1
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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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2
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Gross B, Han SJ, Virgil SC, Stoltz BM. A Convergent Total Synthesis of (+)-Ineleganolide. J Am Chem Soc 2023; 145:7763-7767. [PMID: 36989438 PMCID: PMC10544024 DOI: 10.1021/jacs.3c02142] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Indexed: 03/31/2023]
Abstract
We report the total synthesis of the furanobutenolide-derived diterpenoid (+)-ineleganolide. The synthetic approach relies on a convergent strategy based on the coupling of two enantioenriched fragments, which are derived from (-)-linalool and (+)-norcarvone, respectively. A high-yielding, one-step Michael addition and aldol cascade furnishes a pentacyclic framework as a single diastereomer, thereby overcoming previous challenges in controlling stereochemistry. The endgame features an O2-facilitated C-H oxidation and a samarium diiodide-induced semipinacol rearrangement to furnish the highly rigid central seven-membered ring.
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Affiliation(s)
- Benjamin
M. Gross
- The
Warren and Katharine Schlinger Laboratory for Chemistry and Chemical
Engineering, California Institute of Technology, MC-101-20, Pasadena, California 91125, United States
| | - Seo-Jung Han
- The
Warren and Katharine Schlinger Laboratory for Chemistry and Chemical
Engineering, California Institute of Technology, MC-101-20, Pasadena, California 91125, United States
- Chemical
and Biological Integrative Research Center, KIST and Division of Bio-Medical
Science & Technology, KIST-School, UST, Seoul, 02792, Republic of Korea
| | - Scott C. Virgil
- The
Warren and Katharine Schlinger Laboratory for 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, California Institute of Technology, MC-101-20, Pasadena, California 91125, United States
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3
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Tuccinardi J, Wood JL. Total Syntheses of (+)-Ineleganolide and (-)-Sinulochmodin C. J Am Chem Soc 2022; 144:20539-20547. [PMID: 36283051 PMCID: PMC9651135 DOI: 10.1021/jacs.2c09826] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Indexed: 11/29/2022]
Abstract
Described herein are the first total syntheses of the nor-furanocembranoid natural products (+)-ineleganolide (1) and (-)-sinulochmodin C (2). The synthetic strategy is predicated on a transannular Michael reaction that provides both natural products from a common macrocyclic intermediate and leverages a diastereoselective radical cyclization to furnish a key bicyclic lactone. The latter is further advanced to a macrocyclic precursor via a Nozaki-Hiyama-Kishi cyclization and a one-pot furan oxidation/oxa-Michael cascade. Unexpected stereochemical nuances that guided the evolution and eventual completion of the total synthesis are discussed.
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Affiliation(s)
- Joseph
P. Tuccinardi
- Department of Chemistry and
Biochemistry, Baylor University, One Bear Place 97348, Waco, Texas 76798, United States
| | - John L. Wood
- Department of Chemistry and
Biochemistry, Baylor University, One Bear Place 97348, Waco, Texas 76798, United States
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4
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Rhodium-Catalyzed Aerobic Conversion of 2-Diazo-1,3-dicarbonyls to Vicinal Tricarbonyl Compounds and Their In-Situ Stability Toward Oxidative Degradation. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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5
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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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6
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Abstract
![]()
The marine natural
product scabrolide A was obtained by isomerization
of the vinylogous 1,4-diketone entity of nominal scabrolide B as the
purported pivot point of the biosynthesis of these polycyclic norcembranoids.
Despite the success of this maneuver, the latter compound itself turned
out not to be identical with the natural product of that name. The
key steps en route to the carbocyclic core of these targets were a
[2,3]-sigmatropic rearrangement of an allylic sulfur ylide to forge
the overcrowded C12–C13 bond, an RCM reaction to close the
congested central six-membered ring, and a hydroxy-directed epoxidation/epoxide
opening/isomerization sequence to set the “umpoled”
1,4-dicarbonyl motif and the correct angular configuration at C12.
