Relevant bibliographies by topics / Cyclopropanation reaction

Academic literature on the topic 'Cyclopropanation reaction'

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Published: 9 March 2023

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Journal articles on the topic "Cyclopropanation reaction"

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Calter, Michael A. "Transition Metal-Catalyzed, Asymmetric Reactions of Diazo Compounds." Current Organic Chemistry 1, no. 1 (May 1997): 37–70. http://dx.doi.org/10.2174/1385272801666220121184444.

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The past ten years have seen impressive advances in asymmetric synthesis. This review summarizes the recent advances in a particular set of asymmetric reactions, the reactions of diazo compounds catalyzed by transition metal complexes. Additionally, the emphasis of this summary is on reactions wherein the induction arises from a catalyst or an auxiliary, rather than some inherent asymmetry of the substrate. The covered reactions fall into two reaction types; cyclopropanations and insertions. The cyclopropanation section of this review describes how high stereoselectivities are possible using either chiral auxiliaries or various metal complexes. Both these strategies are effective for producing optically-enriched intermediates; however, the use of catalysts to control the stereochemistry of the cyclopropanation reaction is much more common than the corresponding use of auxiliaries Workers in the asymmetric cyclopropanation field have primarily used Cu(l) and Rh(ll) complexes as catalysts for these reactions, although several complexes of other metals do afford high asymmetric induction. Both inter- and intramolecular cyclopropanations afford synthetically useful selectivities. The insertion section of this review summarizes recent advances in the use of auxiliaries and catalysts for controlling the stereoselectivity of the insertion into various bonds. Insertion into C-H bonds are by far the most intensively studied, although there has been some success with asymmetric insertions into 0-H, S-H, Si-H and C-0 bonds. Complexes of Rh(ll) are almost universally employed for asymmetric insertions. As in the case of cyclopropanations, both inter- and intramolecular insertions can proceed with useful selectivities. Again, catalyst control has proven a more versatile way to control absolute stereochemistry than auxiliary control.
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ZHAO, CUNYUAN, DONG-QI WANG, and DAVID LEE PHILLIPS. "DENSITY FUNCTIONAL STUDY OF SELECTED MONO-ZINC AND GEM-DIZINC RADICAL CARBENOID CYCLOPROPANATION REACTIONS: OBSERVATION OF AN EFFICIENT RADICAL ZINC CARBENOID CYCLOPROPANATION REACTION AND THE INFLUENCE OF THE LEAVING GROUP ON RING CLOSURE." Journal of Theoretical and Computational Chemistry 02, no. 03 (September 2003): 357–69. http://dx.doi.org/10.1142/s0219633603000549.

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We report a theoretical study of the cyclopropanation reactions of EtZnCHI, (EtZn)2CH EtZnCHZnI, and EtZnCIZnI radicals with ethylene. The mono-zinc and gem-dizinc radical carbenoids can undergo cyclopropanation reactions with ethylene via a two-step reaction mechanism similar to that previously reported for the CH2I and IZnCH2 radicals. The barrier for the second reaction step (ring closure) was found to be highly dependent on the leaving group of the cyclopropanation reaction. In some cases, the (di)zinc carbenoid radical undergoes cyclopropanation via a low barrier of about 5–7 kcal/mol on the second reaction step and this is lower than the CH2I radical reaction which has a barrier of about 13.5 kcal/mol for the second reaction step. Our results suggest that in some cases, zinc radical carbenoid species have cyclopropanation reaction barriers that can be competitive with their related molecular Simmons-Smith carbenoid species reactions and produce somewhat different cyclopropanated products and leaving groups.
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Shintani, Ryo, Ayase Ohzono, and Kentaro Shirota. "Phosphinative cyclopropanation of allyl phosphates with lithium phosphides." Chemical Communications 56, no. 79 (2020): 11851–54. http://dx.doi.org/10.1039/d0cc04854b.

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A new cyclopropanation reaction of allyl phosphates with lithium phosphides has been developed to give cyclopropylphosphines, and high selectivity toward cyclopropanation has been realized by conducting the reaction in the presence of HMPA.
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Pyne, Stephen G., Karl Schafer, Brian W. Skelton, and Allan H. White. "Asymmetric Synthesis of Protected 2-Substituted Cyclopropane Amino Acids." Australian Journal of Chemistry 51, no. 2 (1998): 127. http://dx.doi.org/10.1071/c97105.

