Thermal Cycloaddition Reactions Research Articles

ChemInform Abstract: Heterocyclic N‐Sulphinylamines: Cycloadditions to Heteroaryl Substituted δ3‐1,2,3,5‐Thiatriazoline‐1‐oxides and 3,6‐Dihydro‐1,2‐thiazine‐1‐ oxides.

AbstractThe heterocyclic N‐sulphinylamines (I) undergo a thermal cycloaddition reaction with 2,3‐dimethylbutadiene (II) to form the adducts (III).

ChemInform Abstract: Thieno(3,4‐f)‐2,1‐benzisothiazole. Synthesis and Physical Properties of a Novel Fused 14π Heteroarene as well as Its Thermal Cycloaddition Reactions with N,N‐Double Bond Systems.

AbstractThe dione (I) reacts with P4S10 to give the (thermally stable) title compound (II) which contains three masked dipolar systems, represented by the limiting formulas α, β and γ.

ChemInform Abstract: Synthesis of Adamantane Derivatives. Part 73. Thermal Cycloaddition Reactions of Thiocarbonyl Compounds.

AbstractAdamantanthion (I) reagiert mit verschiedenen, z.Tl. in situ dargestellten konjugierten Dienen, 2.B. (II), (IV) und (VIII), unter Cycloaddition zu den entsprechenden spirocyclischen Produkten (III), (V) bis (VII) und (IX).

Thermal cycloaddition reaction of xanthene‐9‐thione with allenes: An ESR study

AbstractDuring the parallel (2 + 2)‐ and (4 + 2)‐cycloaddition reactions of aromatic thiones such as xanthene‐9‐thione with substituted allenes XCHCCH2 (X = OR, SR, NMe2, Ph), a strong ESR signal is observed. This signal is associated with the (4 + 2)‐cycloaddition reaction, affording thiopyran derivatives 3,11b‐dihydro‐2‐(X‐methylene)‐2H‐thiopyrano[4,3,2‐kl]xanthene F or 3,11b‐dihydro‐3X‐2‐methylene‐2H‐thiopyrano[4,3,2‐kl]xanthene E. Computer analyses of this signal made possible its identification as emanating from a 9‐xanthenyl radical substituted at the 1‐ and 9‐positions. The type of xanthenyl radical that is formed in the thermal reaction E rad or F rad depends on the nature of the substituent X at the allenic system H2CCCHX. This investigation shows that where X = Ph and NMe2, xanthenyl radicals of structure E rad are produced, and where X = O‐t‐Bu and S‐t‐Bu xanthenyl radicals of structure F rad are produced. It is striking that this production is so selective.On irradiation (λ>254nm), the production of xanthenyl radicals is enhanced. The conformation of xanthenyl radicals E rad and the role of E rad and F rad in the formation of addition products E and F are discussed.

ChemInform Abstract: Kinetics and Mechanism of the Photochemical and Thermal Cycloaddition Reactions of Thiocarbonyl Compounds with Allenes, Photophysics of Some Thiones (thermal and photochemical cycloaddition via 1,4‐diradicals.

Chemischer InformationsdienstVolume 17, Issue 14 Preparative Organic Chemistry ChemInform Abstract: Kinetics and Mechanism of the Photochemical and Thermal Cycloaddition Reactions of Thiocarbonyl Compounds with Allenes, Photophysics of Some Thiones (thermal and photochemical cycloaddition via 1,4-diradicals. J. KAMPHUIS, J. KAMPHUISSearch for more papers by this authorH. J. T. BOS, H. J. T. BOSSearch for more papers by this author J. KAMPHUIS, J. KAMPHUISSearch for more papers by this authorH. J. T. BOS, H. J. T. BOSSearch for more papers by this author First published: April 8, 1986 https://doi.org/10.1002/chin.198614092AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume17, Issue14April 8, 1986 RelatedInformation

Synthesis of adamantane derivatives. 73. Thermal cycloaddition reactions of thiocarbonyl compounds. 4. Synthesis of novel adamantane-2-spirothiaheterocycles via [4 + 2] cycloaddition reactions of adamantanethione with conjugated dienes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of adamantane derivatives. 73. Thermal cycloaddition reactions of thiocarbonyl compounds. 4. Synthesis of novel adamantane-2-spirothiaheterocycles via [4 + 2] cycloaddition reactions of adamantanethione with conjugated dienesTomonori Katada, Shoji Eguchi, and Tadashi SasakiCite this: J. Org. Chem. 1986, 51, 3, 314–320Publication Date (Print):February 1, 1986Publication History Published online1 May 2002Published inissue 1 February 1986https://doi.org/10.1021/jo00353a008RIGHTS & PERMISSIONSArticle Views175Altmetric-Citations15LEARN 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 (852 KB) Get e-Alerts Get e-Alerts

Studies on diazepines. XXIII Reactions of monocyclic 1H-1,3-diazepines. 1 Cycloaddition reaction with 2,5-dimethyl-3,4-diphenylcyclopentadienone.

