Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"cross-metathesis"”.
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Improvement of propylene yield via butene metathesis
… One of the technologies available is 1-butene metathesis, which describes a one-step process where isomerisation of 1-butene to 2-butene followed by cross-metathesis taking place. Products of the cross metathesis are propene and 2-pentene. In addition ethene and 3-hexene are expected as …
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Phosphate Tethers in Synthesis: The Total Synthesis of Dolabelide C.
… research described herein. Specifically, cross metathesis of various olefin partners with a phosphate tether has been demonstrated. These studies established the Type III olefin reactivity of the exocyclic olefin of the triply allylic bicyclic phosphate tether. Cross metathesis between the …
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Total synthesis of Galbulimima alkaloids. Resin-bound glycosyl phosphates as glycosyl donors.
… 13 is outlined. Sequential use of catalytic cross-coupling and cross-metathesis reactions followed by an intramolecular Diels-Alder reaction provided the required trans-decalin AB ring system and masked the C16-carbonyl as an N-vinyl carbamate for late stage oxidative unveiling as the …
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Enantioselective synthesis of 2,2,5-Tri- and 2,2,5,5-tetrasubstituted tetrahydrofurans and synthesis of diketopiperazine containing natural products
… tetrahydrofurans via ring-opening metathesis/cross-metathesis or oxidative cleavage and refunctionalization. A partial synthesis of the bioactive diketopiperazine containing natural product gliocladin C was achieved in nine steps, and 13.4% overall yield. The synthesis featured …
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The synthesis and benzannulation reactions of (trialkylsilyl)vinylketenes
… by the rearrangement of siloxy alkynes and by cross-metathesis are discussed.
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Asymmetrische Synthese 3-substituierter 4-Methylenproline und Untersuchungen zur Metathese mit vinylischen Sulfoximinen
… part there were investigations towards the cross metathesis or ring closing metathesis of vinylic sulfoximines. The synthesis of (S)-vinylic sulfoximine starting from (S)-N,S-dimethyl-S-phenylsulfoximine succeeded only after activation with a phosphoric acid ester and only in 15% yield. This …
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Towards the Total Synthesis of Spirastrellolide E: Investigations into Advanced Southern Hemisphere Fragments
… novel strategy for hemisphere union, involving a cross metathesis/epoxidation/epoxide ring opening cascade, and describes the synthesis of more than 500 mg of a revised southern hemisphere fragment. In addition, the mechanism of the key directed gold catalyzed spiroketalization is discussed in …
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Engineering novel tandem reactions using organometallic catalysts and (metallo)enzymes
… transformations such as isomerization, olefin metathesis, carbene-mediated insertions and others. On the other hand, metalloenzymes and reductases have been investigated and engineered to catalyze reactions with organic compounds that are synthetically and industri-ally important. First, we …
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Engineering novel tandem reactions using organometallic catalysts and metalloenzymes
… transformations such as isomerization, olefin metathesis, hydroxylation, epoxidation and others. On the other hand, metalloenzymes and enzymes with bound metal centers have been investigated and engineered to catalyze reactions with organic compounds that are synthetically and industrially …
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Applications of titanium-mediated reductive coupling and cyclocarbonylation reactions toward natural product synthesis
… reductive cyclocarbonylation and an imino-alkyne cross-metathesis strategy towards the synthesis of pyrrolizidine and indolizidine alkaloids respectively. The same substrates were employed in both reaction pathways.
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Towards the synthesis of novel protein phosphatase inhibitors
… a convergent approach taking advantage of cross-metathesis methodology, non-aldol aldol and aza-Claisen rearrangements, as well as β-lactam chemistry. We envisage using our synthetic approaches as a platform to generate a wide range of novel “ADDA”-containing analogues, which might lead to …
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Total synthesis of Class II and Class III Galbulimima Alkaloids
… 13 is revised to 2S. Sequential use of catalytic cross-coupling and cross-metathesis reactions followed by an intramolecular Diels-Alder reaction provided the required trans-decalin AB-ring system and masked the Cl 6-carbonyl as an N-vinyl carbamate for late stage unveiling in the form of the …
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Synthesis Of Natural Product-Based Sphingosine Derivatives
… step. Another crucial technique is the Grubbs' cross-metathesis reaction to the side-chain extension. This reaction provides an opportunity to develop various analogs through side-chain modification. Compound (±)-30 was synthesized in 11 steps and compound (±)-31 was synthesized in 10 steps with …
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Solid-supported synthesis of peptidoglycan fragments and their biological evaluation
… is proposed. Thanks to a solid phase platform, cross metathesis was achieved between two easily manufactured chiral synthons, allylglycine anchored to a resin and vinylglycine derivatives. Due to the need of fragments for the study of the peptidoglycan recycling, this modular efficient platform …
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Phosphate Tether-Mediated, One-Pot Metathesis Processes: Application in Small Molecule Synthesis
… The concise approach to this molecule invokes cross-metathesis, chemoselective hydrogenation, regio- and diastereoselective cuprate addition and Mitsunobu esterification as key synthetic transformations. Additionally, a phosphorodiamidite coupling and one-pot, sequential RCM/CM/chemoselective …
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Molybdenum alkylidene complexes : syntheses and applications to olefin metathesis reactions
… Characterization and Activity as Chiral Olefin Metathesis Catalysts. Molybdenum olefin metathesis catalysts that contain previously unexplored aliphatic 1- phenylcyclohexylimido (PhCyN) and 2-phenyl-2-adamantylimido (PhAdN) groups were prepared and shown to be efficient and selective in a …
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Reacciones de metátesis e hidrotiolación como herramientas sintéticas para la obtención de compuestos con interés biológico
… with a biological interest. For this purpose, metathesis and hydrothiolation reactions have been used as key steps. In the first part of this report, we performed a thorough study of the metathesis reaction on 7-azanorbornene systems. Ring rearrangement metathesis (RRM) in …
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Suzuki-Miyaura mediated biphenyl synthesis: a spotlight on the boronate coupling partner
… were also synthesised by using the olefin cross-metathesis reaction of 4-vinylphenylboronic acid pinacol ester. A solid state crystallographic study was undertaken on a small library of methylbiphenylamides to compare the crystal structures of isomers or biphenyls with different functional …
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Exploring IPC Synthase: A POTENTIAL ANTI -LEISHMANIAL DRUG TARGET
… The prepared alkenes were utilised in olefin cross metathesis reactions to yield a library of ceramide mimics variable in the sphingosine backbone. Deprotection-acylation sequence of the protected amino group resulted in variable N-acyl ceramide mimics. Screening of the substrate mimics …
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Towards the Structural Elucidation and Total Synthesis of Hemicalide: Assignment of the C29-C46 Region
… of the C29-C35 and C34-C46 fragments, by olefin cross metathesis, to produce three diastereomers of the fully elaborated C29-C46 region. This work allowed the relative stereochemistry of C31 and C32 to be assigned and established the relationship between the C27-C32 and C36-C45 stereoclusters. …
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