2024; 146:2345-2350. [PMID: 38241031 PMCID: PMC10835656 DOI: 10.1021/jacs.3c13304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/07/2024] [Accepted: 01/11/2024] [Indexed: 02/01/2024]
Abstract
Archangiumide is the first known macrolide natural product comprising an endocyclic allene. For the ring strain that this linear substructure might entail, it was planned to unveil the allene at a very late stage of the projected total synthesis; in actual fact, this was achieved as the last step of the longest linear sequence by using an otherwise globally deprotected substrate. This unconventional timing was made possible by a gold catalyzed rearrangement of a macrocyclic propargyl benzyl ether derivative that uses a -PMB group as latent hydride source to unveil the signature cycloallene; the protecting group therefore gains a strategic role beyond its mere safeguarding function. Although the gold catalyzed reaction per se is stereoablative, the macrocyclic frame of the target was found to impose high selectivity and a stereoconvergent character on the transformation. The required substrate was formed by ring closing alkyne metathesis (RCAM) with the aid of a new air-stable molybdenum alkylidyne catalyst.
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Affiliation(s)
- Jack L. Sutro
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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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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Masiuk US, Faletrov YV, Kananovich DG, Mineyeva IV. Stereodivergent Assembly of 2,6- cis- and - trans-Tetrahydropyrans via Base-Mediated Oxa-Michael Cyclization: The Key Role of the TMEDA Additive. J Org Chem 2023; 88:355-370. [PMID: 36495268 DOI: 10.1021/acs.joc.2c02382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The stereodivergent synthesis of cis- and trans-2,6-disubstituted tetrahydropyrans (THPs) via sodium hexamethyldisilazide-promoted oxa-Michael cyclization of (E)-ζ-hydroxy α,β-unsaturated esters is presented. The cyclization affords the kinetically favored trans-THPs with high stereoselectivity (dr up to 93:7) at a low temperature (-78 °C), while the room-temperature reaction does not produce the thermodynamically preferred cis-THPs as major products and occurs with poor stereocontrol. The addition of tetramethylethylenediamine (TMEDA) significantly improves the stereochemical outcome of the room-temperature cyclization and allows attaining high cis-selectivity (dr up to 99:1). The remarkable effect of TMEDA indicates that the sodium cation plays an important role in controlling the stereoselectivity of the thermodynamically driven process, that is, complexation of the cation with the cyclization products results in diminished selectivity. DFT calculations support this conclusion, indicating a greater difference in Gibbs energies of sodium-free cis- and trans-enolates compared to the respective sodium chelate complexes. The synthetic utility of the method has been demonstrated by the formal syntheses of (+)-Neopeltolide and (-)-Diospongin B and the total synthesis of (-)-Diospongin A.
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Affiliation(s)
- Uladzimir S Masiuk
- Department of Chemistry, Belarusian State University, Leningradskaya 14, 220006 Minsk, Belarus.,School of Science, Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Yaroslav V Faletrov
- Department of Chemistry, Belarusian State University, Leningradskaya 14, 220006 Minsk, Belarus.,Research Institute for Physical Chemical Problems, Belarusian State University, Leningradskaya 14, 220006 Minsk, Belarus
| | - Dzmitry G Kananovich
- School of Science, Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Iryna V Mineyeva
- Department of Chemistry, Belarusian State University, Leningradskaya 14, 220006 Minsk, Belarus
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6
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Mizukami D, Iio K, Oda M, Onodera Y, Fuwa H. Tandem Macrolactone Synthesis: Total Synthesis of (-)-Exiguolide by a Macrocyclization/Transannular Pyran Cyclization Strategy. Angew Chem Int Ed Engl 2022; 61:e202202549. [PMID: 35243740 DOI: 10.1002/anie.202202549] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Indexed: 12/25/2022]
Abstract
Tetrahydropyran-containing macrolactones were synthesized by integrating Meyer-Schuster rearrangement, macrocyclic ring-closing metathesis, and transannular oxa-Michael addition under gold and ruthenium catalysis. Single-step access to a variety of 14- to 20-membered macrolactones containing a tetrahydropyran ring was possible from readily available linear precursors in good yields and with moderate to excellent diastereoselectivity. A 13-step synthesis of (-)-exiguolide, an anticancer marine macrolide, showcased the feasibility of our tandem reaction sequence for macrolactone synthesis and also demonstrated the power of transannular reactions for rapid assembly of the tetrahydropyran rings of the target natural product.
