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  • 1501.
    Volla, Chandra M. R.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium-Catalyzed Aerobic Domino Oxidative Carbocyclization-Alkynylation of Allenynes2013In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, no 52, p. 14209-14213Article in journal (Refereed)
  • 1502.
    Volla, Chandra M. R.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium-Catalyzed Oxidative Domino Carbocyclization-Arylation of Bisallenes2016In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 6, no 10, p. 6398-6402Article in journal (Refereed)
    Abstract [en]

    Herein we report a highly efficient and site selective palladium-catalyzed oxidative carbocyclization arylation reaction of bisallenes and arylboronic acids under operationally simple conditions for the selective synthesis of cyclohexadiene derivatives. The palladium source and the solvent proved to be crucial for the selectivity and the reactivity displayed. Interestingly, in the absence of the nucleophile, an oxidative carbocyclization-beta-elimination pathway predominates. The reaction conditions are compatible with a wide range of functional groups, and the reaction exhibits broad substrate scope. Furthermore, key information regarding the mechanism was obtained using control experiments and kinetic studies.

  • 1503.
    Volla, Chandra M. R.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium-Catalyzed Oxidative Domino Carbocyclization- Carbonylation-Alkynylation of Enallenes2014In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, no 16, p. 4174-4177Article in journal (Refereed)
    Abstract [en]

    An oxidative carbocyclization-carbonylation-alkynylation reaction cascade has been developed using catalytic amounts of palladium(II) salts. The domino reaction proceeds efficiently, giving the corresponding ynones in good to excellent yields under operationally simple conditions. A wide range of aromatic and aliphatic terminal alkynes with various functional groups are tolerated under the reaction conditions.

  • 1504.
    Volla, Chandra M. R.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mazuela, Javier
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium-Catalyzed Oxidative Carbocyclization-Carbonylation of Allenynes and Enallenes2014In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 25, p. 7608-7612Article in journal (Refereed)
    Abstract [en]

    A highly efficient oxidative carbocyclization-carbonylation reaction cascade of allenynes and enallenes has been developed using a Pd-II salt in low catalytic amounts under ambient temperature and pressure (1 atm of carbon monoxide). The use of DMSO as an additive was found to be important for an efficient reaction. A wide range of alcohols as trapping reagents were used to give the corresponding esters in good yields.

  • 1505. von der Lieth, Claus-Wilhelm
    et al.
    Ardà Freire, Ana
    Blank, Dennis
    Campbell, Matthew P.
    Ceroni, Alessio
    Damerell, David R.
    Dell, Anne
    Dwek, Raymond A.
    Ernst, Beat
    Fogh, Rasmus
    Frank, Martin
    Geyer, Hildegard
    Geyer, Rudolf
    Harrison, Mathew J.
    Henrick, Kim
    Herget, Stefan
    Hull, William E.
    Ionides, John
    Joshi, Hiren J.
    Kamerling, Johannis P.
    Leeflang, Bas R.
    Lütteke, Thomas
    Lundborg, Magnus
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Maass, Kai
    Merry, Anthony
    Ranzinger, René
    Rosen, Jimmy
    Royle, Louise
    Rudd, Pauline M.
    Schloissnig, Siegfried
    Stenutz, Roland
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Vranken, Wim F.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Haslam, Stuart M.
    EUROCarbDB: an open-access platform for glycoinformatics2011In: Glycobiology, ISSN 0959-6658, E-ISSN 1460-2423, Vol. 21, no 4, p. 493-502Article in journal (Refereed)
    Abstract [en]

    The EUROCarbDB project is a design study for a technical framework, which provides sophisticated, freely accessible, open-source informatics tools and databases to support glycobiology and glycomic research. EUROCarbDB is a relational database containing glycan structures, their biological context and, when available, primary and interpreted analytical data from high-performance liquid chromatography, mass spectrometry and nuclear magnetic resonance experiments. Database content can be accessed via a web-based user interface. The database is complemented by a suite of glycoinformatics tools, specifically designed to assist the elucidation and submission of glycan structure and experimental data when used in conjunction with contemporary carbohydrate research workflows. All software tools and source code are licensed under the terms of the Lesser General Public License, and publicly contributed structures and data are freely accessible. The public test version of the web interface to the EUROCarbDB can be found at http://www.ebi.ac.uk/eurocarb.

  • 1506. von Langermann, Jan
    et al.
    Kaspereit, Malte
    Shakeri, Mozaffar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lorenz, Heike
    Hedberg, Martin
    Jones, Matthew J.
    Larson, Kerstin
    Herschend, Bjorn
    Arnell, Robert
    Temmel, Erik
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kienle, Achim
    Seidel-Morgenstern, Andreas
    Design of an Integrated Process of Chromatography, Crystallization and Racemization for the Resolution of 2 ',6 '-Pipecoloxylidide (PPX)2012In: Organic Process Research & Development, ISSN 1083-6160, E-ISSN 1520-586X, Vol. 16, no 2, p. 343-352Article in journal (Refereed)
    Abstract [en]

    An integrated process for the chiral separation of the industrially relevant substance 2',6'-pipecoloxylidide (PPX), an intermediate in the manufacture of a number of anesthetics, was developed. By combining three different techniques, chromatography, crystallization, and racemization, high productivity was achieved. All unit operations were executed using a common solvent system, full recycling, and a minimum of solvent exchanges or removals. The target molecule was obtained with an enantiopurity of >99.5 wt %.

