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Artykuły w czasopismach na temat „Diels-Alder cycloaddition reactions”

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Data publikacji: 17 lipca 2024

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1

Grygorenko, Oleksandr O., Viktoriia S. Moskvina, Oleksandr V. Hryshchuk i 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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2

Burnell, D. Jean, i Zdenek Valenta. "π-Facial stereoselectivity in the Diels–Alder reactions of a rigid carbocyclic diene: spiro(bicyclo[2.2.1]heptane-2,1′-[2,4]cyclopentadiene)". Canadian Journal of Chemistry 69, nr 1 (1.01.1991): 179–84. http://dx.doi.org/10.1139/v91-028.

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The plane-nonsymmetrical diene spiro(bicyclo[2.2.1]heptane-2,1′-[2,4]cyclopentadiene) (2) was synthesized, and the π-facial stereoselectivity of its Diels–Alder cycloadditions with three cyclic dienophiles was examined. Adduct ratios were very similar, and the selectivity is surmised to be mainly the result of steric interactions at the transition state. Key words: facial stereoselectivity, Diels–Alder, cycloaddition.

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3

Soares, Maria I. L., Ana L. Cardoso i Teresa M. V. D. Pinho e Melo. "Diels–Alder Cycloaddition Reactions in Sustainable Media". Molecules 27, nr 4 (15.02.2022): 1304. http://dx.doi.org/10.3390/molecules27041304.

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

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4

Zhou, You-Yun, i Christopher Uyeda. "Catalytic reductive [4 + 1]-cycloadditions of vinylidenes and dienes". Science 363, nr 6429 (21.02.2019): 857–62. http://dx.doi.org/10.1126/science.aau0364.

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Cycloaddition reactions provide direct and convergent routes to cycloalkanes, making them valuable targets for the development of synthetic methods. Whereas six-membered rings are readily accessible from Diels-Alder reactions, cycloadditions that generate five-membered rings are comparatively limited in scope. Here, we report that dinickel complexes catalyze [4 + 1]-cycloaddition reactions of 1,3-dienes. The C1partner is a vinylidene equivalent generated from the reductive activation of a 1,1-dichloroalkene in the presence of stoichiometric zinc. Intermolecular and intramolecular variants of the reaction are described, and high levels of asymmetric induction are achieved in the intramolecular cycloadditions using aC2-symmetric chiral ligand that stabilizes a metal-metal bond.

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5

Zezula, Josef, Tomáš Hudlický i Ion Ghiviriga. "Intramolecular Diels-Alder Cycloadditions of cis-Cyclohexadienediols Derived Enzymatically from (2-Azidoethyl)benzene. Construction of Highly Functionalized Bridged Isoquinoline Synthons". Collection of Czechoslovak Chemical Communications 66, nr 8 (2001): 1269–86. http://dx.doi.org/10.1135/cccc20011269.

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(3aR,7aS)-4-(2-Azidoethyl)-2,2-dimethyl-3a,7a-dihydrobenzo[1,3]dioxole (22) was converted in two steps to trienes23and24, which upon heating underwent intramolecular Diels-Alder reactions to give mixtures of isomeric 11,11-dimethyl-5-oxo-10,12-dioxa-4-azatetracyclo[6.5.2.01,6.09,13]pentadec-14-ene-7-carboxylates25,26and27,28, respectively. These products were separated and identified. For comparison, intermolecular Diels-Alder cycloaddition of diene22with maleic anhydride was carried out. Products of this reaction, 1-(2-azidoethyl)-4,4-dimethyl-3,5,10-trioxatetracyclo[5.5.2.02,6.08,12]tetradec-13-ene-9,11-diones (29and30) were converted to methyl ester analogues of31and32in a two-step sequence. The stereochemical outcome of these cycloadditions is discussed as well as their possible utilization in organic synthesis, especially in total synthesis of some alkaloids.

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6

Pratt, Andrew J., Phillip M. Rendle i Peter J. Steel. "Anticancer Prodrug Studies: Diels - Alder Chemistry of 1-Methylthio-1-(p-tolylsulfonyl)ethene". Australian Journal of Chemistry 64, nr 7 (2011): 945. http://dx.doi.org/10.1071/ch10450.

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The reactivity of 1-methylthio-1-(p-tolylsulfonyl)ethene (1) as a dienophile in Diels–Alder chemistry is investigated. Cycloaddition reactions were carried out with a range of pyran-2-ones and isobenzofurans. The initial Diels–Alder adducts have the potential of undergoing fragmentation in chemistry that is relevant to the design of anticancer intercalator prodrugs. The nature of the final products of the reactions provided insights into both the cycloaddition reactions and fragmentation pathways of the adducts. By comparison with a thioether group, the sulfonyl substituent of the dienophile was found to decrease the reactivity and regioselectivity of the cycloaddition chemistry and to facilitate fragmentation of the initial adducts by the elimination of p-toluenesulfinic acid.

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7

Carlini, Rina, Kerianne Higgs, Nicholas Taylor i Russell Rodrigo. "Diels–Alder adducts of ortho-benzoquinones: rearrangements and further transformations". Canadian Journal of Chemistry 75, nr 6 (1.06.1997): 805–16. http://dx.doi.org/10.1139/v97-097.

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ortho-Benzoquinones substituted with an electron-withdrawing group (EWG = CO2Me, COSMe, COCH3, CHO) at C-3 or C-4 react as dienophiles at the C3—C4 double bond in Diels–Alder reactions with several dienes, with predictable regiochemistry. The adducts undergo migration of the "angular" EWG substituent with concomitant aromatization to produce substituted catechols. The bicyclic products can be oxidized in situ and annelated by a further Diels–Alder reaction to yield 9,10-phenanthraquinone systems. When (2E)-2,4-pentadienol is employed as the diene in the second cycloaddition, reaction of the alcoholic hydroxyl group with one of the quinone carbonyl groups results in the production of tetracyclic lactols 22a, 22b, and 23. Keywords: benzoquinone, Diels–Alder, rearrangement, phenanthraquinone, phenanthrofuran.