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Affiliation(s)
- Daichi Mizukami
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Kei Iio
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Mami Oda
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Yu Onodera
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 981-8577, Japan
| | - Haruhiko Fuwa
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
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7
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Mizukami D, Iio K, Oda M, Onodera Y, Fuwa H. Tandem Macrolactone Synthesis: Total Synthesis of (−)‐Exiguolide by a Macrocyclization/Transannular Pyran Cyclization Strategy. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Daichi Mizukami
- Chuo University - Korakuen Campus: Chuo Daigaku - Korakuen Campus Department of Applied Chemistry JAPAN
| | - Kei Iio
- Chuo University - Korakuen Campus: Chuo Daigaku - Korakuen Campus Department of Applied Chemistry JAPAN
| | - Mami Oda
- Chuo University - Korakuen Campus: Chuo Daigaku - Korakuen Campus Department of Applied Chemistry JAPAN
| | - Yu Onodera
- Tohoku University - Katahira Campus: Tohoku Daigaku Graduate School of Life Sciences JAPAN
| | - Haruhiko Fuwa
- Chuo University Department of Applied Chemistry 1-13-27 KasugaBunkyo-ku 112-8551 Tokyo JAPAN
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8
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Guillade L, Mora P, Villar P, Alvarez R, R de Lera A. Total synthesis of nahuoic acid A via a putative biogenetic intramolecular Diels-Alder (IMDA) reaction. Chem Sci 2021; 12:15157-15169. [PMID: 34909158 PMCID: PMC8612404 DOI: 10.1039/d1sc04524e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/26/2021] [Indexed: 11/21/2022] Open
Abstract
Inspired by the biogenetic proposal of an intramolecular Diels-Alder (IMDA) cycloaddition, the total synthesis of natural product nahuoic acid A, a cofactor-competitive inhibitor of the epigenetic enzyme lysine methyl transferase SETD8, has been carried out. A non-conjugated pentaenal precursor was synthesized with high levels of stereoselectivity at seven stereogenic centers and with the appropriate control of double bond geometries. Although the IMDA reaction of the non-conjugated pentaenal using Me2AlCl for catalysis at -40 °C selectively afforded the trans-fused diastereomer corresponding to the Re-endo mode of cycloaddition, under thermal reaction conditions it gave rise to a mixture of diastereomers, that preferentially formed through the exo mode, including the cis-fused angularly-methylated octahydronaphthalene diastereomer precursor of nahuoic acid A. The natural product could be obtained upon oxidation and overall deprotection of the hydroxyl groups present in the Si-exo IMDA diastereomer.
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Affiliation(s)
- Lucía Guillade
- Departamento de Química Orgánica, Facultade de Química, CINBIO, IIS Galicia Sur, Universidade de Vigo 36310 Vigo Spain
| | - Paula Mora
- Departamento de Química Orgánica, Facultade de Química, CINBIO, IIS Galicia Sur, Universidade de Vigo 36310 Vigo Spain
| | - Pedro Villar
- Departamento de Química Orgánica, Facultade de Química, CINBIO, IIS Galicia Sur, Universidade de Vigo 36310 Vigo Spain
| | - Rosana Alvarez
- Departamento de Química Orgánica, Facultade de Química, CINBIO, IIS Galicia Sur, Universidade de Vigo 36310 Vigo Spain
| | - Angel R de Lera
- Departamento de Química Orgánica, Facultade de Química, CINBIO, IIS Galicia Sur, Universidade de Vigo 36310 Vigo Spain
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9
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Nanda SK, Mallik R. Transition Metal-Catalyzed Hydroalkoxylation of Alkynes: An Overview. Chemistry 2021; 27:15571-15604. [PMID: 34343374 DOI: 10.1002/chem.202102194] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Indexed: 01/12/2023]
Abstract
Oxygen-bearing motifs, mainly the congener heterocycles are ubiquitous due to their presence in various natural products and bioactive scaffolds. Although in literature, several strategies have been developed for their synthesis, hydroalkoxylation of alkynes has come forward as a method of choice and has been used extensively. In particular, hydroalkoxylation of alkynes has gained enormous attention from the synthetic community due to the rapid access to a very useful and reactive synthetic intermediate like 'enol ether'. Furthermore, to manifold the utility of these methods, reports have been developed elaborating the generation of 'enol ether' using hydroalkoxylation and their usage in various reactions in cascade or tandem manner. This review focuses on recent development on the hydroalkoxylation of alkynes for the synthesis of oxygen-containing entities.
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Affiliation(s)
- Santosh K Nanda
- Department of Chemistry, School of Applied Science, Centurion University of Technology and Management Paralakhemundi, Odisha, 761211, India
| | - Rosy Mallik
- Department of Chemistry, School of Applied Science, Centurion University of Technology and Management Paralakhemundi, Odisha, 761211, India
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10
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Hillenbrand J, Korber JN, Leutzsch M, Nöthling N, Fürstner A. Canopy Catalysts for Alkyne Metathesis: Investigations into a Bimolecular Decomposition Pathway and the Stability of the Podand Cap. Chemistry 2021; 27:14025-14033. [PMID: 34293239 PMCID: PMC8518412 DOI: 10.1002/chem.202102080] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 11/28/2022]
Abstract
Molybdenum alkylidyne complexes with a trisilanolate podand ligand framework ("canopy catalysts") are the arguably most selective catalysts for alkyne metathesis known to date. Among them, complex 1 a endowed with a fence of lateral methyl substituents on the silicon linkers is the most reactive, although fairly high loadings are required in certain applications. It is now shown that this catalyst decomposes readily via a bimolecular pathway that engages the Mo≡CR entities in a stoichiometric triple-bond metathesis event to furnish RC≡CR and the corresponding dinuclear complex, 8, with a Mo≡Mo core. In addition to the regular analytical techniques, 95 Mo NMR was used to confirm this unusual outcome. This rapid degradation mechanism is largely avoided by increasing the size of the peripheral substituents on silicon, without unduly compromising the activity of the resulting complexes. When chemically challenged, however, canopy catalysts can open the apparently somewhat strained tripodal ligand cages; this reorganization leads to the formation of cyclo-tetrameric arrays composed of four metal alkylidyne units linked together via one silanol arm of the ligand backbone. The analogous tungsten alkylidyne complex 6, endowed with a tripodal tris-alkoxide (rather than siloxide) ligand framework, is even more susceptible to such a controlled and reversible cyclo-oligomerization. The structures of the resulting giant macrocyclic ensembles were established by single-crystal X-ray diffraction.
