Thematische Bibliographien / 1,3-dipolar cycloaddition reaction

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Auswahl der wissenschaftlichen Literatur zum Thema „1,3-dipolar cycloaddition reaction“

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Veröffentlicht am 18. Mai 2024

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Zeitschriftenartikel zum Thema "1,3-dipolar cycloaddition reaction"

WANG, JING-FANG, DONG-QING WEI, CHUN-FANG WANG, YONG YE, YI-XUE LI, YONG LUO, WEN-WU WANG, LUN-ZU LIU und YU-FEN ZHAO. „A THEORETICAL STUDY ON THE MECHANISM OF 2:1 1, 3 DIPOLAR CYCLOADDITION REACTIONS“. Journal of Theoretical and Computational Chemistry 06, Nr. 04 (Dezember 2007): 861–67. http://dx.doi.org/10.1142/s0219633607003489.

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The reactions between nitrile oxides and alkenes are of considerable interest in organic synthesis as the resulting heterocycles are versatile intermediates for the synthesis of natural products and biologically active compounds. In this paper, we design a series of reactions of phosphonyl nitrile oxides with acrylonnitrile, which can give 2:1 cycloaddition products with no crystal structure released so far, and present a detailed theoretical study on the mechanism of the 2:1 1, 3-dipolar cycloaddition reaction, which has been explored with density functional theory calculations at B3LYP/6-31G* level. The results reveal that the following mechanism is quite possible. Firstly, it starts as a normal 1,3-dipolar cycloaddition reaction to produce a regiospecific 1:1 product. Subsequently, highly reactive diisopropanyl phosphonyl nitrile oxide sequentially reacts with the aforementioned regiospecific 1:1 product and gives the corresponding cycloadduct. Further study is underway to expand the scope of this methodology, as well as to ascertain mechanistic details of the cycloaddition process.

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Grygorenko, Oleksandr O., Viktoriia S. Moskvina, Oleksandr V. Hryshchuk und Andriy V. Tymtsunik. „Cycloadditions of Alkenylboronic Derivatives“. Synthesis 52, Nr. 19 (24.06.2020): 2761–80. http://dx.doi.org/10.1055/s-0040-1707159.

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The literature on cycloaddition reactions of boron-containing alkenes is surveyed with 132 references. The data are categorized according to the reaction type ([2+1], [2+2], [3+2], [4+2], and [4+3] cycloadditions). The cyclopropanation and the Diels–Alder reactions of alkenylboronic derivatives have been studied more or less comprehensively, and for some substrates, they can be considered as convenient methods for the rapid regio- and stereoselective construction of even complex cyclic systems. Other types of the cycloadditions, as well as mechanistic aspects of the processes, have been addressed less thoroughly in the previous works.1 Introduction2 [2+1] Cycloaddition2.1 Cyclopropanation2.1.1 With Methylene Synthetic Equivalents2.1.2 With Substituted Carbenoids2.2 Epoxidation2.3 Aziridination3 [2+2] Cycloaddition4 [3+2] Cycloaddition4.1 With Nitrile Oxides4.2 With Diazoalkanes4.3 With Nitrones4.4 With Azomethine Ylides5 [4+2] Cycloaddition6 [4+3] Cycloaddition7 Conclusions and Outlook

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Salem, Mohammed A., Moustafa A. Gouda und Ghada G. El-Bana. „Chemistry of 2-(Piperazin-1-yl) Quinoline-3-Carbaldehydes“. Mini-Reviews in Organic Chemistry 19, Nr. 4 (Juni 2022): 480–95. http://dx.doi.org/10.2174/1570193x18666211001124510.

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Abstract: This review described the preparation of 2- chloroquinoline-3-carbaldehyde derivatives 18 through Vilsmeier-Haack formylation of N-arylacetamides and the use of them as a key intermediate for the preparation of 2-(piperazin-1-yl) quinoline-3-carbaldehydes. The synthesis of the 2- (piperazin-1-yl) quinolines derivatives was explained through the following chemical reactions: acylation, sulfonylation, Claisen-Schmidt condensation, 1, 3-dipolar cycloaddition, one-pot multicomponent reactions (MCRs), reductive amination, Grignard reaction and Kabachnik-Field’s reaction.

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Caraculacu, Adrian A., Elena Scorţanu und Georgeta Caraculacu. „New Parabanate Products by 1, 3-Dipolar Cycloaddition Reaction (‘Criss-Cross’ Cycloaddition)“. High Performance Polymers 11, Nr. 4 (Dezember 1999): 477–82. http://dx.doi.org/10.1088/0954-0083/11/4/311.

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Ogurtsov, Vladimir A., und Oleg A. Rakitin. „New Cycloadditon Reaction of 2-Chloroprop-2-enethioamides with Dialkyl Acetylenedicarboxylates: Synthesis of Dialkyl 2-[4,5-Bis(alkoxycarbonyl)-2-(aryl{alkyl}imino)-3(2H)-thienylidene]-1,3-dithiole-4,5-dicarboxylates“. Molecules 27, Nr. 20 (14.10.2022): 6887. http://dx.doi.org/10.3390/molecules27206887.