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8

Ayadi, Sameh, i Manef Abderrabba. "Étude DFT des réactions de cycloaddition de type Diels–Alder sur le 4-aza-6-nitrobenzofuroxane". Canadian Journal of Chemistry 85, nr 5 (1.05.2007): 331–35. http://dx.doi.org/10.1139/v07-026.

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The purpose of this work is a theoretical study of Diels–Alder reactions between the 4-aza-6-nitrobenzofuroxan 1 with a series of dienophiles 3a–3c. From a thermodynamic and orbital point of view, we discuss the reactivity and the stereoselectivty of these reactions. Activation barriers in the Diels-Alder reactions of compound 1 with a series of dienophiles 3a–3c have been calculated and discussed.Key words: inverse electron demand Diels–Alder (IEDDA), DFT method, 4-aza-6-nitrobenzofuroxane.

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9

Piers, Edward, Richard W. Friesen, Paul Kao, Steven J. Rettig i James Trotter. "Synthesis of functionalized hexahydro-, octahydro-, and decahydro-1H-phenalenes via Diels–Alder reactions of 1-methylene-4a-methoxycarbonyl-1,2,3,4,4a,5,6,7-octahydronaphthalene and related dienes". Canadian Journal of Chemistry 71, nr 9 (1.09.1993): 1463–83. http://dx.doi.org/10.1139/v93-188.

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The results of a study of Diels–Alder reactions of the bicyclic dienes 6–8 with a variety of dienophiles are reported. Although 6 and 7 undergo cycloaddition reactions smoothly and efficiently, thermal Diels–Alder reactions of 8 are generally sluggish or, under the conditions investigated, do not proceed at all. Additions of tetracyanoethylene (TCNE) to 6–8 are highly face-selective, with preferential attack of the dienophile on the side of the dienes opposite to the angular methoxycarbonyl group. Reaction of 7 with maleic anhydride (MAN) is completely face-selective and proceeds preferentially via an endo transition state. Diels–Alder reactions of 6 and 7 with methyl acrylate (MAC) and nitroethylene (NE) are entirely regioselective, but the face-selectivities, which vary from ~2:1 to ~3:1, are rather low. The use of this chemistry as a method for the synthesis of functionalized, stereochemically defined, perhydro-1H-phenalenes is demonstrated.

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10

Kotha, Sambasivarao, Milind Meshram i Nageswara Panguluri. "Advanced Approaches to Post-Assembly Modification of Peptides by Transition-Metal-Catalyzed Reactions". Synthesis 51, nr 09 (25.03.2019): 1913–22. http://dx.doi.org/10.1055/s-0037-1612418.

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We have summarized diverse synthetic approaches for the modification of peptides by employing transition-metal-catalyzed reactions. These methods can deliver unusual peptides suitable for peptidomimetics. To this end, several popular reactions such as Diels–Alder, 1,3-dipolar cycloaddition, [2+2+2] cyclotrimerization, metathesis, Suzuki–Miyaura cross-coupling, and Negishi coupling have been used to assemble modified peptides by post-assembly chemical modification strategies.1 Introduction2 Synthesis of a Cyclic α-Amino Acid Derivative via a Ring-Closing Metathesis Protocol3 Peptide Modification Using a Ring-Closing Metathesis Strategy4 Peptide Modification via a [2+2+2] Cyclotrimerization Reaction5 Peptide Modification by Using [2+2+2] Cyclotrimerization and Suzuki Coupling6 Peptide Modification via a Suzuki–Miyaura Cross-Coupling7 Peptide Modification via Cross-Enyne Metathesis and a Diels–Alder Reaction as Key Steps8 Peptide Modification via 1,3-Dipolar Cycloaddition Reactions9 Modified Peptides via Negishi Coupling10 A Modified Dipeptide via Ethyl Isocyanoacetate11 Conclusions

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11

Cabrera-Trujillo, Jorge Juan, i Israel Fernández. "Understanding exo-selective Diels–Alder reactions involving Fischer-type carbene complexes". Organic & Biomolecular Chemistry 17, nr 11 (2019): 2985–91. http://dx.doi.org/10.1039/c9ob00132h.

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12

Fallis, Alex G. "1998 Alfred Bader Award Lecture Tangents and targets: The synthetic highway from natural products to medicine". Canadian Journal of Chemistry 77, nr 2 (1.02.1999): 159–77. http://dx.doi.org/10.1139/v98-233.

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Synthetic studies directed toward various classes of compounds including taxoids and enediyne systems are described. These investigations include tether-controlled imtramolecular Diels-Alder reactions, carbometallation routes to dienes and furans, the use of carbohydrate building blocks, pentadienyl indium reagents for tandem cycloadditions to steroid and triterpenoid skeletons, and the synthesis of taxamycins and revolveneynes and related cyclophanes.Key words: cycloaddition, taxoids, enediyne, cyclophanes, carbometallation.

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13

Cantín, Ángel, M. Victoria Gomez i Antonio de la Hoz. "Diels–Alder reactions in confined spaces: the influence of catalyst structure and the nature of active sites for the retro-Diels–Alder reaction". Beilstein Journal of Organic Chemistry 12 (13.10.2016): 2181–88. http://dx.doi.org/10.3762/bjoc.12.208.

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Diels–Alder cycloaddition between cyclopentadiene and p-benzoquinone has been studied in the confined space of a pure silica zeolite Beta and the impact on reaction rate due to the concentration effect within the pore and diffusion limitations are discussed. Introduction of Lewis or Brønsted acid sites on the walls of the zeolite strongly increases the reaction rate. However, contrary to what occurs with mesoporous molecular sieves (MCM-41), Beta zeolite does not catalyse the retro-Diels–Alder reaction, resulting in a highly selective catalyst for the cycloaddition reaction.