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Affiliation(s)
- Julius Hillenbrand
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - J. Nepomuk Korber
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
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Kajetanowicz A, Grela K. Nitro and Other Electron Withdrawing Group Activated Ruthenium Catalysts for Olefin Metathesis Reactions. Angew Chem Int Ed Engl 2021; 60:13738-13756. [PMID: 32808704 PMCID: PMC8246989 DOI: 10.1002/anie.202008150] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Indexed: 01/05/2023]
Abstract
Advanced applications of the Nobel Prize winning olefin metathesis reaction require user-friendly and highly universal catalysts. From many successful metathesis catalysts, which belong to the two distinct classes of Schrock and Grubbs-type catalysts, the subclass of chelating-benzylidene ruthenium complexes (so-called Hoveyda-Grubbs catalysts) additionally activated by electron-withdrawing groups (EWGs) provides a highly tunable platform. In the Review, the origin of the EWG-activation concept and selected applications of the resulting catalysts in target-oriented synthesis, medicinal chemistry, as well as in the preparation of fine-chemicals and in materials chemistry is discussed. Based on the examples, some suggestions for end-users regarding minimization of catalyst loading, selectivity control, and general optimization of the olefin metathesis reaction are provided.
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Affiliation(s)
- Anna Kajetanowicz
- Laboratory of Organometallic SynthesisFaculty of ChemistryBiological and Chemical Research CentreUniversity of WarsawŻwirki i Wigury 10102-089WarsawPoland
| | - Karol Grela
- Laboratory of Organometallic SynthesisFaculty of ChemistryBiological and Chemical Research CentreUniversity of WarsawŻwirki i Wigury 10102-089WarsawPoland
- Institute of Organic ChemistryPolish Academy of SciencesKasprzaka 44/5201-224WarsawPoland
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12
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Kajetanowicz A, Grela K. Durch Nitro‐ und andere elektronenziehende Gruppen aktivierte Ruthenium‐Katalysatoren für die Olefinmetathese. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202008150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Anna Kajetanowicz
- Labor für Organometall-Synthese Fakultät für Chemie Biological and Chemical Research Centre Universität Warschau Żwirki i Wigury 101 02-089 Warschau Polen
| | - Karol Grela
- Labor für Organometall-Synthese Fakultät für Chemie Biological and Chemical Research Centre Universität Warschau Żwirki i Wigury 101 02-089 Warschau Polen
- Institut für Organische Chemie Polish Academy of Sciences Kasprzaka 44/52 01-224 Warschau Polen
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13
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Praveen C. Cycloisomerization of π-Coupled Heteroatom Nucleophiles by Gold Catalysis: En Route to Regiochemically Defined Heterocycles. CHEM REC 2021; 21:1697-1737. [PMID: 34061426 DOI: 10.1002/tcr.202100105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/08/2021] [Accepted: 05/11/2021] [Indexed: 11/06/2022]
Abstract
Since the dawn of millennium, catalytic gold chemistry is at the forefront to set off diverse organic reactions via unique activation of π-bonded molecules. Within this purview, cycloisomerization of heteroatom nucleophiles linked to a π-system is one of the well recognized chemistry for the construction of numerous heterocyclic cores. Though the rudimentary aspects of this transformation are reviewed by several groups in different timeline, a holistic view on regiochemistry of such reactions went largely overlooked. Hence, this account emphasizes the gold catalyzed regioselective cycloisomerization of structurally distinctive π-connected hetero-nucleophiles leading to different heterocycles documented in the last two decades. From an application perspective, this account also highlights those methodologies which find a role in the total synthesis of natural products. Wherever appropriate, mechanistic details and contributing factors for selectivity are also discussed.
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Affiliation(s)
- Chandrasekar Praveen
- Electrochemical Power Sources Division, Central Electrochemical Research Institute (CSIR Laboratory), Alagappapuram, Karaikudi, 630003, Sivagangai District, Tamil Nadu, India
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14
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Fürstner A. Lessons from Natural Product Total Synthesis: Macrocyclization and Postcyclization Strategies. Acc Chem Res 2021; 54:861-874. [PMID: 33507727 PMCID: PMC7893715 DOI: 10.1021/acs.accounts.0c00759] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Macrocyclic
natural products are plentiful in
the bacteria, archaea,
and eukaryote domains of life. For the significant advantages that
they provide to the producing organisms, evolution has learned how
to implement various types of macrocyclization reactions into the
different biosynthetic pathways and how to effect them with remarkable
ease. Mankind greatly benefits from nature’s pool, not least
because naturally occurring macrocycles or derivatives thereof serve
as important drugs for the treatment of many serious ailments. In stark contrast, macrocyclization reactions are usually perceived
as difficult to accomplish by purely chemical means. While it is true
that ring closure necessarily entails an entropic loss and may result
in the buildup of (considerable) ring strain that must be compensated
for in one way or the other, it is also fair to note tremendous methodological
advances during the last decades that greatly alleviated this traditional
“macrocycle challenge”. It is therefore increasingly
possible to explore the advantages provided by large as well as medium-size
ring systems in a more systematic manner. This venture also holds
the promise of increasing the “chemical space” amenable
to drug development to a considerable extent. In consideration
of this and other important long-term perspectives,
it is appropriate to revisit the current state of the art. To this
end, a number of vignettes are presented, each of which summarizes
a total synthesis project targeting macrocyclic natural products of
greatly different chemotypes using a variety of transformations to
reach these goals. Although we were occasionally facing “dead
ends”, which are also delineated for the sake of a complete
picture, these case studies illustrate the notion that the formation
of a certain macrocyclic perimeter is (usually) no longer seriously
limiting. In addition to substantial progress in the “classical”
repertoire (macrolactonization and macrolactamization
(pateamine A, spirastrellolide, and belizentrin)), various metal-catalyzed
reactions have arguably led to the greatest leaps forward. Among them,
palladium-catalyzed C–C bond formation (roseophilin and nominal
xestocyclamine A) and, in particular, alkene and alkyne metathesis
stand out (iejimalide, spirastrellolide, enigmazole, ingenamine, and
sinulariadiolide). In some cases, different methods were pursued in
parallel, thus allowing for a critical assessment and comparison. To the extent that the macrocyclic challenge is vanishing, the
opportunity arises to focus attention on the postmacrocyclization
phase. One may stipulate that a well-designed cyclization precursor
does not only ensure efficient ring closure but also fosters and streamlines
the steps that come after the event. One way to do so is dual (multiple)
use in that the functional groups serving the actual cyclization reaction
also find productive applications downstream from it rather than being
subject to simple defunctionalization. In this context,
better insight into the conformational peculiarities of large rings
and the growing confidence in their accessibility in a stereochemically
well defined format rejuvenate the implementation of transannular
reactions or reaction cascades that can lead to rapid and substantial
increases in molecular complexity. The examples summarized herein
showcase such possibilities, with special emphasis on tranannular
gold catalysis and the emerging ruthenium-catalyzed trans-hydrometalation chemistry for the selective functionalization of
alkynes.
