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Xie F, Dong S, Liu J, Yu M, Ren D, Zhao J, Liu X. Enantio- and Diastereoselective Copper-Catalyzed Borylative Coupling of Styrenes and Azadienes. Org Lett 2024; 26:5335-5340. [PMID: 38885466 DOI: 10.1021/acs.orglett.4c01722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Here we disclose a CuB-catalyzed reaction between aurone-derived α,β-unsaturated imines and styrenes to produce 2-substituted benzofuran derivatives bearing both the γ-boryl functionality and α,β-unsymmetric stereogenic centers. The reaction represents the first transition-metal-catalyzed unsymmetric 1,4-Michael additions of azadienes, which would enrich the arsenal of CuB catalysis in organic synthesis. In addition, the synthetically versatile boron-alkylated products can be elaborated by chemical transformations to useful optically active benzofuran heterocycles.
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Affiliation(s)
- Fang Xie
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, China
| | - Shijie Dong
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, China
| | - Jiayi Liu
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, China
| | - Miao Yu
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, China
| | - Deyue Ren
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, China
| | - Jie Zhao
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, China
| | - Xiaodan Liu
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, China
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2
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Zhang Z, Qian X, Gu Y, Gui J. Controllable skeletal reorganizations in natural product synthesis. Nat Prod Rep 2024; 41:251-272. [PMID: 38291905 DOI: 10.1039/d3np00066d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Covering: 2016 to 2023The synthetic chemistry community is always in pursuit of efficient routes to natural products. Among the many available general strategies, skeletal reorganization, which involves the formation, cleavage, and migration of C-C and C-heteroatom bonds, stands out as a particularly useful approach for the efficient assembly of molecular skeletons. In addition, it allows for late-stage modification of natural products for quick access to other family members or unnatural derivatives. This review summarizes efficient syntheses of steroid, terpenoid, and alkaloid natural products that have been achieved by means of this strategy in the past eight years. Our goal is to illustrate the strategy's potency and reveal the spectacular human ingenuity demonstrated in its use and development.
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Affiliation(s)
- Zeliang Zhang
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
| | - Xiao Qian
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
| | - Yucheng Gu
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Jinghan Gui
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
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3
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Patil RD, Pratihar S. Ruthenium(II)-Catalyzed Hydrogenation and Tandem (De)Hydrogenation via Metal-Ligand Cooperation: Base- and Solvent-Assisted Switchable Selectivity. J Org Chem 2024; 89:1361-1378. [PMID: 36283058 DOI: 10.1021/acs.joc.2c01965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A versatile, selective, solvent (methanol vs ethanol)- and base (potassium vs lithium carbonate)-assisted switchable synthesis of saturated ketone and α-methyl saturated ketone from α,β-unsaturated ketone is developed. Mechanistic aspects, evaluated from spectroscopic studies, in situ monitoring of the reaction progress, control studies, and labeling studies, further indicate the involvement of a tandem dehydrogenation-condensation-hydrogenation sequence in the reaction, in which the interconvertible coordination mode (imino N → Ru and amido N-Ru) of coordinated imidazole with Ru(II)-para-cymene is crucial, without which the efficiency and selectivity of the catalyst are completely lost. The catalyst demonstrates good efficiency, selectivity, and functional group tolerance and displays a broad scope (69 examples) for monomethylation and hydrogenation of unsaturated chalcones, double methylation of ketones, and N-methylation of amines.
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Affiliation(s)
- Rahul Daga Patil
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Inorganic Materials and Catalysis Division, CSIR-Central Salt & Marine Chemicals Research Institute, G.B. Marg, Bhavnagar 364002, Gujarat, India
| | - Sanjay Pratihar
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Inorganic Materials and Catalysis Division, CSIR-Central Salt & Marine Chemicals Research Institute, G.B. Marg, Bhavnagar 364002, Gujarat, India
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4
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Larghi EL, Bracca ABJ, Simonetti SO, Kaufman TS. Recent developments in the total synthesis of natural products using the Ugi multicomponent reactions as the key strategy. Org Biomol Chem 2024; 22:429-465. [PMID: 38126459 DOI: 10.1039/d3ob01837g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The total syntheses of selected natural products using different versions of the Ugi multicomponent reaction is reviewed on a case-by-case basis. The revision covers the period 2008-2023 and includes detailed descriptions of the synthetic sequences, the use of state-of-the-art chemical reagents and strategies, as well as the advantages and limitations of the transformation and some remedial solutions. Relevant data on the isolation and bioactivity of the different natural targets are also briefly provided. The examples clearly evidence the strategic importance of this transformation and its key role in the modern natural products synthetic chemistry toolbox. This methodology proved to be a valuable means for easily building molecular complexity and efficiently delivering step-economic syntheses even of intricate structures, with a promising future.