The thermal cycloaddition reaction of 1-ethoxycarbonyl-1H-1, 3-diazepines (4a, b) with 2, 5-dimethyl-3, 4-diphenylcyclopentadienone (5) gave three kinds of 1 : 1 cycloadducts, exo [6+4]π (6), syn-endo [4+2]π (7), and anti-endo [4+2]π (8) cycloadducts, the structures of which were elucidated by spectral analyses and the following photochemical study. Irradiation of the [4+2]π cycloadducts 7 and 8 resulted in an intramolecular [2+2]π cycloaddition to afford the cage compounds 12 and 13, respectively, while the [6+4]π cycloadducts (6), upon irradiation, underwent a retro-reaction to give the bicyclic compounds (11), presumably via the parent 1, 3-diazepines (4).

Thermal cycloaddition reactions of thiocarbonyl compounds. Part 2. 1,3-dipolar cycloaddition reactions of adamantanethione with nitrile oxides, nitrilimines, and diazoalkanes

1,3-Dipolar cycloaddition of adamantanethione (1) with nitrile oxides, nitrilimines, and diazoalkanes occurred smoothly to afford regioselective cycloadducts, adamantane-2-spiro-5′-(1′4′,2′-oxathiazolines)(4a–f), adamantane-2-spiro-2′-(1′,3′,4′-thiadiazolines)(11a–d), and (21b), respectively in high yields. These results are discussed on the basis of FMO and steric effects.

Thermal cycloaddition reactions of thiocarbonyl compounds. Part 1. A novel [4 + 2] cycloaddition reaction of adamantanethione with α,β-unsaturated carbonyl compounds

The thermal cycloaddition reaction of adamantanethione (1) with α,β-unsaturated carbonyl compounds such as acrolein, methacrolein, and methyl vinyl ketone occurred smoothly at 80–140 °C to afford, regioselectively, adamantane-2-spiro-2′-(1′-oxa-3′-thiacyclohex-5′-enes)(3a–e) as novel [4 + 2] cycloadducts in good yield. The nature of this cycloaddition is discussed on the basis of kinetics, solvent effects, and FMO theory.

Thermal cycloaddition reactions of thiocarbonyl compounds. Part 3. A novel [4 + 2] cycloaddition reaction of thiocarbonyl compounds with o-quinone methanides

Thermal cycloaddition reactions of adamantanethione (3) and thiobenzophenone (8a) with o-quinone methanides such as the o-benzoquinone methanides (2a–g) and o-naphthoquinone methanides (2h–j) occurred smoothly at 180–200 °C to afford, regioselectively, the adamantane-2-spiro-2′-[1,3]benzoxathiines (4a–g), the naphth[1,3]oxathiines (4a–g), and the naphty[1,3]oxathiines(4h–j), and the 2,2-diphenyl-1,3-benzoxathiines (9a) and (9g), all novel [4 + 2] cycloadducts, in good yields.

Electron spin resonance investigation of sulphur-33 and nitrogen-15 substituted dithiazol-2-yl and dithiazolidin-2-yl free radicals

Thermal cyclo-addition reactions of tetrasulphur dinitride with certain alkynes generate a new series of stable free radicals possessing the 1,3,2-dithiazolyl ring. The radicals have simple e.s.r. spectra and are potentially useful spin probes or labels. The sharpness of the spectral lines has enabled us to observe natural abundance lines from nitrogen-15, sulphur-33 and carbon-13. The presence of two equivalent sulphur atoms in the heterocyclic ring has been demonstrated by isotopic double labelling with nitrogen-15 and sulphur-33. An isotopic triple labelling experiment with the latter two isotopes and with deuterium was carried out with the related 1,3,2-dithiazolidinyl radicals. Temperature coefficients of coupling constants were measured for both classes of radicals and INDO calculations showed that nitrogen out-of-plane wagging is responsible for all the temperature coefficients.Molecular orbital calculations were performed for the 1,3,2-dithiazolyl and 1,3,2-dithiazolidinyl structures using semi-empirical INDO and ab inito Gaussian 76 computer programs: the optimised structural parameters from both calculations are in good agreement. The INDO calculations gave signs and magnitudes of isotropic coupling constants in overall agreement with those observed experimentally.

The chemistry of 6-dialkylamino-2H-1,3-oxazin-2-ones. Reversible thermal ring-opening and cycloaddition reactions with N-arylmaleimides and 1-diethylaminopropyne. X-Ray crystal structures of a 5H-2-pyridone and a 1H-2-pyridone

Flash-vacuum pyrolysis of the 1,3-oxazin-2-ones (1) and (9) gave the valence-isomeric carbamoylvinyl isocyanates (8) and (10), respectively, which recyclised to the oxazinones at room temperature. The oxazinones reacted with N-arylmaleimides in a Diels–Alder fashion; with 1-diethylaminopropyne, however, the first oxazinone yielded the isomeric pyridones (17) and (21), whose structures were determined by X-ray analysis.