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The 1,3-dipolar cycloaddition of 1,2-dithiole-3-thiones with alkynes to form 1,3-dithioles is one of the most studied reactions in this class of polysulfur-containing heterocycles. Nucleophilic substitution of chlorine atoms in dimethyl 2-(1,2-dichloro-2-thioxoethylidene)-1,3-dithiole-4,5-dicarboxylate, which was obtained by addition one molecules of DMAD to 4,5-dichloro-3H-1,2-dithiole-3-thione, led to a series of 2-chloro-2-(1,3-dithiol-2-ylidene)ethanethioamides. Cycloaddition reaction of 2-chloro-2-(1,3-dithiol-2-ylidene)ethanethioamides with activated alkynes led to the unexpected formation of 2-(thiophen-3(2H)-ylidene)-1,3-dithioles via new intermediate, 1-(1,3-dithiol-2-ylidene)-N-phenylethan-1-yliumimidothioate. Structure of dimethyl2-(4,5-bis(methoxycarbonyl)-2-(phenylimino)thiophen-3(2H)-ylidene)-1,3-dithiole-4,5-dicarboxylate was finally proven by single crystal X-ray diffraction study. Optimized reaction conditions and a mechanistic rationale for the 1,3-dipolar cycloaddition of novel intermediate are presented.

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Winne, Johan, Jan Hullaert, Bram Denoo, Mien Christiaens und Brenda Callebaut. „Heterocycles as Moderators of Allyl Cation Cycloaddition Reactivity“. Synlett 28, Nr. 18 (27.07.2017): 2345–52. http://dx.doi.org/10.1055/s-0036-1588511.

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For the rapid elaboration of polycarbocyclic scaffolds, prevalent in many important families of terpenoid natural products, allyl cations derived from simple heterocyclic alcohols can be used as versatile reaction partners in both (4+3) and (3+2) cycloaddition pathways. Our recent progress in this area is outlined, pointing towards the untapped potential of heterocycles to act as reagents in novel or known but challenging organic transformations.1 Heterocyclic Reagents2 Cycloadditions and Allyl Cations3 Furfuryl Cations in Cycloadditions4 Heterocycle-Substituted Cations in Cycloadditions5 Mechanistic Considerations6 Conclusions and Outlook

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Mohtat, Bita, Seyyed Amir Siadati und Mohammad A. Khalilzadeh. „Understanding the mechanism of the 1,3-dipolar cycloaddition reaction between a thioformaldehyde S-oxide and cyclobutadiene: Competition between the stepwise and concerted routes“. Progress in Reaction Kinetics and Mechanism 44, Nr. 3 (12.05.2019): 213–21. http://dx.doi.org/10.1177/1468678319845863.

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Changing the mechanism of the widely used 1,3-dipolar cycloaddition reaction from its usual asynchronous one-step pattern to the rarely observed stepwise form leads to the emergence of intermediates, side products, and other impurities. Thus, it is crucial to determine the nature of the mechanism of the 1,3-dipolar cycloaddition reaction between a special 1,3-dipole and a specified dipolarophile (by theoretical methods) before using them for synthesizing a desired product. In this study, therefore, we have investigated the possibility of some probable intermediates emergence in the 1,3-dipolar cycloaddition reaction between cyclobutadiene and thioformaldehyde S-oxide. The results showed that emergence of Int (B) (−52.1 kcal mol−1) via transition state (B-1) is favorable both thermodynamically and kinetically (in comparison with all other stepwise routes). That is, developing probable impurities should not be neglected at least in the cases of the reactions between some thioformaldehyde S-oxide and some dipolarophiles.

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El-Sayed, Wael A., und Adel A. H. Abdel-Rahman. „Copper-catalyzed Synthesis and Antimicrobial Activity of Disubstituted 1,2,3-Triazoles Starting from 1-Propargyluracils and Ethyl (4-Azido- 1,2,3-trihydroxybutyl)furan-3-carboxylate“. Zeitschrift für Naturforschung B 65, Nr. 1 (01.01.2010): 57–66. http://dx.doi.org/10.1515/znb-2010-0110.

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1,3-Dipolar cycloaddition reactions of 1-propargyluracils 2a - h with the azido derivative 3 afforded the corresponding 1,2,3-triazoles 4a - h. Hydrazinolysis of the esters 4a - h gave the corresponding acid hydrazides 5a - h. Reaction of 5a - h with carbon disulfide in ethanol afforded 6a - h. The antimicrobial activity of compounds 4 - 6 was determined

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Hunnur, Raveendra K., Prashant R. Latthe und Bharati V. Badami. „1,3-Dipolar Cycloaddition Reactions in Heterocyclic Synthesis. Synthesis of [1-[4-(thiazolyl/imidazothiazolyl/triazolyl)phenyl]-1H-pyrazole-3,4-dicarboxylate esters from 3-(4-acetylphenyl)sydnone“. Journal of Chemical Research 2005, Nr. 9 (September 2005): 592–94. http://dx.doi.org/10.3184/030823405774308907.