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The cyclopropanation reactions of (1a) with ethyl and t-butyl (dimethylsulfuranylidene)acetate proceeded with good diastereoselectivity and resulted in the formation of three diastereoisomeric products. The major diastereoisomeric product ((2a) and (2b), respectively) could be isolated in pure form by simple recrystallization. The stereochemistry of the major cyclopropane product (2b) has been determined by single-crystal X-ray structural analysis. These cyclopropanation products were susceptible to ring opening of the cyclopropane ring upon reduction with sodium borohydride or acid hydrolysis. The reaction of (1b) with ethyl (dimethylsulfuranylidene)acetate gave a mixture of four diastereoisomeric cyclopropanation products. The reactions of (1a) and (1b) with the sulfur ylide derived from 3-methoxycarbonylallyldimethylsulfonium bromide were less successful in terms of product diastereoselectivities.
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Davies, Huw M. L. "Rhodium-Stabilized Vinylcarbenoid Intermediates in Organic Synthesis." Current Organic Chemistry 2, no. 5 (September 1998): 463–88. http://dx.doi.org/10.2174/1385272802666220128232502.

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Abstract: This article will give an overview of the reactions and synthetic utility of rhodium-stabilized vinylcarbenoids, which have been shown in recent years to be versatile synthetic intermediates. They undergo highly diastereoselective cyclopropanations with a wide array of alkenes and dienes, and the resulting vinylcyclopropanes are readily converted to other ring systems. Most notable is the reaction between vinylcarbenoids and dienes, which is a general method for the stereoselective construction of seven-membered carbocycles by means of a tandem cyclopropanation/Cope rearrangement sequence. Efficient insertions into Si-H, C-H, N-H and 0-H bonds can also be achieved by rhodium-stabilized vinylcarbenoids. The synthetic utility of vinylcarbenoid chemistry has been greatly enhanced by the recent development of chiral catalysts and auxiliaries that enable this chemistry to be achieved with high asymmetric induction.
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Cressy, Derek, Cristian Zavala, Anthony Abshire, William Sheffield, and Ampofo Darko. "Tuning Rh(ii)-catalysed cyclopropanation with tethered thioether ligands." Dalton Transactions 49, no. 44 (2020): 15779–87. http://dx.doi.org/10.1039/d0dt03019h.

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Herraiz, Ana G., and Marcos G. Suero. "New Alkene Cyclopropanation Reactions Enabled by Photoredox Catalysis via Radical Carbenoids." Synthesis 51, no. 14 (June 11, 2019): 2821–28. http://dx.doi.org/10.1055/s-0037-1611872.

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We describe the recent emergence of a new approach for the synthesis of cyclopropane rings by means of photoredox catalysis. This methodology relies on the photocatalytic generation of radical carbenoids or carbenoid-like radicals as cyclopropanating species, and is characterized by excellent functional group tolerance, chemoselectivity and the ability to form cyclopropanes with excellent control from E/Z alkene mixtures. The mild reaction conditions and employment of user-friendly reagents are highly attractive features that may lead to this approach being used in academic and industrial laboratories.1 Introduction2 Photoredox-Catalyzed Alkene Cyclopropanations with Radical Carbenoids3 Conclusions and Outlook
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Lorecchio, Chiara, Emanuela Tamburri, Laura Lazzarini, Silvia Orlanducci, Robertino Zanoni, and Pietro Tagliatesta. "Covalent Functionalization of Nanodiamonds by Ruthenium Porphyrin, and Their Catalytic Activity in the Cyclopropanation Reaction of Olefins." Catalysts 10, no. 6 (June 13, 2020): 666. http://dx.doi.org/10.3390/catal10060666.

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Detonation nanodiamonds (DNDs) were functionalized by ruthenium porphyrins and used as catalysts in the cyclopropanation reaction of olefins. The heterogeneous catalyst was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and XPS (X-ray photoelectron spectroscopy). The XPS was used to control the binding of the ruthenium porphyrin to the DNDs’ surface. This catalyst was used in the cyclopropanation reactions of simple olefins and was reused with no loss of activity in four consecutive cycles, after recovering each time by simple centrifugation.
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Papageorgiou, Charles D., Steven V. Ley, and Matthew J. Gaunt. "Organic-Catalyst-Mediated Cyclopropanation Reaction." Angewandte Chemie International Edition 42, no. 7 (February 17, 2003): 828–31. http://dx.doi.org/10.1002/anie.200390222.

