Catalyzed Diels-Alder Reaction Research Articles

Synthesis of decalin synthons of bioactive terpenoids: Lewis acid catalyzed Diels-Alder reactions

Diels-Alder reaction of 1,3,3-trimethyl-2-vinylcyclohexene 1 with conjugated ketones 2 – 7 in the presence of Lewis acid leads to regio- and stereo-selective formation of bicyclic adducts 8 – 13 versatile intermediates to labdanes, abietane and spongian diterpenoids.

Catalysis on Electron Transfer and the Mechanistic Insight into Redox Reactions

Abstract Both thermal and photoinduced electron transfer reactions from one-electron reductants to various organic oxidants such as carbonyl compounds are catalyzed by the presence of acids and metal ions. The acceleration of rates of electron transfer is ascribed to the thermodynamic stabilization of products of electron transfer by the protonation or complexation with metal ions, which results in the positive shift of the reduction potentials of oxidants. In the case of Mg2+-catalyzed electron transfer reduction of p-benzoquinone derivatives, the formation of 1 : 1 and 1 : 2 complexes between semiquinone radical anion and Mg2+ is confirmed by the transient absorption spectra as well as by the ESR spectra. From the spectral change at different Mg2+ concentrations is determined the formation constant (K2) of the 1 : 2 complex. The K2 values of various semiquinone anions determined from the direct detection of the Mg2+ complexes agree well with those estimated from the kinetic analysis on the Mg2+-catalyzed electron transfer reactions. The direct spectroscopic detection of complexes between the semiquinone radical anions and Mg2+, combined with the kinetic analysis of the catalytic effects of Mg2+ on not only the electron transfer reactions but also on various reactions involving p-benzoquinone derivatives such as Mg2+-catalyzed Diels–Alder reactions of anthracenes with p-benzoquinone derivatives, provides a confirmative basis for delineating the catalytic mechanisms of Mg2+ on various types of reactions. A remarkable increase in the reactivity of the photoexcited states of carbonyl compounds in the electron transfer reactions is also found by the complexation with Mg2+. The photoexcitation of the Mg2+ complex results in strong fluorescence in contrast with the nonfluorescent excited states of uncomplexed carbonyl compounds. Thus, various redox reactions of carbonyl compounds via photoinduced electron transfer are made possible by the catalysis of metal ions which form complexes with carbonyl compounds. The fundamental concept and the scope of catalysis on electron transfer are reviewed in this account to provide some insight into the mechanistic viability.

Enantioselective catalytic Diels–Alder reaction of ethyl 2-benzoylacrylate with chiral bis(oxazoline)– or mono(oxazoline)–magnesium complex

The magnesium catalysed Diels–Alder reaction of 2-benzoylacrylate gave the endo-adduct enantioselectively with bis(oxazoline) 5 as a C 2 -symmetric ligand or mono(oxazoline) 4 as a non-C 2 -symmetric ligand.

Weitz' aminium salt initiated electron transfer reactions and application to the synthesis of natural products

A stable cation radical Weitz' aminium salt, tris(4-bromophenyl)aminium hexachloroantimonate (BAHA) initiated electron transfer has been found to efficiently promote a great variety of reactions on electron-rich substrates: e.g. the cation radical pericyclic reactions, the chain-induced cation radical oxygenation of strained olefines and dienes, and several other intriguing reactions on a great variety of electron-rich substrate. The discovery of the Weitz' aminium salt catalysed Diels-Alder reaction has stimulated interest in cation radical chemistry and facilitated the development of a wide range of cation radical pericyclic chemistry. Applications of the method to the synthesis of natural products utilizing BAHA are also presented. Reaction of a lignan precursor, cinnamyl alcohols with BAHA in tetrahydrofuran (THF) gave a furofuran lignan, (+/-)-sesamin in one step. Podophyllum lignans, (+/-)-isopodophyllotoxin and (+/-)-isopicropodophyllin were synthesized by a biomimetic procedure from the doubly unsaturated esters by means of the BAHA induced cation-radical cycloaddition reaction. A new general synthesis for (+/-)-dibenzocyclooctadiene lignans was established utilizing novel synthetic method for quinone derivatives by oxidation with BAHA. Reactions of phenol derivatives using BAHA gave the corresponding quinone derivatives, which may be useful synthon for obtaining quassinoids such as quassin.

Heteropoly acid-catalyzed Diels-Alder reactions

Tungstophosphoric acid supported on silica gel has been shown to catalyze Diels-Alder reactions of quinones. The catalyst is active under mild conditions and can be easily recovered and re- used.

Synthesis, isomerisation and diels-alder reactions of (5 S)-5-phenyl-3,4-dehydromorpholin-2-one

(5 S)-5-Phenyl-3,4-dehydromorpholin-2-one [(5 S)-5-phenyl-5,6-dihydro-2 H-1,4-oxazin-2-one] 2a is prepared by a one-pot bromination / dehydrobromination of (5 S)-5-phenyl morpholin-2-one and undergoes regio- and diastereocontrolled catalysed Diels-Alder reactions.

Mechanistic aspects of aminium salt-catalyzed Diels-Alder reactions: The substrate ionization step

Substituent effects in the aminium salt catalyzed Diels-Alder reactions of 2,3-dimethyl-1,3-butadiene with a series of meta and para substituted β-methylstyrenes are used to probe detailed mechanistic aspects of these reactions. Kinetic studies were carried out using two different aminium salt catalysts and also electrochemically, using anodic potentials corresponding to the oxidation potentials of the aminium salts. Substituent effects in the equilibrium oxidations of the styrene substrates to the corresponding cation radicals were also studied, via oxidation potential measurements. The results indicate rate determining one electron oxidation of the sytrenes to their cation radicals via an outer sphere electron transfer.

