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Cox JB, Kellum AA, Zhang Y, Li B, Smith AB. Total Synthesis of (-)-Bastimolide A: A Showcase for Type I Anion Relay Chemistry. Angew Chem Int Ed Engl 2022; 61:e202204884. [PMID: 35608327 PMCID: PMC9256807 DOI: 10.1002/anie.202204884] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Indexed: 05/31/2024]
Abstract
A highly convergent total synthesis of (-)-bastimolide A (1), a polyhydroxy antimalarial macrolide, has been achieved via a longest linear sequence of twenty steps from commercially available glycidyl ethers. Type I Anion Relay Chemistry (ARC) coupling tactics enable rapid construction of the molecule's 1,5-polylol backbone. A late-stage B-alkyl Suzuki-Miyaura union and an Evans-modified Mukaiyama macrolactonization generate the forty-membered Z-α,β-unsaturated macrocyclic lactone.
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Affiliation(s)
- Joshua B Cox
- Department of Chemistry, University of Pennsylvania, 231 S. 34th street, Philadelphia, PA 19104, USA
| | - Alex A Kellum
- Department of Chemistry, University of Pennsylvania, 231 S. 34th street, Philadelphia, PA 19104, USA
| | - Yiwen Zhang
- Department of Chemistry, University of Pennsylvania, 231 S. 34th street, Philadelphia, PA 19104, USA
| | - Bo Li
- Department of Chemistry, University of Pennsylvania, 231 S. 34th street, Philadelphia, PA 19104, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, 231 S. 34th street, Philadelphia, PA 19104, USA
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2
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Cox JB, Kellum AA, Zhang Y, Li B, Smith AB. Total Synthesis of (−)‐Bastimolide A: A Showcase for Type I Anion Relay Chemistry. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202204884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Joshua B. Cox
- Department of Chemistry University of Pennsylvania 231 S. 34th street Philadelphia PA 19104 USA
| | - Alex A. Kellum
- Department of Chemistry University of Pennsylvania 231 S. 34th street Philadelphia PA 19104 USA
| | - Yiwen Zhang
- Department of Chemistry University of Pennsylvania 231 S. 34th street Philadelphia PA 19104 USA
| | - Bo Li
- Department of Chemistry University of Pennsylvania 231 S. 34th street Philadelphia PA 19104 USA
| | - Amos B. Smith
- Department of Chemistry University of Pennsylvania 231 S. 34th street Philadelphia PA 19104 USA
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3
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Concise Large-Scale Synthesis of Tomatidine, A Potent Antibiotic Natural Product. Molecules 2021; 26:molecules26196008. [PMID: 34641551 PMCID: PMC8512692 DOI: 10.3390/molecules26196008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 11/17/2022] Open
Abstract
Tomatidine has recently generated a lot of interest amongst the pharmacology, medicine, and biology fields of study, especially for its newfound activity as an antibiotic agent capable of targeting multiple strains of bacteria. In the light of its low natural abundance and high cost, an efficient and scalable multi-gram synthesis of tomatidine has been developed. This synthesis uses a Suzuki-Miyaura-type coupling reaction as a key step to graft an enantiopure F-ring side chain to the steroidal scaffold of the natural product, which was accessible from low-cost and commercially available diosgenin. A Lewis acid-mediated spiroketal opening followed by an azide substitution and reduction sequence is employed to generate the spiroaminoketal motif of the natural product. Overall, this synthesis produced 5.2 g in a single pass in 15 total steps and 15.2% yield using a methodology that is atom economical, scalable, and requires no flash chromatography purifications.
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Lam NYS, Stockdale TP, Anketell MJ, Paterson I. Conquering peaks and illuminating depths: developing stereocontrolled organic reactions to unlock nature's macrolide treasure trove. Chem Commun (Camb) 2021; 57:3171-3189. [PMID: 33666631 DOI: 10.1039/d1cc00442e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structural complexity and biological importance of macrolide natural products has inspired the development of innovative strategies for their chemical synthesis. With their dense stereochemical content, high level of oxygenation and macrocyclic cores, we viewed the efficient total synthesis of these valuable compounds as an aspirational driver towards developing robust methods and strategies for their construction. Starting out from the initial development of our versatile asymmetric aldol methodology, this personal perspective reflects on an adventurous journey, with all its trials, tribulations and serendipitous discoveries, across the total synthesis, in our group, of a representative selection of six macrolide natural products of marine and terrestrial origin - swinholide A, spongistatin 1, spirastrellolide A, leiodermatolide, chivosazole F and actinoallolide A.