Solvent effects in thermal (2 + 2) cycloaddition reactions. Intramolecular capture of 1,4-dipolar intermediates vs. (2 + 2) cycloaddition in reactions of 3-(1-pyrrolidinyl)thiophenes with electron-deficient acetylenes

Solvent effects in thermal (2 + 2) cycloaddition reactions. Intramolecular capture of 1,4-dipolar intermediates vs. (2 + 2) cycloaddition in reactions of 3-(1-pyrrolidinyl)thiophenes with electron-deficient acetylenes

Cycloaddition reactions of 1,3-diacetylimidazolin-2-one

1,3-Diacetylimidazolin-2-one, for which a new preparation is described, has been found to undergo thermal cycloaddition reactions with a limited number of dienes; in contrast it undergoes photochemical cycloadditions quite readily.

Cycloaddition reaction of methyl 2-pyronecarboxylates with 1,3-dienes

The experimental results of thermal cycloaddition reactions of methyl 2-pyrone-3-, 4-, 5- and 6-carboxylates with 1,3-dienes and the theoretical approach by a second order perturbation MO method are described. The sequential introduction of a methoxycarbonyl group onto a 2-pyrone ring caused a variety of selectivities in the cycloaddition reactions with 1,3-butadienes. PMO treatment based only on the frontier molecular orbitals failed to account adequately for this selectivity phenomena because the relative magnitudes of the coefficients in the HO and LU orbitals of 2-pyrones were little affected by the introduction of a substituent. PMO treatment including superjacent and subjacent orbitais along with frontier orbitais rationalized excellently the observed selectivity phenomena.

Novel cycloaddition of tetrafluoroethylene to the tetrafluoroethylene radical anion at 95 K: direct observation by EPR studies

The novel cycloaddition reaction C 2F − 4 + C 2F 4 ⇁ c-C 4F − 8 has been observed directly by EPR spectroscopy in organic glasses at 80–95 K. According to the frontier orbital theory, the concerted reaction is symmetry allowed irrespective of whether the interaction is SOMOLUMO or SOMOHOMO, the SOMO of C 2F − 4 being the 5b 1u(σ*) orbital suggested by EPR studies. The assignment of C 2F − 4 as a σ radical also suggests that a concerted [2 + 2] suprafacial mechanism should be considered for the thermal cycloaddition reaction between two neutral C 2F 4 molecules.

Reactions involving fluoride ion Part XIII. Reactions of perfluoro-4-vinylpyridine

Abstract 1-Chloro-1-(2′,3′,5′,6′-tetrafluoropyridyl)tetrafluoroethane, obtained by reaction of chlorotrifluoroethylene with pentafluoropyridine in the presence of caesium fluoride, was dehalogenated over iron at 310°, giving perfluoro-4-vinylpyridine (IV). Reactions of (IV) have been surveyed; nucleophilic attack occurs at both the ring and the difluoromethylene group using MeO- but with PhO-, selective attack at the difluoromethylene group occurred. A dimer is produced by reaction of (IV) with CsF and the intermediate carbanion was trapped with tetrafluoropyridazine. Thermal cyclodimerisation of (IV) gave a single isomer whose structure was established by n.m.r. and by defluorination to a cyclobutene. Cyclobutanes were formed in thermal cycloaddition reactions with chlorotrifluoroethylene and with hexafluoropropene. Photochemical reaction of (IV) with hexafluoroacetone gave an oxetane.

Photochemical and thermal cycloaddition reactions of 1,3-diphenylisobenzofuran with cycloheptatriene

Photochemical and thermal cycloaddition reactions of 1,3-diphenylisobenzofuran with cycloheptatriene

ChemInform Abstract: CYCLOADDITION REACTION OF TROPONOIDS WITH DIMETHYL MALEATE

Thermal cycloaddition reaction of methyl maleate with tropone, 2-chloro-, 2-methoxytropone and tropolone was investigated. Each reaction yielded [4+2] type adducts with high peri- and stereospecificities but with less regioselectivity.

ChemInform Abstract: CYCLOADDITION REACTION OF METHYL COUMALATE WITH CYCLOHEPTATRIENE

AbstractDurch Cycloaddition von Cumalinsäuremethylester (I) an Cycloheptatrien (II) bei 160° wird ein schwer trennbares Produktgemisch erhalten, das nach Hydrierung mit LiAlH4 ein Gemisch mehrerer Verbindungen ergibt, aus dem die Addukte (IIIb) und (IVb) isoliert werden können.