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Bremeyer, Nadine, Stephen C. Smith, Steven V. Ley, and Matthew J. Gaunt. "An Intramolecular Organocatalytic Cyclopropanation Reaction." Angewandte Chemie International Edition 43, no. 20 (May 10, 2004): 2681–84. http://dx.doi.org/10.1002/anie.200454007.

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Dissertations / Theses on the topic "Cyclopropanation reaction"

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SARKAR, ABHIJNAN. "HETEROGENEOUS IRON CATALYZED CYCLOPROPANATION REACTION." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/698432.

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Until now, NGR (nitrogen-enriched graphene) catalysts have mostly been employed for hydrogenation/oxidation reactions. In this piece of work, we expand the field of applicability of an iron NGR catalyst to cyclopropanation reactions. In this work, a heterogeneous Fe-based nitrogen-doped carbon supported catalyst has been successfully employed for the cyclopropanation reaction of alkenes. According to best of our knowledge, this is the first example of a heterogeneous Fe-catalyzed cyclopropanation reaction in today's date. These kinds of materials, generally employed for reduction or oxidation reaction, are now indeed effective catalyst also for carbene transfer reactions. The activity of Fe/Phen@C-800in the reaction was initially explored by using ethyl diazoacetate and α-methylstyrene as substrates as the model transformation. Various parameters such as solvent, temperature, time and catalyst support etc. were changed. The nature of the solvent has a minimal influence both on the reaction yield and diasteroselectivity making this reaction versatile from the media profile. The variation of the reaction temperature furnished the product in slightly lower yield. When a 5-fold amount of the olefin with respect to the diazo compound was used, homocoupling products (diethyl fumarate and diethyl maleate) deriving from EDA were detected in very low amount (<5 %). Even when the amount of olefin was decreased (1.5 eq) homocoupling side products increased, although a very good yield of the cyclopropane was maintained, demonstrating the applicability of the procedure even to more expensive olefins. Interestingly, the catalyst is water tolerant and only a slight decreased yield was obtained using a “wet” solvent. A change in the catalyst support from carbon to inorganic oxides (MgO or SiO2) does not significantly affect the yield and the diastero selectivity. Furthermore control experiments effected by employing catalysts prepared by the same procedure employed for Fe/Phen@C-800, but omitting either Fe(OAc)2 or Phen, resulted in no detectable formation of cyclopropane. Fe/Phen@C-800-catalysts showed good results in dimethoxyethane at 60 °C for 4 h, affording high yields of the desired cyclopropanes (mixture of cis and trans isomers) and only <5 % ethyl maleate and fumarate. The model reaction has been successfully scaled-up to 15-fold without significant variations of yield and diasteroisomeric ratio. The developed protocol allows obtaining several cyclopropanes from aromatic and aliphatic olefins and different diazocompounds. High to excellent yields were obtained for terminal olefins, including geminally substituted ones. Aliphatic olefins require longer reaction times. A moderate trans diastereoselectivity was observed in all cases. The catalysts do not show any activity towards internal olefins and can be used to selectively cyclopropanate a terminal olefin in a substrate containing both internal and terminal olefinic groups. The selectivity for the terminal double bond can be explained by the lack of activity of the catalyst in the case of internal olefins, most likely due to a hindered approach of the substrate to the carbene formed on the surface of the catalyst. Mono substituted diazo compounds (ester or ketone) afforded the corresponding cyclopropanes in excellent yields. More sterically demanding diazocompounds such as t-BDA has a dramatic effect on the diasteroselection, furnishing the cis- isomer only in traces. Disubstituted diazomethanes proved to be more challenging. Mono substituted diazo compounds such as diphenyldiazomethane failed to afford corresponding cyclopropanes under standard conditions, although it yielded the product in moderate yield at a higher temperature and longer reaction time (100 °C for 8h in toluene), while the more stable diazomalonate did not react even under these conditions. The catalysts was recycled several times, but a gradual deactivation is immediately observed since the first recycle. In principle, the loss of activity can be attributed either to metal leaching or to deactivation of the catalyst. After the first recycle, ICP analysis of the solution showed that only 0.1% of the initial iron had been lost in solution. This result indicates that the loss of recycling ability is not due to metal leaching. In order to make the whole process both efficient and effective, two routes of reactivation were explored. Attempted reactivation of the catalyst at 300 °C seems to have a slightly positive effect but that at 400 °C is not effective. The initial catalyst activity was effectively restored using an oxidative reactivation protocol under mild conditions (H2O2, 3 v/v% aqueous solution), which may be of more general use even for other reactions if olefins or other polymerizable compounds are employed as substrates. Oxidative regeneration is typical for catalyst that suffer of physicochemical deactivation (e.g. fouling or poisoning). Indeed, we verified that complete deactivation of the catalyst occurs even by treating the material only with styrene under the reaction conditions and the activity is restored by oxidative treatment. This result indicates the polymerization of the olefin on the catalytic surface as a possible cause for the deactivation rather than a mechanical or thermal modification of the catalyst.
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Bremeyer, Nadine. "An enantioselective organocatalytic intramolecular cyclopropanation reaction." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614801.

