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Zhang YP, Du S, Ma Y, Zhan W, Chen W, Yang X, Zhang H. Structure-Unit-Based Total Synthesis of (-)-Sinulochmodin C. Angew Chem Int Ed Engl 2024; 63:e202315481. [PMID: 38009457 DOI: 10.1002/anie.202315481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 11/21/2023] [Accepted: 11/24/2023] [Indexed: 11/28/2023]
Abstract
Herein we report a structure-unit-based asymmetric total synthesis of sinulochmodin C, a norcembranoid diterpenoid bearing a transannular strained ether bridge β-keto tetrahydrofuran moiety. Our synthetic route features an intramolecular double Michael addition to construct stereospecifically the [7,6,5,5] tetracyclic skeleton, a vinylogous hydroxylation/oxidation procedure or a stereospecific epoxide opening/oxidation sequence to establish the γ-keto enone intermediate, a Lewis acid/Brønsted acid mediated transannular oxa-Michael addition to fuse the β-keto tetrahydrofuran moiety, a Mukaiyama hydration/Pd-C hydrogenation to reverse the C1-configuration of the isopropenyl unit, and a bioinspired transformation of sinulochmodin C into scabrolide A.
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Affiliation(s)
- Yi-Peng Zhang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research and Development of Natural Products, Yunnan Characteristic Plant Extraction Laboratory, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China
| | - Shufei Du
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research and Development of Natural Products, Yunnan Characteristic Plant Extraction Laboratory, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China
| | - Ying Ma
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research and Development of Natural Products, Yunnan Characteristic Plant Extraction Laboratory, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China
| | - Weixin Zhan
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research and Development of Natural Products, Yunnan Characteristic Plant Extraction Laboratory, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China
| | - Wen Chen
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research and Development of Natural Products, Yunnan Characteristic Plant Extraction Laboratory, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China
| | - Xiaodong Yang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research and Development of Natural Products, Yunnan Characteristic Plant Extraction Laboratory, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China
| | - Hongbin Zhang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research and Development of Natural Products, Yunnan Characteristic Plant Extraction Laboratory, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China
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McArthur G, Abel S, Volpin G, Barber DM. Strategies for the Enantioselective Synthesis of 2‐Isoxazolines and 2‐Isoxazolin‐5‐ones Bearing Fully Substituted Stereocenters**. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Gillian McArthur
- Research and Development, Weed Control Chemistry, Bayer AG, Crop Science Division Industriepark Höchst 65926 Frankfurt am Main Germany
| | - Steven Abel
- Research and Development, Weed Control Chemistry, Bayer AG, Crop Science Division Industriepark Höchst 65926 Frankfurt am Main Germany
| | - Giulio Volpin
- Research and Development, Small Molecules Technologies, Process Research, Bayer AG, Crop Science Division Industriepark Höchst 65926 Frankfurt am Main Germany
| | - David M. Barber
- Research and Development, Weed Control Chemistry, Bayer AG, Crop Science Division Industriepark Höchst 65926 Frankfurt am Main Germany
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3
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Truax NJ, Ayinde S, Liu JO, Romo D. Total Synthesis of Rameswaralide Utilizing a Pharmacophore-Directed Retrosynthetic Strategy. J Am Chem Soc 2022; 144:18575-18585. [PMID: 36166374 DOI: 10.1021/jacs.2c08245] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A pharmacophore-directed retrosynthetic strategy was applied to the first total synthesis of the cembranoid rameswaralide in order to simultaneously achieve a total synthesis while also developing a structure-activity relationship profile throughout the synthetic effort. The synthesis utilized a Diels-Alder lactonization process, including a rare kinetic resolution to demonstrate the potential of this strategy for an enantioselective synthesis providing both the 5,5,6- and, through a ring expansion, 5,5,7-tricyclic ring systems present in several Sinularia soft coral cembranoids. A pivotal synthetic intermediate, a tricyclic epoxy α-bromo cycloheptenone, displayed high cytotoxicity with interesting selectivity toward the HCT-116 colon cancer cell line. This intermediate enabled the pursuit of three unique D-ring annulation strategies including a photocatalyzed intramolecular Giese-type radical cyclization and a diastereoselective, intramolecular enamine-mediated Michael addition, with the latter annulation constructing the final D-ring to deliver rameswaralide. The serendipitous discovery of an oxidation state transposition of the tricyclic epoxy cycloheptenone proceeding through a presumed doubly vinylogous, E1-type elimination enabled the facile introduction of the required α-methylene butyrolactone. Preliminary biological tests of rameswaralide and precursors demonstrated weak cytotoxicity; however, the comparable cytotoxicity of a simple 6,7-bicyclic β-keto ester, corresponding to the CD-ring system of rameswaralide, to that of the natural product itself suggests that such bicyclic β-ketoesters may constitute an interesting pharmacophore that warrants further exploration.
