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    Asymmetric transfer hydrogenation of alkyl/aryl or alkyl/methyl ketones catalyzed by known C2-symmetric ferrocenyl-based chiral bis(phosphinite)-Ru(II), Rh(I) and Ir(III) complexes
    (Elsevier Science Sa, 2016) Durap, Feyyaz; Karakas, Duygu Elma; Ak, Bunyamin; Baysal, Akin; Aydemir, Murat
    Known Ru(II), Rh(I) and Ir(III) complexes of C-2-symmetric ferrocenyl based chiral bis(phoshinite) ligands were catalyzed the asymmetric transfer hydrogenation of alkyl/aryl or alkyl methyl ketones. Corresponding secondary alcohols were obtained with high enantioselectivities up to 98% ee and reactivities using iso-propanol as the hydrogen source. (C) 2016 Elsevier B.V. All rights reserved.
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    Chiral phosphinites as efficient ligands for enantioselective Ru(II), Rh(I) and Ir(III)-catalyzed transfer hydrogenation reactions
    (Springer, 2017) Baysal, Akin; Karakas, Duygu Elma; Meric, Nermin; Ak, Bunyamin; Aydemir, Murat; Durap, Feyyaz
    Metal-catalyzed enantioselective transfer reduction of ketones to enantiomerically enriched chiral alcohols has recently attracted attention. Therefore, a series of methyl alkyl or alkyl/aryl ketones have been reduced by using Ru(II), Rh(I) and Ir(III) catalysts based on C (2)-symmetric chiral ferrocenyl phosphinite ligands. The corresponding optically active secondary alcohols were obtained in excellent conversions and moderate-to-good enantioselectivities. The best results were obtained with an iridium catalyst, giving up to 98% conversion and 80% ee.
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    The first application of C2-symmetric ferrocenyl phosphinite ligands for rhodium-catalyzed asymmetric transfer hydrogenation of various ketones
    (Elsevier Science Sa, 2015) Ak, Bunyamin; Aydemir, Murat; Durap, Feyyaz; Meric, Nermin; Baysal, Akin
    Homogeneous catalysis has been responsible for many major recent developments in synthetic organic chemistry. The combined use of organometallic and coordination chemistry has produced a number of new and powerful synthetic methods for important classes of compounds in general and for optically active substances in particular. For this aim, a new class of chiral modular C-2-symmetric ferrocenyl phosphinite ligands has been prepared in good yields by using the inexpensive 1,1'-ferrocenedicarboxyaldehyde and various ferrocene based-amino alcohols as starting materials, and applied in the rhodium(I)-catalyzed asymmetric transfer hydrogenation (ATH) of aromatic ketones to give corresponding secondary alcohols with excellent enantioselectivities and reactivities using isoPrOH as the hydrogen source (up to 99% conversion and 99% ee). The substituents on the backbone of the ligands are found to exhibit a remarkable effect on both the activity and % ee. The structures of these ligands and their complexes have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. (C) 2015 Elsevier B.V. All rights reserved.
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    Highly efficient iridium catalysts based on C2-symmetric ferrocenyl phosphinite ligands for asymmetric transfer hydrogenations of aromatic ketones
    (Pergamon-Elsevier Science Ltd, 2015) Ak, Bunyamin; Aydemir, Murat; Durap, Feyyaz; Meric, Nermin; Elma, Duygu; Baysal, Alan
    A series of chiral modular C-2-symmetric ferrocenyl phosphinite ligands have been synthesized in good yields by using 1,1'-ferrocenedicarboxyaldehyde and various amino alcohols as starting materials, and applied in the iridium(III)-catalyzed asymmetric transfer hydrogenations of aromatic ketones to give the corresponding secondary alcohols with good enantioselectivities and reactivities using 2-propanol as the hydrogen source (up to 98% ee and 99% conversion). The substituents on the backbone of the ligands were found to have a significant effect on both the activity and enantiomeric excess. The structures of these complexes have been clarified by a combination of multinuclear NMR spectroscopy, IR spectroscopy, and elemental analysis. (C) 2015 Elsevier Ltd. All rights reserved.