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Affiliation(s)
- Zhanchao Meng
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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7
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Abstract
We present a case study to demonstrate how complex molecule synthesis can benefit from quantum mechanics (QM) calculations. Theory is applied in two contexts: testing the chemical intuition used in retrosynthetic planning, along with expediting the resolution of unexpected challenges encountered during the course of the synthesis. From a computational lens, we examine retrospectively the strategies employed and the decisions made during our synthetic efforts toward the diterpenoid natural product ineleganolide. Seemingly logical and robust hypotheses are found to be ill-fated after theoretical investigation. Prior knowledge of these issues may have potentially saved valuable time and resources during our synthetic efforts. This cautionary tale suggests that synthetic campaigns can benefit from computational evaluation of synthetic plans.
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Affiliation(s)
- Alexander Q Cusumano
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Brian M Stoltz
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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8
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Biletskyi B, Colonna P, Masson K, Parrain JL, Commeiras L, Chouraqui G. Small rings in the bigger picture: ring expansion of three- and four-membered rings to access larger all-carbon cyclic systems. Chem Soc Rev 2021; 50:7513-7538. [PMID: 34002179 DOI: 10.1039/d0cs01396j] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The release of the inherent ring strain of cyclobutane and cyclopropane derivatives allows a rapid build-up of molecular complexity. This review highlights the state-of-the-art of the ring expansions of three- and four-membered cycles and is organised by types of reactions with emphasis on the reaction mechanisms. Selected examples are discussed to illustrate the synthetic potential of this elegant synthetic tool.
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Affiliation(s)
- Bohdan Biletskyi
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France.
| | - Pierre Colonna
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France.
| | - Kévin Masson
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France.
| | - Jean-Luc Parrain
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France.
| | - Laurent Commeiras
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France.
| | - Gaëlle Chouraqui
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France.
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9
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Budeev A, Kantin G, Dar’in D, Krasavin M. Diazocarbonyl and Related Compounds in the Synthesis of Azoles. Molecules 2021; 26:2530. [PMID: 33926128 PMCID: PMC8123665 DOI: 10.3390/molecules26092530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 12/15/2022] Open
Abstract
Diazocarbonyl compounds have found numerous applications in many areas of chemistry. Among the most developed fields of diazo chemistry is the preparation of azoles from diazo compounds. This approach represents a useful alternative to more conventional methods of the synthesis of azoles. A comprehensive review on the preparation of various azoles (oxazoles, thiazoles, imidazoles, pyrazoles, triazoles, and tetrazoles) from diazocarbonyl and related compounds is presented for the first time along with discussion of advantages and disadvantages of «diazo» approaches to azoles.
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Affiliation(s)
| | | | - Dmitry Dar’in
- Institute of Chemistry, St. Petersburg State University, 198504 Peterhof, Russia; (A.B.); (G.K.)
| | - Mikhail Krasavin
- Institute of Chemistry, St. Petersburg State University, 198504 Peterhof, Russia; (A.B.); (G.K.)
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10
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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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11
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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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12
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Craig RA, Smith RC, Roizen JL, Jones AC, Virgil SC, Stoltz BM. Unified Enantioselective, Convergent Synthetic Approach toward the Furanobutenolide-Derived Polycyclic Norcembranoid Diterpenes: Synthesis of a Series of Ineleganoloids by Oxidation-State Manipulation of the Carbocyclic Core. J Org Chem 2019; 84:7722-7746. [PMID: 31066273 DOI: 10.1021/acs.joc.9b00635] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Late-stage synthetic efforts to advance the enatio- and diastereoselectively constructed [6,7,5,5]-fused tetracyclic scaffold toward the polycyclic norditerpenoid ineleganolide are disclosed. The described investigations focus on oxidation-state manipulation around the central cycloheptane ring. Computational evaluation of ground-state energies of dihydroineleganolide is used to rationalize empirical observations and provide insight for further synthetic development, enhancing the understanding of the conformational constraints of these compact polycyclic structures. Advanced synthetic manipulations generated a series of natural product-like compounds termed the ineleganoloids.
