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Готові списки джерел за темами / Ortho-quinone methides

Добірка наукової літератури з теми "Ortho-quinone methides"

Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 28 січня 2023

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Статті в журналах з теми "Ortho-quinone methides"

1

Chambers, Jeffrey D., Jason Crawford, Haydn W. R. Williams, Claude Dufresne, John Scheigetz, Michael A. Bernstein, and Cheuk K. Lau. "Reactions of 2-phenyl-4H-1,3,2-benzodioxaborin, a stable ortho-quinone methide precursor." Canadian Journal of Chemistry 70, no. 6 (June 1, 1992): 1717–32. http://dx.doi.org/10.1139/v92-216.

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Thermolysis of 1-phenyl-4H-1,3,2-benzodioxaborins generated the corresponding ortho-quinone methides, which were found to undergo intermolecular cycloaddition reactions with ethyl vinyl ether, dihydropyran, β-methylstyrene, cyclohexene, and 1-ethoxy-1-z-trimethylsiloxy-1-propenes to give various substituted chromans. Intramolecular trapping of the quinone methides with an olefin led to the syntheses of several analogs of tetrahydrocannabinols. ortho-Quinone methides, generated by treatment of the 2-phenyl-4H-1,3,2-benzodioxaborins with a Lewis acid, react with various nucleophiles to give the corresponding 1,4-addition products. Thus, alkyl and aryl thiols, alcohols, amine, hydride, allyl trimethylsilane, acetophenone, and diethylmalonate as well as some aryl compounds react with the quinone methide to give various 2-substituted phenols. Intramolecular reaction of the quinone methide with an aryl group led to the preparation of some 4-phenylchromans and tetralins.

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2

Wan, Peter, Beverly Barker, Li Diao, Maike Fischer, Yijian Shi, and Cheng Yang. "1995 Merck Frosst Award Lecture Quinone methides: relevant intermediates in organic chemistry." Canadian Journal of Chemistry 74, no. 4 (April 1, 1996): 465–75. http://dx.doi.org/10.1139/v96-051.

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ortho and para-Quinone methides (2-methylene-3,5-cyclohexadien-1-one and 4-methylene-2,5-cyclohexadien-1-one, respectively) are intermediates in a variety of important chemical systems. In particular, o-quinone methides are useful in synthesis for the construction of chroman ring systems. A brief account of the relevance of quinone methide chemistry will be provided. This is followed by a review of recent studies from our laboratory on efficient methods for the photogeneration of quinone methides, concentrating on the use of hydroxy-substituted benzyl alcohols in aqueous media. It is shown that this method is general since it provides access to o-, m-, and p-quinone methide isomers. When appropriately substituted, all of these quinone methide isomers have been spectroscopically characterized by laser flash photolysis, making this technique the one of choice for studying the dynamics of these reactive intermediates. The mechanism of photochemical generation from hydroxybenzyl alcohols and extensions of the reaction to photogeneration of fluorenyl and biphenyl quinone methides will also be presented. Key words: quinone methide, biphenyl quinone methide, carbocation, photosolvolysis, photodehydroxylation, hetero-Diels–Alder reaction.

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3

Spivey, Alan, Christian Nielsen, and Hossay Abas. "Stereoselective Reactions of ortho-Quinone Methide and ortho-Quinone Methide Imines and Their Utility in Natural Product Synthesis." Synthesis 50, no. 20 (August 14, 2018): 4008–18. http://dx.doi.org/10.1055/s-0037-1610241.

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Herein presented is a review of the reactivity and synthetic utility of ortho-quinone methides and ortho-quinone methide imines. These versatile intermediates have received significant attention in the literature and new methods for their preparation and reaction as well as recent applications in total synthesis are discussed.1 Introduction2 Conjugate Addition Reactions3 Concerted Cycloaddition Reactions4 Stepwise Addition Reactions5 Applications in Total Synthesis6 Conclusion

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4

Huang, Hong-Ming, Xu-Yan Wu, Bo-Rong Leng, Yi-Long Zhu, Xin-Chao Meng, Yu Hong, Bo Jiang, and De-Cai Wang. "Cu(ii)-Catalyzed formal [4 + 2] cycloaddition between quinone methides (QMs) and electron-poor 3-vinylindoles." Organic Chemistry Frontiers 7, no. 2 (2020): 414–19. http://dx.doi.org/10.1039/c9qo01343a.