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Cycloaddition of 3-(4-acetylphenyl)sydnone (1) with DMAD gave dimethyl 1-(4-acetylphenyl)-1H-pyrazole-3,4-dicarboxylate (2), which on bromination yielded the corresponding monobromoacetyl (3) and dibromoacetyl (4) derivatives. Both compounds 3 and 4 on reaction with thiourea and thioacetamide afforded the 2-amino- (5) and the 2-methyl- (6) thiazole derivatives respectively, while compound 3 on reaction with 2-aminothiazole gave the imidazothiazole 7. Compound 3 was converted into its azide (8), which on 1,3-dipolar cycloaddition with DMAD afforded the 1,2,3-triazole-4,5-dicarboxylate (9).

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Mawhinney, Robert C., Heidi M. Muchall und Gilles H. Peslherbe. „A computational study of the 1,3-dipolar cycloaddition reaction mechanism for nitrilimines“. Canadian Journal of Chemistry 83, Nr. 9 (01.09.2005): 1615–25. http://dx.doi.org/10.1139/v05-179.

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The [3+2] and [1+2] cycloaddition pathways between ethene and a series of 13 nitrilimines (R1CNNR2) have been examined by density functional theory [PBE0/6-311++G(2df,pd)] calculations. All reactions have low barriers ranging from 14.14 (R1 = CH3, R2 = H) to 1.01 (R1 = R2 = F) kcal mol1, and large reaction exothermicities consistent with the transient nature of nitrilimines. The [3+2] and [1+2] transition-state structures are very similar, mainly differing in the relative orientation of their fragments and the newly forming CC bond distance, and exhibit only minor deviations from the structures of the reactants. Both reaction pathways are concerted and asynchronous, but the [1+2] reaction has a greater degree of asynchronicity. Examination of the frontier molecular orbitals reveals that both the [3+2] and [1+2] barrier heights are related to two sets of orbital interactions, with the interaction between the lowest unoccupied molecular orbital π [Formula: see text] of nitrilimine and the highest occupied molecular orbital of ethene in common. The second interaction in both cases is carbene-like. A relationship between the weights of the 1,3-dipolar resonance contribution in the various nitrilimines and the corresponding [3+2] barrier heights was not found, but a good correlation could be found between the [1+2] barrier heights and both the 1,3-dipolar and carbene contributions. Inspection of the potential energy surface in the vicinity of the two transition states for the reaction between unsubstituted nitrilimine and ethene suggests that the observed [3+2] product is a result of an initial carbene-like approach of the two fragments followed by a ridge bifurcation that leads to the [3+2] product minimum. Key words: nitrilimines, 1,3-dipole, carbene, [3+2] cycloaddition, [1+2] cycloaddition, density functional theory (DFT).

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Dissertationen zum Thema "1,3-dipolar cycloaddition reaction"

Kafley, Saurav. „Synthesis and 1, 3 -dipolar cycloaddition reaction of N-phenyl £ chlora nitrone“. Thesis, University of North Bengal, 2010. http://hdl.handle.net/123456789/1419.

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Chakraborty, Bhaskar. „Studies of 1, 3 Dipolar cycloaddition reactions with N- cyclohexyl Nitrones“. Thesis, University of North Bengal, 1995. http://hdl.handle.net/123456789/768.

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Toh, Ophilia Ndi. „Synthesis Towards Fulminic Acid and Its Derivatives in 1, 3-Dipolar Cycloaddition Reactions“. Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etd/1982.

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A new approach to fulminic acid cycloadditions has been developed. At reduced temperatures, fulminic acid is generated in situ and undergoes 1, 3-diploar cycloaddition reactions with dipolarophiles to form isoxazolines and/or its dimers. This procedure represents a novel, safe general method for the one-step generation of fulminic acid, which complements existing potentially explosive protocols.

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Bala, Kason. „1, 3-dipolar cycloaddition reactions in aqueous media and investigations into solid phase ether synthesis“. Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397163.

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Rai, Neelam. „Greener synthesis and 1, 3-dipolar cycloaddition reactions of a amino nitrones and studies of biological activities of the cycloadducts“. Thesis, University of North Bengal, 2017. http://ir.nbu.ac.in/handle/123456789/2663.

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Draghici, Cristian. „Discovery of a Novel Ring Fragmentation Reaction; Efficient Preparation of Tethered Aldehyde Ynoates and N-Containing Heterocycles;Radical Addition Approach to Asymmetric Amine Synthesis“. ScholarWorks @ UVM, 2009. http://library.uvm.edu/dspace/bitstream/123456789/224/1/Draghici%20Disssertation.pdf.

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Kamm, Philipp Willi. „Understanding of lambda-orthogonal photo-induced reaction systems“. Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/234293/1/Philipp%20Willi_Kamm_Thesis.pdf.

