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Articles de revues sur le sujet « Carbocyclic systems »

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Auteur : Grafiati
Publié le 18 mai 2024

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1

Boyd, Derek R., Narain D. Sharma, Ludmila V. Modyanova, Jonathan G. Carroll, John F. Malone, Christopher CR Allen, John TG Hamilton, David T. Gibson, Rebecca E. Parales et Howard Dalton. « Dioxygenase-catalyzed cis-dihydroxylation of pyridine-ring systems ». Canadian Journal of Chemistry 80, no 6 (1 juin 2002) : 589–600. http://dx.doi.org/10.1139/v02-062.

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Toluene dioxygenase-catalyzed dihydroxylation, in the carbocyclic rings of quinoline, 2-chloroquinoline, 2-methoxyquinoline, and 3-bromoquinoline, was found to yield the corresponding enantiopure cis-5,6- and -7,8-dihy dro diol metabolites using whole cells of Pseudomonas putida UV4. cis-Dihydroxylation at the 3,4-bond of 2-chloroquino line, 2-methoxyquinoline, and 2-quinolone was also found to yield the heterocyclic cis-dihydrodiol metabolite, (+)-cis-(3S,4S)-3,4-dihydroxy-3,4-dihydro-2-quinolone. Heterocyclic cis-dihydrodiol metabolites, resulting from dihydroxylation at the 5,6- and 3,4-bonds of 1-methyl 2-pyridone, were isolated from bacteria containing toluene, naphthalene, and biphenyl dioxygenases. The enantiomeric excess (ee) values (>98%) and the absolute configurations of the carbocyclic cis-dihydrodiol metabolites of quinoline substrates (benzylic R) and of the heterocyclic cis-diols from quinoline, 2-quinolone, and 2-pyridone substrates (allylic S) were found to be in accord with earlier models for dioxygenase-catalyzed cis-dihydroxylation of carbocyclic arenes. Evidence favouring the dioxygenase-catalyzed cis-dihydroxylation of pyridine-ring systems is presented.Key words: dioxygenases; cis-dihydroxylation, pyridines, 2-pyridones, absolute configurations.
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2

Williams, Andrew C. « The synthesis of carbocyclic aromatic systems ». Contemporary Organic Synthesis 3, no 6 (1996) : 535. http://dx.doi.org/10.1039/co9960300535.

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3

Ando, Wataru. « Polyorganosilicon Compounds in Strained Carbocyclic Systems ». Bulletin of the Chemical Society of Japan 69, no 1 (janvier 1996) : 1–16. http://dx.doi.org/10.1246/bcsj.69.1.

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4

Gleiter, Rolf, et Daniel B. Werz. « Reactions of Metal-Complexed Carbocyclic 4π Systems ». Organometallics 24, no 18 (août 2005) : 4316–29. http://dx.doi.org/10.1021/om0504351.

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WILLIAMS, A. C. « ChemInform Abstract : The Synthesis of Carbocyclic Aromatic Systems ». ChemInform 28, no 19 (4 août 2010) : no. http://dx.doi.org/10.1002/chin.199719292.

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ANDO, W. « ChemInform Abstract : Polyorganosilicon Compounds in Strained Carbocyclic Systems ». ChemInform 27, no 17 (5 août 2010) : no. http://dx.doi.org/10.1002/chin.199617312.

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7

Al Mamari, Hamad H. « Ir-Catalyzed ortho-C-H Borylation of Aromatic C(sp2)-H Bonds of Carbocyclic Compounds Assisted by N-Bearing Directing Groups ». Reactions 5, no 2 (1 mai 2024) : 318–37. http://dx.doi.org/10.3390/reactions5020016.

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C-H borylation is a powerful strategy for the construction of C-B bonds due to the synthetic versatility of C-B bonds. Various transition metals affect the powerful functionalization of C-H bonds, of which Ir is the most common. Substrate-directed methods have enabled directed Ir-catalyzed C-H borylation at the ortho position. Amongst the powerful directing groups in Ir-catalyzed C-H borylation are N-containing carbocyclic systems. This review covers substrate-directed Ir-catalyzed ortho-C-H borylation of aromatic C(sp2)-H bonds in N-containing carbocyclic compounds, such as anilines, amides, benzyl amines, hydrazones, and triazines.
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8

Erian, Ayman W., Yvette A. Issac et Sherif M. Sherif. « A Novel Synthesis of Sulfone Systems as Antimicrobial Agents ». Zeitschrift für Naturforschung B 55, no 1 (1 janvier 2000) : 127–32. http://dx.doi.org/10.1515/znb-2000-0119.