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14

Aronica, Laura, i Gianluigi Albano. "Cyclization Reactions for the Synthesis of Phthalans and Isoindolines". Synthesis 50, nr 06 (31.01.2018): 1209–27. http://dx.doi.org/10.1055/s-0037-1609175.

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Oxygen and nitrogen heterocycles are present in a vast number of natural substrates and biologically active molecules. In particular, phthalan and isoindoline subunits are found in many classes of products such as antibiotics, antioxidants, antimycotics, pigments, and fluorophores. Therefore several procedures dedicated to the construction of these heterocycles have been developed. In this review, a detailed analysis of the literature data regarding the synthesis of these nuclei via cyclization reactions is reported.1 Introduction2 Phthalans2.1 Oxa-Pictet–Spengler Reaction2.2 Garratt–Braverman Cyclization2.3 Diels–Alder and Related Reactions2.4 [2+2+2] Cyclotrimerization of Alkynes2.5 Cycloetherification of ortho-Substituted Aromatics2.6 Tandem Carbonylative Sonogashira Coupling–Cyclization Reactions3 Isoindolines3.1 Amination of Dihalides3.2 Intramolecular Hydroamination3.3 Diels–Alder and Related Reactions3.4 [2+2+2] Cycloaddition Reactions3.5 Tandem Carbonylative Sonogashira Coupling–Cyclization Reactions4 Conclusions

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15

Su, Zhishan, i Chan Kyung Kim. "Trienamine catalysis for asymmetric Diels–Alder reactions of 2,4-dienones: a theoretical investigation". Organic & Biomolecular Chemistry 13, nr 22 (2015): 6313–24. http://dx.doi.org/10.1039/c5ob00797f.

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In the Diels–Alder reactions of 2,4-dienones with two dienophiles, cinchona alkaloid acts as an efficient bifunctional catalyst by generating an extended trienamine π-conjugated system and by orienting the dienophile at an appropriate position for a cycloaddition reaction.

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16

Escalante, Carlos H., Eder I. Martínez-Mora, Carlos Espinoza-Hicks, Alejandro A. Camacho-Dávila, Fernando R. Ramos-Morales, Francisco Delgado i Joaquín Tamariz. "Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole". Beilstein Journal of Organic Chemistry 16 (17.06.2020): 1320–34. http://dx.doi.org/10.3762/bjoc.16.113.

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A highly regio-, chemo- and stereoselective divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles is herein described, starting from 2-formylpyrrole and employing Diels–Alder and Heck arylation reactions. 3-(N-Benzyl-2-pyrrolyl)acrylates and 4-(pyrrol-2-yl)butenones underwent a highly endo-Diels–Alder cycloaddition with maleimides to furnish octahydropyrrolo[3,4-e]indoles, which served as precursors in the regioselective synthesis of aza-polycyclic skeletons via an intramolecular Heck arylation reaction. Through the latter reaction, the 3-(N-benzyl-2-pyrrolyl)acrylates give rise to 3-(pyrrolo[2,1-a]isoindol-3-yl)acrylates. A further oxidative aromatization of the polycyclic intermediates provides the corresponding polycyclic pyrrolo-isoindoles and isoindolo-pyrrolo-indoles. A theoretical study on the stereoselective Diels–Alder reactions, carried out by calculating the endo/exo transition states, revealed the assistance of non-covalent interactions in governing the endo stereocontrol.

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17

Yang, Zhongyue, Song Yang, Peiyuan Yu, Yanwei Li, Charles Doubleday, Jiyong Park, Ashay Patel i in. "Influence of water and enzyme SpnF on the dynamics and energetics of the ambimodal [6+4]/[4+2] cycloaddition". Proceedings of the National Academy of Sciences 115, nr 5 (18.01.2018): E848—E855. http://dx.doi.org/10.1073/pnas.1719368115.

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SpnF is the first monofunctional Diels–Alder/[6+4]-ase that catalyzes a reaction leading to both Diels–Alder and [6+4] adducts through a single transition state. The environment-perturbed transition-state sampling method has been developed to calculate free energies, kinetic isotope effects, and quasi-classical reaction trajectories of enzyme-catalyzed reactions and the uncatalyzed reaction in water. Energetics calculated in this way reproduce the experiment and show that the normal Diels–Alder transition state is stabilized by H bonds with water molecules, while the ambimodal transition state is favored in the enzyme SpnF by both intramolecular hydrogen bonding and hydrophobic binding. Molecular dynamics simulations show that trajectories passing through the ambimodal transition state bifurcate to the [6+4] adduct and the Diels–Alder adduct with a ratio of 1:1 in the gas phase, 1:1.6 in water, and 1:11 in the enzyme. This example shows how an enzyme acts on a vibrational time scale to steer post-transition state trajectories toward the Diels–Alder adduct.

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18

Breton, Gary W., i Kenneth L. Martin. "Exploring the Limits of Reactivity of N-Methyl-1,2,4-triazoline-3,5-dione (MeTAD) with Disubstituted Bicycloalkadienes in the Homo-Diels–Alder Reaction". Organics 4, nr 1 (31.12.2022): 41–48. http://dx.doi.org/10.3390/org4010002.

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The [2+2+2] cycloaddition (homo-Diels–Alder reaction) of N-substituted 1,2,4-triazoline-3,5-diones (TADs) with bicycloalkadienes produces strained heterocyclic compounds. A reaction with the unsubstituted dienes occurs readily to produce only the expected homo-Diels–Alder adducts. However, previous work in the literature showed that the attachment of a single electron-withdrawing group to the diene system results in the formation of not only the expected homo-Diels–Alder adducts, but also interesting “insertion” products. To probe the limits of reactivity of these diene systems, we investigated the reaction of N-methyl-1,2,4-triazoline-3,5-dione (MeTAD) with bicycloalkadienes substituted with two electron-withdrawing groups, i.e., two carbomethoxy or two cyano groups. We hoped to learn whether the reaction still proceeded, and if so, whether the homo-Diels–Alder adducts and/or other types of products were formed. We found that a reaction between MeTAD and the dienes takes place upon substitution with two carbomethoxy groups, albeit at a considerably slower rate than other reactions. The only products observed were the homo-Diels–Alder adducts. However, attachment of two CN groups completely inhibited reactivity.