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Using light as an energy source allows chemical reactions to be carried out with high precision in time and space. In time, because light can be switched on and off, in space, because light can be highly focussed. Further, different colours of light can be used to activate different reactants individually, even when they are present in the same reaction mixture. Herein, a system of two light-sensitive molecules was developed, which react completely sequence-independently with UV or visible light. The wavelength-dependence as well as the influence of chemical-physical parameters on such reactions were investigated in-depth.

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Chandanshive, Jay Zumbar <1983&gt. „Regiocontrolled Synthesis of Pyrazole Derivatives Through 1,3-Dipolar Cycloaddition Reaction And Synthesis of Helicene-Thiourea based and Polymer Supported Soos's Catalyst for Asymmetric Synthesis“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5826/1/Chandanshive_JAY_ZUMBAR_Thesis.pdf.

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In first part we have developed a simple regiocontrolled protocol of 1,3-DC to get ring fused pyrazole derivatives. These pyrazole derivatives were synthesized using 1,3-DC between nitrile imine and various dipolarophiles such as alkynes, cyclic α,β-ketones, lactones, thiocatones and lactums. The reactions were found to be highly regiospecific. In second part we have discussed about helicene, its properties, synthesis and applications as asymmetric catalyst.Due to inherent chirality, herein we have made an attempt to synthesize the helicene-thiourea based catalyst for asymmetric catalysis. The synthesis involved formation of two key intermediates viz, bromo-phenanthrene 5 and a vinyl-naphthalene 10. The coupling of these two intermediates leads to formation of hexahelicene.

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Schmitt, Gérard. „Réactions de l'hydrofluoroborate d'un composé de Reissert sur divers alcenes : Compétition entre cycloaddition dipolaire-1,3 et cycloaddition de Diels-Alder“. Besançon, 1987. http://www.theses.fr/1987BESA2041.

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Berndt, Christian. „Bildungstendenz und Reaktionen von α-Azidoalkoholen“. Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-112553.

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Gegenstand der vorliegenden Arbeit ist die Synthese von α-Azidoalkoholen durch die Reaktion von aliphatischen sowie aromatischen Aldehyden mit Stickstoffwasserstoffsäure. Dabei stellt sich ein Gleichgewicht ein, dessen Lage durch die Ermittlung der Gleichgewichtskonstanten quantitativ bestimmt wird. In jedem Fall besteht die Möglichkeit, den α-Azidoalkohol in der Gleichgewichtsmischung zu charakterisieren und teilweise gelingt die Isolierung der reinen α-Azidoalkohole bei tiefen Temperaturen sowie deren Charakterisierung mittels Tieftemperatur-NMR-Spektroskopie. Die Ausgangsaldehyde für die Synthese der α-Azidoalkohole besitzen elektronenschiebende oder elektronenziehende Substituenten oder sind prochiral oder besitzen funktionelle Gruppe für intramolekulare Reaktionen. Die Titelverbindungen werden mit Cyclooctin im Sinne einer 1,3-dipolaren Cycloaddition abgefangen oder mit Carbonsäurechloriden in die entsprechenden Ester der α-Azidoalkohole überführt. Das nur aus theoretischen Arbeiten bekannte Formylazid wird erstmals aus den α-Azidoalkoholen durch Oxidation hergestellt und in Lösung vollständig charakterisiert. Es werden zudem zahlreiche Alternativsynthesen für Formylazid erfolgreich durchgeführt.

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Bücher zum Thema "1,3-dipolar cycloaddition reaction"

Joseph Johannes Gerardus Steven van Es. 1, 3-cycloaddition reactions of diphenylphosphinoyl-activated azomethine ylides and 2-azaallyl anions: Synthetic applications and mechanistic aspects. 'S-Gravenhage: Pasmans Offsetdrukkerij BV, 1992.

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Buchteile zum Thema "1,3-dipolar cycloaddition reaction"

Gallego, Mar Gómez, und Miguel A. Sierra. „Level 1 — Case 15 Oxazoline N-Oxides as Dipoles in [3+2] Cycloadditions“. In Organic Reaction Mechanisms, 101–6. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-642-18788-9_15.

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Gallego, Mar Gómez, und Miguel A. Sierra. „Level 1 — Case 16 Light-Induced Cycloadditions of N-Phthaloyl α-Amino Acids“. In Organic Reaction Mechanisms, 107–11. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-642-18788-9_16.

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Bartnik, Romuald. „Azomethine, carbonyl and thiocarbonyl ylides“. In Nitrogen, Oxygen and Sulfur Ylide Chemistry, 187–278. Oxford University PressOxford, 2002. http://dx.doi.org/10.1093/oso/9780198500179.003.0003.