  • 1507.
    Västilä, Patrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Development of highly modular ligands for use in asymmetric transition-metal catalyzed reactions2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The synthesis and evaluation of ligands for use in asymmetric transition metal catalyzed reactions is a widely used concept to achieve improved enantioselectivity in a variety of different transformations. The present thesis decribes the synthesis of a number of different oxazoline-based ligands and their use in titanum-catalyzed addition of diethyl zinc to aliphatic and aromatic aldehydes. Interestingly, the presence of catalytic amounts of titanium in our system was sufficient to achieve effective catalysis in contrast to what has been previously reported concerning titanium-catalyzed addition of diethyl zinc to aldehydes.

    The synthesis and evaluation of a library of novel dipeptide-like ligands are described and these ligands were employed in connection with ruthenium-catalyzed transfer hydrogenation of aromatic ketones. Excellent enantioselectivities and yields were obtained.

    Furthermore, the novel concept of forming the ligand and catalyst in situ in a one-pot system was explored. In addition to significant simplification, this approach resulted in improvements in both enantioselectivity (minor) and reaction rate (2-3 fold) compared to previously studied procedures.

    The surprizing influence of alkali salts on ruthenium-catalyzed transfer hydrogenation involving these dipeptide-like ligands are described and discussed. In the presence of these additives the ruthenium-catalyzed transfer hydrogenation performed with higher enantioselecitvity and reactivity.

    Finally, mechanistic studies concerning ruthenium-catalyzed transfer hydrogenation involving the dipeptide-like ligands are also described and discussed.

  • 1508.
    Västilä, Patrik
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pastor, Isidro
    Adolfsson, Hans
    2-(Aminomethyl)-oxazolines: Highly modular scaffold for the preparation of novel asymmetric ligands2005In: Journal of Organic Chemistry, Vol. 70, no 8, p. 2921-2929Article in journal (Refereed)
  • 1509. Västilä, Patrik
    et al.
    Wettergren, Jenny
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    In situ formation of ligand and catalyst- application in ruthenium-catalyzed enantioselective reduction of ketones2005In: Chemical communications, ISSN 1359-7345, no 32, p. 4039-4041Article in journal (Refereed)
  • 1510.
    Västilä, Patrik
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Wettergren, Jenny
    Adolfsson, Hans
    Ruthenium-catalyzed enantioselective reduction of ketones - in situ formation of ligand and catalystManuscript (Other academic)
  • 1511.
    Västilä, Patrik
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zaitsev, Alexey
    Wettergren, Jenny
    Adolfsson, Hans
    The importance of alkali cations in the ruthenium-catalyzed enantioselective transfer-hydrogenation of ketones - novel mechanistic implicationsManuscript (Other academic)
  • 1512. Västilä, Patrik
    et al.
    Zaitsev, Alexey
    Wettergren, Jenny
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Privalov, Timofei
    Adolfsson, Hans
    The Importance of Alkali Cations in the [{RuCl2(p-cymene)}2]-Pseudo-dipeptide-Catalyzed Enantioselective Transfer Hydrogenation of Ketones2006In: Chemistry - A European Journal, ISSN 0947-6539, Vol. 12, no 12, p. 3218-3225Article in journal (Refereed)
  • 1513.
    Wallin, Richard
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kalek, Marcin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bartoszewicz, Agnieszka
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Thelin, Mats
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stawinski, Jacek
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    On the sulfurization of H-phosphonate diesters and phosphite triesters using elemental sulfur2009In: Phosphorus Sulfur and Silicon and the Related Elements, ISSN 1042-6507, E-ISSN 1563-5325, Vol. 184, no 4, p. 908-916Article in journal (Refereed)
  • 1514.
    Wallner, Olov
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium-Catalyzed Synthesis and Transformations of Organometallic Compounds2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is focused on two important fields of palladium catalysis: the development of electrophilic allylic substitution reactions via bis-allylpalladium intermediates; and application of palladium pincer-complexes in the synthesis and transformations of organometallic compounds.

    Palladium-catalyzed electrophilic allylation of aldehyde and imine substrates could be achieved using readily available allyl chlorides and acetates by employing hexamethylditin or bis(pinacolato)diboron reagents. The reaction proceeds under mild and neutral reaction conditions with high regioselectivity, providing the branched homoallylic products. The stereoselectivity of the reaction depends on the steric and electronic effects of the allylic substituents of the substrates. DFT modeling of the electrophilic attack on the bis-allylpalladium intermediate of the reaction revealed the origin of the regio- and stereoselectivity of the reaction.