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The applicability and synthetic potency of novel reagent, 2-aryl-1,1-dicyano-3-(phenylsulfo-nyl)propenes 3 to develop an expeditious convenient synthetic route of unique polyfunctionally substituted carbocyclic and heterocyclic sulfone systems is reported. Chemical and spec­troscopic evidence for the structures of the newly synthesized compounds are described. Some of the obtained compounds were tested for their antimicrobial activity
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Doraghi, Fatemeh, Mohammad Mahdi Aghanour Ashtiani, Fatemeh Moradkhani, Bagher Larijani et Mohammad Mahdavi. « Developments and applications of α-bromonitrostyrenes in organic syntheses ». RSC Advances 14, no 21 (2024) : 14835–46. http://dx.doi.org/10.1039/d4ra02474e.

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In this work, we have described the use of α-bromonitrostyrenes in the synthesis of a wide variety of carbocyclic and heterocyclic compounds under organocatalysis, metal catalysis, and base-catalysis systems as well as catalyst-free reactions.
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10

Wang, Zheng, Yanping Ma, Jingjing Guo, Qingbin Liu, Gregory A. Solan, Tongling Liang et Wen-Hua Sun. « Bis(imino)pyridines fused with 6- and 7-membered carbocylic rings as N,N,N-scaffolds for cobalt ethylene polymerization catalysts ». Dalton Transactions 48, no 8 (2019) : 2582–91. http://dx.doi.org/10.1039/c8dt04892d.

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Mixed carbocyclic-fused bis(arylimino)pyridine-cobalt(ii) chlorides, on activation with either MAO or MMAO, displayed high activities for ethylene polymerization affording linear polyethylene waxes; high selectivity for vinyl end-groups is a feature of MAO-promoted systems.
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11

TV, Ovaska. « Utilization of Tandem Oxyanionic Cyclization/Claisen Rearrangement Strategies for the Construction of Seven and Eight-Membered Carbocyclic Ring Systems ». Medicinal and Analytical Chemistry International Journal 7, no 1 (23 janvier 2023) : 1–6. http://dx.doi.org/10.23880/macij-16000178.

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This article describes the development of microwave-assisted oxyanionic 5-exo-dig cyclization-Claisen rearrangement sequence as a convenient “one-pot” route to a variety of seven- and eight membered carbocyclic ring systems. This process was used as the key transformation for the construction of several natural products, including frondosins A, B, and C.
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12

Rawal, Viresh H., Randall C. Newton et Venkat Krishnamurthy. « Synthesis of carbocyclic systems via radical-induced epoxide fragmentation ». Journal of Organic Chemistry 55, no 18 (août 1990) : 5181–83. http://dx.doi.org/10.1021/jo00305a001.

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13

Gao, Fuye, et D. Jean Burnell. « Diverse carbocyclic systems using geminal acylation as a key process ». Tetrahedron Letters 48, no 46 (novembre 2007) : 8185–88. http://dx.doi.org/10.1016/j.tetlet.2007.09.089.

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14

Yavari, Issa, et Aliyeh Khajeh-Khezri. « Recent Advances in the Synthesis of Hetero- and Carbocyclic Compounds­ and Complexes Based on Acenaphthylene-1,2-dione ». Synthesis 50, no 20 (16 août 2018) : 3947–73. http://dx.doi.org/10.1055/s-0037-1610209.