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Affiliation(s)
- Nelson Y S Lam
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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5
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Xue Y, Yan Y, Jiang K, Chen W, Yang L. Iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes. RSC Adv 2020; 10:14720-14724. [PMID: 35497130 PMCID: PMC9052112 DOI: 10.1039/d0ra02625e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/03/2020] [Indexed: 02/03/2023] Open
Abstract
The first iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes was achieved. The reaction tolerates a wide range of functionalities. Furthermore, this protocol was found to be applicable to the oxidative transformation of allylic acetates. The proposed mechanism involves an oxygen transfer from solvent water to the carbonyl products. The first iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes was effectively achieved.![]()
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Affiliation(s)
- Yuntian Xue
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University Hangzhou 311121 China
| | - Yaolong Yan
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University Hangzhou 311121 China
| | - Kezhi Jiang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University Hangzhou 311121 China
| | - Weifeng Chen
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University Hangzhou 311121 China
| | - Lei Yang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University Hangzhou 311121 China .,Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology Qingdao 266042 China
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6
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Suen LM, Tekle-Smith MA, Williamson KS, Infantine JR, Reznik SK, Tanis PS, Casselman TD, Sackett DL, Leighton JL. Design and 22-step synthesis of highly potent D-ring modified and linker-equipped analogs of spongistatin 1. Nat Commun 2018; 9:4710. [PMID: 30413713 PMCID: PMC6226463 DOI: 10.1038/s41467-018-07259-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/24/2018] [Indexed: 12/03/2022] Open
Abstract
Spongistatin 1 is among the most potent anti-proliferative agents ever discovered rendering it an attractive candidate for development as a payload for antibody-drug conjugates and other targeted delivery approaches. Unfortunately, it is unavailable from natural sources and its size and complex stereostructure render chemical synthesis highly time- and resource-intensive. As a result, the design and synthesis of more acid-stable and linker functional group-equipped analogs that retain the low picomolar potency of the parent natural product requires more efficient and step-economical synthetic access. Using uniquely enabling direct complex fragment coupling crotyl- and alkallylsilylation reactions, we report a 22-step synthesis of a rationally designed D-ring modified analog of spongistatin 1 that is characterized by GI50 values in the low picomolar range, and a proof-of-concept result that the C(15) acetate may be replaced with linker functional group-bearing esters with only minimal reductions in potency.
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Affiliation(s)
- Linda M Suen
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | | | | | | | - Samuel K Reznik
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Paul S Tanis
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Tyler D Casselman
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Dan L Sackett
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - James L Leighton
- Department of Chemistry, Columbia University, New York, NY, 10027, USA.
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7
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Larsen EM, Wilson MR, Taylor RE. Conformation-activity relationships of polyketide natural products. Nat Prod Rep 2015; 32:1183-206. [PMID: 25974024 PMCID: PMC4443481 DOI: 10.1039/c5np00014a] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Polyketides represent an important class of secondary metabolites that interact with biological targets connected to a variety of disease-associated pathways. Remarkably, nature's assembly lines, polyketide synthases, manufacture these privileged structures through a combinatorial mixture of just a few structural units. This review highlights the role of these structural elements in shaping a polyketide's conformational preferences, the use of computer-based molecular modeling and solution NMR studies in the identification of low-energy conformers, and the importance of conformational analogues in probing the bound conformation. In particular, this review covers several examples wherein conformational analysis complements classic structure-activity relationships in the design of biologically active natural product analogues.
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Affiliation(s)
- Erik M Larsen
- University of Notre Dame, Department of Chemistry & Biochemistry, 250 Nieuwland Science Hall, Notre Dame, Indiana, USA.