    Palladium pincer-complexes were employed as catalysts in a variety of reactions such as stannylation, selenylation, allylation, and cross coupling reactions with various electrophiles. Allylic stannylation in the presence of hexamethylditin was achieved by use of an NCN palladium pincer-complex catalyst. In contrast to the reactions catalyzed by traditional palladium catalysts, isolation of functionalized allyl stannanes was possible due to the special features of the pincer-complex catalyst. Extension of the scope of the palladium pincer-complex catalyzed electrophilic allylation reactions was achieved by using potassium trifluoro(allyl)borate instead of allyl stannanes. In addition, asymmetric electrophilic allylation of sulfonimines was achieved by employment of novel BINOL-based palladium pincer-complexes. The enantioselectivity of the pincer-complex catalyst was fine-tuned by employment of substituted analogs of BINOL.

  • 1515.
    Wallner, Olov A.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Potassium Trifluoro-2-propenylborate2007In: Encyclopedia of Reagents for Organic Synthesis, Wiley , 2007Chapter in book (Refereed)
  • 1516.
    Wallner, Olov
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olsson, Vilhelm J
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Eriksson, L.
    Szabó, Kálmán J
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of New Chiral Pincer-Complex Catalysts for Asymmetric Allylation of Sulfonimines2006In: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 359, no 6, p. 1767-1772Article in journal (Refereed)
    Abstract [en]

    Four new chiral pincer-complexes were prepared based on coupling of BINOL and TADDOL moieties with iodoresorcinol followed by oxidative addition of palladium(0). The X-ray analysis of complex 5a revealed that the BINOL rings form a well-defined chiral pocket around the palladium atom. This chiral environment can be further modified by γ-substitution of the BINOL rings. Preliminary studies for electrophilic allylation of sulfonimine 2 with allylstannane revealed that the presented chiral complexes are promising asymmetric catalysts for preparation of chiral homoallyl amines. The best result was achieved employing catalytic amounts of γ-Me BINOL complex 6 affording homoallyl amine 4 with 59% ee and 74% isolated yield.

  • 1517.
    Wallner, Olov
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J
    Employment of Palladium Pincer-Complexes in Phenylselenylation of Organohalides2005In: Journal of Organic Chemistry, ISSN 0022-3263, Vol. 70, no 23, p. 9215-9221Article in journal (Refereed)
  • 1518.
    Wallner, Olov
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J
    Origin of the Regio- and Stereoselectivity in Palladium-Catalyzed Electrophilic Substitution via Bis-allylpalladium Complexes2003In: Chemistry : a European journal, ISSN 0947-6539, Vol. 9, no 17, p. 4025-4030Article in journal (Refereed)
  • 1519.
    Wallner, Olov
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J
    Palladium Pincer Complex-Catalyzed Allylic Stannylation with Hexaalkylditin Reagents2004In: Organic Letters, ISSN 1523-7060, Vol. 6, no 11, p. 1829-1831Article in journal (Refereed)
  • 1520.
    Wallner, Olov
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J
    Palladium-Catalyzed Electrophilic Allylic Substitution of Allyl Chlorides and Acetates via Bis-allylpalladium Intermediates2003In: Journal of Organic Chemistry, ISSN 0022-3263, Vol. 68, no 7, p. 2934-2943Article in journal (Refereed)
  • 1521.
    Wallner, Olov
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J
    Regioselective Palladium-Catalyzed Electrophilic Allylic Substitution in the Presence of Hexamethylditin2002In: Organic letters, ISSN 1523-7060, Vol. 4, no 9, p. 1563-1566Article in journal (Refereed)
  • 1522.
    Wang, Dong
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    New Reactions with Allyl- and Allenylboron Reagents: Transition-Metal-Catalyzed and Transition-Metal-Free Carbon-Carbon Bond Formation Processes2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Organoboron compounds have been widely used in carbon-carbon bond formation reactions in organic synthesis and catalysis. This thesis is focused on cross-coupling reactions of allyl-, allenylboronic acids and their ester derivatives via transition metal catalysis or transition-metal-free processes.

    The first part of the thesis describes Cu-catalyzed C(sp3)-C(sp3) formation reactions involving allylboronic acids and α-diazoketones. This coupling process shows high γ-regioselectivity, resulting in branched allylic products. When stereodefined cyclic allylboronic acids were employed as the substrate, the relative facial configuration was retained in the reaction product.

    The second part involves Pd-catalyzed cross-coupling of allylboronic acid and α-diazoketones. The reaction proceeds with high α-regioselectivity, affording linear allylic products. Accordingly, the palladium- and copper-catalyzed cross-coupling of allylboronic acid and α-diazoketones occurs with opposite regioselectivity.

    The third part concerns a new transition-metal-free carbon-carbon bond formation between allenylboronic acids and in situ generated diazo compounds. The diazo compounds are generated from tosylhydrazones in the presence of base. The reaction is suitable for synthesis of densely substituted conjugated dienes with high Z-selectivity.

    In the final part, the allylation of quinones with allylboronates is presented. The reaction was performed without any catalyst or additive. Various quinones can be employed as substrates, including unsubstituted, monosubstituted benzoquinones and naphthoquinones.

  • 1523.
    Wang, Dong
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    de Wit, Martin J. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of Densely Substituted Conjugated Dienes by Transition-Metal-Free Reductive Coupling of Allenylboronic Acids and Tosylhydrazones2018In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 83, no 15, p. 8786-8792Article in journal (Refereed)
    Abstract [en]

    Tosylhydrazones and allenylboronic acids underwent a transition-metal-free reductive coupling reaction. This process is suitable for synthesis of tetra- and pentasubstituted conjugated dienes. The corresponding allenyl-Bpin substrate showed a very poor reactivity. The reaction is suggested to involve coupling of the in situ formed diazo compound and allenylboronic acid. The intermediate formed in this coupling undergoes allenyl migration followed by protodeboronation to furnish a conjugated diene as major product.

