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Identifier 000417214
Title Ανάπτυξη της πράσινης και βιώσιμης χημείας του διεγερμένου μοριακού οξυγόνου και εφαρμογή της σε συνθετικά προβλήματα
Alternative Title Development of the green and sustainable chemistry of singlet oxygen and its application in synthetic problems
Author Τριανταφυλλάκης, Μύρωνας
Thesis advisor Βασιλικογιαννάκης, Γεώργιος
Reviewer Στρατάκης, Εμμανουήλ
Σμόνου, Ιουλία
Κατερινόπουλος, Χαράλαμπος
Τρικαλίτης, Παντελεήμων
Μήλιος, Κωνσταντίνος
Παυλίδης, Ιωάννης
Abstract In this thesis, 5 new synthetic methodologies initiated by the oxidation of simple furans are presented. Singlet oxygen (1O2) was used as oxidant not only due to the reactivity it exhibits in the particular transformation, but also because of its advantages over alternative reagents that can promote the same reaction. 1O2 is considered the ideal oxidant, as it is characterized by complete atom economy, is abundant, cheap and does not leave any residue, toxic or otherwise. It is therefore fully harmonized with the principles of "green" and sustainable chemistry. In Chapter 2, a methodology for synthesizing 4-methoxy and 4-hydroxy-2- cyclopentenones from substituted furans is described. Oxidation of the furans with photochemically produced 1O2 in MeOH, followed by addition of excess Me2S and a catalytic amount of NaOH afforded 4-methoxy-2-cyclopentenones in good yields and in one synthetic operation. When the addition of base was done in water as a solvent, 4-hydroxy-2-cyclopentenones were isolated as reaction products, again in one synthetic operation. The transformation could also be carried out without the use of any reducing agent when done in water, again leading to 4-hydroxycyclopentenones. An unusual intermediate endoepoxy-bis-hemiacetal was isolated from the last reaction and, consequently, reported for first time in the literature. In Chapter 3, the synthesis of indolizidinones by photooxidation of furylalkylamines is presented. Oxidation of furans, containing a free primary amine group at the 2-alkyl side chain of the furan, with 1O2 followed by addition of excess Me2S led to the formation of unsaturated indolizidinones in one operation. Utilization of methylene blue as a catalyst yielded, in one operation, the further oxidized indolizidinone derivatives. In Chapter 4, the synthesis of octahydroindole derivatives from simple furans is presented. Initial oxidation of 2-substituted furans with 1O2 followed by sequential additions of excess Me2S and a primary amine, led to the formation of 4,5- unsaturated-2-pyrrolidinones. These compounds participated in a [4+2] cycloaddition reaction with α,β-unsaturated aldehydes or ketones affording the corresponding tetrahydropyranpyrrolones in one operation. Dihydroindole derivatives were isolated after an acid catalysed rearrangement and dehydration. In the presence of reducing Et3SiH, the fully reduced octahydroindole derivatives were formed as one diastereomer in the majority of the substrates tested. The synthesis of both octahydroindole and dihydroindole derivatives was also carried out in one synthetic operation starting from simple furans, in an impressive overall transformation. In Chapter 5, the synthesis of substituted 2-oxindoles from simple furans is presented. The tetrahydropyranopyrrolones, which were readily synthesized from substituted furans by a reaction sequence described in Chapter 4, rearranged and aromatized under acidic conditions in the presence of p-chloranil as an oxidant. The transformation afforded substituted 2-oxindoles, which were isolated in very good yields. In Chapter 6 the asymmetric synthesis of bicyclic γ-lactams from simple furans is described. Organocatalytic [3+2] annulation of the 4,5-unsaturated-2- pyrrolidinones, synthesized from simple furans, with activated α, β-unsaturated-β-aryl aldehydes provided the desired compounds in one operation. The diastereoselectivity of the reaction was good and the enantioselectivity was excellent. The relative and absolute stereochemistry of the products was determined by X-ray crystallography and through extensive NMR experiments.
Language Greek
Subject 2-oxindoles
Bicyclic lactams
Διεγερμένο μοριακό οξυγόνο
Δικυκλικές λακτάμες
Issue date 2018-07-20
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses
  Type of Work--Doctoral theses
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