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19

Fulton, Brandon B., Alexia J. Hartzell, H. V. Rasika Dias i Carl J. Lovely. "Room Temperature Diels–Alder Reactions of 4-Vinylimidazoles". Molecules 29, nr 8 (22.04.2024): 1902. http://dx.doi.org/10.3390/molecules29081902.

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In the course of studying Diels–Alder reactions of 4-vinylimidazoles with N-phenylmaleimide, it was discovered that they engage in cycloaddition at room temperature to give high yields of the initial cycloadduct as a single stereoisomer. In certain cases, the product precipitated out of the reaction mixture and could be isolated by simple filtration, thereby avoiding issues with aromatization observed during chromatographic purification. Given these results, intramolecular variants using doubly activated dienophiles were also investigated at room temperature. Amides underwent cycloaddition at room temperature in modest yields, but the initial adducts were not isolable with Nimid-benzyl-protected systems. Attempts to extend these results to the corresponding esters and hydroxamate were less successful with these substrates only undergoing cycloaddition at elevated temperatures in lower yields. Density functional theory calculations were performed to evaluate the putative transition states for both the inter- and intramolecular variants to rationalize experimental observations.

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20

Rao, Nagaraj. "ASYMMETRIC ORGANOCATALYSIS". INDIAN DRUGS 58, nr 10 (16.12.2021): 5–6. http://dx.doi.org/10.53879/id.58.10.p0005.

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Dear Reader, Two basic reactions that were taught to us in the organic chemistry courses were the aldol condensation reaction and the Diels-Alder reaction. In aldol condensation, discovered by the French chemist Charles Wurtz in 1872, an enolate ion reacts with a carbonyl compound in the presence of an acid/ base catalyst to form a β-hydroxy aldehyde or a β-hydroxy ketone, usually followed by dehydration to give a conjugated enone. If the enolate ion and the carbonyl group are present in the same molecule, then the aldol reaction is intramolecular. It is an extremely useful carbon-carbon bond-forming reaction. The Diels-Alder reaction, discovered in 1928 by the German chemist Otto Diels and his student Kurt Alder, is the reaction between a conjugated diene and an alkene, a so-called dienophile, to form an unsaturated six-membered ring. It is called a cycloaddition reaction, since the reaction involves the formation of a cyclic product via a cyclic transition state. Uncatalysed Diels– Alder reactions usually require extended reaction times at elevated pressures and temperatures with the formation of by-products, hence various catalysts are employed. The Diels-Alder reaction also has great industrial relevance and the discoverers were crowned with the 1950 Nobel Prize in Chemistry. The aldol condensation reaction and the Diels-Alder reaction typically require catalysts, basically Brønsted acids, Brønsted bases, Lewis acids or Lewis bases. This triggered the minds of Dr. David MacMillan and Dr. Benjamin List for different reasons at different locations in USA around not so different times, more than twenty years ago, culminating in their being jointly awarded the Nobel Prize in Chemistry for this year.

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21

Tejero, Alvaro G., María Carmona, Ricardo Rodríguez, Fernando Viguri, Fernando J. Lahoz, Pilar García-Orduña i Daniel Carmona. "Synthesis of chiral-at-metal rhodium complexes from achiral tripodal tetradentate ligands: resolution and application to enantioselective Diels–Alder and 1,3-dipolar cycloadditions". RSC Advances 12, nr 53 (2022): 34704–14. http://dx.doi.org/10.1039/d2ra06982b.

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Charlton, James L., Guy L. Plourde i Glenn H. Penner. "Asymmetric induction in Diels–Alder reactions of α-alkoxyorthoquinodimethanes". Canadian Journal of Chemistry 67, nr 6 (1.06.1989): 1010–14. http://dx.doi.org/10.1139/v89-153.

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It has been shown that dienophiles cycloadd selectively to one face of o-quinodimethanes (o-QDMs) bearing chiral α-alkoxy groups. The face selectivity (diastereoselectivity) increases for the series of chiral groups -OCH(Ph)CH3, -OCH(Ph)CH(CH3)2, and -OCH(Ph)C(CH3)3. A similar effect on the face selectivity of the Diels–Alder reactions of chiral alkoxy vinyl ethers for the same series of chiral groups has been noted previously by others. A mechanism has been proposed to explain the face selectivity in the cycloaddition reactions of the alkoxy o-QDMs. Abinitio molecular orbital calculations with geometry optimization on vinyl 1-phenylethyl ether to determine its lowest energy conformations support the proposed mechanism. The absolute stereochemistries of the o-QDM cycloadducts have been determined to verify the predictions of the model. Keywords: o-quinodimethanes, asymmetric, Diels–Alder, cycloaddition.

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23

Williams, C. Luke, Katherine P. Vinter, Chun-Chih Chang, Ruichang Xiong, Sara K. Green, Stanley I. Sandler, Dionisios G. Vlachos, Wei Fan i Paul J. Dauenhauer. "Kinetic regimes in the tandem reactions of H-BEA catalyzed formation of p-xylene from dimethylfuran". Catalysis Science & Technology 6, nr 1 (2016): 178–87. http://dx.doi.org/10.1039/c5cy01320h.

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Bădoiu, Andrei, Yasmin Brinkmann, Florian Viton i E. Peter Kündig. "Asymmetric Lewis acid-catalyzed 1,3-dipolar cycloadditions". Pure and Applied Chemistry 80, nr 5 (1.01.2008): 1013–18. http://dx.doi.org/10.1351/pac200880051013.

