Azuleno[5,6-c]furan and 4-chloroazuleno[4,5-c]furan have been prepared by a tandem cycloaddition-cycloreversion strategy. These azulenofurans are qualitatively more stable than isobenzofuran and were characterised spectroscopically and as their Diels-Alder adducts with N-methylmaleimide.

(±)-Favelanone (1) has been synthesised by a sequence involving as the key step the cycloaddition of 6-methoxy-5-methyl-3-trimethylsilyloxyisobenzofuran-1-carbonitrile (3) to 7-bromo-5,5-dimethylbicyclo[4.1.0]hept-1(7)-ene (4).

The C-13 n.m.r. spectroscopic properties of the title model compounds do not support the 7-oxabicyclo[2.2.1]heptyl and locked arene oxide structural moieties proposed for the metabolite SCH 58450.

The title compounds have been synthesised by a sequence involving as the key step the cyclization of the radical derived from the reaction of tributylstannane with 3,4-diacetoxy-2-bromo-5-methoxybenzyl vinyl ether.

AbstractThe benzonorbornadienes (I), (XII), and (XIV) are treated with dichlorocarbene generated in situ to produce the dichlorobenzobicyclo(3.2.1)octenes (III) and (IV), (XIII), or (XV) via ring expansion of the fused dichlorocyclopropanes primarily formed.

Dehydrochlorination of 6,6-dichloro-3-thiabicyclo[3.1.0]hexane generates a cyclopro, pene which can be trapped with t-BuOH or furan, while 1,5-dibromo-6,6-dimethyl-3-thiabicyclo[3.1.0]hexane undergoes dehydrobromination to afford the highly reactive 4,4-dimethyl-4H-cyclopropa[c]thiophene, which was trapped with isobenzofuran.

Abstract(2 + 2)Cycloaddition reaction of the bicyclic ketone (II) with benzyne, derived from the diazobenzoate (I), yields the tetracyclic product (III).

AbstractThe cyclopropane (I) reacts with tetrabutylammonium fluoride to give the dibromocyclopropene (II).

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAddition of benzyne to bicyclo[4.2.1]nona-2,4,7-trien-9-one and 1,6-methano[10]annuleneIan J. Anthony, Lindsay T. Byrne, Ross K. McCulloch, and Dieter WegeCite this: J. Org. Chem. 1988, 53, 17, 4123–4124Publication Date (Print):August 1, 1988Publication History Published online1 May 2002Published inissue 1 August 1988https://pubs.acs.org/doi/10.1021/jo00252a050https://doi.org/10.1021/jo00252a050research-articleACS PublicationsRequest reuse permissionsArticle Views108Altmetric-Citations5LEARN 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 InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

The title reaction afforded the Diels-Alder adduct 4b,10-ethenobenz [a]azulene (4), while an analogous reaction involving 5,6-dichloroazulene gave the 6,7- and 7,8-dichloro-derivatives of (4). Treatment of (4) with 3,6-di(pyridin-2-yl)-s-tetrazine yielded benz[a]azulene.

Chemischer InformationsdienstVolume 13, Issue 10 Preparative Organic Chemistry ChemInform Abstract: INTRAMOLECULAR DIELS-ALDER REACTIONS OF BENZYNES. APPLICATION TO THE TOTAL SYNTHESIS OF MANSONONE E W. M. BEST, W. M. BESTSearch for more papers by this authorD. WEGE, D. WEGESearch for more papers by this author W. M. BEST, W. M. BESTSearch for more papers by this authorD. WEGE, D. WEGESearch for more papers by this author First published: March 9, 1982 https://doi.org/10.1002/chin.198210115AboutPDF 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 onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume13, Issue10March 9, 1982 RelatedInformation

1,4-Epoxy-1,4-dihydroarenes are converted in high yields into the corresponding arenes with enneacarbonyldiiron in refluxing benzene solution.

The title carbenes, which in principle can all serve as precursors to the reactive hydrocarbon pseudoindene, have been generated by the photolysis of the sodium salts of the tosylhydrazones of (a) benzocyclobutene-1-carboxaldehyde, (b) 2-methylbenzocyclobutenone and (c) o-formylstyrene. Indene was formed in reactions (a) and (c): in the former case deuterium labelling experiments suggest a ring expansion mechanism rather than a pseudoindene intermediate. In the latter case deuterium labelling and trapping experiments implicate a symmetrical isoindene intermediate, which can arise either via pseudoindene, or via direct electrocyclic ring closure of o-styrylcarbene.