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8
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Chen W, Xiong F, Liu Q, Xu L, Wu Y, Chen F. Substrate stereocontrol in bromine-induced intermolecular cyclization: asymmetric synthesis of pitavastatin calcium. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.05.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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9
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Eppe G, Didier D, Marek I. Stereocontrolled Formation of Several Carbon–Carbon Bonds in Acyclic Systems. Chem Rev 2015; 115:9175-206. [DOI: 10.1021/cr500715t] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Guillaume Eppe
- The Mallat Family Laboratory
of Organic Chemistry, Schulich Faculty of Chemistry and The Lise Meitner-Minerva
Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Dorian Didier
- The Mallat Family Laboratory
of Organic Chemistry, Schulich Faculty of Chemistry and The Lise Meitner-Minerva
Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Ilan Marek
- The Mallat Family Laboratory
of Organic Chemistry, Schulich Faculty of Chemistry and The Lise Meitner-Minerva
Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
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10
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Synthesis of 5,6- and 6,6-Spirocyclic Compounds. SYNTHESIS OF SATURATED OXYGENATED HETEROCYCLES I 2014. [DOI: 10.1007/978-3-642-41473-2_5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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11
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Tanis PS, Infantine JR, Leighton JL. Exploiting pseudo C2-symmetry for an efficient synthesis of the F-ring of the spongistatins. Org Lett 2013; 15:5464-7. [PMID: 24111885 PMCID: PMC3845086 DOI: 10.1021/ol402604s] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A concise and efficient synthesis of the F-ring fragment of the potent antimitotic marine macrolide spongistatin 1 has been developed. The key sequence involves double cross-metathesis/Sharpless asymmetric dihydroxylation reactions to establish four stereocenters in a pseudo C2-symmetric array, followed by a selective protection reaction that breaks the pseudosymmetry, establishes a fifth stereocenter, and effectively differentiates the ester termini. Overall, the six contiguous stereocenters in the C(37)-C(45) F-ring fragment are established in just seven steps.
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Affiliation(s)
- Paul S. Tanis
- Department of Chemistry, Columbia University, New York, New York 10027
| | | | - James L. Leighton
- Department of Chemistry, Columbia University, New York, New York 10027
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12
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Fernandes RA, Chowdhury AK. A Synthesis of (-)-(R)- and (+)-(S)-Lavandulol, (+)-Lavandulyl 2-Methylbutanoate, and (+)-Lavandulyl Senecioate through Orthoester Johnson-Claisen Rearrangement. European J Org Chem 2013. [DOI: 10.1002/ejoc.201300520] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Reznik SK, Leighton JL. Toward a more step-economical and scalable synthesis of spongistatin 1 to facilitate cancer drug development efforts. Chem Sci 2013; 4:1497-1501. [PMID: 25165503 PMCID: PMC4142563 DOI: 10.1039/c3sc22186e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An efficient, step-economical, and scalable synthesis of a diene-bearing AB spiroketal fragment of spongistatin 1, and a demonstration of its efficient coupling to an aldehyde derived from silylformylation of a homopropargyl alcohol to produce the entire complex C(13)-C(17) linker region are described. The scalability of the synthesis of the AB spiroketal fragment was demonstrated by the preparation of 34.5 grams by one chemist in ~60 workdays, and more than 40 grams overall. With this material in hand and having established a method for its efficient coupling to the CD fragment, we have set the stage for the rapid synthesis and evaluation of a series of analogs of the CD spiroketal.
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Affiliation(s)
- Samuel K. Reznik
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York, 10027, USA
| | - James L. Leighton
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York, 10027, USA
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Kraus H, Français A, O'Brien M, Frost J, Diéguez-Vázquez A, Polara A, Baricordi N, Horan R, Hsu DS, Tsunoda T, Ley SV. Synthesis of spongistatin 2 employing a new route to the EF fragment. Chem Sci 2013. [DOI: 10.1039/c3sc50304f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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15
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Reznik SK, Marcus BS, Leighton JL. Complex fragment coupling by crotylation: A powerful tool for polyketide natural product synthesis. Chem Sci 2012; 3:3326-3330. [PMID: 25165502 PMCID: PMC4142647 DOI: 10.1039/c2sc21325g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The first examples of the use of crotylation as a stereocontrolled complex fragment coupling strategy are described. Asymmetric aldehyde isoprenylation provides access to 2-substituted-1,3-butadienes that may be subjected to highly regio- and stereoselective 1,4 hydrosilylation with trichlorosilane. After complexation with a chiral diamine, the 2-sub-stituted-cis-crotylsilanes may be employed in highly diastereoselective Sc(OTf)3-catalyzed aldehdye crotylation reactions.
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Affiliation(s)
- Samuel K. Reznik
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York, 10027, USA. Fax: (+1) 212-932-1289; Tel: (+1) 212-854-4262
| | - Brian S. Marcus
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York, 10027, USA. Fax: (+1) 212-932-1289; Tel: (+1) 212-854-4262
| | - James L. Leighton
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York, 10027, USA. Fax: (+1) 212-932-1289; Tel: (+1) 212-854-4262
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16
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Wilson MR, Taylor RE. Toward an enantioselective synthesis of (-)-zampanolide: preparation of the C9-C20 region. Org Lett 2012; 14:3408-11. [PMID: 22720980 DOI: 10.1021/ol301383a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Progress toward the synthesis of the microtubule-stabilizing agent, (-)-zampanolide, is reported. Construction of the 2,6-cis-tetrahydropyran ring was accomplished utilizing ether transfer methodology in conjunction with an intramolecular radical cyclization reaction. Efficient installation of the C16-C20 side chain relied on a one-pot cross-metathesis/olefination sequence, Sharpless epoxidation, and selective reduction of a vinyl epoxide.