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Highly tuned, one-point binding chiral iron and ruthenium complexes selectively coordinate and activate α,β-unsaturated aldehydes and ketones toward asymmetric catalytic Diels-Alder cycloaddition reactions. Here we focus on the application of these transition-metal Lewis acids to asymmetric catalytic 1,3-dipolar cycloaddition reaction between enals and cyclic and acyclic nitrones as well as aryl nitrile oxides to give isoxazolidines and isoxazolines, respectively.

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Duret, Guillaume, Vincent Le Fouler, Philippe Bisseret, Vincent Bizet i Nicolas Blanchard. "Diels-Alder and Formal Diels-Alder Cycloaddition Reactions of Ynamines and Ynamides". European Journal of Organic Chemistry 2017, nr 46 (8.09.2017): 6816–30. http://dx.doi.org/10.1002/ejoc.201700986.

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26

Boger, Dale L., i Christine E. Brotherton. "Diels-alder cycloaddition reactions of cyclopropenone ketals". Tetrahedron 42, nr 11 (styczeń 1986): 2777–85. http://dx.doi.org/10.1016/s0040-4020(01)90567-8.

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27

Laurent, Alain, Nidia P. Villalva-Servín, Pat Forgione, Peter D. Wilson, David V. Smil i Alex G. Fallis. "Part 1: Efficient strategies for the construction of variably substituted bicyclo[5.3.1]undecenones (AB taxane ring systems)". Canadian Journal of Chemistry 82, nr 2 (1.02.2004): 215–26. http://dx.doi.org/10.1139/v03-200.

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Strategies for the construction of cyclic molecules containing variably substituted bicyclo[5.3.1]undecenones (AB taxane ring systems) are described. These routes employ a multi-component coupling protocol that utilizes sequential magnesium-mediated carbometallation of propargyl alcohols and intramolecular DielsAlder reactions (IMDA). The cycloaddition generates the key eight-membered taxane ring as a single diastereomer, induced by preferential Lewis acid (diethylaluminum chloride or boron trifluoride etherate) complexation with the cross-ring oxygens. Both the electronic nature of the dienophile and the neighbouring group non-bonded interactions contribute to the success of these cycloadditions.Key words: magnesium chelate, Lewis acid, intramolecular DielsAlder, cycloaddition.

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28

Tomé, Augusto C., Maria G. P. M. S. Neves i José A. S. Cavaleiro. "Porphyrins and other pyrrolic macrocycles in cycloaddition reactions". Journal of Porphyrins and Phthalocyanines 13, nr 04n05 (kwiecień 2009): 408–14. http://dx.doi.org/10.1142/s1088424609000619.

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Porphyrins and other pyrrolic macrocycles can participate in a range of pericyclic reactions. This review deals mainly with their use in Diels-Alder reactions (as dienes and dienophiles) and in 1,3-dipolar cycloadditions (as 1,3-dipoles and dipolarophiles)

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29

Hou, Ji-Qin, Jiang-Hong Yu, Heng Zhao, Ying-Ying Dong, Qiu-Shi Peng, Bao-Bao Zhang i Hao Wang. "Biomimetic total syntheses of baefrutones A–D, baeckenon B, and frutescones A, D–F". Organic & Biomolecular Chemistry 18, nr 6 (2020): 1135–39. http://dx.doi.org/10.1039/c9ob02490e.

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Biomimetic total syntheses of the natural tasmanone-based meroterpenoids were achieved for the first time via Michael addition, oxidative [4 + 2] cycloaddition, and water-promoted Diels–Alder click reactions.

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30

Bednarek, Melania, i Przemysław Kubisa. "Reversible networks of degradable polyesters containing weak covalent bonds". Polymer Chemistry 10, nr 15 (2019): 1848–72. http://dx.doi.org/10.1039/c8py01731j.

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The synthesis of reversible polyester networks based mainly on the Diels–Alder chemistry, alkene [2 + 2] cycloaddition or transesterification reactions and studies of their reversibility and its consequences are reviewed.

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31

Bauer, John B., Fatima Diab, Cäcilia Maichle-Mössmer, Hartmut Schubert i Holger F. Bettinger. "Synthesis of the [11]Cyclacene Framework by Repetitive Diels–Alder Cycloadditions". Molecules 26, nr 10 (20.05.2021): 3047. http://dx.doi.org/10.3390/molecules26103047.

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The Diels–Alder cycloaddition between bisdienes and bisdienophile incorporating the 7-oxa-bicyclo[2.2.1]heptane unit are well known to show high diastereoselectivity that can be exploited for the synthesis of molecular belts. The related bisdiene 5,6,7,8-tetramethylidene-2-bicyclo[2.2.2]octene is a valuable building block for the synthesis of photoprecursors for acenes, but it has not been employed for the synthesis of molecular belts. The present work investigates by computational means the Diels–Alder reaction between these bisdiene building blocks with syn-1,4,5,8-tetrahydro-1,4:5,8-diepoxyanthracene, which shows that the diastereoselectivity of the Diels–Alder reaction of the etheno-bridged bisdiene is lower than that of the epoxy-bridged bisdiene. The reaction of the etheno-bridged bisdiene and syn-1,4,5,8-tetrahydro-1,4:5,8-diepoxyanthracene in 2:1 ratio yields two diastereomers that differ in the orientation of the oxa and etheno bridges based on NMR and X-ray crystallography. The all-syn diastereomer can be transformed into a molecular belt by inter- and intramolecular Diels–Alder reactions with a bifunctional building block. The molecular belt could function as a synthetic intermediate en route to a [11]cyclacene photoprecursor.

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32

Petko, Dina, Matthew Stratton i William Tam. "Ruthenium-catalyzed Bis-Homo-Diels-Alder reaction: searching for commercially available catalysts and expanding the scope of reaction". Canadian Journal of Chemistry 96, nr 12 (grudzień 2018): 1115–21. http://dx.doi.org/10.1139/cjc-2018-0117.