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    New chiral ruthenium(II)-phosphinite complexes containing a ferrocenyl group in enantioselective transfer hydrogenations of aromatic ketones
    (Pergamon-Elsevier Science Ltd, 2013) Ak, Bunyamin; Elma, Duygu; Meric, Nermin; Kayan, Cezmi; Isik, Ugur; Aydemir, Murat; Durap, Feyyaz
    A new and versatile class of unsymmetrical ferrocenyl-phosphinite ligands possessing a stereogenic center has been prepared from commercially available, inexpensive aminoacids such as, D-, L-phenylglycine and D-, L-phenylalanine, through a concise synthetic procedure. These ligands are not very sensitive to air and moisture, and display good enantioselectivities in the ruthenium-catalyzed asymmetric transfer hydrogenation of acetophenone derivatives, in which up to 91% ee was obtained. A comparison of the catalytic properties of amino alcohols and other analogues based on a ferrocenyl backbone is also discussed briefly. The structures of these ligands and their corresponding complexes have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy, and elemental analysis. (C) 2013 Elsevier Ltd. All rights reserved.
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    A new efficient bis(phosphinite)-ruthenium(II) catalyst system for the asymmetric transfer hydrogenation of aromatic ketones
    (Elsevier Science Sa, 2014) Durap, Feyyaz; Aydemir, Murat; Baysal, Akin; Elma, Duygu; Ak, Bunyamin; Turgut, Yilmaz
    Many chiral ligands bearing phosphorus donor atoms were developed and applied in the area of metal catalyzed asymmetric catalysis. A new chiral bis(phoshinite) ligand was successfully synthesized from optically active (1S,8S)-3,6-[N-(S)-alpha-phenylethyl] diaza-1,8-diphenoxymethyl-1,8-octanediol in high yield. A ruthenium(II) complex generated in situ from [Ru(eta(6)-p-cymene)(mu-Cl)Cl](2), bis(phosphinite) ligand and KOH acts as an active catalyst for asymmetric transfer hydrogenation (ATH) of acetophenone derivatives in isopropyl alcohol (IPA) as both solvent and hydrogen source. The catalytic reaction proceeds cleanly to give enantiomerically enriched secondary alcohols up to 90% or 89% ee's at 50 or 82 degrees C, respectively. (C) 2013 Elsevier B. V. All rights reserved.
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    Readily available ferrocenyl-phosphinite ligands for Ru(II)-catalyzed enantioselective transfer hydrogenation of ketones and fabrication of hybrid heterojunctions
    (Elsevier Science Sa, 2014) Ak, Bunyamin; Aydemir, Murat; Ocak, Yusuf Selim; Durap, Feyyaz; Kayan, Cezmi; Baysal, Akin; Temel, Hamdi
    A variety of phosphinite based on ferrocenyl moiety possessing central chirality have been screened as ligands for ruthenium(II)-catalyzed transfer hydrogenation of acetophenone derivatives using iso-PrOH as the hydrogen source to afford the corresponding product, (R) or (S)-1-phenylethanol derivatives with high conversions and good enantioselectivities. These complexes were also employed in the asymmetric reduction of different prochiral ketones (up to 85% ee). A comparison of the catalytic properties of amino alcohols and other analogs based on ferrocenyl backbone is also discussed briefly. The structures of these ligands and their corresponding complexes have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. Furthermore, organic-inorganic hybrid heterojunctions were also fabricated by forming thin films of ruthenium(II) complexes on n-Si and evaporation of Au as front contact. Current-voltage (I-V) characteristics of the structures showed excellent rectification properties. Electrical parameters including ideality factor, barrier height and series resistance were determined using I-V and capacitance-voltage (C-V) data. Finally, photoelectrical properties of the structures were examined by means of a solar simulator with AM1.5 global filter. (C) 2013 Elsevier B.V. All rights reserved.
