Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Iridium Catalyzed Boration of Dihydroisoquinoline Derivatives(Izmir Institute of Technology, 2022) Yazıcı, Ece; Artok, LeventTransition metal catalyzed borylation reactions have an important place in organometallic chemistry. In recent years, these reactions have been extensively investigated and have become a versatile tool in the synthesis of new organic materials. C-H bonds can be easily transformed into C-B bonds by borylation reactions. In particular, iridium-catalyzed borylation includes significant advances such as mild reaction conditions, additive-free, high efficiency and being in a single step. In this thesis, the borylation of dihydroisoquinolines with a wide range of biological properties was performed for the first time. Investigating the extent of the reaction has led to the development of optimization studies. Besides, the effects of steric and electronic factors on selectivity are also shown. In this new methodology, C3-borylated products with high regioselectivity and yield were formed with the directing effect of the acyl group. The use of AsPh3 as a ligand is critical to the product selectivity of the method. When the reagent scope was investigated, it was determined that the functional group tolerance of the reactions was quite high. Finally, borylated dihydroisoquinolines have been converted into various intermediates by application studies.Master Thesis Palladium Catalyzed Cross Coupling Reactions of Alkenyl Epoxides and Organoboronic Acid Esters(Izmir Institute of Technology, 2018) Eren, Ahmet; Artok, LeventIn organic chemistry, it is a useful method to form a new allylic compounds as a result of 1-3 substitution reactions of allylic compounds which have a good leaving group. These reactions usually require a metal catalyst but one of the most challenging aspects of these applications is the process regio and stereo selectivity for a wide variety of substrate types. Other compounds such as alkenyl epoxides are also useful for 1-3 substitution reactions. An advantage of using alkenyl oxirane compounds is that the oxirane ring is opened in the substitution step to form a hydroxyl group and resulted in the formation of allylic alcohols which are important intermediate product. Metal catalysed and regioselective reactions of terminal alkenyl epoxides with organoborons have been reported in the literature. However, there is no successful method for internal alkenyl oxiranes. Thus, in this study, 1-3 substitution reactions of alkenyl oxiranes were successfully applied, which yielded allylic alcohols with high regio- and stereoselectivity.Master Thesis Palladium-Catalyzed Stereo-Selective 1.2-Addition Reactions of ?,?-Epoxy Esters With Organoborons(Izmir Institute of Technology, 2018) Bilgi, Yasemin; Artok, LeventTransition metal-catalyzed SN2-type addition reactions of allylic compounds having good leaving groups is a valuable reaction procedure in organic chemistry. Vinyl epoxides, as a derivative of allylic compounds, are suitable reagents for substitution reactions with their high reactivity due to the presence of an epoxide ring tensions and a conjugated C-C double bond attached to this ring. The occurrence of a substitution reaction of such reagents over the allylic position allows synthesis of homoallylated alcohols, one of the key building blocks in the synthesis of natural compounds. Organoborans are stable against moisture and air and environmentally friendly compounds and are thought by us to be suitable nucleophiles in these reactions. Within the context of this research, Pd-catalyzed stereo-selective SN2-addition type arylation reactions of γ,δ-epoxy-α,β-unsaturated esters with organoborons were investigated. The reaction mechanism proceeds through formation of π-allylpalladium complex with the help of Pd-AsPh3 combination. The method has enabled to formation of γ-Aryl-δ-hydroxy-α,β-unsaturated esters with high regio- and stereo- selectivity.Master Thesis Coupling Reactions of Enyne Oxiranes With Grignard Reagents(Izmir Institute of Technology, 2016) Aytaç, İsmet Arınç; Artok, LeventLaboratory-synthesized (Z)-2,4-Enyne oxiranes were subjected iron-catalyzed reactions with