  • 1524.
    Wang, Dong
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Copper-Catalyzed, Stereoselective Cross-Coupling of Cyclic Allyl Boronic Acids with alpha-Diazoketones2017In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 19, no 7, p. 1622-1625Article in journal (Refereed)
    Abstract [en]

    In this study; we present the synthesis of new, Stereodefined allylboronic adds employed to investigate the stereochemistry of the Cu-catalyzed cross-coupling of allylboronic acids with alpha-diazoketones. According to our results, this reaction proceeds with retention of the relative configurtion of the allylberonic acid substrate. We suggest that the stereoinduction step involves a syn S(E)2'-type transrnetalation of the allylboronic acid substrate with a Cu-carbene species.

  • 1525. Wang, Lei
    et al.
    Duan, Lele
    Stewart, Beverly
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pu, Maoping
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Liu, Jianhui
    Privalov, Timofei
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Licheng
    Toward Controlling Water Oxidation Catalysis: Tunable Activity of Ruthenium Complexes with Axial Imidazole/DMSO Ligands2012In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 45, p. 18868-18880Article in journal (Refereed)
    Abstract [en]

    Using the combinations of imidazole and dimethyl :sulfoxide (DMSO) as axial ligands and 2,2'-bipyridine-6,6'-dicarboxylate (bda) as the equatorial ligand, we have synthesized six novel ruthenium complexes with noticeably different activity as water oxidation catalysts (WOCs). In four C-s symmetric Ru-II(kappa(3)-bda)(DMSO)L-2 complexes L = imidazole (1), N-methylimidazole (2), 5-methylimidazole (3), and 5-bromo-N-methylimidazole (4). Additionally, in two C-2v symmetric Ru-II(kappa(4)-bda)L-2 complexes L = 5-nitroimidazole (5) and 5-bromo-N-methylimidazole (6), that is, fully equivalent axial imidazoles. A detailed characterization of all complexes and the mechanistic investigation of the catalytic water oxidation have been carried out with a number of experimental techniques, that is, kinetics, electrochemistry and high resolution mass spectrometry (HR-MS), and density functional theory (DFT) calculations. We have observed the in situ formation: of a Ru-II-complex with the accessible seventh coordination position. The measured catalytic activities and kinetics of complex 1-6 revealed details about an important structure activity relation: the connection between the nature of axial ligands in the combination and either the increase or decrease of the catalytic activity. In particular, an axial DMSO group substantially increases the turnover frequency of WOCs reported in article, with the ruthenium-complex having one axial 5-bromo-N-methylimidazole and one axial DMSO: (4), we have obtained a high initial turnover frequency of similar to 180 s(-1). DFT modeling Of the binuclear reaction pathway of the O-O bond formation in catalytic Water oxidation further corroborated the concept of the mechanistic significance of the axial ligands and rationalized the experimentally observed difference in the activity of complexes with imidazole/DMSO and imidazole/imidazole combinations of axial ligands.

  • 1526. Wang, Zhen
    et al.
    Jiang, Wenfeng
    Liu, Jianhui
    Jiang, Weina
    Wang, Yu
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Licheng
    Pendant bases as proton transfer relays in diiron dithiolate complexes inspired by [Fe-Fe] hydrogenase active site2008In: Journal of Organometallic Chemistry, ISSN 0022-328X, Vol. 693, no 17, p. 2828-2834Article in journal (Refereed)
  • 1527. Wang, Zhen
    et al.
    Liu, Jian-Hui
    He, Cheng-Jiang
    Jiang, Shi
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Li-Cheng
    Azadithiolates cofactor of the iron-only hydrogenase and its PR3-monosubstituted derivatives: Synthesis, structure, electrochemistry and protonation2007In: Journal of Organometallic Chemistry, ISSN 0022-328X, E-ISSN 1872-8561, Vol. 692, no 24, p. 5501-5507Article in journal (Refereed)
    Abstract [en]

    The core structure (mu-SCH2)(2)NH[Fe-2(CO)(6)](5) of Fe-only hydrogenases active site model has been synthesized by the condensation of iron carbonyl sulfides, formaldehyde and silyl protected amine. Its monosubstituted complexes (mu-SCH2)(2)NH[Fe-2(CO)(5)PR3] (R = Ph (6), Me (7)) were accordingly prepared. The coordination configurations of 5 and 6 were characterized by X-ray crystallography. Protonation of complex 7 to form the N-protonated product occurs in an acetonitrile solution upon addition of triflic acid. The redox properties of these model complexes were studied by cyclic voltammetry.

