Phd Degree / Doktora

Permanent URI for this collectionhttps://hdl.handle.net/11147/2869

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  • Doctoral Thesis
    Synthesis of Vinylallenols Via Palladium-Caralyzed Arylation Reactions of (z)-2,4 Oxiranes With Organoborons
    (Izmir Institute of Technology, 2016) Ziyanak, Fırat; Artok, Levent; Ziyanak, Fırat; Artok, Levent; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    Allenes are important functional groups especially in synthetic organic chemistry. Due to their unique reactivity and high level of chirality transfer, allenes can be used as building blocks in the synthesis of complex molecules. In recent decades transition-metal catalyzed synthesis of allenes with organometallic reagents has become attractive method. For the synthesis of functionalized allenes, addition of different nucleophiles with the help of various transition metals to propargylic compounds bearing a leaving group has been mostly used. Transition metals are crucial for these reactions for shifting them from SN2 to SN2’ for the formation of allenes. Within the context of this research, a novel palladium-catalyzed arylation reactions of (Z)-2,4-enyne oxiranes with organoborons have been investigated. As a result of the 1,5-substitution reaction, aryl-substituted vinylallenes bearing a hydroxyl group on the allylic position (7-aryl-3,5,6-trien-2-ol) were obtained in high yields and diastereoselectivities. We were able to also disclose that Diels-Alder adducts could be obtained with excellent endo and facial selectivities when the vinylallen types of this study were reacted with dienophiles.
  • 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 Technology
    Transformations 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.