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Affiliation(s)
- Matthew R Wilson
- Department of Chemistry and Biochemistry and the Walther Cancer Research Center, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, USA
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17
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Waser M. Enamine Catalysis. ASYMMETRIC ORGANOCATALYSIS IN NATURAL PRODUCT SYNTHESES 2012:7-44. [DOI: 10.1007/978-3-7091-1163-5_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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18
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Smith AB, Risatti CA, Atasoylu O, Bennett CS, Liu J, Cheng H, TenDyke K, Xu Q. Design, synthesis, and biological evaluation of diminutive forms of (+)-spongistatin 1: lessons learned. J Am Chem Soc 2011; 133:14042-53. [PMID: 21761891 PMCID: PMC3164888 DOI: 10.1021/ja2046167] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The design, synthesis, and biological evaluation of two diminutive forms of (+)-spongistatin 1, in conjunction with the development of a potentially general design strategy to simplify highly flexible macrocyclic molecules while maintaining biological activity, have been achieved. Examination of the solution conformations of (+)-spongistatin 1 revealed a common conformational preference along the western perimeter comprising the ABEF rings. Exploiting the hypothesis that the small-molecule recognition/binding domains are likely to comprise the conformationally less mobile portions of a ligand led to the design of analogues, incorporating tethers (blue) in place of the CD and the ABCD components of the (+)-spongistatin 1 macrolide, such that the conformation of the retained (+)-spongistatin 1 skeleton would mimic the assigned solution conformations of the natural product. The observed nanomolar cytotoxicity and microtubule destabilizing activity of the ABEF analogue provide support for both the assigned solution conformation of (+)-spongistatin 1 and the validity of the design strategy.
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Affiliation(s)
- Amos B Smith
- Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, Department of Chemistry, University of Pennsylvania , Philadelphia, 19104, United States.
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Qi Y, Ma S. The medicinal potential of promising marine macrolides with anticancer activity. ChemMedChem 2011; 6:399-409. [PMID: 21302362 DOI: 10.1002/cmdc.201000534] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 01/08/2011] [Indexed: 12/12/2022]
Abstract
Marine natural products have become a major source of new chemical entities in the discovery of potential anticancer agents that potently suppress various molecular targets. In particular, the marine macrolides, which include an array of novel biomolecules endowed with outstanding cytotoxic and/or antiproliferative activities, are a prominent class of marine natural products that offer continued promise for breakthroughs in anticancer research. Herein we highlight some recent studies of promising marine macrolides, paying particular attention to their discovery, anticancer activities, mechanisms of action, chemical synthesis, and representative analogues.
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Affiliation(s)
- Yunkun Qi
- Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Shandong University, 44, West Culture Road, Jinan 250012, PR China
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21
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Nesbitt CL, McErlean CSP. Total synthesis of C19 lipid diols containing a 2,5-disubstituted-3-oxygenated tetrahydrofuran. Org Biomol Chem 2011; 9:2198-208. [DOI: 10.1039/c0ob00754d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Six-Membered Ring Systems:. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/s0959-6380(11)22015-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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23
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Bepary S, Yoon IK, Lee GH. Facile and Large Scale Synthesis of Diverse 4-O-Protected 2,3-O-Isopropylidene-D-erythrose. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.12.3788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Flowers CL, Vogel P. Short diastereoselective synthesis of the C1-C13 (AB spiroacetal) and C17-C28 fragments (CD spiroacetal) of spongistatin 1 and 2 through double chain-elongation reactions. Chemistry 2010; 16:14074-82. [PMID: 20963739 DOI: 10.1002/chem.201002204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A unique and practical synthetic sequence for rapid access to polyketides and to further the spiroacetals derived from them, which utilizes a bidirectional Hosomi-Sakurai allylation approach around key allylsilanes in the synthesis of the AB and CD ring systems of spongistatin 1 and 2, is reported. The synthesis of the AB spiroacetal 9 requires 13 steps, with a longest linear sequence of seven steps in an overall yield of 27%. The synthesis of the CD spiroacetal 13 requires 15 steps, with a longest linear sequence of 11 steps in an overall yield of 30%. Both syntheses start from but-3-enol.
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Affiliation(s)
- Christopher L Flowers
- Laboratory of Glycochemistry and Asymmetric Synthesis (LGSA), Swiss Institute of Technology (EPFL), Batochime, 1015 Lausanne, Switzerland
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