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Du J, Fu S, Liu B. A Photoinduced Radical Cascade Cyclization for the Synthesis of Angularly Fused Tricyclic Compounds. Org Lett 2024. [PMID: 38805032 DOI: 10.1021/acs.orglett.4c01497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
A photoinduced electron transfer (PET)-triggered cascade reaction has been devised for the conversion of second-generation enol silyl ethers into angularly fused tricyclic scaffolds. Utilizing readily available and cost-effective DCA and phenanthrene as the catalytic systems, this cascade transformation is achieved with high efficiency. The reaction demonstrates a good substrate scope and excellent stereoselectivity, thereby enriching the realm of PET-induced cascade reactions. Additionally, the radical adducts generated through this process can serve as valuable subunits for the synthesis of complex molecules.
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Affiliation(s)
- Jiaxin Du
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Shaomin Fu
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Bo Liu
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
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Hirata T, Ogasawara Y, Yamashita Y, Kobayashi S. α-Alkylation of Ketones with Alkenes Enabled by Photoinduced Activation of Silyl Enol Ethers in the Presence of a Small Amount of Water. Org Lett 2021; 23:5693-5697. [PMID: 34264686 DOI: 10.1021/acs.orglett.1c01824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Under blue-light irradiation conditions with a photocatalyst [1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene], silyl enol ethers reacted with alkenes in the presence of a small amount of water to afford the α-alkylation products in good to high yields. A thiol cocatalyst was found to expand the substrate scope of the reaction.
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Affiliation(s)
- Tsubasa Hirata
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yoshihiro Ogasawara
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yasuhiro Yamashita
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shu Kobayashi
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Amine grafted Fe3O4 immobilized graphene oxide as a recyclable and effectual nanocomposite for the regioselective ring opening reaction. RESEARCH ON CHEMICAL INTERMEDIATES 2021. [DOI: 10.1007/s11164-021-04509-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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4
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Direct allylic C-H alkylation of enol silyl ethers enabled by photoredox-Brønsted base hybrid catalysis. Nat Commun 2019; 10:2706. [PMID: 31221955 PMCID: PMC6586846 DOI: 10.1038/s41467-019-10641-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/21/2019] [Indexed: 11/27/2022] Open
Abstract
Strategies for altering the reaction pathway of reactive intermediates are of significant importance in diversifying organic synthesis. Enol silyl ethers, versatile enolate equivalents, are known to undergo one-electron oxidation to generate the radical cations that spontaneously form electrophilic α-carbonyl radicals via elimination of the silyl groups. Here, we demonstrate that close scrutiny of the property of the radical cations as strong C–H acids enables the identification of a catalyst system consisting of an iridium-based photosensitizer and 2,4,6-collidine for the generation of nucleophilic allylic radicals from enol silyl ethers through one-electron oxidation-deprotonation sequence under light irradiation without the desilylation of the radical cation intermediates. The resultant allylic radicals engage in the addition to electron-deficient olefins, establishing the selective allylic C-H alkylation of enol silyl ethers. This strategy is broadly applicable, and the alkylated enol silyl ethers can be transformed into highly functionalized carbonyl compounds by exploiting their common polar reactivity. Allylic C–H activation of enol silyl ethers via one-electron oxidation is usually accompanied by undesired desilylation. Here, under hybrid photoredox and Brønsted base catalysis, the authors show the mild functionalization of enol silyl ethers, providing a platform to access an array of complex carbonyl compounds.
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Yang Z, Li H, Zhang L, Zhang MT, Cheng JP, Luo S. Organic Photocatalytic Cyclization of Polyenes: A Visible-Light-Mediated Radical Cascade Approach. Chemistry 2015; 21:14723-7. [PMID: 26332702 DOI: 10.1002/chem.201503118] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Indexed: 11/07/2022]
Abstract
A visible-light-mediated, organic photocatalytic stereoselective radical cascade cyclization of polyprenoids is described. The desired cascade cyclization products are achieved in good yields and high stereoselectivities with eosin Y as photocatalyst in hexafluoro-2-propanol. The catalyst system is also suitable for 1,3-dicarbonyl compounds, which require only catalytic amounts of LiBr to promote the formation of the corresponding enols.
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Affiliation(s)
- Zhongbo Yang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, The Chinese Academy of Sciences, Beijing, 100190 (China), Fax: (+86)-10-6255-4449http://luosz.iccas.ac.cn
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300071 (China)
| | - Han Li
- Center of Basic Molecular Science (CBMS) Department of Chemistry, Tsinghua University, Beijing, 100084 (China)
| | - Long Zhang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, The Chinese Academy of Sciences, Beijing, 100190 (China), Fax: (+86)-10-6255-4449http://luosz.iccas.ac.cn
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300071 (China)
| | - Ming-Tian Zhang
- Center of Basic Molecular Science (CBMS) Department of Chemistry, Tsinghua University, Beijing, 100084 (China).
| | - Jin-Pei Cheng
- Center of Basic Molecular Science (CBMS) Department of Chemistry, Tsinghua University, Beijing, 100084 (China)
| | - Sanzhong Luo
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, The Chinese Academy of Sciences, Beijing, 100190 (China), Fax: (+86)-10-6255-4449http://luosz.iccas.ac.cn.
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300071 (China).