Thermal decomposition of the sodium salts of benzocyclobutenone tosylhydrazone and 2-methylbenzocyclobutenone tosylhydrazone in benzene affords 9a,10-dihydrobenz[α]azulene 4 and trans-10-methyl-9a, 10-dihydrobenz[α]azulene 3, respectively. A mechanism involving initially the addition of the carbene benzocyclobutenylidene, or its 2-Me derivative, to the benzene ring is postulated. A proposed intermediate in the reaction, spiro [benzocyclobutene 1,7' cyclohepta-1',3',5'-triene] 12 has been synthesised, and shown to give rise to 4 under the reaction conditions. The rate of rearrangement of 12 → 4 has been measured, and the activation energy determined: Ea = 125.9 ± O.8 KJmol−1 and A = 1.38 × lO14sec−1. The mechanism for the rearrangement must involve ring opening of the benzocyclobutene moiety of 12 to give an o- xylylene intermediate which is postulated to possess considerable diradical character. At 71.8 °, this ring opening is 2.7 × 106 times faster than the ring opening of the parent benzocyclobutene molecule. The decomposition of the sodium salt of 2-(7' -cyclohepta-1',3',5' trienyl)benzaldehyde tosylhydrazone has also been investigated and is shown to yield 4a,10-dihydrobenz[α]azulene, 9,10-dihydrobenz[α]azulene and 8,9-benzotricyclo [5.3.0.02.10]deca-3,5,8-triene. A mechanism involving intramolecular 1,3-dipolar addition of a diazo grouping to a cycloheptatriene Π-bond, followed by decomposition of the resulting pyrazoline intermediate, is proposed.

Benzynes, generated either by the debromination of an appropriately substituted (o-dibromobenzene, or by the thermolysis of a substituted diazotized anthranilic acid, have been trapped intramolecularly by an attached furan moiety. One such adduct (41) has been transformed into 6,9-dimethylnaphtho[1,8-bc]pyran-3(2H)-one (43), which served as the key intermediate for the total synthesis of the title compounds, all of which are derivatives of 6,9-dimethylnaphtho[1,8-bc]pyran-7,8-quinone.

Abstract3,6‐Dibrom‐ anthranilsäure (I) wird in Forum ihres Diazoniumsalzes (II) in Gegenwart von Furan (III) zugesetzt, wobei das Addukt (IV) über eine Dehydrobenzol‐Zwischenstufe erhalten wird.

The title compounds have been synthesised by sequences involving as the key step the trapping of arynes with furan.

The reaction of benzyne (generated by the thermolysis of o- diazoniobenzoate) with the following alkenes has been examined: 1,1-dichloroethene (5) (vinylidene chloride), 1,1-dichloro-propene (7), 1,1-dichloro-2-methylpropene (17), 2-methylprop-1-en-1-yl acetate (18) and 2-chloro-prop-2-enenitrile (α-chloroacrylonitrile) (22). Substituted bicyclo[4,2,0]octa-1,3,5-trienes resulting from 2+2 cycloaddition were obtained from (5), (7), and (22), while the reaction involving the en01 acetate (18) gave only 'ene' product, and that involving (17) gave an intractable mixture. (Z)- and (E)-1-Chloro-2-(o-chlorophenyl)propene were obtained as minor products in the reaction of benzyne with (7): these products result from a chlorine atom transfer to the aromatic ring, and a novel mechanism involving a diradical → carbene rearrangement is postulated.

AbstractDie Titelverbindung (I) (1H‐NMR‐Spektrum) wird durch CrOa‐Oxidation des Dehydrobenzol‐Cycloheptatrien‐ Addukts (IV), Allylbromierung und nachfolgende Dehydrobromierung dargestellt.

AbstractAus dem Na‐tosylhydrazon (I) erhält man beim Erhitzen in Gegenwart von Benzol über eine Carben‐Zwischenstufe analog (VI) das Addukt (III), das mit Trityl‐tetrafluoroborat zu (V) dehydriert wird.