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Commercially available ruthenium catalyst, Cp*RuCl(COD), was found to be active in catalyzing Bis-Homo-Diels-Alder [2+2+2] cycloaddition reactions between 1,5-cyclooctadiene and various alkynes giving moderate to good yields (35%–92%). The presence of electron donating groups, especially hydroxyl groups, greatly enhanced the reactivity of the alkyne moiety in the cycloaddition. The reaction was also found to be successful even in the presence of bulky substituents on the alkynes.

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33

Hamzehloueian, Mahshid, Saeid Yeganegi, Yaghoub Sarrafi, Kamal Alimohammadi i Marzieh Sadatshahabi. "A theoretical investigation on the regioselectivity of the intramolecular hetero Diels-Alder and 1,3-dipolar cycloaddition of 2-vinyloxybenzaldehyde derivatives". Journal of the Serbian Chemical Society 79, nr 8 (2014): 911–24. http://dx.doi.org/10.2298/jsc140121012h.

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The present study reports a systematic computational analysis of the two possible pathways, fused and bridged, for an intramolecular hetero Diels-Alder (IMHDA) and an intramolecular 1,3-dipolar cycloaddition (IMDCA) of 2-vinyloxybenzaldehyde derivatives. The potential energy surface analysis for both reactions is in agreement with experimental observations. The activation energies associated with the two regioisomeric channels in IMHDA reaction show that the bridged product is favored, although in IMDCA, the most stable TS results the fused product. The global electronic properties of fragments within each molecule were studied to discuss the reactivity patterns and charge transfer direction in the intramolecular processes. The asynchronicity of the bond formation and aromaticity of the optimized TSs in the Diels-Alder reaction as well as cycloaddition reaction were evaluated. Finally, 1H NMR chemical shifts of the possible regioisomers have been calculated using the GIAO method which of the most stable products are in agreement with the experimental data in the both reaction.

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34

Jursic, Branko S. "AM1 semiempirical study of benzopyrroles as dienes for Diels-Alder reaction". Canadian Journal of Chemistry 74, nr 1 (1.01.1996): 114–20. http://dx.doi.org/10.1139/v96-015.

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A qualitative approach for quick evaluation of the reactivity of dienes such as cyclopentadiene, furan, pyrrole, indole, and isoindole for Diels–Alder reactions was applied. As qualitative methods, the frontier molecular orbital (FMO) energy gap and the Hammond postulate through bond orders and energy of the reaction were evaluated for such dienophiles as ethylene, 1,3-dioxa-4-cyclopentene, and maleic anhydride. It was demonstrated that pyrrole and benzopyrroles are poor dienes in comparison with cyclopentadiene and furan. Because the reaction is controlled by the HOMO of the diene there are special cases when isoindole can react as a diene, while the loss of indole aromaticity in the course of the reaction precludes the cycloaddition. Geometries of transition structures and the accompanying activation energies were calculated for pyrrole, indole, and isoindole as dienes. The stereoselectivity of the reaction is discussed and compared with experimental results. Key words: benzopyrroles as dienes, Diels–Alder cycloaddition, Hammond postulate.

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35

Brossard, Dominique, Pascal Retailleau, Vincent Dumontet, Philippe Breton, Sandy Desrat i Fanny Roussi. "Fast & easy preparation of 3D scaffolds from methyl benzoate by a diversity oriented synthesis strategy based on Diels–Alder and ene-reactions". Organic & Biomolecular Chemistry 15, nr 26 (2017): 5585–92. http://dx.doi.org/10.1039/c7ob01236e.

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36

Koçak, Ramazan, i Arif Daştan. "Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles". Beilstein Journal of Organic Chemistry 17 (15.03.2021): 719–29. http://dx.doi.org/10.3762/bjoc.17.61.

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The synthesis of novel polycyclic π-conjugated dihydropyridazines, pyridazines, and pyrroles was studied. Dihydropyridazine dyes were synthesized by inverse electron-demand Diels–Alder cycloaddition reactions between a dibenzosuberenone and tetrazines that bear various substituents. The pyridazines were synthesized in high yields by oxidation of dihydropyridazine-appended dibenzosuberenones with PIFA or NO. p-Quinone derivatives of pyridazines were also obtained by H-shift isomerization following the inverse electron-demand Diels–Alder reaction of tetrazines with p-quinone dibenzosuberenone. Then these pyridazines were converted to the corresponding pyrroles by reductive treatment with zinc. It was observed that all the dihydropyridazines obtained gave absorbance and emission at long wavelengths.

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37

Gribble, G. W. "Novel chemistry of indole in the synthesis of heterocycles". Pure and Applied Chemistry 75, nr 10 (1.01.2003): 1417–32. http://dx.doi.org/10.1351/pac200375101417.

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Indoles that are substituted at the 2- or 3-position with electron-withdrawing groups (nitro, phenylsulfonyl) undergo nucleophilic addition, 1,3-dipolar cycloaddition, and Diels–Alder reactions to give a variety of indoles, pyrroloindoles, and carbazoles. New methods for the synthesis of furo[3,4-b]indoles and the novel ring system furo[3,4-b]pyrrole are described for the first time. Diels–Alder reactions of furo[3,4-b]pyrroles afford indoles after dehydration of the primary cycloadducts. Efficient syntheses of both 2- and 3-nitroindoles from indole are reported, and the first generation and successful electrophilic trapping of a 2,3-dilithioindole has been achieved.

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38

Çapan, İrfan, i Süleyman Servi. "Synthesis of New C2-Symmetric Chiral Benzimidazole Derivatives Having Norbornene/Dibenzobarrelene Skeletons". Letters in Organic Chemistry 17, nr 10 (17.11.2020): 801–5. http://dx.doi.org/10.2174/1570178616666190731105327.

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Racemic dicarboxylic acids were synthesized from the Diels-Alder cycloaddition reactions which formed the dibenzobarrelene and norbornene skeletons. The pure enantiomers of these compounds were obtained using brucine as the chiral auxiliary. Novel C2-symmetric chiral benzimidazole derivatives were synthesized from the reaction of the diaminobenzene and enantiomeric dicarboxylic acids in the presence of boric acid.