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    Ruthenium, rhodium and iridium complexes of the furfuryl-2-(N-diphenylphosphino)methylamine ligand: Molecular structure and catalytic activity
    (Pergamon-Elsevier Science Ltd, 2012) Kayan, Cezmi; Meric, Nermin; Aydemir, Murat; Baysal, Akin; Elma, Duygu; Ak, Bunyamin; Sahin, Ertan
    The reaction of furfurylamine with two equivalents of PPh2Cl in the presence of Et3N affords furfuryl-2-(N,N-bis(diphenylphosphino)amine), (Ph2P)(2)NCH2-C4H3O (1). The corresponding ruthenium(II) complex trans-[Ru((PPh2)(2)NCH2-C4H3O)(2)Cl-2] (3) was synthesized by reacting 1 with [Ru(eta(6)-p-cymene)(mu-Cl)Cl](2). The reaction of furfurylamine with one equivalent of PPh2Cl gives Ph2PNHCH2-C4H3O (2). The reaction of 2 with [Ru(eta(6)-p-cymene)(mu-Cl)Cl](2), [Ru(eta(6)-benzene)(mu-Cl)Cl](2), [Rh(mu-Cl)(cod)](2) and [Ir(eta(5)-C5Me5)(mu-Cl)Cl](2) yields the complexes [Ru(Ph2PNHCH2-C4H3S)(eta(6)-p-cymene)Cl-2] (4), [Ru(Ph2PNHCH2-C4H3O)(eta(6-)benzene)Cl-2] (5), [Rh(Pb2PNHCH2-C4H3O)(cod)Cl] (6) and [Ir(Ph2PNHCH2-C4H3O)(eta(5)-C5Me5)Cl-2] (7), respectively. All the complexes were isolated from the reaction solution and fully characterized by analytical and spectroscopic methods. The structure of [Ru(Ph2PNHCH2-C4H3O)(eta(6)-p-cymene)Cl-2] (4) was also determined by single crystal X-ray diffraction. Complexes 3-7 are suitable precursors forming highly active catalysts in the transfer hydrogenation of a variety of simple ketones. Notably, the catalysts obtained by using the ruthenium complexes [Ru(Ph2PNHCH2-C4H3O)(eta(6)-p-cymene)Cl-2] (4) and [Ru(Ph2PNHCH2-C4H3O)(eta(6)-benzene)Cl-2] (5) are much more active in the transfer hydrogenation, converting the carbonyls to the corresponding alcohols in 97-99% yields (TOF <= 300 h(-1)), compared to analogous rhodium and iridium complexes and the trans-Ru(II)-p-cymene bis(phosphino)amine complex. (c) 2012 Elsevier Ltd. All rights reserved.
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    Screening of C2-symmetric chiral phosphinites as ligands for ruthenium(II)-catalyzed asymmetric transfer hydrogenation of prochiral aromatic ketones
    (Elsevier Science Sa, 2013) Elma, Duygu; Durap, Feyyaz; Aydemir, Murat; Baysal, Akin; Meric, Nermin; Ak, Bunyamin; Turgut, Yilmaz
    Metal-catalyzed transfer hydrogenation processes provide a widely-used alternative to direct hydrogenation processes of ketones. As part of an ongoing program, we report enantioselective C-2-symmetric bis(phosphinite)-ruthenium(II) catalytic systems for the transfer hydrogenation of prochiral aromatic ketones. The new catalytic systems can readily be formed under in situ conditions from C-2-symmetric chiral bis(phosphinite) ligands and [Ru(eta(6)-p-cymene)(mu-Cl)Cl](2) in transfer hydrogenation reaction media. These chiral ruthenium catalytic systems serve as catalyst precursors for the asymmetric transfer hydrogenation of acetophenone derivatives in iso-PrOH and giving the corresponding optical active secondary alcohols up to 94% ee. (C) 2013 Elsevier B.V. All rights reserved.