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Acenaphthylene-1,2-dione has been utilized in a wide range of reactions as a starting material for the synthesis of hetero- and carbocyclic compounds and complexes. This review provides a short summary of the recent advances in the application of acenaphthylene-1,2-dione in the synthesis of hetero- and carbocyclic systems and bioactive compounds. In addition, the applications of acenaphthylene-1,2-dione in the synthesis of spiro compounds, propellanes, and ligands in catalyst reactions, from 2002 to early 2018, are included.1 Introduction2 Synthesis of Spiro Compounds Employing Acenaphthylene-1,2-dione2.1 Methods for the Construction of Spiro Compounds2.1.1 By 1,3-Dipolar Cycloaddition of Acenaphthylene-1,2-dione via Azomethine Ylides2.1.2 By Multicomponent Reactions of Acenaphthylene-1,2-dione with C–H Acidic Compounds2.1.3 By Reaction of Acenaphthylene-1,2-dione with Zwitterionic Intermediates2.1.4 By Substitution and Multicomponent Reactions of Acenaphth- ylene-1,2-dione with Different Nucleophiles3 Synthesis of Propellanes by Employing Acenaphthylene-1,2-dione3.1 Methods for the Construction of Propellanes Based on Acenaph- thylene-1,2-dione3.1.1 By Reaction of Acenaphthylene-1,2-dione with Nucleophiles3.1.2 By Reaction of Acenaphthylene-1,2-dione with Binucleophiles4 Synthesis of Ligands Employing Acenaphthylene-1,2-dione for Catalyst Reactions5 Synthesis of Novel Hetero- and Carbocyclic Compounds Employing Acenaphthylene-1,2-dione5.1 By Reaction of Acenaphthylene-1,2-dione with Nucleophiles5.2 By Reaction of Acenaphthylene-1,2-dione with Zwitterionic Intermediates5.3 By Ring Opening and Ring Enlargement6 Conclusion
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15

Lautens, Mark, Dino Alberico, Cyril Bressy, Yuan-Qing Fang, Brian Mariampillai et Thorsten Wilhelm. « Palladium-catalyzed ring-forming reactions : Methods and applications ». Pure and Applied Chemistry 78, no 2 (1 janvier 2006) : 351–61. http://dx.doi.org/10.1351/pac200678020351.

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Several Pd-catalyzed cyclization methods were developed, including norbornene-mediated Catellani-type reactions, a Pd-catalyzed coupling reaction of aryl iodides and allyl moieties, and a tandem C-N/C-C coupling of gem-dihalovinyl systems. These ring-forming methods were applied to the synthesis of highly functionalized carbocyclic and heterocyclic compounds. Intermolecular Pd-catalyzed methods for synthesis of highly substituted arene compounds were also developed.
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16

Soares, Maria I. L., Ana L. Cardoso et Teresa M. V. D. Pinho e Melo. « Diels–Alder Cycloaddition Reactions in Sustainable Media ». Molecules 27, no 4 (15 février 2022) : 1304. http://dx.doi.org/10.3390/molecules27041304.

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Diels–Alder cycloaddition reaction is one of the most powerful strategies for the construction of six-membered carbocyclic and heterocyclic systems, in most cases with high regio- and stereoselectivity. In this review, an insight into the most relevant advances on sustainable Diels–Alder reactions since 2010 is provided. Various environmentally benign solvent systems are discussed, namely bio-based derived solvents (such as glycerol and gluconic acid), polyethylene glycol, deep eutectic solvents, supercritical carbon dioxide, water and water-based aqueous systems. Issues such as method’s scope, efficiency, selectivity and reaction mechanism, as well as sustainability, advantages and limitations of these reaction media, are addressed.
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17

Gahman, Timothy C., et Larry E. Overman. « Stereoselective synthesis of carbocyclic ring systems by pinacol-terminated Prins cyclizations ». Tetrahedron 58, no 32 (août 2002) : 6473–83. http://dx.doi.org/10.1016/s0040-4020(02)00658-0.

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18

Klimova, Elena I., Marcos Martı́nez Garcı́a, Tatiana Klimova, Cecilio Alvarez Toledano, Ruben Alfredo Toscano et Lena Ruı́z Ramı́rez. « Synthesis of ‘three-petal’ carbocyclic systems based on s-cis-diferrocenyltrienes ». Journal of Organometallic Chemistry 649, no 1 (avril 2002) : 86–93. http://dx.doi.org/10.1016/s0022-328x(02)01127-0.

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19

RAWAL, V. H., R. C. NEWTON et V. KRISHNAMURTHY. « ChemInform Abstract : Synthesis of Carbocyclic Systems via Radical-Induced Epoxide Fragmentation. » ChemInform 22, no 6 (23 août 2010) : no. http://dx.doi.org/10.1002/chin.199106147.