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TACHON, CHRISTINE. "Diphosphirannes : nouvelle reaction de cyclopropanation en chimie du phosphore." Toulouse 3, 1989. http://www.theses.fr/1989TOU30094.

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Le memoire presente concerne une nouvelle reaction de cyclopropanation en serie phosphoree conduisant a la formation de diphosphiranes. La structure de ces nouveaux synthons a ete determinee par rmn et par diffraction rx. Une premiere approche de la reactivite de ces synthons est presentee
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Solorio, Alvarado César Rogelio. "Gold (i)-catalyzed Retro-Cyclopropanation Reaction and Development of Trindane-Based Approach Toward c60." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/51876.

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La cicloisomerización de 1,5-, 1,6- y 1,7-eninos catalizada por Au(I) y Au(III) ha sido desarrollada con un enfoque sintético y mecanístico. Los aportes hechos hasta el momento nos han permitido elucidar de modo general la reactividad de los complejos catiónicos de oro(I) (Esquema R1). Se demostró que en la ciclación de 1,6-eninos B1, la migración propargílica 1,5 del éter metílico tenía lugar originando la estructura base de los globuloles, una familia de productos naturales. Sin embargo al explorar la reactividad de 1,7- eninos C1, tuvo lugar una migración propargílica 1,6, dando lugar a la formación de benzo[C]fluorenos. Alternativamente con una sustitución similar en los eninos de partida utilizando los 1,6-eninos D1 (esquema R2) tuvo lugar una nueva reacción catalizada por oro. En este caso, un nuevo proceso de anulación catalizado por complejos catiónicos de oro(I) nos condujo a la formación de naftalenos 1,3-disustituidos E1 (esquema R2) Los naftalenos 1,3-disustituidos son una clase de compuestos no accesibles de manera convencional mediante acoplamiento cruzado o por sustitución electrófila aromática. Durante el estudio de anulación con D1, determinamos el mecanismo de esta reacción. Encontramos que este proceso tiene lugar vía cicloisomerización 6- endo-dig generando un dihidronaftaleno D2 (esquema R2), que tras migración [1,2] de hidógeno genera D3. Tras protodemetalación, genera el enol eter D4. Retro-ciclopropanación sobre D4 origina un naftaleno 1,3-bisustituido E1, junto con la formación de un carbeno libre de oro(I) G1 para dar lugar a un bisciclopropano tetracíclico F1. Esta es la primera vez que se observa el proceso de reto-ciclopropanación en química de oro.
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Hillier, Michael Campion. "The intramolecular cyclopropanation reaction and its application towards the synthesis of pseudopeptides and natural products /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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Aldajaei, Jamal. "Determination of the factors that affect the gas-phase reactivity of metal-centered cyclopropanation catalysts and examination of the properties of their reaction products." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3393.

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Gas phase studies of organometallic systems have provided deep insight into reaction mechanisms and reaction intermediates. In this thesis, several metal/ligand systems were examined in an effort to form metal carbenes in the gas phase. With cobalt and iron porphyrins, the carbene undergoes metal-ligand insertion. With copper bis-oxazolines, metal carbenes tend to undergo metal-ligand insertion and a Wolff rearrangement. To avoid insertions, we turned to a rigid ligand, 1, 10-phenanthroline. Under ESI conditions, a copper (I) complex with phenanthroline can be formed. When treated with diazoacetate esters, the dominant product results from addition with loss of nitrogen followed by loss of CO. This appears to be the result of a Wolff rearrangement of the metal carbene to give a metal ketene complex that spontaneously loses CO. There is no evidence of any stable metal carbenes in this reaction system. Trimethylsilyldiazomethane was also used as a carbene precursor, and its reaction with the copper phenanthroline complex gives addition with loss of nitrogen; but the product exhibits no carbene reactivity with alkenes. Here computational modeling suggests that the metal carbene undergoes a 1, 2 methyl migration, giving an exceptionally stable sila-alkene complex with the copper. As an alternative path to a metal carbene, we have used ESI to form a complex between the copper (I) phenanthroline and betaine (N, N, N-trimethylglycine). Under CID, this complex wills decarboxylates to give a copper ylide complex. Further CID leads to loss of trimethylamine and the formation of a complex between methylene and the copper phenanthroline. Depending on the CID conditions, two isobaric products are formed. One exhibits no carbene reactivity and the other readily gives carbene behavior with alkenes. The former is likely a metal-ligand insertion product, and the latter is the true metal carbene species. We explored the reactions of the carbene with electron-rich alkenes, such as ethyl vinyl ether and 3, 4-dihydro-2H-pyran, and electron-deficient alkenes, such as trichloroethylene.
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Herlé, Bart. "Stereoselective Cyclopropanations via Gold(I)-Catalyzed Retro-Buchner Reactions." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/454770.