  • 1528. Wang, Zhen
    et al.
    Liu, Jianhui
    He, Chengjiang
    Jiang, Shi
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Licheng
    Diiron azadithiolates with hydrophilic phosphatriazaadamantane ligand as iron-only hydrogenase active site models: Synthesis, structure, and electrochemical study2007In: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 360, no 7, p. 2411-2419Article in journal (Refereed)
    Abstract [en]

    Three novel complexes (mu-adt)[Fe-2(CO)(5)PTA] (2-PTA), (mu-adt)[Fe-2(CO)(4)PTA(2)](2-PTA(2)) and (mu-adt)[Fe-2(CO)(5)DAPTA] (2-DAPTA), where adt is SCH2N(CH2CH2CH3)CH2S, PTA stands for 1,3,5-triaza-7-phosphaadamantane and DAPTA is 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane, were prepared as the models of the iron hydrogenase active site through controlled CO displacement of (mu-adt)[Fe-2(CO)(6)] with PTA and DAPTA. The coordination configurations of 2-PTA and 2-PTA(2) were characterized by X-ray crystallography. The disubstituted diiron complex 2-PTA(2) features a basal/apical coordination mode, instead of the typical transoid basal/basal configuration. Protonation of three complexes only occurred at the bridging-N atom, rather than at the tertiary nitrogen atom on the PTA or DAPTA ligands. Electrochemical properties of the complexes were studied in acetonitrile or a mixture of acetonitrile and water in the presence of acetic acid, by cyclic voltammetry. The current sensitivity of the reduced species to acid concentration in the presence of H2O is greater than in the pure CH3CN solution.

  • 1529. Wangsell, Fredrik
    et al.
    Gustafsson, Karin
    Kvarnström, Ingemar
    Borkakoti, Neera
    Edlund, Michael
    Jansson, Katarina
    Lindberg, Jimmy
    Hallberg, Anders
    Rosenquist, Asa
    Samuelsson, Bertil
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of potent BACE-1 inhibitors incorporating a hydroxyethylene isostere as central core2010In: European Journal of Medicinal Chemistry, ISSN 0223-5234, E-ISSN 1768-3254, Vol. 45, no 3, p. 870-882Article in journal (Refereed)
    Abstract [en]

    We herein describe the design and synthesis of a series of BACE-1 inhibitors incorporating a P1-substituted hydroxyl ethylene transition state isostere. The synthetic route starting from commercially available carbohydrates yielded a pivotal lactone intermediate with excellent stereochemical control which subsequently could be diversified at the PI-position. The final inhibitors were optimized using three different amines to provide the residues in the P2'-P3' position and three different acids affording the residues in the P2-P3 position. In addition we report on the stereochemical preference of the P1'-methyl substituent in the synthesized inhibitors. All inhibitors were evaluated in an in vitro BACE-I assay where the most potent inhibitor, 34-(R), exhibited a BACE-1 IC50 Value of 3.1 nM.

  • 1530. Wangsell, Fredrik
    et al.
    Nordeman, Patrik
    Savmarker, Jonas
    Emanuelsson, Rikard
    Jansson, Katarina
    Lindberg, Jimmy
    Rosenquist, Asa
    Samuelsson, Bertil
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Larhed, Mats
    Investigation of alpha-phenylnorstatine and alpha-benzylnorstatine as transition state isostere motifs in the search for new BACE-1 inhibitors2011In: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 19, no 1, p. 145-155Article in journal (Refereed)
    Abstract [en]

    Inhibition of the BACE-1 protease enzyme has over the recent decade developed into a promising drug strategy for Alzheimer therapy. In this report, more than 20 new BACE-1 protease inhibitors based on alpha-phenylnorstatine, alpha-benzylnorstatine, iso-serine, and beta-alanine moieties have been prepared. The inhibitors were synthesized by applying Fmoc solid phase methodology and evaluated for their inhibitory properties. The most potent inhibitor, tert-alcohol containing (R)-12 (IC(50) = 0.19 mu M) was co-crystallized in the active site of the BACE-1 protease, furnishing a novel binding mode in which the N-terminal amine makes a hydrogen bond to one of the catalytic aspartic acids.

  • 1531.
    Warner, Madeleine
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hydrogen transfer reactions catalyzed by a cyclopentadienyl ruthenium complex: Mechanistic studies and dynamic kinetic resolution.2010Licentiate thesis, comprehensive summary (Other academic)
  • 1532.
    Warner, Madeleine
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Racemization of Olefinic Alcohols by a Cyclopentadienyl Ruthenium Carbonyl Complex: Study of the Inhibiting Effect of the Carbon-Carbon Double BondManuscript (preprint) (Other academic)
  • 1533.
    Warner, Madeleine
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ruthenium-Catalyzed Hydrogen Transfer Reactions: Mechanistic Studies and Chemoenzymatic Dynamic Kinetic Resolutions2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The main focus of this thesis lies on transition metal-catalyzed hydrogen transfer reactions. In the first part of the thesis, the mechanism for racemization of sec-alcohols with a ruthenium complex, Ru(CO)2Cl(η5-C5Ph5) was studied.