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39

Mlostoń, Grzegorz, Yuriy Shermolovich i Heinz Heimgartner. "Synthesis of Fluorinated and Fluoroalkylated Heterocycles Containing at Least One Sulfur Atom via Cycloaddition Reactions". Materials 15, nr 20 (17.10.2022): 7244. http://dx.doi.org/10.3390/ma15207244.

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Fluorinated heterocycles constitute an important group of organic compounds with a rapidly growing number of applications in such areas as medicinal chemistry, agrochemicals production, polymer chemistry, as well as chemistry of advanced materials. In the latter case, fluorinated thiophenes are considered as a lead class of compounds with numerous spectacular applications. On the other hand, cycloaddition reactions offer a superior methodology for stereo-chemically controlled synthesis of heterocycles with a diverse ring size and a variable number of heteroatoms. A comprehensive review of methods based on cycloaddition reactions and applied for construction of fluorinated and/or fluoroalkylated S-heterocycles has not yet been published. For this reason, the main goal of the presented review was to fill the existing gap and to summarize the results published over last six decades. In this context, the [3+2]- and [4+2]-cycloadditions (Huisgen reactions, and Diels–Alder reactions, respectively) are of special importance. Some questions related to the discussed mechanisms of cycloaddition processes observed in reactions with electron deficient, fluorinated substrates (dipolarophiles and dienophiles), and electron-rich sulfur containing counter partners, are of fundamental importance for the development of interpretations of organic reaction mechanisms.

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40

Korol, Nataliya, Mikhailo Slivka i Oksana Holovko-Kamoshenkova. "Cycloaddition reactions of 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione (PTAD) and 4-methyl-3H-1,2,4-triazole-3,5(4H)-dione (MTAD): A short review". Organic Communications 13, nr 4 (26.12.2020): 146–54. http://dx.doi.org/10.25135/acg.oc.88.20.11.1870.

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The sources, describing cycloaddition reactions with the participation of 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione (PTAD) and 4-methyl-3H-1,2,4-triazole-3,5(4H)-dione (MTAD) were reviewed from the middle 1970s and they are mentioned in chronological order. It was noted that the most investigated are Diels-Alder reactions and cycloaddition to a few cyclic mono- and dienes. Stereochemistry of obtained products are also described.

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41

Beck, Janina, Olaf Fuhr, Martin Nieger i Stefan Bräse. "A versatile Diels–Alder approach to functionalized hydroanthraquinones". Royal Society Open Science 7, nr 11 (listopad 2020): 200626. http://dx.doi.org/10.1098/rsos.200626.

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The synthesis of highly substituted hydroanthraquinone derivatives with up to three stereogenic centres via a Diels–Alder reaction, starting from easily accessible 2-substituted naphthoquinones, is described. The [4+2]-cycloaddition is applicable for a broad range of substrates, runs under mild conditions and results in high yields. The highly regioselective outcome of the reactions is enabled by a benzoyl substituent at C2 of the dienophiles. The obtained hydroanthraquinones can be further modified and represent ideal substrates for follow-up intramolecular coupling reactions to create unique bicyclo[3.3.1] or -[3.2.2]nonane ring systems which are important natural product skeletons.

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42

Spino, Claude, i Jason Crawford. "2-Carbomethoxy-1,3-butadiene: an electronically activated diene in [4 + 2] cycloadditions with electron-deficient dienophiles". Canadian Journal of Chemistry 71, nr 7 (1.07.1993): 1094–97. http://dx.doi.org/10.1139/v93-145.

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Cross Diels–Alder reactions between 2-carbomethoxy-1,3-butadiene 1 and electron-rich dienes were carried out. It was found that diene 1 had a higher reactivity than even the well-known Danishefsky diene in its Diels–Alder cycloaddition with electron-deficient dienophiles. In addition, (Z)-1-methylthio-3-carbomethoxy-1,3-butadiene 11 was found to have a higher reactivity than (Z)-1-methylthio-1,3-butadiene and (Z)-2-carbomethoxy-1,3-hexadiene, while both (E)- and (Z)-1,2-(bis)-carbomethoxy-1,3-butadiene 14 reacted efficiently with maleic anhydride to give the corresponding cy-cloadduct 15.

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43

Bates, Robert W., Andrew J. Pratt, Phillip M. Rendle i Ward T. Robinson. "Diels - Alder Reactions of 1,1-Bis(methylthio)ethene with Pyran-2-ones." Australian Journal of Chemistry 51, nr 5 (1998): 383. http://dx.doi.org/10.1071/c97128.

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Bis(methylthio)ethene has been shown to undergo Diels–Alder cycloaddition reactions with a range of simple and aryl-fused pyran-2-ones. These reactions can be brought about under either high-temperature or high-pressure conditions. These reactions are all regiospecific and in each case only a single product is isolated, either the initial bridged adduct or an aromatized product generated through decarboxylation. Although this dienophile is less reactive than the corresponding oxygen analogue it is still possible for cycloaddition chemistry to compete effectively with decarboxylation chemistry.

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44

Moore, Jonathan C., E. Stephen Davies, Darren A. Walsh, Pallavi Sharma i John E. Moses. "Formal synthesis of kingianin A based upon a novel electrochemically-induced radical cation Diels–Alder reaction". Chem. Commun. 50, nr 83 (2014): 12523–25. http://dx.doi.org/10.1039/c4cc05906a.

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The application of electrochemical reactions in natural product synthesis has burgeoned in recent years. We herein report a formal synthesis of the complex and dimeric natural product kingianin A, which employs an electrochemically-mediated radical cation Diels–Alder cycloaddition as the key step.

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45

de Sousa, Andrea L. F., José E. P. Cardoso Filho, Blanka Wladislaw, Liliana Marzorati i Claudio Di Vitta. "Studies on chemo- and diastereo-selectivity of the Diels–Alder reactions of sulfinyltoluquinones with cyclopentadiene". Canadian Journal of Chemistry 87, nr 8 (sierpień 2009): 1135–43. http://dx.doi.org/10.1139/v09-070.