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Affiliation(s)
- Enrique L Larghi
- Instituto de Química Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquímicas y Farmacéuticas - Universidad Nacional de Rosario, Suipacha 531 (2000), Rosario, Argentina.
| | - Andrea B J Bracca
- Instituto de Química Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquímicas y Farmacéuticas - Universidad Nacional de Rosario, Suipacha 531 (2000), Rosario, Argentina.
| | - Sebastián O Simonetti
- Instituto de Química Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquímicas y Farmacéuticas - Universidad Nacional de Rosario, Suipacha 531 (2000), Rosario, Argentina.
| | - Teodoro S Kaufman
- Instituto de Química Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquímicas y Farmacéuticas - Universidad Nacional de Rosario, Suipacha 531 (2000), Rosario, Argentina.
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5
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Liu J, Gao S, Miliordos E, Chen M. Asymmetric Syntheses of ( Z)- or ( E)-β,γ-Unsaturated Ketones via Silane-Controlled Enantiodivergent Catalysis. J Am Chem Soc 2023; 145:19542-19553. [PMID: 37639380 PMCID: PMC11144060 DOI: 10.1021/jacs.3c02595] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Cu-catalyzed highly stereoselective and enantiodivergent syntheses of (Z)- or (E)-β,γ-unsaturated ketones from 1,3-butadienyl silanes are developed. The nature of the silyl group of the dienes has a significant impact on the stereo- and enantioselectivity of the reactions. Under the developed catalytic systems, the reactions of acyl fluorides with phenyldiemthylsilyl-substituted 1,3-diene gave (Z)-β,γ-unsaturated ketones bearing an α-tertiary stereogenic center with excellent enantioselectivities and high Z-selectivities, where the reactions with triisopropylsilyl-substituted 1,3-butadiene formed (E)-β,γ-unsaturated ketones with high optical purities and excellent E-selectivities. The products generated from the reactions contain three functional groups with orthogonal chemical reactivities, which can undergo a variety of transformations to afford synthetically valuable intermediates.
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Affiliation(s)
- Jiaming Liu
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - Shang Gao
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, P. R. China
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - Ming Chen
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
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6
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Collins S, Sieber JD. Development of regiodivergent asymmetric reductive coupling reactions of allenamides to access heteroatom-rich organic compounds. Chem Commun (Camb) 2023; 59:10087-10100. [PMID: 37529849 DOI: 10.1039/d3cc03013j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
Organic compounds of biological importance often contain multiple stereogenic C-heteroatom functional groups (e.g. amines, alcohols, and ethers). As a result, synthetic methods to access such compounds in a reliable and stereoselective fashion are important. In this feature article, we present a strategy to enable the introduction of multiple C-heteroatom functional groups in a regiodivergent cross-coupling approach through the use of reductive coupling chemistry employing allenamides. Such processes allow for opportunities to access different heteroatom substitution patterns from the same starting materials.
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Affiliation(s)
- Stephen Collins
- Virginia Commonwealth University, Department of Chemistry 1001 West Main Street, Richmond, VA 23284, USA.
| | - Joshua D Sieber
- Virginia Commonwealth University, Department of Chemistry 1001 West Main Street, Richmond, VA 23284, USA.
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7
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Ghosh T, Bhakta S. Advancements in Gold-Catalyzed Cascade Reactions to Access Carbocycles and Heterocycles: An Overview. CHEM REC 2023; 23:e202200225. [PMID: 36543388 DOI: 10.1002/tcr.202200225] [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: 09/30/2022] [Revised: 12/03/2022] [Indexed: 12/24/2022]
Abstract
This review summarizes recent developments (from 2006 to 2022) in numerous important and efficient carbo- and heterocycle generations using gold-catalyzed cascade protocols. Herein, methodologies involve selectivity, cost-effectiveness, and ease of product formation being controlled by the ligand as well as the counter anion, catalyst, substrate, and reaction conditions. Gold-catalyzed cascade reactions covered different strategies through the compilation of various approaches such as cyclization, hydroarylation, intermolecular and intramolecular cascade reactions, etc. This entitled reaction is also useful for the synthesis of spiro, fused, bridged carbo- and heterocycles.