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La formació de carbens bencílics d’or(I) a partir de cicloheptatriens substituïts en la posició 7, a través de la reacció de retro-Buchner, ha aparegut recentment com una alternativa segura i versàtil a la descomposició de diazocompostos. No obstant, la formació de dits carbens requereix altes temperatures, limitant la seva aplicació. El treball d’aquest tesi doctoral s’ha dedicat a superar aquesta desavantatge i millorar la versatilitat de la transformació. Els derivats de 1H-ciclopropa[l]fenantrè, que s’assemblen al tautòmer norcaradiè del cicloheptatriè, es descomponen per donar lloc a carbens lliures mitjançant la irradiació amb llum. Es va investigar la formació de carbens d’or(I) amb derivats de fenantrè mitjançant la reacció de retro-Buchner. No obstant, no es va trobar cap millora significativa amb respecte l’ús de derivats de cicloheptatriè. Per altre banda, la generació de carbens al·lílics d’or(I) a partir de 7-alquenilcicloheptatriens, té lloc a temperatures significativament més baixes. Tenint en compte aquest fet, es va desenvolupar una reacció de ciclopropanació d’olefines per donar vinil-ciclopropans i vinil-aminociclopropans amb bons rendiments i elevada selectivitat per donar l’isòmer cis. Els derivats de 7-alquenil-cicloheptatriè es formen en un sol pas a partir d’aldehids i cetones emprant un nou reactiu del tipus Julia-Kocienski. Addicionalment, utilitzant tècniques experimentals i computacionals, es van estudiar els mecanismes mediats per or(I) de la reacció de retro-Buchner, de la ciclopropanació i de la reacció de epimerització dels vinil-ciclopropans. Això va permetre el desenvolupament d’un model esteroquímic avançat per a les reaccions de ciclopropanació catalitzades per or(I). El coneixement aportat per els estudis mecanístics i la síntesi millorada de derivats de cicloheptatriè van permetre la síntesi de derivats de cicloheptatriè més congestionats estèricament, què donen lloc a carbens d’or(I) a temperatura ambient i són el punt de partida per al desenvolupament d’una ciclopropanació enantioselectiva de gran aplicació.
La formación de carbenos bencílicos de oro(I) a partir de cicloheptatrienos sustituídos en la posición 7, a través de la reacción de retro-Buchner, ha surgido recientemente como una alternativa segura y versátil a la descomposición de diazocompuestos. Sin embargo, la formación de dichos carbenos tiene lugar a altas temperaturas, limitando su aplicación. El trabajo de esta tesis doctoral se dedicó a superar esta desventaja y a mejorar la versatilidad de la transformación. Los derivados de 1H-ciclopropa[l]fenantreno, que se asemejan al tautómero norcaradieno del cicloheptatrieno, se descomponen para dar lugar a carbenos libres mediante irradiación con luz. Se investigó la formación de carbenos de oro(I) con derivados de fenantreno, a través de la reacción de retro-Buchner. No obstante, no se encontró ninguna mejora significativa con respecto al uso de derivados de cicloheptatrieno. Por otro lado, la generación de carbenos alílicos de oro(I) a partir de 7-alquenil-cicloheptatrienos, tiene lugar a temperaturas significativamente más bajas. Dada esta observación, se desarrolló una