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20

Griffith, Daniel R., et Aaron H. Shoemaker. « Synthetic Approaches to Non-Tropane, Bridged, Azapolycyclic Ring Systems Containing Seven-Membered Carbocycles ». Synthesis 53, no 01 (11 septembre 2020) : 65–78. http://dx.doi.org/10.1055/s-0040-1707385.

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AbstractThis Short Review highlights various synthetic approaches to bridged azabicyclic ring systems containing seven-membered carbocyclic rings. Such ring systems are common to a number of biologically active natural products. The seven-membered ring in such systems is generally formed in one of four ways: 1) cyclization of an acyclic precursor; 2) ring expansion or rearrangement of a different ring size; 3) cycloaddition; and 4) use of a synthetic building block with the seven-membered ring already present. Representative examples of each approach from both total synthesis and methodological studies are discussed, with an emphasis on work publishedin the last twenty years.1 Introduction2 Cyclization Reactions3 Ring Expansions and Rearrangements4 Cycloadditions5 Strategies Involving Seven-Membered Ring Building Blocks6 Conclusion
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21

Wu, Xiang, Ming-Li Li, Dian-Feng Chen et Shu-Sen Chen. « Enantioselective Construction of [6,5,6]-Carbocyclic Systems by Organo/Metal-Catalyzed Sequential Reactions ». Journal of Organic Chemistry 79, no 10 (25 avril 2014) : 4743–50. http://dx.doi.org/10.1021/jo5006729.

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22

Garcia-Fandiño, Rebeca, Eva M. Codesido, Eduardo Sobarzo-Sánchez, Luis Castedo et Juan R. Granja. « Tandem RCM of Dienynes for the Construction of Taxol-Type Carbocyclic Systems ». Organic Letters 6, no 2 (janvier 2004) : 193–96. http://dx.doi.org/10.1021/ol036062m.

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23

Willetts, Andrew. « Bicyclo[3.2.0]carbocyclic Molecules and Redox Biotransformations : The Evolution of Closed-Loop Artificial Linear Biocatalytic Cascades and Related Redox-Neutral Systems ». Molecules 28, no 21 (24 octobre 2023) : 7249. http://dx.doi.org/10.3390/molecules28217249.

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The role of cofactor recycling in determining the efficiency of artificial biocatalytic cascades has become paramount in recent years. Closed-loop cofactor recycling, which initially emerged in the 1990s, has made a valuable contribution to the development of this aspect of biotechnology. However, the evolution of redox-neutral closed-loop cofactor recycling has a longer history that has been integrally linked to the enzymology of oxy-functionalised bicyclo[3.2.0]carbocyclic molecule metabolism throughout. This review traces that relevant history from the mid-1960s to current times.
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24

Durakov, S. A., A. A. Kolobov et V. R. Flid. « Features of heterogeneous catalytic transformations of strained carbocyclic compounds of the norbornene series ». Fine Chemical Technologies 17, no 4 (30 septembre 2022) : 275–97. http://dx.doi.org/10.32362/2410-6593-2022-17-4-275-297.

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Objectives. Catalytic processes involving norbornene (NBN) and norbornadiene (NBD) offer exceptional opportunities for the synthesis of a wide range of hard-to-reach polycyclic hydrocarbons. The problems of selectivity and manufacturability of these reactions are fundamentally important for their practical implementation. The aim of this review is to summarize the latest advances in the field of designing heterogeneous catalysts for the preparation and transformation of promising NBN- and NBD-derivatives with the maintenance of a strained carbocyclic framework in isomerization and dimerization reactions of these compounds.Results. Various strategies for the selection of catalysts and prospects for the development of heterogeneous catalysis for syntheses based on NBN and NBD derivatives were considered. The possibility of selective cyclic dimerization and isomerization of NBN and NBD was shown. The factors that affect the direction of the reactions and make it possible to maintain the strained norbornane structure were discussed.Conclusions. An analysis of the current state of this problem showed that at present, the technological parameters of the conversion of NBD and NBN derivatives with the participation of heterogeneous catalysts are significantly inferior to homogeneous systems. In order to improve the productivity of these processes and design catalyst regeneration, further investigations are required. However, some progress in these areas has already been made. In a number of processes, it is possible not only to maintain the strained carbocyclic framework, but also to establish ways to control regio- and stereo-selectivity. In some cases, the use of heterogeneous catalysts allows the process to be direct into a completely new path, which has no analogues for homogeneous systems.
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Chen, Jia-Rong, Xiao-Qiang Hu, Liang-Qiu Lu et Wen-Jing Xiao. « Formal [4+1] Annulation Reactions in the Synthesis of Carbocyclic and Heterocyclic Systems ». Chemical Reviews 115, no 11 (20 mai 2015) : 5301–65. http://dx.doi.org/10.1021/cr5006974.

