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Showing 1 to 20 of 32 for “"[2+2]-Cycloaddition"”.

  1. Synthesis of 3-aminocyclobutenones via [2 + 2] cycloaddition of ynamides and ketenes

    Aguirre Kohnen, Amanda L. (Amanda Lucille)Massachusetts Institute of Technology2012

    … classes of ketenes in intermolecular [2 + 2] cycloaddition to afford substituted cyclobutenones with complete regioselectivity. The cycloaddition substrates are easily assembled from amine derivatives by copper-catalyzed N-alkynylation with acetylenic bromides. The alkynylation reaction …

    mit Repository record

  2. Studies Directed Toward the Synthesis of Germacranolides via [2+2] Cycloaddition Followed by Ring Expansion/Elimination of β-Lactones

    Yates, Bryan E.

    eiu Repository record

  3. Stereoselective Intramolecular Rhodium(I)-Catalyzed [(3+2+2)] Cycloaddition Reactions of Alkylidenecyclopropanes (ACPs) for the Concise Synthesis of Bridged Tricyclic Products

    Zhu, Yu2025

    Transition metal-catalyzed higher-order [m+n+o] cycloadditions are an important class of reactions for constructing elaborate carbocycles and heterocycles in a highly convergent manner. In particular, cycloadditions with alkylidenecyclopropanes (ACPs) as three-carbon synthons offer a versatile …

    queens Repository record

  4. CRYSTAL ENGINEERING STUDIES ON THE MOLECULAR SALTS AND SILVER(I) COORDINATION COMPOUNDS FOR [2+2] CYCLOADDITION REACTION IN THE SOLID STATE

    GOUTAM KUMAR KOLE2011

    … analysed in terms of their solid state [2 + 2] cycloaddition reaction to synthesize a particular isomer of the corresponding cyclobutane compounds. The crucial role of the anions in the selective preorganization before photodimerization and the acid catalysed isomerisation of the cyclobutane …

    nus Repository record

  5. I. [2 +2] Cycloaddition and benzannulation of 2-iodoynamides and application to the construction of highly substituted indoles : II. Synthesis of furo[2,3-g]thieno[2,3-e]indole via a benzannulation strategy

    Wang, Yu-Pu, Ph. D. Massachusetts Institute of TechnologyMassachusetts Institute of Technology2015

    … undergo efficient and regioselective [2 + 2] cycloaddition with ketene to produce cyclobutenones that are useful synthetic building blocks. Reaction of 2-iodoynamides and vinylketenes generated in situ from cyclobutenones proceeds via a pericyclic cascade mechanism to produce highly …

    mit Repository record

  6. Typselektivität und Diastereoselektivität in den Oxidationen von chiralen oxazolidinonsubstituierten Encarbamaten mit Singulettsauerstoff, Dimethyldioxiran und meta-Chlorperbenzoesäure

    Bosio, SaraUniversität Würzburg

    … die Typselektivität (En-Reaktion versus [2+2]-Cycloaddition) kontrolliert. Bei der [2+2]-Cycloaddition der Encarbamate I mit Singulettsauerstoff (1O2) und der Epoxidierung mit DMD und mCPBA wurden hohe Diastereoselektivitäten beobachtet. Die folgenden Ergebnisse wurden erzielt: 1. Die …

    wurz-thes Repository record

  7. Development of Nickel and Zirconium Mediated Cycloadditions for the Synthesis of Substituted Pentacene

    Deaton, Kimberly RaeUniversity of Illinois at Urbana-Champaign2015

    The regioselectivity of the [2+2+2] cycloaddition of nickel-benzynes and 1,3-diynes could be maintained when asymmetrically substituted 1,3-diynes were employed. The ability to incorporate an asymmetric 1,3-diyne into the oligoacene backbone provided substituents that could be differentiated in …

    uiuc Repository record

  8. Regio- und stereoselektive Synthese von Sesquiterpenen und hormonell aktiven Cholesterinderivaten

    Schmidt, Arndt W.Technische Universität Dresden

    … wird die Anwendung der Lewis-Säure vermittelten Cycloadditionen von Allylsilanen an alpha,beta-ungesättigte Carbonylverbindungen beschrieben. Das Sesquiterpen Isocomen wurde unter Anwendung der [3+2]-Cycloaddition an Enone synthetisch hergestellt. Die [2+2]-Cycloaddition an Acrylsäurederivate …

    qucosa-diss

  9. Synthesis of Aryl Ynol Ethers and Their Synthetic Applications

    Zhang, WenhanUT Southwestern Medical Center2016

    … Moreover, we discovered a hetero-[2+2]-cycloaddition reaction between aryl ketenes and aryl ynol ethers, and the forming cyclobutenones could undergo a retro-4π/6π electrocyclization reaction to afford naphthlenes. Finally, we utilized this novel electrocyclization in the synthesis of …

    utswmed Repository record

  10. Preparation of benzoenyne -allenes, enyne -isocyanates and enyne -carbodiimides and their applications in the synthesis of polycyclic aromatic hydrocarbons and heterocycles