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Анотація:

A new Cu(ii)-catalyzed formal [4 + 2] cycloaddition between quinone methides (QMs) including para-quinone methides (p-QMs) and ortho-quinone methides (o-QMs) and electron-poor 3-vinylindoles was established.

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5

Bai, Wen-Ju, Jonathan G. David, Zhen-Gao Feng, Marisa G. Weaver, Kun-Liang Wu, and Thomas R. R. Pettus. "The Domestication of ortho-Quinone Methides." Accounts of Chemical Research 47, no. 12 (December 3, 2014): 3655–64. http://dx.doi.org/10.1021/ar500330x.

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6

Tanaka, Kenta, Yosuke Asada, and Yujiro Hoshino. "A new cycloaddition profile for ortho-quinone methides: photoredox-catalyzed [6+4] cycloadditions for synthesis of benzo[b]cyclopenta[e]oxepines." Chemical Communications 58, no. 15 (2022): 2476–79. http://dx.doi.org/10.1039/d1cc06332d.

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7

Liang, Dong, Li-Ping Tan, Wen-Jing Xiao, and Jia-Rong Chen. "Inverse-electron-demand [4+2] cycloaddition of photogenerated aza-ortho-quinone methides with 1,3,5-triazinanes: access to perfluoroalkylated tetrahydroquinazolines." Chemical Communications 56, no. 26 (2020): 3777–80. http://dx.doi.org/10.1039/d0cc00747a.

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8

Mayer, Martin, Maik Pahl, Matthias Spanka, Max Grellmann, Marcel Sickert, Christoph Schneider, Knut R. Asmis, and Detlev Belder. "Unravelling the configuration of transient ortho-quinone methides by combining microfluidics with gas phase vibrational spectroscopy." Physical Chemistry Chemical Physics 22, no. 8 (2020): 4610–16. http://dx.doi.org/10.1039/c9cp06435d.

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9

Xu, Jianfeng, Shiru Yuan, Jingyi Peng, Maozhong Miao, Zhengkai Chen, and Hongjun Ren. "Base-mediated diastereoselective [4 + 3] annulation of in situ generated ortho-quinone methides with C,N-cyclic azomethine imines." Organic & Biomolecular Chemistry 15, no. 36 (2017): 7513–17. http://dx.doi.org/10.1039/c7ob01783a.

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10

Saha, Satyajit, Santosh Kumar Alamsetti, and Christoph Schneider. "Chiral Brønsted acid-catalyzed Friedel–Crafts alkylation of electron-rich arenes with in situ-generated ortho-quinone methides: highly enantioselective synthesis of diarylindolylmethanes and triarylmethanes." Chemical Communications 51, no. 8 (2015): 1461–64. http://dx.doi.org/10.1039/c4cc08559k.

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Більше джерел

Дисертації з теми "Ortho-quinone methides"

1

Moya, Eduardo. "Ortho-quinone methides from the pyrolysis of substituted benzyltriphenylphosphonium compounds." Thesis, University of Kent, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235694.

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2

Mondatori, Martina. "Addizione di Michael organocatalitica asimmetrica di composti 1,3-dicarbonilici ad orto-chinoni metidi: un nuovo e semplice approccio alla preparazione di 4H-cromeni e croman-2-oni otticamente attivi." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7273/.