    The reaction between 5-hexen-2-ol and Ru(CO)2(Ot-Bu)(η5-C5Ph5) was studied with the aim to elucidate the origin of the slow racemization observed for this sec-alcohol. Two diastereomers of an alkoxycarbonyl complex, which has the double bond coordinated to ruthenium, were characterized by NMR and in situ FT-IR spectroscopy. The observed inhibition of the rate of racemization for substrates with double bonds provided further confirmation of the importance of a free coordination site on ruthenium for β-hydride elimination. Furthermore, we observed that CO exchange, monitored by 13C NMR using 13CO, occurs with both the precatalyst, Ru(CO)2Cl(η5-C5Ph5), and the active catalytic intermediate, Ru(CO)2(Ot-Bu)(η5-C5Ph5). It was also found that added CO has an inhibitory effect on the rate of racemization of (S)-1-phenylethanol. Both these observations provide strong support for reversible CO dissociation as a key step in the racemization mechanism.

    In the second part of this thesis, Ru(CO)2Cl(η5-C5Ph5) was combined with an enzymatic resolution catalyzed by a lipase, leading to several efficient dynamic kinetic resolutions (DKR). DKR of exocyclic allylic alcohols afforded the corresponding acetates in high yields and with excellent enantiomeric excess (ee). The products were utilized as synthetic precursors for α-substituted ketones and lactones. DKR of a wide range of homoallylic alcohols afforded the products in good to high yields and with high ee. The homoallylic acetates were transformed into 5,6-dihydropyran-2-ones in a short reaction sequence. Furthermore, DKR of a wide range of aromatic β-chloroalcohols afforded the products in high yields and with excellent ee. The β-chloro acetates were further transformed into chiral epoxides.

  • 1534.
    Warner, Madeleine C.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic Aspects on Cyclopentadienylruthenium Complexes in Catalytic Racemization of Alcohols2013In: Accounts of Chemical Research, ISSN 0001-4842, E-ISSN 1520-4898, Vol. 46, no 11, p. 2545-2555Article, review/survey (Refereed)
    Abstract [en]

    Cyclopentadienylruthenium complexes commonly serve as efficient transition metal catalysts in the racemization of alcohols. The combination of the racemization reaction with enzymatic resolution leads to dynamic kinetic resolution (DKR). In DKR, a theoretical yield of 100% is possible, making it a powerful tool for enantioselective synthesis. In this Account, we summarize the most important mechanistic aspects of racemization of alcohols reported over the past decade based on both experimental and computational results. Precatalyst activation is often necessary, either by heating the reaction or by adding an alkoxide-type base. The subsequent alcohol-alkoxide exchange is rapid and introduces the substrate into the catalytic cycle. This exchange requires a free coordination site, which may be created via several different mechanisms. Following alkoxide formation, racemization occurs via beta-hydride elimination and subsequent readdition. In cyclopentadienyldicarbonylruthenium alkoxide complexes, which are 18-electron complexes, researchers originally considered two mechanisms for the creation of the free coordination site required for beta-hydride elimination: a change in hapticity of the cyclopentadienyl ligand from eta 5 to eta 3 and dissociation of a CO ligand. Based on computational and experimental results, we have found strong support for the pathway involving CO dissociation. Researchers had also wondered if the substrate remains coordinated to the metal center (the inner-sphere mechanism) during the hydrogen transfer step(s). Using competition and crossover experiments, we found strong evidence for an inner-sphere mechanism. In summary, we have obtained a detailed picture of the racemization of alcohols by cyclopentadienylruthenium catalysts, leading to the development of more efficient catalytic systems for racemization.

  • 1535.
    Warner, Madeleine C.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Racemization of Olefinic Alcohols by a Carbonyl(cyclopentadienyl)ruthenium Complex: Inhibition by the Carbon-Carbon Double Bond2015In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 11, p. 2388-2393Article in journal (Refereed)
    Abstract [en]

    In this article, racemization of various olefinic sec-alcohols by Ru(CO)(2)((5)-C5Ph5)Cl was investigated. The racemization of three aliphatic sec-alcohols with different chain lengths containing terminal double bonds was studied. A dramatic decrease of the racemization rate was found for these sec-alcohols compared to that of the corresponding saturated substrates. The slow racemization rate of the former alcohols is ascribed to coordination of the double bond to the ruthenium centre, which blocks the free site needed for -hydride elimination. This mechanism was supported by a recent study, in which 5-hexen-2-ol was found to form an alkoxycarbonyl complex having the double bond coordinated to the ruthenium atom. Aliphatic sec-alcohol substrates with a di- or trisubstituted double bond were found to give a lower degree of inhibition of the racemization rate than the substrates with a monosubstituted double bond.

  • 1536.
    Warner, Madeleine C.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Casey, Charles P.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Shvo's Catalyst in Hydrogen Transfer Reactions2011In: BIFUNCTIONAL MOLECULAR CATALYSIS, 2011, p. 85-125Conference paper (Refereed)
    Abstract [en]

    This chapter reviews the use of Shvo's catalyst in various hydrogen transfer reactions and also discusses the mechanism of the hydrogen transfer. The Shvo catalyst is very mild to use since no activation by base is required in the transfer hydrogenation of ketones or imines or in the transfer dehydrogenation of alcohols and amines. The Shvo catalyst has also been used as an efficient racemization catalyst for alcohols and amines. Many applications of the racemization reaction are found in the combination with enzymatic resolution leading to a dynamic kinetic resolution (DKR). In these dynamic resolutions, the yield based on the starting material can theoretically reach 100%. The mechanism of the hydrogen transfer from the Shvo catalyst to ketones (aldehydes) and imines as well as the dehydrogenation of alcohols and amines has been studied in detail over the past decade. It has been found that for ketones (aldehydes) and alcohols, there is a concerted transfer of the two hydrogens involved, whereas for typical amines and imines, there is a stepwise transfer of the two hydrogens. One important question is whether the substrate is coordinated to the metal or not in the hydrogen transfer step(s). The pathway involving coordination to activate the substrate is called the inner-sphere mechanism, whereas transfer of hydrogen without coordination is called the outer-sphere mechanism. These mechanistic proposals together with experimental and theoretical studies are discussed.