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Abstract Simple addition of a carbene or carbenoid to a C-N double bond would be expected to result in the formation of an azomethine ylide. This is consistent with electrophilic attack of the carbene at the nitrogen atom lone pair. Formation of ylides in this manner was reviewed by Padwa and Hornbuckle in 1991. The reaction of carbenes with simple imines (Schiff bases) to form azomethine ylides, which then undergo 1,3-dipolar cycloaddition with a second molecule of imine, was first reported in 1972. Bartnik and Mloston subsequently extended this method by using various dipolarophiles. Catalytic decomposition of phenyldiazomethane with N-benzylidenemethylamine results in the formation of a trans-1,3-dipole which then undergoes [3+2]-cycloaddition with an available 1r-bond. This is illustrated by the synthesis of 1-methyl-2,5-diphenyl-3,4-dicarboxylic acid dimethyl ester 1 from phenyldiazomethane, N-benzylidenemethylamine and dimethyl maleate (Scheme 3.1.1). This reaction takes place in a highly diastereoselective manner giving only the r-2,t-3,t-4,t-5 isomer (Beilstein’s r,c,t-system).

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Taber, Douglass F. „Alkaloid Synthesis: (+)-Deoxoprosopinine (Krishna), Alkaloid (–)-205B (Micalizio), FR901483 (Huang), (+)-Ibophyllidine (Kwon), (–)-Lycoposerramine-S (Fukuyama), (±)-Crinine (Lautens)“. In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0060.

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Palakodety Radha Krishna of the Indian Institute of Chemical Technology observed (Synlett 2012, 2814) high stereocontrol in the addition of allyltrimethylsilane to the cyclic imine derived from 1. The product piperidine 2 was carried onto (+)-deoxoprosopinine 3. Glenn C. Micalizio of Scripps Florida condensed (J. Am. Chem. Soc. 2012, 134, 15237) the amine 4 with 5. The ensuing intramolecular dipolar cycloaddition led to 6, which was carried onto the Dendrobates alkaloid (–)-205B 7. Pei-Qiang Huang of Xiamen University showed (Org. Lett. 2012, 14, 4834) that the quaternary center of 9 could be established with high diastereoselectivity by activation of the lactam 8, then sequential addition of two different Grignard reagents. Subsequent stereoselective intramolecular aldol condensation led to FR901843 10. More recently, Professor Huang, with Hong-Kui Zhang, also of Xiamen University, published (J. Org. Chem. 2013, 78, 455) a full account of this work. In an elegant application of the power of phosphine-catalyzed intermolecular allene cycloaddition, Ohyun Kwon of UCLA added (Chem. Sci. 2012, 3, 2510) 12 to the imine 11 to give 13. The cyclization elegantly set two of the four stereogenic centers of (+)-ibophyllidine 14. Tohru Fukuyama of the University of Tokyo initiated (Angew. Chem. Int. Ed. 2012, 51, 11824) a cascade cyclization between the enone 15 and the chiral auxiliary 16. The product lactam 17 was carried onto (–)-lycoposerramine-S 18. Mark Lautens explored (J. Am. Chem. Soc. 2012, 134, 15572) the utility of the intramolecular aryne ene reaction, as illustrated by the cyclization of 19 to 20. Oxidation cleavage of the vinyl group of 20 followed by an intramolecular carbonyl ene reaction led to (±)-crinine 21.

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Taber, Douglass. „Stereocontrolled Carbocyclic Construction: (-)-Mintlactone (Bates), (-)-Gleenol (Kobayashi), (-)-Vibralactone C (Snider)“. In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0081.

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Nigel S. Simpkins, now at the University of Birmingham, found (Chem. Commun. 2008, 5390) that the prochiral cyclopropane amide 1 could be deprotonated to give, after alkylation, the substituted cyclopropane 3 with high enanantio- and diastereocontrol. In the course of a synthesis of (+)-Lineatin, Ramon Alibés of the Universitat Autònoma de Barcelona optimized (J. Org. Chem. 2008, 73, 5944) the photochemical cycloaddition of 4 and 5 to give, after reductive dechlorination, the cyclobutene 6. In a related reaction, José L. García Ruano and M. Rosario Martín of the Universidad Autónoma de Madrid observed (J. Org. Chem. 2008, 73, 9366) that the cycloaddition of 8 to 7 proceeded with high regio- and diastereocontrol, to give the cyclopentene 9. Joseph M. Ready of UT Southwestern in Dallas developed (Angew. Chem. Int. Ed. 2008, 47, 7068) a powerful new cyclopentannulation, condensing the cyclopropane derived from the addition of 11 to 10 with the protected ynolate 12 to give 13, in the presence of a modified Lewis acid catalyst. Chun-Chen Liao of the National Tsing Hua University, Hsinchu described (Angew. Chem. Int. Ed. 2008, 47, 7325) the oxidative ring contraction of the o-alkoxy phenol 14 to the cyclopentenone 15. Stéphane Quideau of the Université de Bordeaux reported (Organic Lett. 2008, 10, 5211) a related ring contraction. We uncovered (J. Org. Chem. 2008, 73, 9479) a simple protocol for the in situ conversion of an ω-alkenyl ketone such as 16 to the corresponding diazo compound, leading, via dipolar cycloaddition, to the adduct 17. Ulrich Zutter of Roche Basel described (J. Org. Chem. 2008 , 73, 4895), in a synthesis of Tamiflu, the hydrogenation of 19 to give the cyclohexane with all-cis diastereocontrol. Selective removal of the methyl ethers with trimethylsilyl iodide set the stage for enzymatic ester hydrolysis, delivering 20 in high ee.