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The work described in this thesis deals with the development of the asymmetric organocatalytic conjugate addition reaction of 1,3-dicarbonyl compounds to ortho-quinone methides. Due to their instability, these synthetically appealing intermediates have not been fully exploited in catalytic asymmetric settings. In this work, the instability of ortho-quinone methides is overcome by their generation in situ under mild basic conditions, starting from the corresponding sulfonyl derivatives. The bifunctional catalysts used are able to activate both substrates for the reaction, by means of a synergic action of the two catalytic sites, inducing at the same time high enantioselection in the addition step. The reaction leads to the generation of a 2-alkylphenolic framework, featuring a chiral centre at the benzylic position. In particular, the employment of acetylacetone and Meldrum acid as nucleophiles has allowed the obtainment of 4H-chromenes and chroman-2-ones in good yields and generally excellent enantioselectivities. These compounds are synthetic precursors of several natural products, some of which showing interesting biological activity, and of some active pharmaceutical ingredients used in commercial drugs.

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3

Boulven, Manon. "Conception, synthèse et évaluation biologique de nouveaux composés hétérocycliques anticoagulants à usage rodonticide." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI106.

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A ce jour, les anticoagulants commerciaux souffrent de deux inconvénients majeurs : leur rémanence avec, pour certains d’entre eux, une demi-vie hépatique proche des 300 jours causant des intoxications secondaires sur les prédateurs des rongeurs, ainsi que le développement de nombreuses mutations génétiques causé par l’utilisation intensive de ces composés, rendant inopérant l’utilisation de certains AVKs commerciaux. Face à ce constat, l’Union Européenne envisage d’interdire l’utilisation de tels composés. La mission prioritaire est donc de trouver un anticoagulant capable de gérer les populations de rongeurs sans affecter leurs prédateurs. Les recherches mises en avant par Adrien Montagut (Thèse 2011-2014) ont permis d’aboutir à une structure type d’anticoagulants, dérivés de la 4-hydroxycoumarine. Actuellement, AMR361 a été testé in vitro sur l’ensemble des mutations de VKORC1 et in vivo sur rats sauvages, et constitue le premier AVK développé qui répond à l’ensemble des caractéristiques du cahier des charges initial. La première partie de mon projet de thèse consistait à compléter l’étude biologique sur le noyau 4-hydroxycoumarine en amenant de la diversité fonctionnelle sur la position para du noyau aromatique. D’un point de vue biologique, l’allongement du bras espaceur sur la chaîne latérale par l’utilisation de fonctions telles que les amides ou amides inversés ou l’introduction d’un groupement diméthyle sur le pont méthylène ont été étudiés afin d’analyser les paramètres d’efficacité et de rémanence. Cependant, la plupart des composés synthétisés appartenant à la famille des 4-hydroxycoumarines font déjà l’objet d’un brevet déposé par l’entreprise Liphatech en 1999. L’étude de nouveaux noyaux, dont certains sont analogues à la 4-hydroxycoumarine, de même que la fonctionnalisation du noyau 4-hydroxycoumarine sur la partie aromatique, a permis l’accès à des structures plus diverses. Ces perspectives originales pour l’innovation ont été introduites pour contourner les brevets déjà existants
To date, commercial anticoagulants suffer from two major inconveniences: their persistence causing secondary poisoning of rodent predators and the development of many genetic mutations caused by the intensive use of these compounds. As a result, the European Union plans to prohibit the use of such compounds. Consequently, the priority task is to find an anticoagulant that can control the rodent populations without affecting their predators. The research of Dr. Adrien Montagut (PhD, 2011-2014) have led to the structure type of an anticoagulant derived from 4-hydroxycoumarin. Currently, AMR361 was tested in vitro on all VKORC1 mutations and in vivo on wild rats. It is the first AVK developed that responds to all the characteristics of the initial specification. The first part of my PhD was to complete the biological study on 4-hydroxycoumarin core by bringing functional diversity on the para position of the aromatic ring. From a biological point of view, the lengthening of the spacer arm on the side chain by use of various functions or the introduction of a dimethyl group on the methylene bridge were studied in order to analyze the effectiveness and persistence parameters. However, most of the synthesized compounds belonging to the family of 4-hydroxycoumarins are already described in a patent filed by Liphatech company in 1999. The study of new cores which are similar to the 4-hydroxycoumarin or the functionalization of the aromatic part of the 4-hydroxycoumarin has provided access to more diverse structures. These original possibilities for innovation have been introduced to circumvent existing patents

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4

Spence, Justin Thomas James. "Biomimetic synthesis of natural products via reactions of ortho-quinone methides." Thesis, 2016. http://hdl.handle.net/2440/102583.