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26

Gahman, Timothy C., et Larry E. Overman. « ChemInform Abstract : Stereoselective Synthesis of Carbocyclic Ring Systems by Pinacol-Terminated Prins Cyclizations. » ChemInform 33, no 50 (18 mai 2010) : no. http://dx.doi.org/10.1002/chin.200250061.

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27

KRYGOWSKI, T. M., et M. CYRANSKI. « ChemInform Abstract : Aromatic Character of Carbocyclic π-Electron Systems Deduced from Molecular Geometry ». ChemInform 28, no 42 (3 août 2010) : no. http://dx.doi.org/10.1002/chin.199742352.

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28

Malik, Arfa Abrar, Wenhong Yang, Zhifeng Ma et Wen-Hua Sun. « The Catalytic Activities of Carbocyclic Fused Pyridineimine Nickel Complexes Analogues in Ethylene Polymerization by Modeling Study ». Catalysts 9, no 6 (12 juin 2019) : 520. http://dx.doi.org/10.3390/catal9060520.

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In this work, two carbocyclic fused pyridineimine nickel analogue systems (Ni1 and Ni2) with different fused member rings were investigated to reveal the relationship between catalyst structure and reaction activity. Multiple linear regression analysis was performed by means of five electronic descriptors and two steric descriptors, including the Hammett constant (F), effective net charge (Qeff), energy difference (ΔE), HOMO–LUMO energy gap (Δε1, Δε2), open cone angle (θ), and bite angle (β). Very good values of correlation coefficient (R2) over 0.938 were obtained by using a combination of effective net charge (Qeff) and open cone angle (θ) for both individual analysis and comparisons between analogue systems. By analyzing the contribution of descriptors, it indicates that the dominant descriptor is effective net charge (Qeff) in the Ni1 system and open cone angle (θ) in Ni2 systems, respectively. This may explain the different variation trends of catalytic activities in two Ni complexes systems as a function of substituents.
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29

Sotomayor, N., et E. Lete. « Aryl and Heteroaryllithium Compounds by Metal - Halogen Exchange. Synthesis of Carbocyclic and Heterocyclic Systems ». Current Organic Chemistry 7, no 3 (1 février 2003) : 275–300. http://dx.doi.org/10.2174/1385272033372987.

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30

Danishefsky, Samuel J., et James E. Audia. « An application of the ireland reaction to the stereospecific synthesis of fused carbocyclic systems. » Tetrahedron Letters 29, no 12 (janvier 1988) : 1371–74. http://dx.doi.org/10.1016/s0040-4039(00)80299-3.

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31

Barluenga, José, Ana Álvarez-Fernández, Tatiana Suárez-Rodríguez, Ángel L. Suárez-Sobrino et Miguel Tomás. « A Simple Metal-Promoted Three-Step Access to n/5/m Angular Carbocyclic Systems ». Organic Letters 15, no 3 (11 janvier 2013) : 488–91. http://dx.doi.org/10.1021/ol303269r.

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32

Xuan, Jun, Liang-Qiu Lu, Jia-Rong Chen et Wen-Jing Xiao. « Visible-Light-Driven Photoredox Catalysis in the Construction of Carbocyclic and Heterocyclic Ring Systems ». European Journal of Organic Chemistry 2013, no 30 (9 juillet 2013) : 6755–70. http://dx.doi.org/10.1002/ejoc.201300596.

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33

Wu, Xiang, Ming-Li Li, Dian-Feng Chen et Shu-Sen Chen. « ChemInform Abstract : Enantioselective Construction of [6,5,6]-Carbocyclic Systems by Organo/Metal-Catalyzed Sequential Reactions. » ChemInform 45, no 43 (10 octobre 2014) : no. http://dx.doi.org/10.1002/chin.201443081.