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Taber, Douglass F. „The Lee Synthesis of (−)-Crinipellin A“. In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0098.

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The crinipellins are the only tetraquinane natural products. The enone crinipellins, including crinipellin A 3, have anticancer activity. Hee-Yoon Lee of the Korea Advanced Institute of Science and Technology (KAIST) envisioned (J. Am. Chem. Soc. 2014, 136, 10274) the assembly of 2 and thus 3 by the intramolecular dipolar cycloaddition of the diazoalkane derived from the tosylhydrazone 1. The initial cyclopentene was prepared from commercial 4 following the Williams procedure. Conjugate addition of the Grignard reagent 5 in the presence of TMS-Cl led to the silyl enol ether 6. Regeneration of the enolate followed by allylation gave 7. The preparation of the racemic ketone was completed by ozonolysis followed by selective reduction and protection. Addition of hydride in an absolute sense led to separable 1:1 mixture of diastereomers. Reoxidation of one of the diastereomers delivered enantiomerically enriched 8. A few steps later, after coupling with 10, the sidechain stereocenter was set by Sharpless asymmetric epoxidation. Oxidation of 11 gave the aldehyde, that was converted to the alkyne 12 by the Ohira protocol. Addition of the Grignard reagent 13 gave the allene 14 as an inconsequential 1:1 mixture of diastereomers. Deprotection then led to the tosylhydrazone 1. The transformation of 1 to 2 proceeded by initial formation of the diazo alkane 15. Intramolecular dipolar cycloaddition gave 16, that lost N2 to give the trimethylene–methane diradical 17. The insertion into the distal alkene proceeded with remarkable stereocontrol, to give 2 as a single diastereomer—in 87% yield from 1. Direct α-hydroxylation of the ketone derived from 2 gave the wrong diastereomer, and hydride addition to 18 reduced the wrong ketone. As an alternative, the enantiomerically-pure sulfoximine anion was added to the more reactive ketone, and the product was reduced and protected to give 19. Allylic oxidation converted the alkene to the enone, and heating to reflux in toluene reversed the sulfoximine addition, leading to 20. Epoxidation of 20 followed by α-methylenation delivered the enone 21, that proved to be particularly sensitive. Eventually, success was found with TASF. With a similarly sensitive substrate, Douglass F. Taber of the University of Delaware observed (J. Am. Chem. Soc. 1998, 120, 13285) that TBAF in THF buffered with solid NH4Cl worked well.

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Taber, Douglass F. „Tethered Diels-Alder Cycloaddition: (±)-Neovibsanin B (Imagawa, Nishizawa), Valerenic Acid (Mulzer), (-)-Himandrine (Movassaghi), (±)-Pallavicinolide A (Wong), (+)-Phomopsidin (Nakada)“. In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0077.

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It has generally been observed that prospective intramolecular Diels-Alder cycloadditions that would form a γ-lactone are reluctant to proceed. In the course of a synthesis of (±)-neovibsanin B 4, Hiroshi Imagawa and Mugio Nishizawa of Tokushima Bunri University reversed (Organic Lett. 2009, 11, 1253) the usual connectivity and found that the dienyl ester 1 could be induced to cyclize to 3. The solvent 2 improved both the yield and the diastereoselectivity of the cycloaddition. It was not surprising that Johann Mulzer of the University of Vienna could see (Organic Lett. 2009, 11, 1151) no evidence of cyclization on heating the acrylate 5. In contrast, following the lead of Barriault, they found that MgBr2 -tethered cycloaddition of methyl acrylate 7 with the alcohol 6 proceeded smoothly, to give 8, which they carried on to valerenic acid 9. Intramolecular Diels-Alder reactions to form 6,6-systems are often facile. Mohammad Movassaghi of MIT, en route to (-)-himandrine 12, showed (J. Am. Chem. Soc. 2009, 131, 9648) that the tetraene 10 cyclized to 11 at 95°C with 5:1 dr. In this case the solvent was the more typical acetonitrile with 10% diethyl aniline. The intramolecular Diels-Alder reaction is concerted but nonsynchronous (Tetrahedron Lett. 1981, 22, 5141), with β-bond formation preceding α-bond formation. This contributes to the reluctance of 8 to cyclize. In contrast, Henry N. C. Wong of the Chinese University of Hong Kong observed (Angewandte Chem. Int. Ed. 2009, 48, 2351) that the tetraene 13, which is polarity matched, cyclized to 14 spontaneously as soon as it was formed. Functional group conversion completed the synthesis of (±)-pallavicinolide A 15. The transannular Diels-Alder (TADA) reaction can proceed with high diastereocontrol, but the factors directing these cyclizations are not completely understood. In the course of a synthesis of (+)-phomopsidin 18, Masahisa Nakada of Waseda University found (Tetrahedron 2009, 65, 888) that 16 led to 17 with 16:1 dr. In contrast, the triene epimeric to 16 at the silyloxy group cyclized with only 2:1 dr.