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Affiliation(s)
- Robert A Craig
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Russell C Smith
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Jennifer L Roizen
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Amanda C Jones
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Scott C Virgil
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Brian M Stoltz
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , California 91125 , United States
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13
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Deng M, Zhang X, Li Z, Chen H, Zang S, Liang G. Rapid Construction of the Common [5-5-6] Tricyclic Ring Skeleton in Polycyclic Cembranoids and Norcembranoids via Intramolecular 1,3-Dipolar Cycloaddition. Org Lett 2019; 21:1493-1496. [PMID: 30789271 DOI: 10.1021/acs.orglett.9b00285] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A synthetically challenging bowl-shaped [5-5-6] tricyclic framework commonly seen in many polycyclic cembranoids and norcembranoids was strategically established in a convenient six-step sequence featuring an intramolecular 1, 3-dipolar cycloaddition reaction. Synthetic manipulations of such a valuable intermediate were explored for future applications.
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Affiliation(s)
- Meng Deng
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Xiao Zhang
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Zining Li
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Hongbin Chen
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Shaoli Zang
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Guangxin Liang
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Nankai University , Tianjin 300071 , China
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14
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Tsuruda K, Tokumoto T, Inoue N, Nakajima M, Nemoto T. Synthesis of 7-Membered Ring Carbocycles via a Palladium-Catalyzed Intramolecular Allylic Alkylation-Isomerization-Cope Rearrangement Cascade. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800230] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Kazuki Tsuruda
- Graduate School of Pharmaceutical Sciences; Chiba University; 1-8-1, Inohana, Chuo-ku 260-8675 Chiba Japan
| | - Takahisa Tokumoto
- Graduate School of Pharmaceutical Sciences; Chiba University; 1-8-1, Inohana, Chuo-ku 260-8675 Chiba Japan
| | - Naoya Inoue
- Graduate School of Pharmaceutical Sciences; Chiba University; 1-8-1, Inohana, Chuo-ku 260-8675 Chiba Japan
| | - Masaya Nakajima
- Graduate School of Pharmaceutical Sciences; Chiba University; 1-8-1, Inohana, Chuo-ku 260-8675 Chiba Japan
| | - Tetsuhiro Nemoto
- Graduate School of Pharmaceutical Sciences; Chiba University; 1-8-1, Inohana, Chuo-ku 260-8675 Chiba Japan
- Molecular Chirality Research Center; Chiba University; 1-33, Yayoi-cho, Inage-ku 263-8522 Chiba Japan
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15
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Craig RA, Smith RC, Roizen JL, Jones AC, Virgil SC, Stoltz BM. Development of a Unified Enantioselective, Convergent Synthetic Approach Toward the Furanobutenolide-Derived Polycyclic Norcembranoid Diterpenes: Asymmetric Formation of the Polycyclic Norditerpenoid Carbocyclic Core by Tandem Annulation Cascade. J Org Chem 2018; 83:3467-3485. [PMID: 29464957 PMCID: PMC5889334 DOI: 10.1021/acs.joc.7b02825] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An enantioselective and diastereoselective approach toward the synthesis of the tetracyclic scaffold of the furanobutenolide-derived polycyclic norditerpenoids is described. Focusing on synthetic efforts toward ineleganolide, the synthetic approach utilizes a palladium-catalyzed enantioselective allylic alkylation for the construction of the requisite chiral tertiary ether. A diastereoselective cyclopropanation-Cope rearrangement cascade enabled the convergent assembly of the ineleganolide [6,7,5,5]-tetracyclic scaffold. Investigation of substrates for this critical tandem annulation process is discussed along with synthetic manipulations of the [6,7,5,5]-tetracyclic scaffold and the attempted interconversion of the [6,7,5,5]-tetracyclic scaffold of ineleganolide to the isomeric [7,6,5,5]-core of scabrolide A and its naturally occurring isomers. Computational evaluation of ground-state energies of late-stage synthetic intermediates was used to guide synthetic development and aid in the investigation of the conformational rigidity of these highly constrained and compact polycyclic structures.
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Affiliation(s)
- Robert A. Craig
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Russell C. Smith
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jennifer L. Roizen
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Amanda C. Jones
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Scott C. Virgil
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Brian M. Stoltz
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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