Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Iron-Promoted 1,5-Substitution Reaction of Endocyclic Enyne Oxiranes With Memgbr: a Stereoselective Method for the Synthesis of Exocyclic 2,4,5-Trienol Derivatives(MDPI, 2023) Kuş, Melih; Omur, Cenk; Karaca, Sila; Artok, LeventThe iron-promoted 1,5-substitution reaction of endocyclic oxiranes with MeMgBr yields exocyclic 2,4,5-trienols with high diastereomeric ratios of up to 100:0. However, for the method's success, the oxirane ring must have a trans-configuration. The reactions exhibit strong stereoselectivity concerning the methylation mode and the configuration of the resulting exocyclic double bond. Enantiomerically pure enyne oxiranes can be synthesized through Sharpless asymmetric dihydroxylation and subsequent manipulations. With these reagents, it has been possible to produce exocyclic 2,4,5-trienols in enantiopure forms. Importantly, this process maintains chirality without degradation during the center-to-axis transfer of chirality.Article Citation - WoS: 2Citation - Scopus: 2Palladium-Catalysed Regio- and Stereoselective Arylative Substitution of Gamma,delta-Epoxy Esters and Amides by Sodium Tetraaryl Borates(Royal Society of Chemistry, 2020) Bilgi, Yasemin; Kuş, Melih; Artok, LeventPalladium-catalysed reactions of gamma,delta-epoxy-alpha,beta-unsaturated esters and amides with NaBAr(4)reagents proceeded regio- and stereoselectively, producing allylic homoallyl alcohols with aryl-substituents in the allylic position for a wide range of substrates. AsPh(3)was found to be a competent ligand for the arylation reaction, whereas phosphine ligand/Lewis acidic organoboron combinations favoured the substitution reaction by oxygen nucleophiles (e.g.H2O, ROH).Article Citation - WoS: 6Citation - Scopus: 6Palladium-Catalysed Reactions of Conjugated Enyne Oxiranes With Organoborons: a Diastereoselective Method of the Synthesis of 2,4,5-Trienol Derivatives(Elsevier, 2017) Ziyanak, Fırat; Kuş, Melih; Alkan Karadeniz, Leman; Artok, LeventA palladium-catalysed reaction of conjugated enyne oxiranes with organoboron reagents is described. This method allows aryl-substituted vinylallenes containing a hydroxyl group on the allylic position to be synthesized, with good diastereomeric ratios, under mild conditions.Article Citation - WoS: 9Citation - Scopus: 10Iron-Promoted 1,5-Substitution (sn2' Reactions of Enyne Acetates and Oxiranes With Grignard Reagents(Wiley, 2017) Taç, Doğan; Aytaç, İsmet Arınç; Karatavuk, Ali Osman; Kuş, Melih; Ziyanak, Fırat; Artok, LeventAcetate derivatives of 2-en-4-yne alcohols 1 and enyne oxiranes 4 regioselectively underwent 1,5-substitution (SN2′′) reactions with Grignard reagents in the presence of an iron compound to provide vinylallenes exclusively with the (E)-configuration. An alkali salt was needed to avoid the hydride-promoted reductive 1,5-substitution pathway for 1, whereas no such additive was needed for the effective conversion of 4 into the desired alkylated or arylated vinylallene structure.Article Citation - WoS: 21Citation - Scopus: 21Palladium-Catalyzed Alkoxycarbonylation of Conjugated Enyne Oxiranes: a Diastereoselective Method for the Synthesis of 7-Hydroxy(American Chemical Society, 2015) Kuş, Melih; Artok, Levent; Aygün, MuhittinPalladium-catalyzed alkoxycarbonylative 1,5-substitution of conjugated enyne oxiranes provides 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 π-allylpalladium and σ-vinylallenyl palladium complexes. The major diastereomeric form of the product is determined by the configuration of the alkenyl moiety of the substrate.Article Citation - WoS: 21Citation - Scopus: 21Regio- and Stereoselective Synthesis of 2,3,5-Trienoates by Palladium-Catalyzed Alkoxycarbonylation of Conjugated Enyne Carbonates(American Chemical Society, 2014) Karagöz, Ezgi Şule; Kuş, Melih; Akpınar, Gürkan