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Affiliation(s)
- T Ghosh
- Department of Chemistry, Jadavpur University, Kolkata, 700 032, West Bengal, India.,Department of Applied Chemistry, Maulana Abul Kalam Azad University of Technology, West Bengal, Haringhata-741249, Nadia, West Bengal, India
| | - S Bhakta
- Department of Applied Chemistry, Maulana Abul Kalam Azad University of Technology, West Bengal, Haringhata-741249, Nadia, West Bengal, India
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8
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Kincaid JRA, Caravez JC, Iyer KS, Kavthe RD, Fleck N, Aue DH, Lipshutz BH. A sustainable synthesis of the SARS-CoV-2 M pro inhibitor nirmatrelvir, the active ingredient in Paxlovid. Commun Chem 2022; 5:156. [PMID: 36465589 PMCID: PMC9685088 DOI: 10.1038/s42004-022-00758-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/12/2022] [Indexed: 11/24/2022] Open
Abstract
Pfizer's drug for the treatment of patients infected with COVID-19, Paxlovid, contains most notably nirmatrelvir, along with ritonavir. Worldwide demand is projected to be in the hundreds of metric tons per year, to be produced by several generic drug manufacturers. Here we show a 7-step, 3-pot synthesis of the antiviral nirmatrelvir, arriving at the targeted drug in 70% overall yield. Critical amide bond-forming steps utilize new green technology that completely avoids traditional peptide coupling reagents, as well as epimerization of stereocenters. Likewise, dehydration of a primary amide to the corresponding nitrile is performed and avoids use of the Burgess reagent and chlorinated solvents. DFT calculations for various conformers of nirmatrelvir predict that two rotamers about the tertiary amide would be present with an unusually high rotational barrier. Direct comparisons with the original literature procedures highlight both the anticipated decrease in cost and environmental footprint associated with this route, potentially expanding the availability of this important drug worldwide.
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Affiliation(s)
- Joseph R. A. Kincaid
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
| | - Juan C. Caravez
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
| | - Karthik S. Iyer
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
| | - Rahul D. Kavthe
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
| | - Nico Fleck
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
| | - Donald H. Aue
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
| | - Bruce H. Lipshutz
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
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9
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Jin S, Zhao X, Ma D. Divergent Total Syntheses of Napelline-Type C20-Diterpenoid Alkaloids: (-)-Napelline, (+)-Dehydronapelline, (-)-Songorine, (-)-Songoramine, (-)-Acoapetaldine D, and (-)-Liangshanone. J Am Chem Soc 2022; 144:15355-15362. [PMID: 35948501 DOI: 10.1021/jacs.2c06738] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The napelline-type alkaloids possess an azabicyclo[3.2.1]octane moiety and an ent-kaurane-type tetracyclic skeleton (6/6/6/5) along with varied oxidation patterns embedded in the compact hexacyclic framework. Herein, we disclose a divergent entry to napelline-type alkaloids that hinges on convergent assembly of the ent-kaurane core using a diastereoselective intermolecular Cu-mediated conjugate addition and subsequent intramolecular Michael addition reaction as well as rapid construction of the azabicyclo[3.2.1]octane motif via an intramolecular Mannich cyclization. The power of this strategy has been demonstrated through efficient asymmetric total syntheses of eight napelline-type alkaloids, including (-)-napelline, (-)-12-epi-napelline, (+)-dehydronapelline, (+)-12-epi-dehydronapelline, (-)-songorine, (-)-songoramine, (-)-acoapetaldine D, and (-)-liangshanone.
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Affiliation(s)
- Shicheng Jin
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
| | - Xiangbo Zhao
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
| | - Dawei Ma
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
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10
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Adak S, Lukowski AL, Schäfer RJB, Moore BS. From Tryptophan to Toxin: Nature's Convergent Biosynthetic Strategy to Aetokthonotoxin. J Am Chem Soc 2022; 144:2861-2866. [PMID: 35142504 PMCID: PMC9004672 DOI: 10.1021/jacs.1c12778] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Aetokthonotoxin (AETX) is a cyanobacterial neurotoxin that causes vacuolar myelinopathy, a neurological disease that is particularly deadly to bald eagles in the United States. The recently characterized AETX is structurally unique among cyanotoxins and is composed of a pentabrominated biindole nitrile. Herein we report the discovery of an efficient, five-enzyme biosynthetic pathway that the freshwater cyanobacterium Aetokthonos hydrillicola uses to convert two molecules of tryptophan to AETX. We demonstrate that the biosynthetic pathway follows a convergent route in which two functionalized indole monomers are assembled and then reunited by biaryl coupling catalyzed by the cytochrome P450 AetB. Our results revealed enzymes with novel biochemical functions, including the single-component flavin-dependent tryptophan halogenase AetF and the iron-dependent nitrile synthase AetD.