Grignard reagents. The reactions afforded majorly E-configured vinylallenes with a hydroxyl group on the allylic carbon as the 1,5-(SN2'')-substitution products. However, in some case, along with the desired vinyllallenes products, 1,1- (SN2) and 1,3-substitution (SN2’) by-products were also recovered. Diastereo-selectivity of the method is strictly reliant on the syn/anti mode of the alkylation process. This study provides a new methodology for the synthesis of vinylallenes which are potential building blocks of biological active molecules.Master Thesis Synthesis of Allyl Alcohols by Paladium-Catalyzed 1,3-Substitution Reactions of Alkenyl Epoxides With Organoborons(Izmir Institute of Technology, 2016) Kıbrıs, Erman; Artok, Levent1,3-Substitution reactions of allylic compounds having a good leaving group is a prominent method in Organic Chemistry for the synthesis of new allylic reagents with an exchanged functional group. These reactions usually require the use of metal catalysts and one of the most challenging aspects for these applications is the regio- and stereo-selectivity of the process for a wide range of substrate types. Other compounds such as vinyl epoxides are also acceptable for substitution reactions. An important advantage of using these reagents is that opening of the oxirane ring during the substitution process lead to the generation of a hydroxyl group and as a result affords allyl alcohols which are important intermediaries in organic syntheses. An example of regio-selective metal-catalyzed reactions of vinyl epoxides having a terminal alkenyl group with environmentally benign organoborons was reported in the literature. However, no such success could be achieved with vinyl epoxides with an internal alkenyl group. Therefore, within the context of this method internal vinyl epoxides were successfully subjected to 1,3-substitution reactions with organoborons which yielded arylated allyl alcohols in both a regio- and stereo-selective manner. The method is applicable under quite mild conditions where a palladium-AsPh3 combination is used to activate the process.Master Thesis Thermal and Photodehydrogenation Reactions of Terpenes Over Zeolites(Izmir Institute of Technology, 2003) Tuzcuoğlu, Esra; Artok, LeventIn this thesis study, catalytic activity of cation exchanged (Na+, Li+, Ca2+, K+, Cs+) zeolite Y, especially NaY, and various microporous and mesoporous (Na exchanged, Beta, Mordenite, and NaX, CsNaX, MCM-41, Montmorillonite KSF and amorphous Silica) catalysts was investigated in the dehydrogenation reaction of terpenes to p-cymene.The results suggested that, there are two types of acid sites are present in cation exchanged zeolites from NH4Y, which are Br Bronsted and Lewis sites. a-terpinene, disproportionated by Br Bronsted acid catalysis into 3-p-menthene and p-cymene, and pcymene was also formed by direct dehydrogenation of a-terpinene can possibly occur with the participation of Lewis acid sites in cation exchanged zeolite Y. Best conversion to p-cymene were observed in the NaHY, LiHY and CaHY exchange from NH4Y that have relatively small cations, which more acidic than the larger ones.With the catalysts that have Bronsted acid sites except ion-exchanged zeolite Y, no conversion or only acid catalyzed isomerization reactions occur that shows the Bronsted acidity was not enough to catalyze the dehydrogenation of a-terpinene. Also Lewis acidic character and the structure morphology are the most important factors affecting the conversion. Lewis acidity is influenced from the cation and zeolite type.Master Thesis Acylation of 2-Methoxynaphthalene Over Ion-Exchanged Beta Zeolite(Izmir Institute of Technology, 2002) Kantarlı, İsmail Cem; Artok, LeventFriedel Crafts acylation of 2-Methoxynaphthalene was carried out over various ion-exchanged . zeolites (Mn+., where Mn+: In3+, Zn2+, Al3+, Fe3+, La3+) with various anhydride (acetic, propionic and benzoic anhydrides), or acyl chloride (acetyl, propionyl and benzoyl chlorides) acylating reagents. The results suggested that selectivity towards the 6-substituted products was higher with the larger size anhydrides, propionic and benzoic anhydrides. The metal cation type within the zeolite