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Taber, Douglass F. „C–O Ring Construction: (+)-Varitriol (Liu), (+)-Isatisine A (Panek), (+)-Herboxidiene/GEX1A (Ghosh), (–)-Englerin A (Chain), Platensimycin (Lear/Wright)“. In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0050.

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En route to (+)-varitriol 4, Xue-Wei Liu of Nanyang Technological University coupled (Org. Lett. 2011, 13, 42) the glycosyl fluoride derived from 1 with the alkynyl fluoroborate salt 2 to give 3. James S. Panek of Boston University condensed (Org. Lett. 2011, 13, 502) the enantiomerically pure allyl silane 6 with the aldehyde 5 to give the tetrahydrofuran 7. Further elaboration led to (+)-isatisine A 8, the only alkaloid so far isolated from the roots and leaves of the traditional Asian folk medicine Isatis indigotica. Arun K. Ghosh of Purdue University effected (Org. Lett. 2011, 13, 66) oxidative ring expansion of the enantiomerically pure furan 9 to give, after reduction, the enone 10. This established the tetrahydropyran of (+)-herboxidiene 11, also known as GEXIA. William J. Chain of the University of Hawaii observed (J. Am. Chem. Soc. 2011, 133, 6553) unusual diastereoselectivity in the conjugate addition of the enone 12 to the enantiomerically pure aldehyde 13. Although eight diastereomers could have been formed, the reaction mixture was 2/3 the diastereomer 14. Reductive cyclization (SmI2) of 14 then led to (–)-englerin A 15. Martin J. Lear of the National University of Singapore cyclized (Org. Lett. 2010, 12, 5510) the enantiomerically pure lactol 16 to 17 with catalytic Bi(OTf)3. Dennis L. Wright of the University of Connecticut prepared (Org. Lett. 2011, 13, 2263) 21 by dipolar cycloaddition of 20 to 19. Both 17 and 21 were carried on via intramolecular alkylation toward platensimycin 18.

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Taber, Douglass F. „Diels–Alder Cycloaddition: Sarcandralactone A (Snyder), Pseudopterosin (−)-G-J Aglycone (Paddon-Row/Sherburn), IBIR-22 (Westwood), Muironolide A (Zakarian), Platencin (Banwell), Chatancin (Maimone)“. In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0080.

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En route to sarcandralactone A 3, Scott A. Snyder of Scripps Florida effected (Angew. Chem. Int. Ed. 2015, 54, 7842) Diels–Alder cycloaddition of the activated enone 1 to the Danishefsky diene. On exposure to trifluoroacetic acid, the adduct was unraveled to the ene dione 2. Michael N. Paddon-Row of the University of New South Wales and Michael S. Sherburn of the Australian National University prepared (Nature Chem. 2015, 7, 82) the allene 4 in enantiomerically-pure form. Sequential cycloaddition with 5 followed by 6 gave an adduct that was decarbonylated to 7. Further cycloaddition with nitroethylene 8 led to the pseudopterosin (−)-G-J aglycone 9. The protein–protein interaction inhibitor JBIR-22 12 contains a quaternary α-amino acid pendant to a bicyclic core. Nicholas J. Westwood of the University of St. Andrews set (Angew. Chem. Int. Ed. 2015, 54, 4046) the absolute configuration of the core 11 by using an organocatalyst to activate the cyclization of 10. Metal catalysts can also be used to set the absolute configuration of a Diels–Alder cycloaddition. In the course of establishing the structure of the marine natural product muironolide A 15, Armen Zakarian of the University of California, Santa Barbara cyclized (J. Am. Chem. Soc. 2015, 137, 5907) the enol form of 13 preferentially to the diastereomer 14. Unactivated intramolecular Diels–Alder cycloadditions have been carried out with more and more challenging substrates. A key step in the synthesis (Chem. Asian. J. 2015, 10, 427) of (−)-platencin 18 by Martin G. Banwell, also of the Australian National University, was the cyclization of 16 to 17. In another illustration of the power of the unactivated intramolecular Diels–Alder reaction, Thomas J. Maimone of the University of California, Berkeley cyclized (Angew. Chem. Int. Ed. 2015, 54, 1223) the tetraene 19 to the tricycle 20. Allylic chlorination followed by reductive cyclization converted 20 to chatancin 21.

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Lambert, Tristan H. „Total Synthesis of C–O Natural Products“. In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0049.

