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dc.contributor.advisorPrasad, Kavirayani R
dc.contributor.authorNagaraju, CH
dc.date.accessioned2018-07-18T11:41:54Z
dc.date.accessioned2018-07-30T15:13:20Z
dc.date.available2018-07-18T11:41:54Z
dc.date.available2018-07-30T15:13:20Z
dc.date.issued2018-07-18
dc.date.submitted2015
dc.identifier.urihttp://etd.iisc.ac.in/handle/2005/3840
dc.identifier.abstracthttp://etd.iisc.ac.in/static/etd/abstracts/4712/G26995-Abs.pdfen_US
dc.description.abstractFirst section of chapter 1 deals with gold catalyzed synthesis of ring fused furo[3,2,b]pyrans and furo[3,2,b]furans. Furo[3,2,b]pyrans and furo[3,2,b]furans are ubiquitous structural segments found in a number of natural products including polyether containing marine toxins. Synthesis of furo[3,2,b]pyrans 2a was accomplished from the bis-propargyl ethers 1a, while the synthesis of furo[3,2,b]furans 2b was accomplished from the prenyl propargyl ethers 1b. Scheme 1: Synthesis of furo[3,2,b]pyrans and furo[3,2,b]furans Second section of chapter 1 describes an unusual ring-contraction rearrangement route to functionalized 2,8-oxymethano-bridged di and triquinane. During the course of investigations concerning the total synthesis of 6-oxabicyclo[3.2.1]octane framework containing natural products, an unusual ring-contraction rearrangement sequence was observed in the reaction of 5-substituted 1-methyl-4-isopropenyl-6-oxabicyclo[3.2.1]octan-8-ones 4 to the 2,8-oxymethano-bridged diquinanes 5. The reaction was further demonstrated in the synthesis of triquinane 7 framework. Scheme 2: Synthesis of functionalized di and triquinane In third section of chapter 1 gold catalyzed synthesis of isochromanones and isoquinolones from suitable substituted allyl propargyl ethers was discussed. Synthesis of isochromanones and isoquinolones comprising a quaternary center with high diastereoselectivity was realized via AuCl3 catalyzed tandem intramolecular exo-dig heterocyclization/enol isomerization/Claisen rearrangement sequence in excellent yields. The reaction was general and amenable for the synthesis of structurally diverse analogues. Scheme 3: Synthesis of isochromanones and isoquinolones Forth section of chapter 1 consists of gold catalyzed intramolecular hydroalkoxylation assisted ring opening of furans to the corresponding saturated -keto esters. During the course investigations concerning gold catalyzed intramolecular enyne cyclization reactions, an interesting ring opening of furans in furyl propargyl alcohols to the corresponding tetrahydrofuran appended saturated -keto esters exclusively driven by intramolecular hydroalkoxylation of the alkyne was observed. Reaction of furyl propargyl alcohols without free hydroxyl group, under similar conditions afforded the conjugated enynes involving dehydration/ketalization. Scheme 4: Synthesis of saturated -keto esters and enynes Chapter 2 delineates the enantiospecific synthesis of bicyclo[4.2.2]decadienes 15 via gold catalyzed tandem enyne cyclization, semipinacol rearrangement reaction. Bicyclodecadienes are key structural units of natural products nakafuran-8 and pallescensin B. Scheme 5: Synthesis of bicyclo[4.2.2]decadienesen_US
dc.language.isoen_USen_US
dc.relation.ispartofseriesG26995en_US
dc.subjectPolycyclic Systemsen_US
dc.subjectDiquinaneen_US
dc.subjectTriquinaneen_US
dc.subjectIsochromanonesen_US
dc.subjectIsoquinolonesen_US
dc.subjectTandem Enyne Cyclizationen_US
dc.subjectγ-keto Estersen_US
dc.subject.classificationOrganic Chemistryen_US
dc.titleConstruction of Complex Polycyclic Systems using Gold Catalyzed Intramolecular Diyne/Enyne/ Hydroalkoxylation Reactionsen_US
dc.typeThesisen_US
dc.degree.namePhDen_US
dc.degree.levelDoctoralen_US
dc.degree.disciplineFaculty of Scienceen_US


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