reacción de ciclopropanación de olefinas para dar vinil-ciclopropanos y vinil-aminociclopropanos en buenos rendimientos y con elevada selectividad para el isómero cis. Los derivados de 7-alquenil-cicloheptatrieno son formados en un sólo paso a partir de aldehídos y cetonas utilizando un nuevo reactivo de tipo Julia-Kocienski. Adicionalmente, utilizando técnicas experimentales y computacionales, se estudiaron los mecanismos mediados por oro(I) de la reacción de retro-Buchner, de la ciclopropanación y de la reacción de epimerización de los vinilciclopropanos. Esto permitió el desarrollo de un modelo estereoquímico avanzado para las reacciones de ciclopropanación catalizadas por oro(I). El conocimiento aportado por los estudios mecanísticos y la síntesis mejorada de derivados de cicloheptatrieno, permitieron la síntesis de derivados de cicloheptatrieno más estéricamente congestionados, que dan lugar a carbenos de oro(I) a temperatura ambiente y son el punto de partida para el desarrollo de una ciclopropanción enantioselectiva de gran aplicación.
The formation of benzylic gold(I) carbenes from 7-substituted cycloheptatrienes via a retro-Buchner reaction has recently emerged as a safe and versatile alternative to decomposition of diazo compounds. However, the carbene formation takes places at high temperatures, which puts a limit on its application. The work in this thesis is dedicated to overcome this drawback and enhance the versatility of this transformation. Free carbenes can be generated from light-induced decomposition of 1H-cyclopropa[l]phenanthrenes, which bear great resemblance to the norcaradiene tautomer of cycloheptatriene. Therefore, the propensity to form gold(I) carbenes via the retro-Buchner reaction of phenanthrene derivatives was investigated, albeit without finding significant improvements over the cycloheptatriene derivatives. The formation of allylic gold(I) carbenes from 7-alkenyl cycloheptatrienes takes place at significantly lower temperatures. Based on this observation, a highly cis-selective olefin cyclopropanation reaction has been developed, affording vinylcyclopropanes and vinyl-aminocyclopropanes in moderate to good yield. The 7-alkenyl cycloheptatriene derivatives can be formed in a single step from aldehydes and ketones by a novel Julia-Kocienski reagent. The mechanisms of the gold(I)-mediated retro-Buchner, cyclopropanation, and epimerization reactions for vinylcyclopropanes have been studied experimentally and computationally, which led to the development of an advanced stereomodel for gold(I)-catalyzed cyclopropanation reactions. Owing to the mechanistic insights, and the improved strategy for the synthesis of cycloheptatriene reagents, a sterically encumbered cycloheptatriene derivative was developed, which allows the formation of gold(I) carbenes at room temperature, paving the way for a broad-scope enantioselective cyclopropanation reaction.
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Hartikka, Antti. "Towards Rational Design of Asymmetric Catalyst for Organometallic and Organocatalytic Reactions." Doctoral thesis, Uppsala : University Library / Universitetsbiblioteket, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7905.