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Weiping Tang at the University of Wisconsin, Madison reported (J. Am. Chem. Soc. 2013, 135, 12434) the total synthesis of the tropone-containing norditerpenes hainanolidol 6 and harringtonolide 7 by making use of a strategic [5+2] oxidopyrylium cycloaddition. First, the known ketone 1 was converted through a number of steps to cycloaddition precursor 2. Treatment with DBU then effected the key cycloaddition to furnish the complex polycyclic compound 3. Additional manipulations revealed structure 4 with the lactone ring in place. The tropone ring of the natural structures was constructed by reaction of the cycloheptadiene moiety of 4 with singlet oxygen followed by Kornblum- DeLaMare rearrangement with DBU to afford ketone 5. Double elimination using TsOH then produced hainanolidol 6. The free hydroxyl of 6 was engaged in a C–H-functionalizing cyclization using Pd(OAc)₄ to yield harringtonolide 7 as well. Hanfeng Ding at Zhejiang University developed (Angew. Chem. Int. Ed. 2013, 52, 13256) a concise route to indoxamycin F 12 (as well as the related indoxamycins A and C). The complex intermediate 9 was accessed in only four steps from the bicyclic ketone 8, which in turn was prepared by a route involving an Ireland–Claisen rearrangement and a reductive 1,6-enyne cyclization (not shown). An impressive oxa-conjugate addition/methylenation reaction to produce 11 was accomplished by treatment of 9 with Grignard 10 followed by Eschenmoser’s salt. Some final decorative work then led to indoxamycin F 12. The strained polycyclophane natural product cavicularin 18 was synthesized in enantioenriched form by an innovative strategy reported (Angew. Chem. Int. Ed. 2013, 52, 10472) by Keisuke Suzuki at the Tokyo Institute of Technology.

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Konferenzberichte zum Thema "1,3-dipolar cycloaddition reaction"

Diaconu, Dumitrela, Violeta Mangalagiu, Dorina Amariucai-Mantu, Vasilichia Antoci, Ramona Danac und Ionel Mangalagiu. „1,3-dipolar cycloaddition reactions of benzimidazolium-ylides to an activated symmetric alkyne“. In Scientific seminar with international participation "New frontiers in natural product chemistry". Institute of Chemistry, Republic of Moldova, 2023. http://dx.doi.org/10.19261/nfnpc.2023.ab27.

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The cycloaddition reactions represent an important way to obtain cyclic structures and take place between two or more reactants containing double or triple bonds in the molecule. After Huisgen, the addition of 1,3-dipole to a dipolarophile, takes place through a concerted mechanism, when two  bonds are formed. [1,2] The purpose of this research is to study the Huisgen [3+2] dipolar cycloaddition reactions carried out in a conventional way (stirring at room temperature) and non-conventional way (ultrasonic irradiation), between benzimidazolium-ylides and an activated symmetric substituted alkyne - dimethyl acetylenedicarboxylate (DMAD) - as dipolarophile. [3-5] The Huisgen 3+2 dipolar cycloaddition reaction of benzimidazolium ylides to dymethyl acetylenedicarboxilate (DMAD) afford generating of three types of hybrid quinoline-benzimidazole cycloadducts and, according with the source of energy and solvent used the reactions pathway could be conducted selective.

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Flanders, B., R. Cheville, D. Grischkowsky und N. F. Scherer. „Pulsed Terahertz Spectroscopy of Solutions: Experiment and Memory Function Analysis“. In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.fa.5.

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Understanding the magnitudes and time-scales of the intermolecular interactions that occur during a chemical reaction in the liquid phase is a central problem in condensed phase studies. Assuming linear response and validity of the Fluctuation-Dissipation theorem, knowledge of the processes and related time scales by which the neat solvent molecules fluctuate and relax in an equilibrium system (that is, in the absence of the strong perturbation produced by a reacting chromophore) is directly related to knowing the solvent modes available for acceptance of excess energy during the course of a reaction.1 Such equilibrium spectra may be obtained from optical Kerr effect studies2 or far-infrared (i. e. terahertz) dipolar absorption measurements.3

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Wynne, Klaas, C. Galli und R. M. Hochstrasser. „Vibrational Coherence in Charge Transfer“. In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/up.1992.tud3.

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The role of vibrational coherence in highly efficient, ultrafast electron transfer (ET) systems has recently come under investigation [1]. In the conventional theories for ET the vibrational coordinate plays an essential role: in the Sumi-Marcus theory [2] this mode facilitates ET from the excited state whereas in the Jortner-Bixon theory [3] it provides for additional decay channels in the inverted regime. In these theories it is a priori assumed that these vibrational motions are thermally equilibrated and motion along the reaction coordinate is limited by the longitudinal relaxation time of the solvent. However, recently ultrafast ET has been observed in which the transfer rate greatly exceeds the relaxation time of the solvent. For example in intermolecular ET between nile blue and the electron donating solvent N,N’-dimethylaniline (DMA) the transfer rate is 50 times larger than the solvent dipolar reorientation time [4]. In betaines g the observed ET rates exceed the theoretical predictions by a factor of 108 [5] and subpicosecond ET was recently observed for C60 in DMA [6].

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