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Lash, Timothy D. « Organometallic Chemistry within the Structured Environment Provided by the Macrocyclic Cores of Carbaporphyrins and Related Systems ». Molecules 28, no 3 (3 février 2023) : 1496. http://dx.doi.org/10.3390/molecules28031496.

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The unique environment within the core of carbaporphyrinoid systems provides a platform to explore unusual organometallic chemistry. The ability of these structures to form stable organometallic derivatives was first demonstrated for N-confused porphyrins but many other carbaporphyrin-type systems were subsequently shown to exhibit similar or complementary properties. Metalation commonly occurs with catalytically active transition metal cations and the resulting derivatives exhibit widely different physical, chemical and spectroscopic properties and range from strongly aromatic to nonaromatic and antiaromatic species. Metalation may trigger unusual, highly selective, oxidation reactions. Alkyl group migration has been observed within the cavity of metalated carbaporphyrins, and in some cases ring contraction of the carbocyclic subunit takes place. Over the past thirty years, studies in this area have led to multiple synthetic routes to carbaporphyrinoid ligands and remarkable organometallic chemistry has been reported. An overview of this important area is presented.
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35

Bailey, William F., et Justin D. Fair. « Intramolecular carbolithiation cascades as a route to a highly strained carbocyclic framework : competition between 5-exo-trig ring closure and proton transfer ». Beilstein Journal of Organic Chemistry 9 (14 mars 2013) : 537–43. http://dx.doi.org/10.3762/bjoc.9.59.

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The preparation of fairly strained carbocyclic ring systems by intramolecular 5-exo-trig ring closure has been well documented, and the absence of proton transfers that would compromise such cyclizations is a hallmark of this chemistry. In an effort to explore the limitations of this approach to more highly strained systems, the preparation of a stellane (tricyclo[3.3.0.03,7]octane) framework by an intramolecular carbolithiation cascade involving three coupled 5-exo-trig cyclizations of the vinyllithium derived from 2-bromo-4-vinyl-1,6-heptadiene by lithium–bromine exchange was investigated. The cascade does not afford the stellane; rather, the cascade is terminated after two cyclizations by a proton transfer that occurs by an intermolecular process catalyzed by trace amounts of endo-5-methyl-2-methylenebicyclo[2.2.1]heptane present in reaction mixtures as a consequence of inadvertent quenching of an intermediate alkyllithium during prolonged reaction times at room temperature.
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36

Zander, M. « The Intra-annular Internal Heavy-atom Effect on the Fluorescence and Phosphorescence Properties of Oxygen, Sulphur or Selenium Containing Heterocyclic Systems Related to Dibenzo [b,n] perylene ». Zeitschrift für Naturforschung A 44, no 11 (1 novembre 1989) : 1116–18. http://dx.doi.org/10.1515/zna-1989-1113.

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Fluorescence and phosphorescence properties of dibenzo [2,3:10,11] perylo [1,12-bcd] furan (1), dibenzo [2,3:10,11] perylo [1,12-bcd] thiophene (2), and dibenzo [2,3:10,11 ] perylo [1,12-bcd] selenophene (3) have been studied. Fluorescence quantum yields as well as phosphorescence lifetimes correlate linearly with where ck are the Hückel AO coefficients in the HOMO of the parent carbocyclic system dibenzo [b, n] perylene (4) on carbon centres k to which the hetero-atom is bound, and ζ is the spin-orbit coupling constant of the heavy-atom present. The half-value concentration of fluorescence quenching (quencher: methyl iodide) of 1 - 3 increases with increasing strength of the internal heavy-atom effect present
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37

Chen, Jia-Rong, Xiao-Qiang Hu, Liang-Qiu Lu et Wen-Jing Xiao. « ChemInform Abstract : Formal [4+1] Annulation Reactions in the Synthesis of Carbocyclic and Heterocyclic Systems ». ChemInform 46, no 35 (13 août 2015) : no. http://dx.doi.org/10.1002/chin.201535268.

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38

Cieśla, J. M., R. Stolarski et D. Shugar. « Cyclic phosphates of some antiviral acyclonucleosides : relationship between conformation and substrate/inhibitor properties in some enzyme systems. » Acta Biochimica Polonica 40, no 2 (30 juin 1993) : 251–60. http://dx.doi.org/10.18388/abp.1993_4826.