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Castano, B. "SYNTHESIS, CHARACTERIZATION AND CATALYTIC ACTIVITY OF CHIRAL TETRAAZAMACROCYCLE - PC-L* -CU(I) AND AG (I) COMPLEXES." Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/229590.

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Homogeneous catalysis is a constantly growing and evolving area of study: in the last forty years many discoveries have been reported in both industrial and academic fields. Thanks to the use of organometallic catalysts, many inorganic and organic reactions of great importance have been revolutionized, so that homogeneous catalysis is now essential in many aspects of organic chemistry and for several industrial processes. On the other hand, heterogeneous catalysis is important because of its easier application in industry. Heterogeneous single site catalysts in many cases show superior performances in terms of activity, selectivity and recyclability coupling together the advantages of heterogeneous and homogeneous systems. It is important to note that the most commonly used ligands to form catalytic complexes often need really complicated synthesis so that the cost of the catalyst becomes excessive. In our research group we are focusing on the synthesis of molecules obtainable in few synthetic steps and easy to modify in order to be used as asymmetric ligands for transition metals. In particular we have prepared and fully characterised a small library of non-chiral and chiral pyridine containing macrocyclic ligands (Pc-L) possessing the same donor properties but with either C1, C2 or C2v symmetry. The strategy adopted for the synthesis of these macrocyclic ligands is very flexible and allows for structural modifications. Relative basicity of the four nitrogens atoms and metal complexation of Pc-L ligands with different copper(I) salts were studied. The use of [Cu(I)(Pc-L)] complexes was investigated at first in Henry catalytic reaction under mild conditions. The remarkable diastereoselectivity observed when isatine was reacted with nitroethane under the optimised catalytic conditions is worth to note, considering the easy access to a highly functionalized isatine skeleton. However, further studies on the ligand steric requirements in order to achieve significant enantioselectivities are required. Then [Cu(I)(Pc-L)] complexes were tested as competent catalysts in asymmetric cyclopropanation reactions, at first under homogenous conditions in 1,2-dichloroethane. Cyclopropanes were obtained in good to excellent yields and enantiomeric excesses up to 99%. Thanks to the collaboration with Dr. Dal Santo, we have developed supported hydrogen-bonded (SHB) chiral copper(I) complexes. These supported catalysts showed good performances in cyclopropanation reactions under heterogeneous conditions in batch. The heterogeneised systems showed higher or comparable activities than the homogeneous counterpart and a good recyclability, allowing the use of more environmentally friendly n-hexane as solvent in place of 1,2-dichloroethane. Cyclopropanes were obtained in good to excellent yields and enantiomeric excesses up to 67%. We did not observe any significant Cu leaching when employing n-hexane as a reaction medium and the catalytic system is of truly heterogeneous nature, since the filtered solution is not catalytically active. The observed confinement effects are more dependent on the employed solvent (non-polar vs halogenated) than to the kind of support (ordered or non-ordered). Worth to note is the fact that even commercial silica can be used as a support, without any need of structural modification of the ligand in order to strongly graft the complex. Thanks to the three month collaboration with Prof. David J. Cole-Hamilton from the University of St. Andrews (UK), these catalytic system based on SHB chiral copper(I) complexes were also tested as competent catalysts for asymmetric cyclopropanation reactions under flow conditions allowing the use of more eco-sustainable CO2 as a vector instead of solvents normally used for these reactions. The heterogeneised systems under flowing CO2 showed comparable or even higher chemoselectivities than the homogeneous counterpart. In terms of enantioselection excellent results were obtained also with non-activated alkenes like 1-octene where ees are comparable to those observed in the homogenous phase. Interestingly, all the data in CO2 were obtained at 40°C, while the best temperature for the cyclopropanation reaction in the homogenous phase was 0°C. Moreover supported catalysts showed a good recyclability and the TON number has been increased (up to 440). The catalysts system remained active up to 25 h without any loss in catalytic activity and chemoselectivity improved upon prolonged reaction times. Catalyst were stable and robust with a negligible copper leaching (0.007% of total copper). Future studies will be devoted to optimise the ligand design in order to improve the stereo-selective outcome of the reaction. Collaborating with Dr. Giorgio Abbiati, we next extend our studied on metal complexes testing our ligands with other metal ions in order to explore the coinage group. We have prepared silver(I) complexes of Pc-L* with different silver(I) salts. The [Ag(I)(Pc-L)] complexes demonstrated to be suitable catalysts for the synthesis of 1-alkoxyisocromenes starting from various 2-alkynylbenzaldehydes and different primary and secondary alcohols. Best results were obtained with BF4-complex. The approach is characterised by absolute regioselectivity, mild reaction condition, good to excellent reaction yields, cleanness of the reaction, reduced purification steps. The [Ag(I)(Pc-L)] complexes are quite stable, versatile and can be used under open-air atmosphere. The reaction mechanism was investigated by in depth NMR studies and an aimed intramolecular trapping experiment. Our efforts are now devoted to the development of an enantioselective version of this transformation. Finally the synthesis of several tiosemicarbazide derived Schiff base copper complexes has been reported. They have been fully characterised with spectral and analytical experiments. All synthesised complexes showed excellent catalytic activities in cyclopropanation reactions and TON up to 18,400 could be obtained. In contrast to the prolonged EDA addition time generally required to reduce the formation of homo-coupling products in cyclopropanation, we found those complexes very selective. Furthermore, a single addition of EDA is required to yield the desired cyclopropanes in excellent yields. Moreover, the catalysts are very robust and no decrease in yield was observed even after three catalytic runs. Several cyclopropanes have been obtained in good to excellent yields even from non-activated olefins. In the case of the cyclopropanation of (-)b-pinene, out of four possible diastereoisomers, only one product was formed that could be isolated pure in 84% yield.
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Jubault, Philippe. "Génération électrochimique de carbanions α-phosphorés α, α-dihalogénés : électrosynthèse de gem-dihalogénoalcènes et de cycloalkylphosphonates. Mise en évidence d'un phénomène d'activation électrochimique du magnésium." Rouen, 1996. http://www.theses.fr/1996ROUES018.

