WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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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: 1Citation - Scopus: 1Rhodium(i)-Catalyzed Co-Gas Arylative Dual-Carbonylation of Alkynes With Arylboronic Acids Via the Formyl C-H Activation of Formaldehyde(Georg Thieme Verlag, 2021) Morimoto, Tsumoru; Wang, Chuang; Tanimoto, Hiroki; Artok, Levent; Kakiuchi, KiyomiThe rhodium(I)-catalyzed reaction of alkynes with aryl-boronic acids in the presence of formaldehyde results in a CO-gas-free arylative dual-carbonylation to produce gamma-butenolide derivatives. The simultaneous loading of phosphine-ligated and phosphine-free rhodium(I) complexes is required for efficient catalysis. The former complex catalyzes the abstraction of a carbonyl moiety from formaldehyde through the activation of its formyl C-H bond (decarbonylation) and the latter catalyzes the subsequent dual-incorporation of the resulting carbonyl unit (carbonylation). The use of larger amounts of the phosphine-ligated rhodium(I) complex generates more carbonyl units, leading to the formation gamma-butenolides via the dual-incorporation of the carbonyl unit.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: 6Citation - Scopus: 6Palladium-Catalyzed Coupling of 2-En Carbonates With Terminal Alkynes(Elsevier Ltd., 2018) Taç, Doğan; Artok, LeventThe first palladium-catalysed coupling of the carbonates of (E)-configured conjugated enynols with terminal alkynes is described. This method allows the synthesis of vinyl-allenynes with good yields. It has been determined that the method is not suitable for the (Z)-configured substrates.Article Citation - WoS: 13Citation - Scopus: 14Rhodium(i)-Catalyzed Carbonylative Arylation of Alkynes With Arylboronic Acids Using Formaldehyde as a Carbonyl Source(Georg Thieme Verlag, 2014) Wang, Chuang; Morimoto, Tsumoru; Kanashiro, Hiroyuki; Tanimoto, Hiroki; Nishiyama, Yasuhiro; Kakiuchi, Kiyomi; Artok, LeventThe rhodium(I)-catalyzed reaction of alkynes with arylboronic acids in the presence of formaldehyde resulted in a carbon monoxide gas-free carbonylative arylation to yield α,β-enones. The simultaneous loading of phosphine-ligated and phosphine-free rhodium(I) complexes is required for efficient catalysis, which catalyze the abstraction of a carbonyl moiety from formaldehyde (decarbonylation) and its subsequent introduction into the substrate (carbonylation), respectively.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.Article Citation - WoS: 11Citation - Scopus: 2Synthesis of Α,β-Unsaturated Ketones by Rhodium-Catalyzed Carbonylative Arylation of Internal Alkynes With Arylboronic Acids(Georg Thieme Verlag, 2008) Kuş, Melih; Aksın Artok, Özge; Ziyanak, Fırat; Artok, LeventThe Rh-catalyzed reaction of arylboronic acids with internal alkynes under a CO atmosphere in the presence of an acid additive afforded α,β-unsaturated ketones as the major products. Hydroacylation of internal alkynes, except in the case of diaryl acetylenes, proceeded in syn fashion, yielding the E-configured isomer. A mixture of E- and Z-isomers was obtained with diphenyl acetylene. Reactions were also highly regioselective for various nonsymmetric alkynes.Article Citation - WoS: 27Citation - Scopus: 30Rhodium Catalyzed Reaction of Internal Alkynes With Organoborons Under Co Atmosphere: a Product Tunable Reaction(Elsevier Ltd., 2009) Artok, Levent; Kuş, Melih; Aksın, Özge; Dege, Fatma Nurcan; Özkılınç, Fatma YeldaAlkynes react with organoborons under a CO atmosphere in the presence of a rhodium(I) catalyst to afford mainly 5-aryl-2(5H)-furanones, α,β-unsaturated ketones, and indanones. The product selectivity can be tuned by modifying the reaction conditions.Article Citation - WoS: 85Citation - Scopus: 88Effect of Immobilization on Catalytic Characteristics of Saturated Pd-N Carbenes in Mizoroki-Heck Reactions(Elsevier Ltd., 2006) Aksın, Özge; Türkmen, Hayati; Artok, Levent; Çetinkaya, Bekir; Ni, Chaoying; Büyükgüngör, Orhan; Özkal, ErhanA saturated Pd-N-heterocyclic complex was immobilized on an amorphous silica. The complex itself is of very high thermal stability. However, TEM observations, hot filtration, reusability, and poisoning tests all revealed that the complex acted only as a precatalyst to highly active Pd species in Mizoroki-Heck reactions when immobilized. The complex appears more stable when used under homogeneous reaction conditions. The immobilized complex afforded high turnover numbers, 104-105. The higher turnover frequencies were realized at the lower Pd concentrations, which is a characteristic property of ligand-free Pd catalyzed reactions.