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Fariña-Ramos M, García C, Martín VS, Álvarez-Méndez SJ. Synthetic efforts on the road to marine natural products bearing 4- O-2,3,4,6-tetrasubstituted THPs: an update. RSC Adv 2021; 11:5832-5858. [PMID: 35423108 PMCID: PMC8694735 DOI: 10.1039/d0ra10755g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 01/26/2021] [Indexed: 11/21/2022] Open
Abstract
Scientific literature is inundated with secondary metabolites from marine sources. In this ocean of natural products, the presence of recurring patterns has traditionally led scientists to unravel the biosynthetic mechanisms that naturally yield these products, as well as to imitate Nature to prepare them in the laboratory, especially when promising bioactivities and stimulating molecular architectures are involucrate. For instance, natural products containing multisubstituted oxygenated rings and macrocyclic lactones are recurrently selected as targets for developing total syntheses. Thus, in the last decades a noteworthy number of synthetic works regarding miyakolide, madeirolide A and representative compounds of polycavernosides, lasonolides and clavosolides have come to fruition. Up to now, these families of macrolides are the only marine natural products bearing a tetrasubstituted tetrahydropyran ring with carbon substituents at positions 2, 3 and 6, as well as an oxygen at position 4. Their splendid structures have received the attention of the synthetic community, up to the point of starring in dozens of articles, and even some reviews. This work covers all the synthetic studies towards miyakolide and madeirolide A, as well as the synthetic efforts performed after the previous specialised reviews about lasonolide A, polycavernoside A and clavosolides, published in 2006, 2007 and 2016, respectively. In total, this review summarises 22 articles in which these marine natural products with 4-O-2,3,4,6-tetrasubstituted tetrahydropyrans have the leading role.
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Affiliation(s)
- Marta Fariña-Ramos
- Departamento de Química Orgánica, Universidad de La Laguna Avda Astrofísico Francisco Sánchez 38206 La Laguna Tenerife Spain
- Instituto Universitario de Bio-Orgánica Antonio González, Síntesis Orgánica Sostenible, Unidad Asociada al CSIC, Universidad de La Laguna Avda Astrofísico Francisco Sánchez 38206 La Laguna Tenerife Spain
| | - Celina García
- Departamento de Química Orgánica, Universidad de La Laguna Avda Astrofísico Francisco Sánchez 38206 La Laguna Tenerife Spain
- Instituto Universitario de Bio-Orgánica Antonio González, Síntesis Orgánica Sostenible, Unidad Asociada al CSIC, Universidad de La Laguna Avda Astrofísico Francisco Sánchez 38206 La Laguna Tenerife Spain
| | - Víctor S Martín
- Departamento de Química Orgánica, Universidad de La Laguna Avda Astrofísico Francisco Sánchez 38206 La Laguna Tenerife Spain
- Instituto Universitario de Bio-Orgánica Antonio González, Síntesis Orgánica Sostenible, Unidad Asociada al CSIC, Universidad de La Laguna Avda Astrofísico Francisco Sánchez 38206 La Laguna Tenerife Spain
| | - Sergio J Álvarez-Méndez
- Departamento de Química Orgánica, Universidad de La Laguna Avda Astrofísico Francisco Sánchez 38206 La Laguna Tenerife Spain
- Instituto Universitario de Bio-Orgánica Antonio González, Síntesis Orgánica Sostenible, Unidad Asociada al CSIC, Universidad de La Laguna Avda Astrofísico Francisco Sánchez 38206 La Laguna Tenerife Spain
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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 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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17
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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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18
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Kaczanowska K, Trzaskowski B, Peszczyńska A, Tracz A, Gawin R, Olszewski TK, Skowerski K. Cross metathesis with acrylates:
N
‐heterocyclic carbene (NHC)‐
versus
cyclic alkyl amino carbene (CAAC)‐based ruthenium catalysts, an unanticipated influence of the carbene type on efficiency and selectivity of the reaction. ChemCatChem 2020. [DOI: 10.1002/cctc.202001268] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
| | - Bartosz Trzaskowski
- Centre of New Technologies University of Warsaw Banacha 2c 02-097 Warszawa Poland
| | | | | | - Rafał Gawin
- Apeiron Synthesis SA Duńska 9 54-427 Wrocław Poland
| | - Tomasz K. Olszewski
- Wroclaw University of Science and Technology Faculty of Chemistry Wybrzeze Wyspianskiego 29 50-370 Wroclaw Poland
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19
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Liniger M, Neuhaus CM, Altmann KH. Ring-Closing Metathesis Approaches towards the Total Synthesis of Rhizoxins. Molecules 2020; 25:E4527. [PMID: 33023218 PMCID: PMC7582377 DOI: 10.3390/molecules25194527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 02/01/2023] Open
Abstract
Efforts are described towards the total synthesis of the bacterial macrolide rhizoxin F, which is a potent tubulin assembly and cancer cell growth inhibitor. A significant amount of work was expanded on the construction of the rhizoxin core macrocycle by ring-closing olefin metathesis (RCM) between C(9) and C(10), either directly or by using relay substrates, but in no case was ring-closure achieved. Macrocycle formation was possible by ring-closing alkyne metathesis (RCAM) at the C(9)/C(10) site. The requisite diyne was obtained from advanced intermediates that had been prepared as part of the synthesis of the RCM substrates. While the direct conversion of the triple bond formed in the ring-closing step into the C(9)-C(10) E double bond of the rhizoxin macrocycle proved to be elusive, the corresponding Z isomer was accessible with high selectivity by reductive decomplexation of the biscobalt hexacarbonyl complex of the triple bond with ethylpiperidinium hypophosphite. Radical-induced double bond isomerization, full elaboration of the C(15) side chain, and directed epoxidation of the C(11)-C(12) double bond completed the total synthesis of rhizoxin F.