  • 1537.
    Warner, Madeleine C.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Nagendiran, Anuja
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bogár, Krisztián
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantioselective Route to Ketones and Lactones from Exocyclic Allylic Alcohols via Metal and Enzyme Catalysis2012In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 14, no 19, p. 5094-5097Article in journal (Refereed)
    Abstract [en]

    A general and efficient route for the synthesis of enantiomerically pure a-substituted ketones and the corresponding lactones has been developed. Ruthenium- and enzyme-catalyzed dynamic kinetic resolution (DKR) with a subsequent Cu-catalyzed alpha-allylic substitution are the key steps of the route. The a-substituted ketones were obtained in high yields and with excellent enantiomeric excess. The methodology was applied to the synthesis of a naturally occurring caprolactone, (R)-10-methyl-6-undecanolide, via a subsequent Baeyer-Villiger oxidation.

  • 1538.
    Warner, Madeleine C.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Shevchenko, Grigory A.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Jouda, Suzan
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bogar, Krisztian
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dynamic Kinetic Resolution of Homoallylic Alcohols: Application to the Synthesis of Enantiomerically Pure 5,6-Dihydropyran-2-ones and delta-Lactones2013In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 41, p. 13859-13864Article in journal (Refereed)
    Abstract [en]

    Dynamic kinetic resolution of various homoallylic alcohols with the use of Candida antarctica lipaseB and ruthenium catalyst 2 afforded homoallylic acetates in high yields and with high enantioselectivity. These enantiopure acetates were further transformed into homoallylic acrylates after hydrolysis of the ester function and subsequent DMAP-catalyzed esterification with acryloyl chloride. After ring-closing metathesis 5,6-dihydropyran-2-ones were obtained in good yields. Selective hydrogenation of the carboncarbon double bond afforded the corresponding -lactones without loss of chiral information.

  • 1539.
    Warner, Madeleine C
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Verho, Oscar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    CO dissociation mechanism in racemization of alcohols by a cyclopentadienyl ruthenium dicarbonyl catalyst2011In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 133, no 9, p. 2820-2823Article in journal (Refereed)
    Abstract [en]

    13CO exchange studies of racemization catalyst (η5-Ph5C5)Ru(CO)2Cl and (η5-Ph5C5)Ru(CO)2(Ot-Bu) by 13C NMR spectroscopy are reported. CO exchange for the active catalyst form, (η5-Ph5C5)Ru(CO)2(Ot-Bu) is approximately 20 times faster than that for the precatalyst (η5-Ph5C5)Ru(CO)2Cl. An inhibition on the rate of racemization of (S)-1-phenylethanol was observed on addition of CO. These results support the hypothesis that CO dissociation is a key step in the racemization of sec-alcohols by (η5-Ph5C5)Ru(CO)2Cl, as also predicted by DFT calculations.

  • 1540. Watcharinyanon, Somsakul
    et al.
    Puglia, Carla
    Göthelid, Emmanuelle
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Moons, Ellen
    Johansson, Lars S.O.
    Molecular orientation of thiol-derivatized tetraphenylporphyrin on gold studied by XPS and NEXAFS2009In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 603, no 7, p. 1026-1033Article in journal (Refereed)
  • 1541. Wei, Wen-Jie
    et al.
    Siegbahn, Per E. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Liao, Rong-Zhen
    Theoretical Study of the Mechanism of the Nonheme Iron Enzyme EgtB2017In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 56, no 6, p. 3589-3599Article in journal (Refereed)
    Abstract [en]

    EgtB is a nonheme iron enzyme catalyzing the C - S bond formation between gamma-glutamyl cysteine (gamma GC) and N-alpha-trimethyl histidine (TMH) in the ergothioneine biosynthesis. Density functional calculations were performed to elucidate and delineate the reaction mechanism of this enzyme. Two different mechanisms were considered, depending on whether the sulfoxidation or the S C bond formation takes place first. The calculations suggest that the S - O bond formation occurs first between the thiolate and the ferric superoxide, followed by homolytic O-O bond cleavage, very similar to the case of cysteine dioxygenase. Subsequently, proton transfer from a second-shell residue Tyr377 to the newly generated iron - oxo moiety takes place, which is followed by proton transfer from the TMH imidazole to Tyr377, facilitated by two crystallographically observed water molecules. Next, the S C bond is formed between gamma GC and TMH, followed by proton transfer from the imidazole CH moiety to Tyr377, which was calculated to be the rate-limiting step for the whole reaction, with a barrier of 17.9 kcal/mol in the quintet state. The calculated barrier for the rate-limiting step agrees quite well with experimental kinetic data. Finally, this proton is transferred back to the imidazole nitrogen to form the product. The alternative thiyl radical attack mechanism has a very high barrier, being 25.8 kcal/mol, ruling out this possibility.