    Li, Hongbin2019

    … in certain cases the intramolecular [2+2] cycloaddition reaction of the chlorinated benzoenyne-allene intermediates occurred preferentially to form 1H-cyclobut[a]indenes. Competition from the intramolecular [2+2] cycloaddition reaction could be avoided with the non-chlorinated …

    wvu Repository record

  11. Strategies for the synthesis of bioactive compounds: biomimetic approaches to the Salinosporamides and the hexadehydro-Diels-Alder reaction

    Willoughby, Patrick2013

    … uncatalyzed intramolecular ketene-ketone [2+2] cycloaddition of an amidoketene precursor. We also propose a transition state that places the C2 substituent pseudo-equatorial, allowing for enhanced stereoselectivity during bis-cyclization. Enolate formation from a thioester followed by internal …

    umn Repository record

  12. Enantioselective nucleophile-catalyzed cycloadditions

    Wilson, Jonathan E., Ph. D. Massachusetts Institute of TechnologyMassachusetts Institute of Technology2007

    … of an asymmetric nucleophile-catalyzed [2+2] cycloaddition of ketenes with aldehydes. This is the first report of a catalytic enantioselective synthesis of trisubstituted [beta]-lactones. Two enantioselective phosphine-catalyzed [3+2] cycloadditions of allenoates are detailed in Chapter 2. A …

    mit Repository record

  13. Part I. Total Synthesis and Structural Revision of (±)-Tricholomalides A and B. Part II. Synthetic Studies towards (+)-Cortistatin A

    Wang, Zhang2011

    … annulation, followed by a ketene-olefin [2+2] cycloaddition to introduce the lactone ring. Then a Grignard-type reaction appended the isopropenyl moiety, and the synthesis of tricholomalides A and B was achieved. During the course of synthesis, the structures of tricholomalides A and B were …

    columbia-diss Repository record

  14. Synthesis of pyridines via [4 + 2] cycloadditions of vinylallenes with azadienophiles

    Hamzik, Philip J. (Philip Jonathan)Massachusetts Institute of Technology2015

    … substituted pyridines that involve [4 + 2] cycloadditions of vinylallenes with azadienophiles. Part II of this thesis describes a unimolecular, formal [2 + 2 + 2] cycloaddition strategy for the synthesis of tricyclic pyridines based on intramolecular propargylic ene/imino Diels-Alder …

    mit Repository record

  15. Synthetic studies towards total synthesis of bielschowskysin

    GOVINDAN SUBRAMANIAN2010

    … butenolide was prepared in 13 steps and [2+2] cycloaddition was carried out under the UV lamps to form the tricyclic core of bielschowskysin. After making the tricyclic core, retrosynthetic analysis of key intermediate leads to left and right fragment. Left fragment, seleno-lactone was prepared …

    nus Repository record

  16. Novel Photochemical Methodologies for Diversity Oriented Synthesis and Screening of Combinatorial Libraries

    Valiulin, Roman Askatovich2001

    … are capable of photoinduced alkene-arene [2+2] cycloaddition producing different dienes, which can either dimerize or be introduced into a double-tandem [4<sub>π</sub>+2<sub>π</sub>]·[2<sub>π</sub>+2<sub>π</sub>]·[4<sub>π</sub>+2<sub>π</sub>]·[2<sub>π</sub>+2<sub>π</sub>] synthetic sequence, …

    denver Repository record

  17. New routes to enantioenriched substances through small organic molecules

    Boschi, Francesca <1980>Alma Mater Studiorum - Università di Bologna2009

    … and bicyclo[3.2.0]hept-3-en-6-ones through a cycloaddition strategy is reported. The fundamental step is a [2+2]-cycloaddition of an enantiopure amide derived from the reaction between a set of acids and an oxazolidinone as the chiral auxiliary. The inter- and intramolecular cycloaddition of …

    bologna Repository record

  18. Entwicklung photosensitiver Polymernetzwerke mit Formgedächtniseigenschaften

    Jünger, OliverPublikationsserver der RWTH Aachen University2002

    … is controlled by the light-induced [2+2]-cycloaddition of cinnamates. The synthesis of amorphous covalently linked polyacrylate networks is reported. Acrylate monomers containing cinnamic acid groups lead to photoreactive groups in polymer side- chains. Those monomers are prepared by …

    aachen Repository record

  19. Synthesis of derivatives of 4H-cyclopenta[ def]phenanthren-4-one and development of synthetic strategies for the polycyclic aromatic hydrocarbons with carbon frameworks represented on the surface of C60

    Han, Xiaoqing2019

    … then afforded the formal [4+2] Diels-Alder cycloaddition adduct 60, which in turn underwent tautomerization to give 61. Reduction with tri-n-butyltin hydride then gave the ketal 62 in 46% overall yield from 56a. Hydrolysis of the ketal 62 gave the ketone 51 in 97% yield.;Another derivative …

    wvu Repository record

  20. Pericyclic reactions in organic synthesis

    Robinson-Surry, Julia M. (Julia Mae)Massachusetts Institute of Technology2011

    … describes a formal, metal-free, [2 + 2 + 2] cycloaddition strategy based on a cascade of two pericyclic processes. An intramolecular propargylic ene reaction of a 1,6-diyne is used to generate a vinylallene, which then reacts in an inter- or intramolecular Diels-Alder reaction with an alkenyl …

    mit Repository record

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