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Affiliation(s)
| | | | - Karl-Heinz Altmann
- ETH Zürich, Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, 8093 Zürich, Switzerland; (M.L.); (C.M.N.)
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20
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Ikeuchi K, Murasawa K, Arai T, Yamada H. p-Methylbenzyl 2,2,2-Trichloroacetimidate: Simple Preparation and Application to Alcohol Protection. CHEM LETT 2020. [DOI: 10.1246/cl.200303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kazutada Ikeuchi
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
- Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Kentaro Murasawa
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Tomoki Arai
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Hidetsohi Yamada
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
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21
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Kumar MS, Sharma SA. Toxicological effects of marine seaweeds: a cautious insight for human consumption. Crit Rev Food Sci Nutr 2020; 61:500-521. [PMID: 32188262 DOI: 10.1080/10408398.2020.1738334] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Marine environment is a rich and diverse source for many biologically active substances including functional foods and nutraceuticals. It is well exploited for useful compounds, natural products and aquaculture industry; and seaweeds is one of the major contributors in terms of both food security and healthy nutrition. They are well-known due to their enormous benefits and is consumed globally in many countries. However, there is lack of attention toward their toxicity reports which might be due toxic chemical compounds from seaweed, epiphytic bacteria or harmful algal bloom and absorbed heavy metals from seawater. The excess of these components might lead to harmful interactions with drugs and hormone levels in the human body. Due to their global consumption and to meet increasing demands, it is necessary to address their hazardous and toxic aspects. In this review, we have done extensive literature for healthy seaweeds, their nutritional composition while summarizing the toxic effects of selected seaweeds from red, brown and green group which includes- Gracilaria, Acanthophora, Caulerpa, Cladosiphon, and Laminaria sp. Spirulina, a microalgae (cyanobacteria) biomass is also included in toxicity discussion as it an important food supplement and many times shows adverse reactions and drug interactions. The identified compounds from seaweeds were concluded to be toxic to humans, though they exhibited certain beneficial effects too. They have an easy access in food chain and thus invade the higher trophic level organisms. This review will create an awareness among scientific and nonscientific community, as well as government organization to regulate edible seaweed consumption and keep them under surveillance for their beneficial and safe consumption.
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Affiliation(s)
- Maushmi S Kumar
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS, Mumbai, India
| | - Simran A Sharma
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS, Mumbai, India
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22
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Mata G, Wölfl B, Fürstner A. Synthesis and Molecular Editing of Callyspongiolide, Part 1: The Alkyne Metathesis/
trans
‐Reduction Strategy. Chemistry 2018; 25:246-254. [DOI: 10.1002/chem.201804987] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Guillaume Mata
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Bernhard Wölfl
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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23
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Karier P, Ungeheuer F, Ahlers A, Anderl F, Wille C, Fürstner A. Metathesis at an Implausible Site: A Formal Total Synthesis of Rhizoxin D. Angew Chem Int Ed Engl 2018; 58:248-253. [DOI: 10.1002/anie.201812096] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Pol Karier
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Felix Ungeheuer
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Andreas Ahlers
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Felix Anderl
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Christian Wille
- 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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Karier P, Ungeheuer F, Ahlers A, Anderl F, Wille C, Fürstner A. Metathesis at an Implausible Site: A Formal Total Synthesis of Rhizoxin D. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201812096] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Pol Karier
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Felix Ungeheuer
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Andreas Ahlers
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Felix Anderl
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Christian Wille
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
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25
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Pagar VV, RajanBabu TV. Tandem catalysis for asymmetric coupling of ethylene and enynes to functionalized cyclobutanes. Science 2018; 361:68-72. [PMID: 29976822 DOI: 10.1126/science.aat6205] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 05/15/2018] [Indexed: 02/02/2023]
Abstract
Transformation of simple precursors into structurally complex cyclobutanes, present in many biologically important natural products and pharmaceuticals, is of considerable interest in medicinal chemistry. Starting from 1,3-enynes and ethylene, both exceptionally inexpensive starting materials, we report a cobalt-catalyzed route to vinylcyclobutenes, as well as the further enantioselective addition of ethylene to these products to form complex cyclobutanes with all-carbon quaternary centers. These reactions can proceed in discrete stages or in a tandem fashion to achieve three highly selective carbon-carbon bond formations in one pot using a single chiral cobalt catalyst.