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Solution conformations, and substrate/inhibitor properties towards several phosphodiesterases and other nucleolytic enzymes, have been investigated for the cyclic phosphates of various acyclonucleosides, some with known antiviral activity, including 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (DHPG) and its carbocyclic congener, 9-(3,4-dihydroxybutyl)guanine (DHBG),9-[4-hydroxy-2-(hydroxymethyl)- butyl]-guanine (2HM-HBG), and 9-(2,3-dihydroxypropyl)guanine (HPG). Conformations of the cyclic phosphate rings were derived from analysis of the 1H-1H and 1H-31P vicinal coupling constants in the 1H n.m.r. spectra, subsequently optimalized by minimalization of the internal energy. The resulting structures were examined with respect to their ability to recognize various specific phosphodiesterases and nucleases, and some structural parameters were delineated for acyclonucleotide interactions. Qualitative data are presented for inhibitory properties of the acyclonucleoside cyclic phosphates, and, in those instances where they were substrates, kinetic constants were evaluated. An unusual finding was the apparent ability of nuclease P1 to hydrolyse a five-membered cyclic phosphate ring of an acyclonucleoside.
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39

Harrowven, David, Wei Sun et Dharyl Wilson. « Steric Buttressing Changes Torquospecificity in Thermal Cyclo­butenone Rearrangements, Providing New Opportunities for 5H-Furanone Synthesis ». Synthesis 49, no 14 (13 juin 2017) : 3091–106. http://dx.doi.org/10.1055/s-0036-1588850.

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Thermally induced rearrangements of 4-hydroxycyclo­butenones are known to provide clean and reliable access to an array of useful carbocyclic and fused heterocyclic ring systems. Rarely, such reactions have been diverted to an alternative pathway leading to furanone formation. Herein, we show that these switches in the course of the rearrangement occur when a substrate bears a bulky substituent and are due to adverse steric buttressing as the transition state for electrocyclisation is approached. We also show how the reaction provides new opportunities for furanone synthesis and how bulky proton and halogen surrogates can be used to divert classical rearrangement pathways toward furanone formation. Additionally, we show that classical rearrangement pathways can be promoted by the simple expedient of alcohol protection.
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40

Chambournier, Gilles, Venkat Krishnamurthy et Viresh H. Rawal. « Radical Induced Cyclopropane Fragmentation—H-Abstraction—Cyclization Cascade : Synthesis of Carbocyclic Systems Containing Bridgehead Methyl Groups ». Tetrahedron Letters 38, no 36 (septembre 1997) : 6313–16. http://dx.doi.org/10.1016/s0040-4039(97)01450-0.

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41

Xuan, Jun, Liang-Qiu Lu, Jia-Rong Chen et Wen-Jing Xiao. « ChemInform Abstract : Visible-Light-Driven Photoredox Catalysis in the Construction of Carbocyclic and Heterocyclic Ring Systems ». ChemInform 45, no 1 (12 décembre 2013) : no. http://dx.doi.org/10.1002/chin.201401252.

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Barluenga, Jose, Ana Alvarez-Fernandez, Tatiana Suarez-Rodriguez, Angel L. Suarez-Sobrino et Miguel Tomas. « ChemInform Abstract : A Simple Metal-Promoted Three-Step Access to n/5/m Angular Carbocyclic Systems ». ChemInform 44, no 24 (23 mai 2013) : no. http://dx.doi.org/10.1002/chin.201324043.

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43

Trost, Barry M., Zhongxing Huang et Ganesh M. Murhade. « Catalytic palladium-oxyallyl cycloaddition ». Science 362, no 6414 (1 novembre 2018) : 564–68. http://dx.doi.org/10.1126/science.aau4821.

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Exploration of intermediates that enable chemoselective cycloaddition reactions and expeditious construction of fused- or bridged-ring systems is a continuous challenge for organic synthesis. As an intermediate of interest, the oxyallyl cation has been harnessed to synthesize architectures containing seven-membered rings via (4+3) cycloaddition. However, its potential to access five-membered skeletons is underdeveloped, largely due to the thermally forbidden (3+2) pathway. Here, the combination of a tailored precursor and a Pd(0) catalyst generates a Pd-oxyallyl intermediate that cyclizes with conjugated dienes to produce a diverse array of tetrahydrofuran skeletons. The cycloaddition overrides conventional (4+3) selectivity by proceeding through a stepwise pathway involving a Pd-allyl transfer and ring closure sequence. Subsequent treatment of the (3+2) adducts with a palladium catalyst converts the heterocycles to the carbocyclic cyclopentanones.
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44

Lash, Timothy D. « Carbaporphyrins, porphyrin isomers and the legacy of Emanuel Vogel ». Journal of Porphyrins and Phthalocyanines 16, no 05n06 (mai 2012) : 423–33. http://dx.doi.org/10.1142/s1088424612300017.