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In recent times, natural product synthesis has become central to many scientific fields; from chemistry, through to biology and pharmacology. As synthetic chemists, natural products are attractive targets due to their interesting and complex structures, combined with some intriguing biological properties. One field that is of particular interest is the use of a biomimetic approach towards the synthesis of complex natural products. This thesis will describe the use ortho-quinone methides and cascade reactions towards the biomimetic synthesis of the penilactones A and B, the peniphenones A-D, virgatolide B and epicolactone. The total synthesis of ent-penilactone A and penilactone B has been achieved via biomimetic Michael reactions between tetronic acids and o-quinone methides. A fivecomponent cascade reaction between a tetronic acid, formaldehyde, and a resorcinol derivative that generates four carbon-carbon bonds, one carbon-oxygen bond and two stereocenters in a one-pot synthesis of penilactone A is also reported. The total synthesis of peniphenones A-D has been achieved via Michael reactions between appropriate nucleophiles and a common ortho-quinone methide intermediate. This strategy, which was based on a biosynthetic hypothesis, minimised the use of protecting groups and thus facilitated concise syntheses of the natural products. The most complex target, the benzannulated spiroketal peniphenone A, was synthesised enantioselectively in nine linear steps from commercially available starting materials. A synthesis for the ortho-quinone methide precursor of virgatolide B has been developed. A simplified enol ether was employed for the biomimetic [4+2] cycloaddition reaction to afford a simplified virgatolide B analogue. An isomerised compound containing a cis fused ring junction, thought to arise via a [4+2] cycloaddition of an ortho-quinone methide and an endocyclic enol ether formed by acid catalysed tautomerisation in situ will also be reported. Finally, preliminary studies towards the synthesis of epicolactone have been conducted. A synthesis of the proposed key proposed biosynthetic intermediate epicoccone B has been achieved in four steps. Efforts towards the synthesis of epicoccine via our proposed cycloetherification route proved to be challenging. Furthermore, the synthesis of epicolactone through our proposed biosynthesis was not viable, which was also observed by Trauner and co-workers in their 2014 synthesis of dibefurin.
Thesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2016.

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5

Barbato, Keith Steven. "Enantioselective multicomponent organoboron reactions of ortho-quinone methide intermediates catalyzed by chiral biphenols." Thesis, 2016. https://hdl.handle.net/2144/17059.

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Ortho-quinone methides are reactive intermediates with wide ranging applications in organic synthesis. However, their propensity to rearomatize renders them transitory and reactive, which has made their implementation in organic synthesis challenging. An asymmetric and organocatalytic multicomponent reaction platform was developed to address this challenge by accessing ortho-quinone methide intermediates in situ through a Friedel-Crafts hydroxy-alkylation condensation of phenols, aldehydes, and boronates. This approach provided a practical and general method to access to chiral di- and triaryl methane products in high yields and enantioselectivities from commercially available starting materials. An unanticipated cyclization pathway was discovered while exploring the scope of the reaction that afforded 2,4-diarylchroman products from an electron rich styrenyl boronate. Reaction conditions were optimized to select for the cyclization pathway, which afforded chroman products with high levels of enantio- and diastereoselectivity. The myristinin natural products are DNA polymerase-β inhibitors and DNA-damaging agents that contain a privileged chroman scaffold within their core. The multicomponent cyclization strategy was applied towards the synthesis of the myristinin natural products without success. To circumvent issues with reactivity, the multicomponent reaction platform was extended to an intermolecular cycloaddition of in situ generated ortho-quinone methides from phenols, aldehydes, and styrenes to provide 2,4-diarylchromans. The core of myristinins B/C was synthesized using the multicomponent cycloaddition strategy providing high yield and diastereoselectivity with remarkable step economy. An enantioselective version of the multicomponent cycloaddition reaction was developed utilizing triisopropyl borate Lewis acid and a chiral biphenol.
2018-06-21T00:00:00Z

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6

Chen, Chia-Wei, and 陳家偉. "1.Iodine-Promoted Generation of ortho-Quinone Methide Intermediate and its Application for C－S Bond Cross－Coupling Reaction2.CuI/Oxalic Diamide-Catalyzed Cross－Coupling of Thiols with Aryl Bromides." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/55653412691026136869.