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Affiliation(s)
- Vinayak Vishnu Pagar
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - T V RajanBabu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
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26
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Pflästerer D, Rudolph M, Hashmi ASK. Gold-Catalyzed Hydrofunctionalizations and Spiroketalizations of Alkynes as Key Steps in Total Synthesis. Isr J Chem 2018. [DOI: 10.1002/ijch.201700056] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Daniel Pflästerer
- Heidelberg University; Organisch-Chemisches Institut; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Matthias Rudolph
- Heidelberg University; Organisch-Chemisches Institut; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - A. Stephen K. Hashmi
- Heidelberg University; Organisch-Chemisches Institut; Im Neuenheimer Feld 270 69120 Heidelberg Germany
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27
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Xie X, Lu B, Li W, Zhang Z. Coordination determined chemo- and enantioselectivities in asymmetric hydrogenation of multi-functionalized ketones. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2017.07.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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28
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Iwasaki K, Sasaki S, Kasai Y, Kawashima Y, Sasaki S, Ito T, Yotsu-Yamashita M, Sasaki M. Total Synthesis of Polycavernosides A and B, Two Lethal Toxins from Red Alga. J Org Chem 2017; 82:13204-13219. [PMID: 29124933 DOI: 10.1021/acs.joc.7b02293] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polycavernosides A and B are glycosidic macrolide natural products isolated as the toxins causing fatal human poisoning by the edible red alga Gracilaria edulis (Polycavernosa tsudai). Total synthesis of polycavernosides A and B has been achieved via a convergent approach. The synthesis of the macrolactone core structure is highlighted by the catalytic asymmetric syntheses of the two key fragments using hetero-Diels-Alder reaction and Kiyooka aldol reaction as the key steps, their union through Suzuki-Miyaura coupling, and Keck macrolactonization. Finally, glycosylation with the l-fucosyl-d-xylose unit and construction of the polyene side chain through Stille coupling completed the total synthesis of polycavernosides A and B.
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Affiliation(s)
- Kotaro Iwasaki
- Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Satori Sasaki
- Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Yusuke Kasai
- Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Yuki Kawashima
- Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shohei Sasaki
- Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Takanori Ito
- Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University , 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-0845, Japan
| | - Makoto Sasaki
- Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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29
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Bihelovic F, Vulovic B, Saicic RN. Gold(I)-Catalyzed C−O/C−C Bond-Forming Domino Reactions and Their Synthetic Applications. Isr J Chem 2017. [DOI: 10.1002/ijch.201700033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Filip Bihelovic
- Faculty of Chemistry; University of Belgrade; Studentski trg 16, P.O. Box 51 11158 Belgrade Serbia
| | - Bojan Vulovic
- Faculty of Chemistry; University of Belgrade; Studentski trg 16, P.O. Box 51 11158 Belgrade Serbia
| | - Radomir N. Saicic
- Faculty of Chemistry; University of Belgrade; Studentski trg 16, P.O. Box 51 11158 Belgrade Serbia
- Serbian Academy of Sciences and Arts; Knez Mihailova 35 Belgrade
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30
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Gómez-Palomino A, Pellicena M, Krämer K, Romea P, Urpí F, Aullón G, Padrón JM. Total synthesis of (+)-herboxidiene/GEX 1A. Org Biomol Chem 2017; 15:1842-1862. [DOI: 10.1039/c7ob00072c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient synthesis of herboxidiene is granted from highly stereoselective aldol reactions from two lactate-derived ketones and an oxa-Michael cyclization.
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Affiliation(s)
- Alejandro Gómez-Palomino
- Departament de Química Inorgànica i Orgànica
- Secció de Química Orgànica
- and Institut de Biomedicina (IBUB)
- Universitat de Barcelona
- 08028 Barcelona
| | - Miquel Pellicena
- Departament de Química Inorgànica i Orgànica
- Secció de Química Orgànica
- and Institut de Biomedicina (IBUB)
- Universitat de Barcelona
- 08028 Barcelona
| | - Katrina Krämer
- Departament de Química Inorgànica i Orgànica
- Secció de Química Orgànica
- and Institut de Biomedicina (IBUB)
- Universitat de Barcelona
- 08028 Barcelona
| | - Pedro Romea
- Departament de Química Inorgànica i Orgànica
- Secció de Química Orgànica
- and Institut de Biomedicina (IBUB)
- Universitat de Barcelona
- 08028 Barcelona
| | - Fèlix Urpí
- Departament de Química Inorgànica i Orgànica
- Secció de Química Orgànica
- and Institut de Biomedicina (IBUB)
- Universitat de Barcelona
- 08028 Barcelona
| | - Gabriel Aullón
- Departament de Química Inorgànica i Orgànica
- Secció de Química Inorgànica
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - José M. Padrón
- BioLab
- Instituto Universitario de Bio-Orgánica “Antonio González” (IUBO-AG)
- Centro de Investigaciones Biomédicas de Canarias (CIBICAN)
- Universidad de La Laguna
- Spain
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31
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Knezz SN, Waltz TA, Haenni BC, Burrmann NJ, McMahon RJ. Spectroscopy and Photochemistry of Triplet 1,3-Dimethylpropynylidene (MeC3Me). J Am Chem Soc 2016; 138:12596-604. [PMID: 27640734 DOI: 10.1021/jacs.6b07444] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Photolysis (λ > 472 nm) of 2-diazo-3-pentyne (11) affords triplet 1,3-dimethylpropynylidene (MeC3Me, (3)3), which was characterized spectroscopically in cryogenic matrices. The infrared, electronic absorption, and electron paramagnetic resonance spectra of MeC3Me ((3)3) are compared with those of the parent system (HC3H) to ascertain the effect of alkyl substituents on delocalized carbon chains of this type. Quantum chemical calculations (CCSD(T)/ANO1) predict an unsymmetrical equilibrium structure for triplet MeC3Me ((3)3), but they also reveal a very shallow potential energy surface. The experimental IR spectrum of triplet MeC3Me ((3)3) is best interpreted in terms of a quasilinear, axially symmetric structure. EPR spectra yield zero-field splitting parameters that are typical for triplet carbenes with axial symmetry (|D/hc| = 0.63 cm(-1), |E/hc| = ∼ 0 cm(-1)), while theoretical analysis suggests that the methyl substituents confer significant spin polarization to the carbon chain. Upon irradiation into the near-UV electronic absorption (λmax 350 nm), MeC3Me ((3)3) undergoes 1,2-hydrogen migration to yield pent-1-en-3-yne (4), a photochemical reaction that is typical of carbenes bearing a methyl substituent. This facile process apparently precludes photoisomerization to other interesting C5H6 isomers, in contrast to the rich photochemistry of the parent C3H2 system.