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La première partie de ce travail concerne la génération électrochimique d'ylures de phosphore α,α-dihalogénés à partir de sels de phosphonium polyhalogénés et leur utilisation pour la synthèse de gem-dihalogénoalcènes selon une réaction de Wittig. Au cours de l'électrosynthèse de gem-difluoroalcènes, nous observons un phénomène particulier d'activation électrochimique de l'anode de magnésium que nous appelons activation électrochimique du magnésium. Ce phénomène permet la synthèse rapide et efficace de nombreux gem-dihalogénoalcènes. Nous proposons une interprétation pour ce mécanisme d'activation, étayée par la caractérisation des intermédiaires réactionnels. Dans la seconde partie de ce travail, ce phénomène d'activation électrochimique de l'anode de magnésium est utilisé pour la génération électrochimique du carbanion du trichlorométhylphosphonate de diisopropyle qui est engagé dans des réactions d'alkylation, de cyclopropanation et de cycloalkylation. De plus, des électrosynthèses en un seul réacteur de cyclopropylphosphonates β-substitués, de cyclopropylphosphonates α,β-substitués et de cycloalkylphosphonates sont développées.
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Books on the topic "Cyclopropanation reaction"

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Hardee, David James. Part 1 : Lanthanum Triflate-Catalyzed Cyclopropanation via Intramolecular Methylene Transfer. Part 2: Reaction Design with Aromatic Ions - Nucleophilic Acyl Substitution and Organophotoredox Catalysts. [New York, N.Y.?]: [publisher not identified], 2011.

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Book chapters on the topic "Cyclopropanation reaction"

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Charette, André B., Hélène Lebel, and Marie-Noelle Roy. "Asymmetric Cyclopropanation and Aziridination Reactions." In Copper-Catalyzed Asymmetric Synthesis, 203–38. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664573.ch8.

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Kamimura, Akio. "[2+1]-Type Cyclopropanation Reactions." In Methods and Applications of Cycloaddition Reactions in Organic Syntheses, 1–66. Hoboken, New Jersey: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118778173.ch01.

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Intrieri, Daniela, Daniela M. Carminati, and Emma Gallo. "Iron-Catalyzed Cyclopropanation of Alkenes by Carbene Transfer Reactions." In Non-Noble Metal Catalysis, 163–89. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2018. http://dx.doi.org/10.1002/9783527699087.ch7.

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Doyle, Michael P. "Chiral Dirhodium(II) Carboxamidates for Asymmetric Cyclopropanation and Carbon-Hydrogen Insertion Reactions." In Modern Rhodium-Catalyzed Organic Reactions, 341–55. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527604693.ch15.

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Nishiyama, Hisao, Hideki Matsumoto, Soon-Boon Park, and Kenji Itoh. "Novel Chiral Ruthenium-Bis(Oxazolinyl)Pyridine and Bis-(Oxazolinyl)-Bipyridine Complexes: Asymmetric Cyclopropanation of Styrene with Diazoacetates." In Chiral Reactions in Heterogeneous Catalysis, 197–201. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-1909-6_21.

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Rowlands, G. J. "Cyclopropanation (The Simmons–Smith Reaction)." In Acetals: Hal/X and O/O, S, Se, Te, 1. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-029-00126.

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Meigh, J. P. K. "Cyclopropanation by the Simmons–Smith Reaction." In Six-Membered Hetarenes with Two Unlike or More than Two Heteroatoms and Fully Unsaturated Larger-Ring Heterocycles, 1. Georg Thieme Verlag KG, 2004. http://dx.doi.org/10.1055/sos-sd-017-01441.

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Scott, P. J. H., and P. G. Steel. "Cyclopropanation of Esters and Acyl Sulfonamides (Kulinkovich Reaction)." In Alcohols, 1. Georg Thieme Verlag KG, 2008. http://dx.doi.org/10.1055/sos-sd-036-00371.

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Salan, J. "Ring Enlargement of the Cyclopropane Intermediate Formed by a Simmons–Smith Cyclopropanation Reaction." In Ketones, 1. Georg Thieme Verlag KG, 2005. http://dx.doi.org/10.1055/sos-sd-026-00426.

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Arvidsson, P. I., P. P. Bose, and T. Naicker. "Cyclopropanation Reactions☆." In Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-12-409547-2.11462-3.

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Conference papers on the topic "Cyclopropanation reaction"

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Dirceu Megiatto Junior, Jackson, and Kamila Cristina Dos Santos. "Study of Cyclopropanation Reactions Using Co(II)Tetraphenylporphyrin as Catalysts for Preparation of Rotaxanes." In XXIII Congresso de Iniciação Científica da Unicamp. Campinas - SP, Brazil: Galoá, 2015. http://dx.doi.org/10.19146/pibic-2015-38091.

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