Eray; Artok, LeventPalladium-catalyzed carbonylation of 2,4-enyne carbonates in an alcohol and under balloon pressure of CO proceeds through 1,5-substitution to yield (E)-2,3,5-trienoates. The olefin geometry of the substrate is important to control the overall stereochemistry of this alkoxycarbonylation method. The reaction proceeds through successive formation of π-allylpalladium with an R3 group oriented syn and σ-allenyl palladium complexes.Article Citation - WoS: 7Citation - Scopus: 7Rhodium-Catalysed Alkoxycarbonylative Cyclisation Reactions of 1,6-Enynes(John Wiley and Sons Inc., 2011) Ziyanak, Fırat; Kuş, Melih; Artok, LeventThe rhodium-catalysed carbonylation of 1,6-enynes possessing an electron-deficient alkenyl moiety in an alcohol reagent in the presence of a rhodium complex proceeded stereo- and chemoselectively to afford exocyclic α,β-enoates.Article Citation - WoS: 14Citation - Scopus: 15Rhodium- and Palladium-Catalyzed 1,5-Substitution Reactions of 2-En Acetates and Carbonates With Organoboronic Acids(American Chemical Society, 2011) Üçüncü, Muhammed; Karakuş, Erman; Kuş, Melih; Akpınar, Gürkan Eray; Aksın Artok, Özge; Krause, Norbert; Karaca, Sıla; Elmaci, Nuran; Artok, LeventTwo methods involving the rhodium-catalyzed reaction of 2-en-4-yne acetates and the palladium-catalyzed reaction of 2-en-4-yne carbonates with organoboronic acids were investigated; both afforded exclusively the (E)-configured vinylallenes. The coordinative interaction of the rhodium with the acetate group promoted the δ-elimination of Rh(I)-OAc from the alkenylrhodium intermediate II in both syn and anti modes, with the syn-elimination being the major path. DFT calculations revealed that a conformer of this intermediate (II), which can lead to the (E)-configured vinylallene product via the syn-elimination mode, is energetically the most favorable conformer. The rhodium-catalyzed procedure is not applicable to reactions involving (E)-configured enyne acetates, because the geometry of the alkenylrhodium intermediate that is derived from the corresponding (E)-enyne acetate would not allow such coordinative interaction to occur. The palladium-catalyzed method, which proceeds through formation of the σ-vinylallenylpalladium intermediate, B, is suitable for both the (E)- and (Z)-configured enyne carbonates and appears to have a wider scope for both organoboronic acids and enyne substrates. The palladium-catalyzed reaction of an enantiomerically enriched enyne carbonate proceeded with racemization.Article Citation - WoS: 37Citation - Scopus: 38Palladium-Catalyzed Alkoxycarbonylation of (z)-2 Carbonates Leading To 2,3,5-Trienoates(American Chemical Society, 2011) Akpınar, G. Eray; Kuş, Melih; Üçüncü, Muhammed; Karakuş, Erman; Artok, LeventPd(0)-catalyzed carbonylation of (Z)-2-en-4-yn carbonates in the presence of a balloon pressure of CO in an alcohol donates vinylallenyl esters with an exclusively E-configuration and in high yields. The fact that no such reactivity could be observed with E-configured enyne carbonates may indicate that the reaction is promoted via the cooperative coordination of palladium with both alkynyl and carbonate moieties.Article Citation - WoS: 15Citation - Scopus: 14Rhodium Catalysed Chemo- and Stereoselective Arylative and Alkenylative Cyclisation Reactions of Unsymmetric Diynes Containing a Terminal Alkyne Moiety With Organoboronic Acids(Royal Society of Chemistry, 2010) Artok, Levent; Kuş, Melih; Ürer, Bağdagül N.; Türkmen, Gülşah; Aksın Artok, ÖzgeUnsymmetric diynes possessing a terminal alkyne moiety reacted with organoboronic acids both chemo- and stereoselectively to afford arylated or alkenylated exocyclic dienes by catalysis from the [Rh(cod)OCH 3] 2 complex. The use of a polar protic solvent, e.g. CH 3OH is required for the success of the process under mild conditions. © 2010 The Royal Society of Chemistry.