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Affiliation(s)
- Stephanie N Knezz
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Terese A Waltz
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Benjamin C Haenni
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Nicola J Burrmann
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Robert J McMahon
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
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32
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Clarke PA, Nasir NM, Sellars PB, Peter AM, Lawson CA, Burroughs JL. Synthesis of 2,6-trans- and 3,3,6-trisubstituted tetrahydropyran-4-ones from Maitland-Japp derived 2H-dihydropyran-4-ones: a total synthesis of diospongin B. Org Biomol Chem 2016; 14:6840-52. [PMID: 27340028 DOI: 10.1039/c6ob01182a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
6-Substituted-2H-dihydropyran-4-one products of the Maitland-Japp reaction have been converted into tetrahydropyrans containing uncommon substitution patterns. Treatment of 6-substituted-2H-dihydropyran-4-ones with carbon nucleophiles led to the formation of tetrahydropyran rings with the 2,6-trans-stereochemical arrangement. Reaction of the same 6-substituted-2H-dihydropyran-4-ones with l-Selectride led to the formation of 3,6-disubstituted tetrahydropyran rings, while trapping of the intermediate enolate with carbon electrophiles in turn led to the formation 3,3,6-trisubstituted tetrahydropyran rings. The relative stereochemical configuration of the new substituents was controlled by the stereoelectronic preference for pseudo-axial addition of the nucleophile and trapping of the enolate from the opposite face. Application of these methods led to a synthesis of the potent anti-osteoporotic diarylheptanoid natural product diospongin B.
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Affiliation(s)
- Paul A Clarke
- Department of Chemistry, University of York, Heslington, York, North Yorks YO10 5DD, UK.
| | - Nadiah Mad Nasir
- Department of Chemistry, University of York, Heslington, York, North Yorks YO10 5DD, UK.
| | - Philip B Sellars
- Department of Chemistry, University of York, Heslington, York, North Yorks YO10 5DD, UK.
| | - Alejandra M Peter
- Department of Chemistry, University of York, Heslington, York, North Yorks YO10 5DD, UK.
| | - Connor A Lawson
- Department of Chemistry, University of York, Heslington, York, North Yorks YO10 5DD, UK.
| | - James L Burroughs
- Department of Chemistry, University of York, Heslington, York, North Yorks YO10 5DD, UK.
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33
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Schaubach S, Gebauer K, Ungeheuer F, Hoffmeister L, Ilg MK, Wirtz C, Fürstner A. A Two-Component Alkyne Metathesis Catalyst System with an Improved Substrate Scope and Functional Group Tolerance: Development and Applications to Natural Product Synthesis. Chemistry 2016; 22:8494-507. [DOI: 10.1002/chem.201601163] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Indexed: 01/02/2023]
Affiliation(s)
| | - Konrad Gebauer
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Felix Ungeheuer
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | | | - Marina K. Ilg
- 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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34
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Rodríguez E, Grayson MN, Asensio A, Barrio P, Houk KN, Fustero S. Chiral Brønsted Acid-Catalyzed Asymmetric Allyl(propargyl)boration Reaction of ortho-Alkynyl Benzaldehydes: Synthetic Applications and Factors Governing the Enantioselectivity. ACS Catal 2016. [DOI: 10.1021/acscatal.6b00209] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Elsa Rodríguez
- Departamento
de Química Orgánica, Universidad de Valencia, Av. Vicente
Andrés Estellés s/n, E-46100 Burjassot, Spain
| | - Matthew N. Grayson
- Department
of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Amparo Asensio
- Departamento
de Química Orgánica, Universidad de Valencia, Av. Vicente
Andrés Estellés s/n, E-46100 Burjassot, Spain
| | - Pablo Barrio
- Departamento
de Química Orgánica, Universidad de Valencia, Av. Vicente
Andrés Estellés s/n, E-46100 Burjassot, Spain
| | - K. N. Houk
- Department
of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Santos Fustero
- Departamento
de Química Orgánica, Universidad de Valencia, Av. Vicente
Andrés Estellés s/n, E-46100 Burjassot, Spain
- Laboratorio
de Moléculas Orgánicas, Centro de Investigación Príncipe Felipe, E-46012 Valencia, Spain
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35
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Pflästerer D, Hashmi ASK. Gold catalysis in total synthesis – recent achievements. Chem Soc Rev 2016; 45:1331-67. [DOI: 10.1039/c5cs00721f] [Citation(s) in RCA: 600] [Impact Index Per Article: 75.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The most recent achievements of gold catalysed transformations applied in total synthesis of natural products are reviewed and analysed.
