Phd Degree / Doktora
Permanent URI for this collectionhttps://hdl.handle.net/11147/2869
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Doctoral Thesis Metal-Catalyzed Coupling Reactions of Conjugated Enyne Alcohol Derivatives With Organometallics: an Effective Method in Synthesis of Functionalized Vinylallenes(Izmir Institute of Technology, 2016) Taç, Doğan; Artok, Levent; Artok, Levent; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyTransformations of organic compounds using transition metals are common methods in the toolbox of a synthetic chemist. Metal catalyzed C-C couplings are one of the most useful technique in this toolbox. Conjugate addition of soft/hard carbon nucleophiles to form allenes which are synthetically and pharmaceutically key precursors has been of great interest. Within the scope of this thesis functionalized vinylallene derivatives were prepared in two different types of new methods. The first method is Pd/Cu-catalyzed conjugate addition of terminal alkynes on enyne carbonates. The other method is iron-catalyzed conjugate addition of Grignard reagents on enyne acetates. In the case of the former method, alkynyl-substituted vinylallenes (1,3,4-trien-6-yne) were prepared with optimized conditions up to 91% yield in relatively short reaction periods. The optimized conditions of the cross coupling were successfully applied with various types of terminal alkynes and enyne substrates. The latter method involves the synthesis of alkylated vinylallenes with up to 90% yield with proper conditions.Doctoral Thesis Transition Metal Catalayzed 1,5-Substitution Reactions of Conjugated Enyne Oxiranes Leading To Allylic Hydroxy Substituted Vinylallenes(Izmir Institute of Technology, 2015) Kuş, Melih; Artok, Levent; Kuş, Melih; Artok, Levent; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyTransition metal-catalyzed reactions are atom economical and environmentally benign processes, which make them superior to traditional stoichiometric reactions. Transition metal-catalyzed carbonylation reactions of unsaturated systems has become an important methodology for the synthesis of carbonyl containing synthetically valuable compounds. One of these types of reactions is the alkoxycarbonylation of unsaturated systems over transition metals in the presence of alcohol and under CO atmosphere (Scrivanti, et. al. 1998). Pionering works on palladium-catalyzed alkoxycarbonylation of allylic and propargylic systems with a leaving group at an apropriate positions leading to β,γ-unsaturated and allene esters, respectively have been established by several research groups (Tsuji, et al. 2004). Recently, Artok and co-workers developed new methods for the construction of functionalized vinylallene esters via palladium-catalyzed alkoxycarbonylation of 2,4-enyne carbonates (Akpınar, et al. 2011). After tuning the reaction conditions precisely, the methodology could be improved to allow a high degree of center-to-axial chirality transfer (Karagöz, et al. 2014). Within the context of this study, palladium-catalyzed alkoxycarbonylative 1,5-substitution of conjugated enyne oxiranes was also found to provide a diastereoselective route to (E)-configured 7-hydroxy-2,3,5-trienoates. The reactions proceeded in a highly stereoselective manner, possibly through sequential formation of -allylpalladium and -vinylallenyl palladium complexes. The major diastereomeric form of the product was determined by the configuration of the alkenyl moiety of the substrate.