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Affiliation(s)
- Nathanyal J Truax
- Department of Chemistry & Biochemistry, Baylor University, 101 Bagby Avenue, Waco, Texas 76710, United States
| | - Safiat Ayinde
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Jun O Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Daniel Romo
- Department of Chemistry & Biochemistry, Baylor University, 101 Bagby Avenue, Waco, Texas 76710, United States
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Abstract
Covering: 1986 to 2020Natural products are an enduring source of chemical information useful for probing biologically relevant chemical space. Toward gathering further structure-activity relationship (SAR) information for a particular natural product, synthetic chemists traditionally proceeded first by a total synthesis effort followed by the synthesis of simplified derivatives. While this approach has proven fruitful, it often does not incorporate hypotheses regarding structural features necessary for bioactivity at the synthetic planning stage, but rather focuses on the rapid assembly of the targeted natural product; a goal that often supersedes the opportunity to gather SAR information en route to the natural product. Furthermore, access to simplified variants of a natural product possessing only the proposed essential structural features necessary for bioactivity, typically at lower oxidation states overall, is sometimes non-trivial from the original established synthetic route. In recent years, several synthetic design strategies were described to streamline the process of finding bioactive molecules in concert with fathering further SAR studies for targeted natural products. This review article will briefly discuss traditional retrosynthetic strategies and contrast them to selected examples of recent synthetic strategies for the investigation of biologically relevant chemical space revealed by natural products. These strategies include: diversity-oriented synthesis (DOS), biology-oriented synthesis (BIOS), diverted-total synthesis (DTS), analogue-oriented synthesis (AOS), two-phase synthesis, function-oriented synthesis (FOS), and computed affinity/dynamically ordered retrosynthesis (CANDOR). Finally, a description of pharmacophore-directed retrosynthesis (PDR) developed in our laboratory and initial applications will be presented that was initially inspired by a retrospective analysis of our synthetic route to pateamine A completed in 1998.
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Affiliation(s)
- Nathanyal J Truax
- Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76710, USA.
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Hafeman NJ, Loskot SA, Reimann CE, Pritchett BP, Virgil SC, Stoltz BM. The Total Synthesis of (-)-Scabrolide A. J Am Chem Soc 2020; 142:8585-8590. [PMID: 32223255 DOI: 10.1021/jacs.0c02513] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The first total synthesis of the norcembranoid diterpenoid scabrolide A is disclosed. The route begins with the synthesis of two chiral pool-derived fragments, which undergo a convergent coupling to expediently introduce all 19 carbon atoms of the natural product. An intramolecular Diels-Alder reaction and an enone-olefin cycloaddition/fragmentation sequence are then employed to construct the fused [5-6-7] linear carbocyclic core of the molecule and complete the total synthesis.
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Affiliation(s)
- Nicholas J Hafeman
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 101-20, Pasadena, California 91125, United States
| | - Steven A Loskot
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 101-20, Pasadena, California 91125, United States
| | - Christopher E Reimann
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 101-20, Pasadena, California 91125, United States
| | - Beau P Pritchett
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 101-20, Pasadena, California 91125, United States
| | - Scott C Virgil
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 101-20, Pasadena, California 91125, United States
| | - Brian M Stoltz
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 101-20, Pasadena, California 91125, United States
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Truax NJ, Ayinde S, Van K, Liu JO, Romo D. Pharmacophore-Directed Retrosynthesis Applied to Rameswaralide: Synthesis and Bioactivity of Sinularia Natural Product Tricyclic Cores. Org Lett 2019; 21:7394-7399. [PMID: 31498642 DOI: 10.1021/acs.orglett.9b02713] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A pharmacophore-directed retrosynthesis strategy applied to rameswaralide provided simplified precursors bearing the common 5,5,6 (red) and 5,5,7 (blue) skeleton present in several cembranoid and norcembranoids from Sinularia soft corals. Key steps include a Diels-Alder lactonization organocascade delivering the common 5,5,6 core and a subsequent ring expansion affording a 5,5,7 core serviceable for the synthesis of rameswaralide. Initial structure-activity relationships of intermediates en route to the natural product have revealed interesting differential and selective cytotoxicity.
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Affiliation(s)
- Nathanyal J Truax
- Department of Chemistry & Biochemistry , Baylor University , Waco , Texas 76710 , United States
| | - Safiat Ayinde
- Department of Pharmacology and Molecular Sciences , John Hopkins School of Medicine , 725 North Wolfe Street , Baltimore , Maryland 21205 , United States
| | - Khoi Van
- Department of Chemistry & Biochemistry , Baylor University , Waco , Texas 76710 , United States
| | - Jun O Liu
- Department of Pharmacology and Molecular Sciences , John Hopkins School of Medicine , 725 North Wolfe Street , Baltimore , Maryland 21205 , United States
| | - Daniel Romo
- Department of Chemistry & Biochemistry , Baylor University , Waco , Texas 76710 , United States
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