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Photochemical reactions of 1,2-diketones with silyl enol ethers. RESEARCH ON CHEMICAL INTERMEDIATES 2015. [DOI: 10.1007/s11164-013-1203-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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7
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Guo X, Mayr H. Manifestation of Polar Reaction Pathways of 2,3-Dichloro-5,6-dicyano-p-benzoquinone. J Am Chem Soc 2013; 135:12377-87. [DOI: 10.1021/ja405890d] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Xingwei Guo
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13 (Haus F),
81377 München, Germany
| | - Herbert Mayr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13 (Haus F),
81377 München, Germany
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Eshghi H, Hassankhani A. Phosphorus pentoxide supported on silica gel and alumina (P2O5/SiO2, P2O5/Al2O3) as useful catalysts in organic synthesis. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2012. [DOI: 10.1007/s13738-011-0057-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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10
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Affiliation(s)
- Norbert Hoffmann
- Laboratoire des Réactions Sélectives et Applications, UMR 6519 CNRS et Université de Reims Champagne-Ardenne, UFR Sciences, B.P. 1039, F-51687 Reims, Cedex 02, France
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11
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Aulenta F, Berndt M, Brüdgam I, Hartl H, Sörgel S, Reissig HU. A New, Efficient and Stereoselective Synthesis of Tricyclic and Tetracyclic Compounds by Samarium Diiodide Induced Cyclisations of Naphthyl-Substituted Arylketones—An Easy Access to Steroid-Like Skeletons. Chemistry 2007; 13:6047-62. [PMID: 17487910 DOI: 10.1002/chem.200700057] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this report, we present the application of samarium diiodide induced cyclisations of naphthyl-substituted ketones towards an easy and stereoselective access to tri- and tetracyclic-functionalised compounds. Typical naphthalene derivatives were studied to investigate the scope and limitations of this novel cyclisation process. The model substrates studied demonstrate that the samarium ketyl cyclisations are essentially restricted to the formation of six-membered rings. The diastereoselectivity of these reactions is strongly influenced by the connection of the alkyl side chain to the naphthalene core. Gamma-naphth-1-yl-substituted ketones furnished cyclisation products, such as 17 or 22-26, as single diastereomers, whereas gamma-naphth-2-yl-substituted precursors gave mixtures of diastereomers--as demonstrated by the conversion of model compound 10 into tricyclic products 18 a/18 b, or that of cyclohexanone derivative 33 into tetracyclic diastereomers 34 a/34 b. Cyclic ketones as ketyl precursors furnished steroid-like tetracyclic skeletons; however, due to the cis/cis fusion of rings B/C and C/D these products have an "unnatural" bowl-like shape. Several of the cyclisation products have been identified by X-ray analyses, which not only proved the constitutions, but also the relative configurations and the preferred conformations. Steroid analogue 23 was subjected to subsequent transformations, which demonstrate that the styrene-like double bond of such compounds can be used for further structural diversification. First attempts to synthesise related azasteroids by incorporating nitrogen atoms into the ketone moiety are also reported. Thus, pyrrolidine derivatives 44 and 47 as well as piperidine derivatives 50 and 52 were subjected to samarium diiodide induced cyclisations. The expected tetracyclic products 48, 49 a/49 b, 51 and 53 a/53 b were obtained in moderate to good yields. The stereoselectivities observed follow the rules already established for the all-carbon precursors. The resulting products, bearing a nitrogen atom in ring D, are interesting azasteroid analogues with "unnatural" configuration.
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Affiliation(s)
- Francesca Aulenta
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
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Fagnoni M, Dondi D, Ravelli D, Albini A. Photocatalysis for the Formation of the C−C Bond. Chem Rev 2007; 107:2725-56. [PMID: 17530909 DOI: 10.1021/cr068352x] [Citation(s) in RCA: 570] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maurizio Fagnoni
- Department of Organic Chemistry, The University of Pavia, Viale Taramelli 10, 27100 Pavia, Italy
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Selva M, Perosa A, Tundo P, Brunelli D. Selective N,N-Dimethylation of Primary Aromatic Amines with Methyl Alkyl Carbonates in the Presence of Phosphonium Salts. J Org Chem 2006; 71:5770-3. [PMID: 16839162 DOI: 10.1021/jo060674d] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the presence of onium salts, at 140-170 degrees C, methyl alkyl carbonates [1a-c, ROCO2Me, R = MeO(CH2)2[O(CH2)2]n; n = 2-0, respectively] react with primary aromatic amines (XC6H4NH2, X= p-OMe, p-Me, H, p-Cl, p-CO2Me, o-Et, and 2,3-Me2C6H3NH2) to yield the corresponding N,N-dimethyl derivatives (ArNMe2) with high selectivity (up to 96%) and good isolated yields (78-95%). Phosphonium salts (e.g., Ph3PEtI and n-Bu4PBr) are particularly efficient catalysts. Overall, a solvent-free reaction is coupled with safe methylating agents (1a-c) made from nontoxic dimethyl carbonate.
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Affiliation(s)
- Maurizio Selva
- Dipartimento di Scienze Ambientali dell'Università Ca' Foscari, and Consorzio Interuniversitario "La Chimica per l'Ambiente" (INCA), UdR di Venezia, Calle Larga S. Marta, 2137-30123 Venezia, Italy.
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