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Showing 1 to 20 of 124 for “"Asymmetric synthesis"”.
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Asymmetric synthesis involving silicon
… silylated diols (17 pairs) have been prepared by asymmetric dihydroxylation of the corresponding allyl and vinylsilanes using Sharpless catalysts. Chiral analysis of these silyl diols was carried out by <sup>1</sup>H NMR methods in the presence of Eu(hfc)<sub>3</sub>. Enantiomeric purity of some …
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Asymmetric synthesis of novel anthracyclinones
The synthesis of novel C9-halogenated anthracyclinones by Lewis acid promoted cyclisations of ortho-methallyl anthraquinonyl chiral dioxanes has been investigated. Tin tetrachloride-N,N-dimethylformamide promoted cyclisation of the dioxane (30) proceeded with excellent stereoselectivity to give an …
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Optimisation of chemoenzymatic processes in asymmetric synthesis
… the optimisation of chemoenzymatic methods in asymmetric synthesis. Modern synthetic organic chemistry has experienced an enormous growth in biocatalytic methodologies; enzymatic transformations and whole cell bioconversions have become generally accepted synthetic tools for asymmetric …
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Asymmetric synthesis of benzylic and heterobenzylic amines
… with 1,3-diphenyl-2-propenyl ethyl carbonate. Asymmetric synthesis of 2-(2-pyridyl)aziridines from chiral 2-pyridineimines bearing a stereogenic center at the nitrogen atom was development. The envisioned route involves the addition of chloromethyllithium to the imine derived from …
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The study of the asymmetric synthesis of lignans
The work in this thesis focuses on the asymmetric synthesis of lignans by approaches such as Diels-Alder reactions, asymmetric alkylation reactions, and intramolecular oxidative coupling reactions. In addition to developing asymmetric synthetic methodologies for chiral lignans, an investigation of …
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The asymmetric synthesis of amino acids via electrophilic glycinates
A new asymmetric synthesis of α-monosubstituted-α-amino acids using D- and L-erythro-4-benzy loxycarbonyl-5,6-diphenyl-2,3,5,6-tetrahydro-1,4-oxazin-2-ones 108 as amino acid templates is described. Bromination of 108 with NBS generates the key electrophilic glycinate 132 which couples with a …
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Asymmetric synthesis of 2-deoxystrptamine analogues as potential RNA ligends
Contains fulltext : 27450.pdf (Publisher’s version ) (Open Access)
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The Asymmetric Synthesis Of The C1'-C10' Portion of Pamamycin-621A
This thesis describes the synthesis of the C1'-C10' portion 72 of the pamamycin-621A using a cuprate conjugate addition to join enone fragment 52 and organostannane fragment 64a. Fragments 52 and 64a were both synthesized from (S)-methylketene dimer 51.
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Asymmetric Synthesis of 1,3-Amino Alcohols and Tropinone Derivatives From Enantiopure Sulfinimines
… The intent of this research is to the develop asymmetric syntheses of piperidine-containing syn and anti 1,3-amino alcohols as well as tropinone and tropane-containing derivatives using sulfinimines (N-sulfinyl imines) as precursors for acid-catalyzed cascade cyclizations. Chiral N-sulfinyl …
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The asymmetric synthesis of enol phosphates and their application in total synthesis
The synthesis of a wide range of highly valuable enol phosphate products has been carried out. The use of carbon centred magnesium bases, previously developed in the group has allowed the formation of kinetic enol phosphate products under room temperature conditions. By applying specific quench …
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Asymmetric synthesis of an advanced intermediate for the preparation of zaragozic acid Ax3.
Asymmetric synthesis of an advanced intermediate for the preparation of zaragozic acid Ax3.
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Functionalised azetidines: a study of their synthetic accessibility and application in asymmetric synthesis
Contains fulltext : 30104_funcaz.pdf (Publisher’s version ) (Open Access)
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Asymmetric Synthesis of Nitrogen Containing Bioactive Compounds via the Utilization of Enantiopure p-Toluenesulfinimines
… research was to develop new methods for the asymmetric synthesis of amine derivatives using p-toluenesulfinimines. Enantiopure sulfinimines are versatile chiral building blocks for the asymmetric synthesis of alkaloids. Sulfinimines were prepared by the condensation of (S)- or …
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The asymmetric synthesis of (2S,3R)-capreomycidine and the total synthesis of capreomycin IB
An efficient and asymmetric synthesis of the non-proteinogenic amino acid (2S,3R)-capreomycidine is presented. The synthesis features a novel aluminum enolate-aldimine reaction with a chiral glycinate, which sets both stereocenters. A concise and high-yielding approach to the unnatural amino acid …
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New methods for the asymmetric synthesis of α-alkylated ketones and 1,3-amino alcohols
… synthons and have found widespread use in total synthesis. The asymmetric alkylation of ketones represents one of the most powerful and longstanding procedures in organic chemistry. Surprisingly, however, only one effective methodology is available, and this involves the use of chiral …
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Asymmetric synthesis of amines by the catalytic enantioselective additions of hydrazoic acid to ketenes
The development of a planar-chiral catalyst for the enantioselective additions of HN3 to hindered ketenes was investigated. It was demonstrated that a new planar-chiral catalyst (1.5) is an excellent catalyst for the enantioselective addition of HN3 to hindered ketenes, en route to enantioenriched …
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