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Annulation

Distribution by Scientific Domains
Chemistry95%
Life Sciences4%
Distribution within Chemistry
Organic Chemistry88%
General & Introductory Chemistry9%

Terms modified by Annulation

  • annulation reaction
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    Selected Abstracts

    Enantio- and Diastereomerically Pure Decalins by Deslongchamps-Type Annulation of Dienolates Containing a Chiral Lactone Substituent

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2007
    Thomas Tricotet
    Abstract A conceptionally novel 1,3-asymmetric induction has been established. It controls the relative and absolute configuration of up to 5 stereocenters. They emerge from the anionic Diels,Alder reactions ("Deslongchamps annulations") between oxocyclohexenecarboxylates 25, 29 and dienolates 26, 30. The latter contain a ,-lactone. A Ph3Si,CH2 substituent therein controls the asymmetry of C,C bond formation with ds , 10:1. Strangely, the preferred sense of attack of the dienophile is contrasteric. Cycloadduct 31 was processed by an unprecedented fluoride-induced ambient-temperature tandem fragmentation. It turned the lactone moiety into an allyl group and the ,-oxo (trimethylsilyl)ethyl ester into a ketone. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

    A New Glucose: Towards Conformationally Locked Hexoses through Annulation

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2005
    Goverdhan Mehta
    Abstract A new family of surface-modified carbohydrates with locked, axial-rich conformations and bipolarofacial architectures has been developed with the aid of carbocyclic ring annulation. These novel trans -decalin-based carbohydrates have been synthesized, from simple aromatic precursors such as tetralin, through the ozonolysis of an appropriately protected allylic alcohol, followed by a cascade of intramolecular acetalizations to generate the sugar pyran moiety. The stereoselective synthesis of (racemic) cyclohexane-annulated ,-glucopyranoside and ,-glucofuranoside from a common annulated trans -cyclohexadiene diol (trans -CHD) precursor underscores the versatility of our approach. The efficacy of the annulation stratagem in generating carbohydrate diversity has been demonstrated through the synthesis of two regioisomeric annulated gulose derivatives, which differ only in the site of ring annulation on the sugar moiety. The mapping of the MLP surface and solid-state architecture of the new sugar shows that cycloalkane annulation results in surface modification and fine-tuning of sugar hydrophilicity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

    Gold-Catalyzed Synthesis of Bicyclo[3.2.0]heptenes via a Formal [3+2]/[2+2]-Annulation of Allylsilane with 4-Methoxybut-2-yn-1-ols

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010
    Chun-Yao Yang
    Abstract This work reports the novel gold-catalyzed [3+2]/[2+2]-annulation of allylsilane with 4-methoxybut-2-yn-1-ols that yields highly strained bicyclo[3.2.0]heptene products efficiently and stereoselectively. [source]

    Direct Synthesis of Dihydrobenzo[a]carbazoles via Palladium-Catalyzed Domino Annulation of Indoles

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010
    Farnaz Jafarpour
    Abstract A straightforward one-step synthesis of annulated indoles via palladium-catalyzed, norbornene-mediated sequential intermolecular aryl ortho -alkylation/intramolecular indole CH activation has been devised. This method provides an efficient route to a wide variety of substituted 6,11-dihydro-5H -benzo[a]carbazoles from readily accessible 3-bromoalkylindoles and iodoarenes. [source]

    Palladium-Catalyzed Annulation of 2-(1-Alkynyl)benzenamines with Disulfides: Synthesis of 3-Sulfenylindoles

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 16 2009
    Yan-Jin Guo
    Abstract 3-Sulfenylindoles can be efficiently prepared in moderate to good yields from 2-(1-alkynyl)benzenamines and disulfides using the palladium/air catalytic systems. The study also provides a useful route to the synthesis of fipronil analogues. [source]

    Synthesis of Fluorenes via the Palladium-Catalyzed 5- exo-dig Annulation of o -Alkynylbiaryls