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Sulfinyltoluquinones (2a–2c) were submitted to thermal or catalyzed [4+2] cycloaddition reactions with cyclopentadiene. For p-tolylsulfinyltoluquinones (2b) and (2c), almost complete C2–C3-chemo- and unlike-diastereoselectivity was achieved by catalysis with ZnBr2, yielding adducts 6. Under thermal conditions, Diels–Alder reaction took place at the C5–C6 double bonds of quinones 2a–2c, generating mixtures of diastereoisomeric like- and unlike-adducts 4.

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46

Charlton, James L., i Shawn Maddaford. "The mechanism of stereoselectivity in the cycloaddition reactions of α-hydroxy-ortho-quinodimethanes with the fumarate of methyl lactate and mandelate". Canadian Journal of Chemistry 71, nr 6 (1.06.1993): 827–33. http://dx.doi.org/10.1139/v93-110.

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The Diels–Alder cycloaddition reaction of the fumarate of methyl lactate or methyl mandelate with α-hydroxy-ortho-quinodimethane produces an unexpected exo product with very high asymmetric induction. Experiments and calculations have been carried out that show that the origin of the stereoselectivity in these reactions is related to hydrogen bonding between the α-hydroxy-o-quinodimethane and the lactate or mandelate group in the dienophile.

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47

Zeller, Matthias, Allen D. Hunter, Paul Sampson i Nataliya Chumachenko. "1-[(E)-Butadienylsulfonyl]-3,3-dimethylbut-2-yl methacrylate". Acta Crystallographica Section E Structure Reports Online 62, nr 4 (15.03.2006): o1369—o1370. http://dx.doi.org/10.1107/s1600536806008014.

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The title compound, C14H22O4S, was synthesized as a precursor for intramolecular Diels–Alder cycloaddition reactions. The (E)-buta-1,3-dienyl and methacrylate ester systems adopt an s–trans conformation in the solid state, with the two π units in both cases being almost coplanar.

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48

Gillard, James R., Michael J. Newlands, John N. Bridson i D. Jean Burnell. "π-Facial stereoselectivity in the Diels–Alder reactions of benzene oxides". Canadian Journal of Chemistry 69, nr 9 (1.09.1991): 1337–43. http://dx.doi.org/10.1139/v91-199.

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The Diels–Alder reactions of N-phenylmaleimide and dimethyl acetylenedicarboxylate with benzene oxide (1,3,5-cyclohexatriene 1,2-oxide, 3) and its more substituted derivatives 1,2-dimethyl-1,3,5-cyclohexatriene 1,2-oxide (7) and 10-oxatricyclo[4.3.1.0]deca-2,4-diene (11) in a kinetic manner gave exclusively products of addition anti to the plane-nonsymmetrical oxygen. The structures of the adducts were determined unequivocally by nuclear Overhauser enhancements in their 1H nuclear magnetic resonance spectra and by X-ray crystallographic methods. The π-facial stereoselectivity was rationalized in terms of unfavorable orbital interactions, steric hindrance between the dienophile and the syn face of benzene oxide, and σ-donation by the oxygen. Key words: cycloaddition, Diels–Alder, syn-anti, π-facial stereoselectivity, benzene oxide.

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49

Jasiński, Radomir. "On the Question of Stepwise [4+2] Cycloaddition Reactions and Their Stereochemical Aspects". Symmetry 13, nr 10 (11.10.2021): 1911. http://dx.doi.org/10.3390/sym13101911.

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Even at the end of the twentieth century, the view of the one-step [4+2] cycloaddition (Diels-Alder) reaction mechanism was widely accepted as the only possible one, regardless of the nature of the reaction components. Much has changed in the way these reactions are perceived since then. In particular, multi-step mechanisms with zwitterionic or diradical intermediates have been proposed for a number of processes. This review provided a critical analysis of such cases.

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50

Ward, Dale E., Thomas E. Nixey, Yuanzhu Gai, Matthew J. Hrapchak i M. Saeed Abaee. "Intramolecular Diels–Alder reactions of 2H-thiopyran dienes". Canadian Journal of Chemistry 74, nr 7 (1.07.1996): 1418–36. http://dx.doi.org/10.1139/v96-160.

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A systematic survey of IMDA reactions of 4-[tris(2-methylethyl)silyl]oxy-2H-thiopyran derivatives with potential dienophiles tethered at the C-2, C-3, C-5, and C-6 positions is presented. Cycloaddition was not observed with a C3 or C4 tether and an unactivated terminal olefin as dienophile. IMDA adducts could be obtained when dienophiles activated by a carbomethoxy group were employed. Compounds having the activated dienophile attached via a C3 tether to C-2 of the 2H-thiopyran gave adducts with high stereoselectivity. Substrates having the dienophile attached to C-3 with a C3 or C4 tether cyclized readily. With an (E)-enoate as the dienophile, the stereoselectivity was poor (endo:exo = 1.1–2.5:1) and essentially independent of reaction conditions (i.e., thermal vs. Lewis acid mediated). With the(Z)-enoate, a 7:1 mixture of endo:exo IMDA adducts was obtained under thermal conditions; with Lewis acid catalysis, isomerization of the dienophile was competitive with cycloaddition. Type II IMDA adducts were not observed with C-5 tethered substrates. Compounds having the dienophile attached to C-6 via a C3 or a five-atom tether also failed to give IMDA adducts. No evidence for isomerization of the 2H-thiopyran dienes by [1,5] sigmatropic rearrangement was observed. The endo adducts from IMDA reactions of the C-3 tethered substrates can be desulfurized to obtain synthetically useful trans-fused hydrindans and decalins with angular methyl groups. Key words: intramolecular Diels–Alder, 2H-thiopyran, cis-substituted 1,3-diene surrogate, trans-octahydro-3a-methyl-1H-indene derivatives, trans-decahydro-4a-methylnapthalene derivatives.

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