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碩士
國立中興大學
化學系所
105
In the first part of this thesis, a new and efficient method has been described for generation of o-quinone methides via iodine-induced dehydroxylation of 2-(hydroxymethyl)phenols. The formed reactive o-quinone methide intermediates were trapped by thiols providing stable 2-[(alkyl or arylthio)methyl]phenols under mild conditions. The second part of this thesis, we report a general copper-catalyzed cross-coupling of thiols with aryl bromides by using N-aryl-N''-alkyl oxalic diamide (L3) or N,N''-dialkyl oxalic diamide (L5) as the ligands. Both aryl- and alkyl thiols can be coupled with unactivated aryl bromides to give the desired products in good yields for the first time. Furthermore, this system features broad substrate scope and good tolerance of functional groups. Importantly, the oxalic diamides are stable and can be prepared easily from commercially available cheap starting materials.

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Частини книг з теми "Ortho-quinone methides"

1

Taber, Douglass. "Transition Metal-Mediated Ring Construction: The Yu Synthesis of 1-Desoxyhypnophilin." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0075.

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Both 1 and 3 are inexpensive prochiral starting materials. Tae-Jong Kim of Kyungpook National University devised (Organomet. 2008, 27, 1026) a chiral Cu catalyst that efficiently converted 1 (other ring sizes worked as well) to the enantiomerically pure ester 2. Alexandre Alexakis of the University of Geneva found (Adv. Synth. Cat. 2008, 350, 1090) a chiral Cu catalyst that mediated the enantioselective coupling of 3 with Grignard reagents such as 4 . The π-allyl Pd complex derived from 6 is also prochiral. Barry M. Trost of Stanford University showed (Angew. Chem. Int. Ed. 2008, 47, 3759) that with appropriate ligand substitution, coupling with the phthalimide 7 proceeded to give 8, readily convertible to (-)-oseltamivir (Tamiflu) 9, in high ee. Jonathan W. Burton of the University of Oxford found (Chem Commun. 2008, 2559) that Mn(OAc)3 -mediated cyclization of 10 delivered the lactone 12 with high diastereocontrol. John Montgomery of the University of Michigan observed (Organic Lett. 2008, 10, 811) that the Ni-catalyzed cyclization of 12 also proceeded with high diastereocontrol. Ken Tanaka of the Tokyo University of Agriculture and Technology combined (Angew. Chem. Int. Ed. 2008, 47, 1312) Rh-catalyzed ene-yne cyclization of 14 with catalytic ortho C-H functionalization, leading to 16 in high ee. Eric N. Jacobsen of Harvard University designed (Angew. Chem. Int. Ed. 2008, 47, 1469) a chiral Cr catalyst for the intramolecular carbonyl ene reaction, that converted 17 to 18 in high ee. Using a stoichiometric prochiral Cr carbene complex 20 and the enantiomerically-pure secondary propargylic ether 19, Willam D. Wulff of Michigan State University prepared (J. Am. Chem. Soc. 2008, 130, 2898) a facially-selective Cr-complexed o -quinone methide intermediate, that cyclized to 21 with high ee. A variety of methods have been put forward for the transition metal-mediated construction of polycarbocyclic systems. One of the more powerful is the enantioselective Rh-catalyzed stitching of the simple substrate 22 into the tricycle 23 devised (J. Am. Chem. Soc. 2008, 130, 3451) by Takanori Shibata of Waseda University. Inter alia, ozonolysis of 23 delivered the cyclopentane 24 containing two all-carbon quaternary centers.

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