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009
    Natalia Chernyak
    Abstract The direct palladium-catalyzed intramolecular hydroarylation of o -alkynylbiaryls proceeded in a highly stereoselective manner producing fluorenes 2, the products of 5- exo-dig cyclization, in excellent yields. The cascade intermolecular arylation, incorporated in this transformation, allowed for the efficient synthesis of fully substituted fluorenes 12. These cyclizations proceed more rapidly with electron-deficient benzene rings which, in combination with a substantial isotope effect observed, strongly supports a CH activation mechanism for the key annulation step. [source]

    Tuning Electronic and Steric Effects: Highly Enantioselective [4+1] Pyrroline Annulation of Sulfur Ylides with ,,,-Unsaturated Imines,

    ANGEWANDTE CHEMIE, Issue 26 2010
    Liang-Qiu Lu
    Sterische und elektronische Effekte: Mithilfe einer neuartigen [4+1]-Cycloaddition von atropisomeren Schwefel-Yliden 1 und ungesättigten Iminen 2 gelingt die Synthese enantiomerenangereicherter Pyrroline 3 in hohen Ausbeuten. Die beobachteten hohen Stereoselektivitäten wurden anhand einer Konformationsanalyse der Ylide erklärt. [source]

    Catalytic Enantioselective Dieckmann-Type Annulation: Synthesis of Pyrrolidines with Quaternary Stereogenic Centers,

    ANGEWANDTE CHEMIE, Issue 10 2010
    Jonathan
    Neues gelernt: Eine Cyclisierung vom Dieckmann-Typ ermöglichte die Synthese der Titelverbindungen mit bis zu 96,%,ee (siehe Schema; Bn=Benzyl). Das Vorliegen einer ,-koordinierenden Einheit im Substrat führt zu einer Konkurrenz zwischen Cyclisierung und Eliminierung, die durch die Art des chiralen Liganden beeinflusst wird. Eine mechanistische Erklärung für diese Beobachtungen wird vorgestellt. [source]

    9-Stannafluorenes: 1,4-Dimetal Equivalents for Aromatic Annulation by Double Cross-Coupling,

    ANGEWANDTE CHEMIE, Issue 41 2009
    Ikuhiro Nagao
    Doppelt genäht hält besser: Die palladiumkatalysierte Anellierung von 9,9-Dimethyl-9-stannafluorenen oder -dithienostannolen an 1,2-Dihalogenarene führt direkt und in hohen Ausbeuten zu einer Vielfalt von polycyclischen aromatischen Kohlenwasserstoffen (siehe Schema). 1,1-Dibrom-1-alkene ergeben analog Dibenzofulvene in ausgezeichneten Ausbeuten. [source]

    ChemInform Abstract: Synthesis of Dihydrobenzofurans via Palladium-Catalyzed Annulation of 1,3-Dienes by o-Iodoaryl Acetates.

    CHEMINFORM, Issue 42 2010
    Roman V. Rozhkov
    Abstract The widely applicable reaction proceeds with excellent regio- and stereoselectivity. [source]

    ChemInform Abstract: o-Benzenedisulfonimide as a Reusable Broensted Acid Catalyst for an Efficient and Facile Synthesis of Quinolines via Friedlaender Annulation.

    CHEMINFORM, Issue 33 2010
    Margherita Barbero
    No abstract is available for this article. [source]

    ChemInform Abstract: Direct Stereoselective Synthesis of 1-Amino-2,5-diarylcyclohexanecarboxylic Acid Derivatives Based on a [5 + 1] Annulation of Divinyl Ketone and Isocyanoacetate.

    CHEMINFORM, Issue 31 2010
    Dawei Zhang
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Rhodium-Catalyzed [3 + 2] Annulation of Indoles.

    CHEMINFORM, Issue 28 2010
    Yajing Lian
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Enantioselective Synthesis of 3,4-Dihydroisoquinolin-1(2H)-ones by Nickel-Catalyzed Denitrogenative Annulation of 1,2,3-Benzotriazin-4(3H)-ones with Allenes.