Asymmetric Diels-Alder reactions employing modified camphor-derived oxazolidin-2-one chiral auxiliaries

Transposition of the dormant methyl group from C-1 in chiral oxazolidin-2-one 2 to C-7 in a six step synthetic sequence from (1 R)-camphor 5 creates a novel transfigomer 4 with sufficient π-topological bias to induce excellent levels of asymmetric induction in Lewis-acid catalysed Diels-Alder reactions of its α, β-unsaturated carboximide derivatives with cyclopentadiene. Further modification of 4 by replacement of the C-7 methyl group with an ethyl substituent raises the level of diastereoselectivity for the acrylate derivative 11a from 81 to >95% d.e..

The influence of ligand bite angle on the enantioselectivity of copper(II)-catalysed Diels–Alder reactions

Novel spirobis(oxazolines) provide excellent levels of stereocontrol in copper-catalysed Diels–Alder reactions; the larger the ligand bite angle the higher the enantioselection (up to 98.4% ee).

Indium trichloride (InCl3) catalysed Diels–Alder reaction in water

Indium trichloride (InCl3) is found to catalyse the Diels–Alder reaction in water; the catalyst can be easily recovered from water after the reaction is completed and can be reused.

Lewis‐acid catalysis of carbon carbon bond forming reactions in water

AbstractIn this article, we review the recent progress that has been made in the field of Lewis‐acid catalysis of carbon carbon‐bond‐forming reactions in aqueous solution. Since water hampers the hard hard interactions between the catalyst and the reactant, it often complicates catalysis. However, once coordination has taken place, water can have beneficial effects on rates and selectivities of Lewis acid catalysed Diels Alder reactions, aldol reactions, allylation reactions, Barbier and Mannich type reactions as well as Michael additions.

Lewis Acid Catalyzed Diels-Alder Reaction of 3-Phenylthio-2-quinolinones with Siloxydiene. Synthesis of the Intermediate for Dynemicin A Core.

Preparation of the 1-methoxycarbonyl-3-phenylthio-2-quinolinone (10) from dihydro-2-quinolinone (5) and its Diels-Alder reaction with 2-trimethylsilyloxy-1, 3-butadiene under Lewis acid catalyst is described. Conversion of the D-A adduct (11) to 9-phenenthridinone ketal (16) will open a new synthetic route to a dynemicin A core structure.

Cation Radical Catalyzed Diels-Alder Reaction of Electron-Rich Allenes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCation Radical Catalyzed Diels-Alder Reaction of Electron-Rich AllenesM. Schmittel and C. WoehrleCite this: J. Org. Chem. 1995, 60, 25, 8223–8230Publication Date (Print):December 1, 1995Publication History Published online1 May 2002Published inissue 1 December 1995https://doi.org/10.1021/jo00130a022RIGHTS & PERMISSIONSArticle Views376Altmetric-Citations24LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-AlertsSupporting Info (2)»Supporting Information Supporting Information Get e-Alerts

An Yttrium‐Based Strong Lewis Acid for the Heterogeneous Catalysis of the Diels–Alder Reaction

Excellent endo:exo selectivities can be achieved in heterogeneously catalyzed Diels-Alder reactions, even in the case of dienophiles such as 1-3 with cyclopentadiene. The key to the success is a new yttrium-based, strong Lewis acid catalyst, whose synthesis and characterization is described.

A Base Catalyzed Diels-Alder Reaction of 3-Hydroxy-2-Pyrone

A base catalyzed Diels-Alder reaction of 3-hydroxy-2-pyrone with various electron-deficient dienophiles gave cycloadducts in nearly quantitative yields. The reactions proceeded with complete stereospecificity and regioselectivity. A base catalyzed Diels-Alder reaction of 3-hydroxy-2-pyrone ( 1 ) with dienophile ( 2 ) afforded cycloadducts 3 and 4 in nearly quantitative yield.

A base catalyzed Diels-Alder reaction of 3-hydroxy-2-pyrone

Abstract A base catalyzed Diels-Alder reaction of 3-hydroxy-2-pyrone with various electron-deficient dienophiles gave cycloadducts in nearly quantitative yields. The reactions proceeded with complete stereospecificity and regioselectivity.

The Catalytic Diels-Alder Reaction Using Combined Catalyst System of Diphenyltin Sulfide or Lawesson’s Reagent and Silver Perchlorate

The Catalytic Diels-Alder Reaction Using Combined Catalyst System of Diphenyltin Sulfide or Lawesson’s Reagent and Silver Perchlorate

An Undergraduate Organic Synthesis, Spectroscopy, and Molecular Modeling Project: Asymmetric Lewis Acid Catalyzed Diels-Alder Reaction of Menthyl Acrylate with Cyclopentadiene

A project designed to demonstrate chromatography, spectroscopy, and molecular modeling; includes sample data and analysis.

The Catalytic Diels-Alder Reaction Using Combined Catalyst System of Diphenyltin Sulfide or Lawesson’s Reagent and Silver Perchlorate

Abstract Catalytic Diels-Alder reactions between several 1,3-dienes and α,β-unsaturated ketones are effectively promoted by the combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.

Homogeneous catalysis: use of chiral titanocene complexes for asymmetric catalytic Diels–Alder reactions

A stable, chiral diaquo titanocene complex is an excellent catalyst for certain Diels–Alder reactions giving good enantioselectivity which indicates that catalysis occurs by metal rather than by proton activation of the dienophile.