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Affiliation(s)
- Daniel Pflästerer
- Organisch-Chemisches Institut
- Universität Heidelberg
- 69120 Heidelberg
- Germany
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36
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Ahlers A, de Haro T, Gabor B, Fürstner A. Concise Total Synthesis of Enigmazole A. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201510026] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Andreas Ahlers
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Teresa de Haro
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Barbara Gabor
- 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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Ahlers A, de Haro T, Gabor B, Fürstner A. Concise Total Synthesis of Enigmazole A. Angew Chem Int Ed Engl 2015; 55:1406-11. [DOI: 10.1002/anie.201510026] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Indexed: 12/26/2022]
Affiliation(s)
- Andreas Ahlers
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Teresa de Haro
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Barbara Gabor
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
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38
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Volchkov NV, Lipkind MB, Novikov MA, Nefedov OM. Aluminum oxide-induced gas-phase ring-opening in methyl substituted gem-difluorocyclopropanes, leading to 2-fluorobuta-1,3-dienes and vinylacetylenes. Russ Chem Bull 2015. [DOI: 10.1007/s11172-015-0914-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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39
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Lackner AD, Fürstner A. The Triple-Bond Metathesis of Aryldiazonium Salts: A Prospect for Dinitrogen Cleavage. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201506546] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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40
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Lackner AD, Fürstner A. The Triple-Bond Metathesis of Aryldiazonium Salts: A Prospect for Dinitrogen Cleavage. Angew Chem Int Ed Engl 2015; 54:12814-8. [DOI: 10.1002/anie.201506546] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Indexed: 01/02/2023]
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41
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Ungeheuer F, Fürstner A. Concise Total Synthesis of Ivorenolide B. Chemistry 2015; 21:11387-92. [DOI: 10.1002/chem.201501765] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Felix Ungeheuer
- Max‐Planck‐Institut für Kohlenforschung, 45470 Mülheim/Ruhr (Germany)
| | - Alois Fürstner
- Max‐Planck‐Institut für Kohlenforschung, 45470 Mülheim/Ruhr (Germany)
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42
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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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43
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Bailey GA, Fogg DE. Acrylate metathesis via the second-generation Grubbs catalyst: unexpected pathways enabled by a PCy3-generated enolate. J Am Chem Soc 2015; 137:7318-21. [PMID: 26030596 DOI: 10.1021/jacs.5b04524] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The diverse applications of acrylate metathesis range from synthesis of high-value α,β-unsaturated esters to depolymerization of unsaturated polymers. Examined here are unexpected side reactions promoted by the important Grubbs catalyst GII. Evidence is presented for attack of PCy3 on the acrylate olefin to generate a reactive carbanion, which participates in multiple pathways, including further Michael addition, proton abstraction, and catalyst deactivation. Related chemistry may be anticipated whenever labile metal-phosphine complexes are used to catalyze reactions of substrates bearing an electron-deficient olefin.
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Affiliation(s)
- Gwendolyn A Bailey
- Center for Catalysis Research and Innovation and Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N6N5 Canada
| | - Deryn E Fogg
- Center for Catalysis Research and Innovation and Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N6N5 Canada
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44
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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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45
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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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46
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The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2013. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2014.09.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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47
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Hoffmeister L, Fukuda T, Pototschnig G, Fürstner A. Total Synthesis of an Exceptional Brominated 4-Pyrone Derivative of Algal Origin: An Exercise in Gold Catalysis and Alkyne Metathesis. Chemistry 2015; 21:4529-33. [DOI: 10.1002/chem.201500437] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 02/03/2023]
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48
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Scully SS, Zheng SL, Wagner BK, Schreiber SL. Synthesis of oxazocenones via gold(I)-catalyzed 8-endo-dig hydroalkoxylation of alkynamides. Org Lett 2015; 17:418-21. [PMID: 25569027 PMCID: PMC4323038 DOI: 10.1021/ol503273v] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Several benzoxazocenones have been found to exhibit novel cellular activities. In the present study, we report a gold(I)-catalyzed 8-endo-dig hydroalkoxylation reaction of alkynamides to access analogous oxazocenone scaffolds. This methodology provided an advanced intermediate, which was elaborated to a des-benzo analog of a bioactive benzoxazocenone.
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Affiliation(s)
- Stephen S Scully
- Center for the Science of Therapeutics, Broad Institute , 415 Main Street, Cambridge, Massachusetts 02142, United States
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49
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Yang Y, Zhang X, Yu B. O-Glycosylation methods in the total synthesis of complex natural glycosides. Nat Prod Rep 2015; 32:1331-55. [DOI: 10.1039/c5np00033e] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We highlight the total syntheses of 33 complex natural O-glycosides, with a particular focus on the O-glycosylation methods that enable the connection of the saccharides and aglycones.
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Affiliation(s)
- You Yang
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
- China
| | - Xiaheng Zhang
- State Key Laboratory of Bio-organic and Natural Products Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
- China
| | - Biao Yu
- State Key Laboratory of Bio-organic and Natural Products Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
- China
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50
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Goodwin JA, Aponick A. Regioselectivity in the Au-catalyzed hydration and hydroalkoxylation of alkynes. Chem Commun (Camb) 2015; 51:8730-41. [DOI: 10.1039/c5cc00120j] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The issue of regioselectivity in the Au-catalyzed hydration and hydroalkoxylation of alkynes is a perpetual challenge that essentially remains an unsolved problem with respect to general solutions.
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Affiliation(s)
- Justin A. Goodwin
- Department of Chemistry
- Center for Heterocyclic Compounds
- University of Florida
- Gainesville
- USA
| | - Aaron Aponick
- Department of Chemistry
- Center for Heterocyclic Compounds
- University of Florida
- Gainesville
- USA
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