    CHEMINFORM, Issue 28 2010
    Motoshi Yamauchi
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Direct Synthesis of Dihydrobenzo[a]carbazoles via Palladium-Catalyzed Domino Annulation of Indoles.

    CHEMINFORM, Issue 25 2010
    Farnaz Jafarpour
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Efficient Synthesis of Benzothieno[3,2-d]imidazo[1,2-a]pyrimidine-2,5-(1H, 3H)-diones via a Tandem aza-Wittig/Heterocumulene-Mediated Annulation.

    CHEMINFORM, Issue 24 2010
    Sheng-Zhen Xu
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: L-Proline-Catalyzed Three-Component Domino [3 + 2 + 1] Annulation for the Regio- and Diastereoselective Synthesis of Highly Substituted Thienothiopyrans Containing Three or Four Stereocenters.

    CHEMINFORM, Issue 18 2010
    Sethuraman Indumathi
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Phosphine-Catalyzed [4 + 3] Annulation for the Synthesis of Highly Functionalized Bicyclo[3.2.2]nonadienes.

    CHEMINFORM, Issue 5 2010
    Suqing Zheng
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Stereocontrolled Synthesis of Oxaspirobicycles via Prins-Pinacol Annulation.

    CHEMINFORM, Issue 4 2010
    Satish N. Chavre
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Junjappa,Ila Annulation: ,-Oxoketene Dithioacetal Mediated Synthesis of Substituted Benzotriazoles.

    CHEMINFORM, Issue 49 2009
    Nitinkumar S. Shetty
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Stereocontrolled Synthesis of Spirooxindoles Through Lewis Acid-Promoted [5 + 2]-Annulation of Chiral Silyl Alcohols.

    CHEMINFORM, Issue 48 2009
    Yun Zhang
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Asymmetric Tandem Michael Addition,Wittig Reaction to Cyclohexenone Annulation.

    CHEMINFORM, Issue 46 2009
    Yan-kai Liu
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Disubstituted Benzenes from Acyclic Precursors by a [5 + 1] Annulation.

    CHEMINFORM, Issue 43 2009
    David S. B. Daniels
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: [4 + 2] Annulation , Convenient Synthesis of Substituted Dihydropyranones in Aqueous Media.

    CHEMINFORM, Issue 34 2009
    Yan Ouyang
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Palladium-Catalyzed Annulation of Haloanilines and Halobenzamides Using Norbornadiene as an Acetylene Synthon: A Route to Functionalized Indolines, Isoquinolinones, and Indoles.

    CHEMINFORM, Issue 27 2009
    Praew Thansandote
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Palladium-Catalyzed Annulation of Acyloximes with Arynes (or Alkynes): Synthesis of Phenanthridines and Isoquinolines.

    CHEMINFORM, Issue 21 2009
    Thibaud Gerfaud
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Palladium-Catalyzed Annulation of vic-Bis(pinacolatoboryl)alkenes and -phenanthrenes with 2,2,-Dibromobiaryls: Facile Synthesis of Functionalized Phenanthrenes and Dibenzo[g,p]chrysenes.

    CHEMINFORM, Issue 8 2009
    Masaki Shimizu
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Enantioselective Synthesis of Spirocyclic Benzopyranones by Rhodium-Catalyzed Intermolecular [4 + 2] Annulation.

    CHEMINFORM, Issue 47 2008
    Daiki Hojo
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Cationic Palladium(II)-Catalyzed Highly Enantioselective [3 + 2] Annulation of 2-Acylarylboronic Acids with Substituted Alkynes.

    CHEMINFORM, Issue 17 2008
    Miao Yang
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Quinine Synthesis Studies: A Radical,Ionic Annulation via Mn-Mediated Addition to Chiral N-Acylhydrazones.

    CHEMINFORM, Issue 12 2008
    Chandra Sekhar Korapala
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]