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Affiliation(s)
- Sanjoy Adak
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093, United States
| | - April L Lukowski
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093, United States
| | - Rebecca J B Schäfer
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093, United States
| | - Bradley S Moore
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093, United States
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093, United States
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11
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Cuan Y, Li W, Dou Y, Yang G. Facile and scalable synthesis of baphicacanthin A by a two-pot procedure. Nat Prod Res 2021; 37:1439-1443. [PMID: 34852687 DOI: 10.1080/14786419.2021.2011275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Facile two-pot total synthesis of baphicacanthin A, a natural phenoxazinone alkaloid isolated from the roots of Baphicacanthus cusia which has been utilized as a traditional chinese medicine to effectively treat disease caused by coronavirus, has been developed from simple and commercially available starting materials. Catalytic aerobic oxidative cross-cyclocondensation of equimolar 2-aminophenol and 3-methoxy-2-hydroxylphenol in water was used to construct the key molecular skeleton 2-hydroxy-3H-phenoxazin-3-one. Gram scale synthesis was realized in 80% overall yield with practical convenience.
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Affiliation(s)
- Yalong Cuan
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, China
| | - Wenhao Li
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, China
| | - Yingchao Dou
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, China
| | - Guanyu Yang
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, China
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12
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Martínez RF, Cravotto G, Cintas P. Organic Sonochemistry: A Chemist's Timely Perspective on Mechanisms and Reactivity. J Org Chem 2021; 86:13833-13856. [PMID: 34156841 PMCID: PMC8562878 DOI: 10.1021/acs.joc.1c00805] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 01/17/2023]
Abstract
Sonochemistry, the use of sound waves, usually within the ultrasonic range (>20 kHz), to boost or alter chemical properties and reactivity constitutes a long-standing and sustainable technique that has, however, received less attention than other activation protocols despite affordable setups. Even if unnecessary to underline the impact of ultrasound-based strategies in a broad range of chemical and biological applications, there is considerable misunderstanding and pitfalls regarding the interpretation of cavitational effects and the actual role played by the acoustic field. In this Perspective, with an eye on mechanisms in particular, we discuss the potentiality of sonochemistry in synthetic organic chemistry through selected examples of past and recent developments. Such examples illustrate specific controlling effects and working rules. Looking back at the past while looking forward to advancing the field, some essentials of sonochemical activation will be distilled.
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Affiliation(s)
- R. Fernando Martínez
- Department
of Organic and Inorganic Chemistry, Faculty of Sciences, and IACYS-Green
Chemistry and Sustainable Development Unit, University of Extremadura, 06006 Badajoz, Spain
| | - Giancarlo Cravotto
- Dipartimento
di Scienza e Tecnologia del Farmaco, Universita
degli Studi di Torino, via P. Giuria 9, Torino 10125, Italy
| | - Pedro Cintas
- Department
of Organic and Inorganic Chemistry, Faculty of Sciences, and IACYS-Green
Chemistry and Sustainable Development Unit, University of Extremadura, 06006 Badajoz, Spain
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14
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Ju W, Wang X, Tian H, Gui J. Asymmetric Total Synthesis of Clionastatins A and B. J Am Chem Soc 2021; 143:13016-13021. [PMID: 34398601 DOI: 10.1021/jacs.1c07511] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Herein we report the first total synthesis of polychlorinated steroids clionastatins A and B, which was accomplished asymmetrically by means of a convergent, radical fragment coupling approach. Key features of the synthesis include an Ireland-Claisen rearrangement to introduce the C5 stereocenter (which was ultimately transferred to the C10 quaternary stereocenter of the clionastatins via a traceless stereochemical relay), a regioselective acyl radical conjugate addition to join the two fragments, an intramolecular Heck reaction to install the C10 quaternary stereocenter, and a diastereoselective olefin dichlorination to establish the synthetically challenging pseudoequatorial dichlorides. This work also enabled us to determine that the true structures of clionastatins A and B are in fact C14 epimers of the originally proposed structures.
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Affiliation(s)
- Wei Ju
- CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Xudong Wang
- CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Hailong Tian
- CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Jinghan Gui
- CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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