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Vogel discovered a large number of bridged annulene structures, including constitutional porphyrin isomers, heteroporphyrinoid species such as the tetraoxaporphyrin dication, corrole isomers and novel expanded porphyrinoid systems. In this review, the impact of Vogel's work on the author's research program is discussed. Carbaporphyrinoid systems with one or two carbocyclic rings replacing the usual pyrrole subunits have been synthesized and their diatropic characteristics can be related to the presence of 18π electron delocalization pathways within these macrocycles. The preparation of a dideazaporphyrin also provides strong support for the concept, espoused by Vogel, that porphyrins are examples of bridged annulenes. Ring contractions of azuliporphyrins to benzocarbaporphyrins with tert-butyl hydroperoxide in the presence of base have been proposed to involve a Cope rearrangement where a cycloheptatriene unit rearranges to give a norcaradiene-fused carbaporphyrinoid, followed elimination of tert-butyl alcohol, and Vogel's investigations into these types of valence tautomerization processes provides insights into these unusual transformations. In addition, a new class of porphyrin isomers has been synthesized and these porphyrin analogs extend the observations previously made for N-confused porphyrins and Vogel's constitutional isomers.
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McCombie, Stuart W., Sue-Ing Lin et Susan F. Vice. « New reactions of hydrazides. Part 1 : Directed ortho- and lateral metalation of aromatic carbocyclic and heterocyclic systems ». Tetrahedron Letters 40, no 50 (décembre 1999) : 8767–70. http://dx.doi.org/10.1016/s0040-4039(99)01876-6.

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46

Li, Yang, Jin-Xia Li, Xuan-Hui Ouyang, Qiu-An Wang et Jin-Heng Li. « Manganese-Catalyzed Intermolecular Oxidative Annulation of Alkynes with γ-Vinyl Aldehydes : An Entry to Bridged Carbocyclic Systems ». Organic Letters 19, no 22 (27 octobre 2017) : 6172–75. http://dx.doi.org/10.1021/acs.orglett.7b03086.

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Gómez, Generosa, Hilda Rivera, Isela García, Laura Estévez et Yagamare Fall. « The furan approach to carbocyclic systems. Synthesis of cyclohexane derivatives from butenolides through an intramolecular Michael addition ». Tetrahedron Letters 46, no 35 (août 2005) : 5819–22. http://dx.doi.org/10.1016/j.tetlet.2005.06.137.

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Dumez, Estelle, Anne-Catherine Durand, Martial Guillaume, Pierre-Yves Roger, Robert Faure, Jean-Marc Pons, Gaëtan Herbette, Jean-Pierre Dulcère, Damien Bonne et Jean Rodriguez. « Michael Addition Initiated Carbocyclization Sequences with Nitroolefins for the Stereoselective Synthesis of Functionalized Heterocyclic and Carbocyclic Systems ». Chemistry - A European Journal 15, no 45 (15 octobre 2009) : 12470–88. http://dx.doi.org/10.1002/chem.200901433.

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Shiota, H., K. Nitta, T. Naito, Y. Mimura et T. Maruyama. « Clinical evaluation of carbocyclic oxetanocin G eyedrops in the treatment of herpes simplex corneal ulcers. » British Journal of Ophthalmology 80, no 5 (1 mai 1996) : 413–15. http://dx.doi.org/10.1136/bjo.80.5.413.

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Weinreb, Steven, Wenchun Chao et Matthew Meketa. « Ring-Closing Metathesis of Vinyl Chlorides for Formation of 5-, 6- and 7-Membered Carbocyclic and Heterocyclic Systems ». Synthesis 2004, no 12 (2 avril 2004) : 2058–61. http://dx.doi.org/10.1055/s-2004-822327.

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