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Vyhivskyi O, Baudoin O. Total Synthesis of the Diterpenes (+)-Randainin D and (+)-Barekoxide via Photoredox-Catalyzed Deoxygenative Allylation. J Am Chem Soc 2024; 146. [PMID: 38618944 PMCID: PMC11046436 DOI: 10.1021/jacs.4c02224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/30/2024] [Accepted: 04/02/2024] [Indexed: 04/16/2024]
Abstract
We report the first enantioselective total synthesis of diterpenoid randainin D, which possesses a hydroazulenone core with a β-substituted butenolide moiety on the cycloheptane ring. The trans-5/7 ring system was formed via a highly challenging ring-closing metathesis delivering the tetrasubstituted cycloheptenone. The butenolide moiety was installed via a novel deoxygenative allylation under Ir-photoredox catalysis, employing methyl oxalate as a red/ox tag. Moreover, the developed allylation was successfully utilized in the 7-step total synthesis of (+)-barekoxide. This study suggests that this deoxygenative allylation method is a promising strategy for the formation of Cq-C(sp3) bonds (Cq = quaternary center) in the context of natural product synthesis.
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Affiliation(s)
- Oleksandr Vyhivskyi
- Department of Chemistry, University
of Basel, St. Johanns-Ring
19, CH-4056 Basel, Switzerland
| | - Olivier Baudoin
- Department of Chemistry, University
of Basel, St. Johanns-Ring
19, CH-4056 Basel, Switzerland
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2
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Liu H, Ji DW, Min XT, Mei YK, Sun SH, Zhang G, Hu YC, Chen QA. Disproportionation-Inspired Construction of Highly Functionalized Bicyclo[3.2.1]octanes. Org Lett 2023; 25:1878-1882. [PMID: 36916741 DOI: 10.1021/acs.orglett.3c00397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
The formation of one unavoidable byproduct in traditional disproportionation reactions limits their applications in synthesis. Inspired by convergent disproportionation, we develop an iodine-induced cyclization and oxidation of allylic alcohols to produce highly functionalized bicyclo[3.2.1]octanes through creation of six new bonds. Guided by the mechanism, we elaborated a variety of other bicyclo[3.2.1]octanes bearing distinct groups with presynthesized dienes and enones as the starting materials. This work provides a divergent access to bicyclo[3.2.1]octane frameworks.
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Affiliation(s)
- Heng Liu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ding-Wei Ji
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xiang-Ting Min
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Yong-Kang Mei
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shao-Han Sun
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gong Zhang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan-Cheng Hu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Qing-An Chen
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Suzuki T, Ikeda W, Kanno A, Ikeuchi K, Tanino K. Diastereoselective Synthesis of trans-anti-Hydrophenanthrenes via Ti-mediated Radical Cyclization and Total Synthesis of Kamebanin. Chemistry 2023; 29:e202203511. [PMID: 36529687 DOI: 10.1002/chem.202203511] [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: 11/11/2022] [Revised: 12/16/2022] [Accepted: 12/17/2022] [Indexed: 12/23/2022]
Abstract
Ent-kaurenes consist of an ABC-ring based on a trans-anti-hydrophenanthrene skeleton and a D ring with an exomethylene. Highly oxygen-functionalized ent-kauren-15-ones have promising antiinflammatory pharmacological activity. In this study, we developed a novel diastereoselective synthesis of trans-anti-hydrophenanthrenes via a Ti-mediated reductive radical cyclization. We also demonstrated the applicability of this method by developing the first total synthesis of (±)-kamebanin (longest linear sequence; 17 steps, overall yield; 6.5 %). Furthermore, this synthesis provided a formal semi-pinacol rearrangement for the construction of the quaternary carbon at C8 and a novel Thorpe-Ziegler-type reaction for the construction of the D-ring.
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Affiliation(s)
- Takahiro Suzuki
- Department of Chemistry, Faculty of Science, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
| | - Wataru Ikeda
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
| | - Ayaka Kanno
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
| | - Kazutada Ikeuchi
- Department of Chemistry, Faculty of Science, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
| | - Keiji Tanino
- Department of Chemistry, Faculty of Science, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
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Plangger I, Wurst K, Magauer T. Short, Divergent, and Enantioselective Total Synthesis of Bioactive ent-Pimaranes. Org Lett 2022; 24:7151-7156. [PMID: 36170466 PMCID: PMC7613685 DOI: 10.1021/acs.orglett.2c02843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present the first total synthesis of eight ent-pimaranes via a short and enantioselective route (11-16 steps). Key features of the divergent synthesis are a Sharpless asymmetric dihydroxylation, a Brønsted acid catalyzed cationic bicyclization, and a mild Rh-catalyzed arene hydrogenation for rapid access to a late synthetic branching point. From there on, selective functional group manipulations enable the synthesis of ent-pimaranes bearing different modifications in the A- and C-rings.
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Affiliation(s)
- Immanuel Plangger
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Thomas Magauer
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold-Franzens-University Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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Chen Y, Gong H, Cheng L, Lin Q. Recent Progress on Transition-Metal-Mediated Reductive C(sp3)–O Bond Radical Addition and Coupling Reactions. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/a-1848-3005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AbstractIn this short review, we summarize the recent developments on thermo-driven C(sp3)–O bond radical scission methods and their applications in the construction of C(sp3)–C bonds via conjugate addition with activated double bonds and reductive coupling mediated by economic 3d metals, in particular nickel. We have arranged the review based on three approaches for C(sp3)–O bond radical scission (vide infra). After generating the radical intermediates, their subsequent transformation into C(sp3)–C bonds enabled by C(sp3)–O cross-electrophile coupling with carbon electrophiles is discussed in detail.1 Introduction2 Direct Single-Electron Transfer to a C(sp3)–O Bond3 Radical Scission of Activated C(sp3)–O Bonds via Single-Electron Transfer to Protecting Groups4 In Situ Activation of Alcohols5 Summary and Outlook
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Affiliation(s)
- Yunrong Chen
- Center for Supramolecular Chemistry and Catalysis and Department of Chemistry, Shanghai University
| | - Hegui Gong
- Center for Supramolecular Chemistry and Catalysis and Department of Chemistry, Shanghai University
| | - Li Cheng
- School of Materials Science and Engineering, Shanghai University
| | - Quan Lin
- School of Materials Science and Engineering, Shanghai University
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