significantly influenced the extent of conversion and product distribution. That La3+ exchanged zeolite displayed higher selectivity for the 6-position acylated product with anhydrides ascribed mainly to narrowing of channels by the presence of La(OH)2+ ions that leave no room for the formation of more bulky isomeric forms and to enhanced Bronsted acidity of the zeolite. With acyl chlorides, the recovery of ketone products was found to be remarkably low. 1-Acyl-2-methoxynaphthalenes actively underwent deacylation when acyl chlorides were used as the acylation reagent.Master Thesis Palladium-Catalyzed Alkoxycarbonylation Reactions of (e)-2 Carbonates(Izmir Institute of Technology, 2013) Karagöz, Ezgi Şule; Artok, LeventTransition metal-catalyzed carbon-carbon bond formation reactions are well-rounded methods to synthetic organic chemistry. One type of these reactions is the alkoxycarbonylation reactions performed in the presence of a transition metal catalyst, an alcohol and carbon monoxide atmosphere. Investigations on palladium-catalyzed alkoxycarbonylation reaction of allylic compounds leading to β,γ-unsaturated esters have been performed. Moreover propargyl derivatives are prominent reactants for palladium-catalyzed alkoxycarbonylation reactions to yield allene esters which proceed through a σ-allenylpalladium intermediate. Palladium-catalyzed alkoxycarbonylation reaction of some enantio-enriched propargylic derivatives that facilitate unique centre-to-axis chirality transfer is still inadequate and essential. In this study, the palladium-catalyzed alkoxycarbonylation reaction of E-configured 2,4-enyne carbonates which afforded exclusively ester functionalized (E)-configured vinylallenes through the formation of σ-vinylallenylpalladium species was performed. Moreover the chirality transfer of the proposed method was also surveyed over an enantio-enriched E-enyne carbonate.Master Thesis Suzuki Reactions Over Palladium Loaded Y Zeolite(Izmir Institute of Technology, 2002) Bulut Güllübağ, Hatice; Artok, LeventIn this study, the use of Pd(II) loaded NaY type zeolite as a catalyst in the Suzukiinvestigated.For this aim, Pd(OAc)2, and [Pd(NH3)4]Cl2 complexes were loaded into NaY zeolite in order to form an appropriate catalyst system. Pd(NH3)42+ loaded Y type zeolite was calcined to obtain Pd(II) form Pd(OAc)2 loaded Y type zeolite showed high activity in the reactions of 4-iodoanisole and 4-bromoanisole with arylboronic acid. However the reusability which is an important property of heterogeneous catalyst could not be provided, the following studies were continued with Pd(II) loaded Y type zeolite.When, 4-iodo and 4-bromoanisole reactives were used in the presence of Pd(II) loaded Y type zeolite, 60-100% biaryl products were obtained. The amount and type of the base and DMF:H2O ratio have high effects on the yield. In order to prove that the reaction took place in heterogeneous phase, at the end of the reaction Pd analysis of the solution was performed by AAS technique. It was found that the Pd amount in solution was trace.Master Thesis Short-Time Suzuki Reactions of Arly Halides Catalyzed by Palladium-Loaded Nay Zeolite Under Aerobic Conditions(Izmir Institute of Technology, 2006) Durgun, Gülay; Artok, LeventThe palladium-catalyzed Suzuki cross-coupling reaction is a powerful methods used in the synthesis of biaryl compounds.In this study, the Suzuki reactions of aryl bromides and chlorides with arylboronic acid were carried out over a Pd(NH3)42+-loaded NaY type zeolite. On the basis of our results, the Pd(NH3)42+-loaded NaY zeolite was found to be highly active for the Suzuki reactions of wide range of aryl bromides and electron poor aryl chlorides at low Pd concentrations (0.1-0.001mol %Pd), in air and at short times (5-45 minutes). The presence of relatively large amount of zeolite (1-4 g) was crucial for the success of the reactions with aryl chlorides. It was determined that there was a synergistic effect of the water- zeolite pair on the reaction rate.It was found that reactions were catalyzed dissolved palladium species. However,the palladium was largely recovered and only traces of palladium remained within the solution at the end of reaction (<0.8 ppm).