  • 1542. Wellens, Adinda
    et al.
    Garofalo, Corinne
    Nguyen, Hien
    Van Gerven, Nani
    Slättegård, Rikard
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hernalsteens, Jean-Pierre
    Wyns, Lode
    Oscarson, Stefan
    De Greve, Henri
    Hultgren, Scott
    Bouckaert, Julie
    Intervening with urinary tract infections using anti-adhesives based on the crystal structure of the FimH-oligomannose-3 complex2008In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 3, no 4, p. e2040; 1-13Article in journal (Refereed)
  • 1543.
    Wettergren, Jenny
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selective transfer hydrogenations: Catalyst development and mechanistic investigations2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    By generating a library of amino acid-based ligands, pseudo-dipeptides, and combining them with transition metals, we have created selective and efficient ruthenium and rhodium catalysts for the asymmetric transfer hydrogenation of ketones. The ruthenium-catalyzed reaction was studied in detail, and we found that alkali metals play a crucial role for the reactivity and selectivity of the reaction. Furthermore, we have performed kinetic studies on the catalytic system, and the experimental data does neither support the established inner-sphere nor the classical outer-sphere mechanism. Hence, a novel mechanism for the ruthenium-pseudo-dipeptide-catalyzed transfer hydrogenation is proposed. In this unprecedented outer-sphere mechanism, a hydride and an alkali metal ion are transferred from the donor to the ruthenium complex in the rate determining step.

    In addition, the pseudo-dipeptide ligands were employed in the rhodium-catalyzed transfer hydrogenation of aryl alkyl ketones to yield the corresponding alcohols in high yields and excellent enantioselectivities (up to 98% ee). The study revealed that the alkali metals, so important in the ruthenium analogue of the reaction, do not improve the enantioselectivity of the reaction. Deuterium labeling experiments showed that the reaction follows the mono hydridic route.

    Furthermore, a novel method for efficient catalyst screening has been developed. We have demonstrated that ligand synthesis, catalyst formation, and enantioselective catalysis can be performed using an in situ one-pot procedure. The efficacy of the concept was demonstrated in the enantioselective reduction of ketones. In addition to the simplification of the catalyst formation, this approach resulted in improvement of the product ee.

    Finally, the development of a reduction protocol for the transfer hydrogenation of ketones to alcohols without the involvement of transition metal catalysts is described. Using microwave irradiation, a range of ketones was efficiently reduced in high yields using catalytic amounts of lithium 2-propoxide in 2-propanol.

  • 1544.
    Wettergren, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    In Situ Formation of Ligand and Catalyst: Application in Ruthenium-Catalyzed Enantioselective Reduction of Ketones2007In: Regio- and Stereo-Controlled Oxidations and Reductions, Wiley, England , 2007, p. 121-124Chapter in book (Refereed)
  • 1545.
    Wettergren, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Buitrago, Elina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ryberg, Per
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic Investigation on the Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Pseudo-Dipeptides Ruthenium complexes2009In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, no 23, p. 5709-5718Article in journal (Refereed)
    Abstract [en]

    Lithium-powered: A kinetic investigation into the asymmetric transfer hydrogenation of non-activated aryl alkyl ketones, catalyzed by N-Boc-protected -amino acid hydroxyamide ruthenium–arene complexes, has revealed that the reactions proceed through an unprecedented bimetallic outer-sphere mechanism. Under optimized conditions, these catalysts provide access to secondary alcohols in high yields and with excellent enantioselectivities (>99 % ee).

    The combination of N-Boc-protected -amino acid hydroxyamides (pseudo-dipeptides) and [{Ru(p-cymene)Cl2}2] resulted in the formation of superior catalysts for the asymmetric transfer hydrogenation (ATH) of non-activated aryl alkyl ketones in propan-2-ol. The overall kinetics of the ATH of acetophenone to form 1-phenylethanol in the presence of ruthenium pseudo-dipeptide catalysts were studied, and the individual rate constants for the processes were determined. Addition of lithium chloride to the reaction mixtures had a strong influence on the rates and selectivities of the processes. Kinetic isotope effects (KIEs) for the reduction were determined and the results clearly show that the hydride transfer is rate-determining, whereas no KIEs were detected for the proton transfer. From these observations a novel bimetallic outer-sphere-type mechanism for these ATH process is proposed, in which the bifunctional catalysts mediate the transfer of a hydride and an alkali metal ion between the hydrogen donor and the substrate. Furthermore, the use of a mixture of propan-2-ol and THF (1:1) proved to enhance the rates of the ATH reactions. A series of aryl alkyl ketones were reduced under these conditions in the presence of 0.5 mol % of catalyst, and the corresponding secondary alcohols were formed in high yields and with excellent enantioselectivities (>99 % ee) in short reaction times.

  • 1546.
    Wettergren, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Buitrago, Elina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ryberg, Per
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic investigations into the asymmetric transfer hydrogenation of ketones catalyzed by pseudo-dipeptide ruthenium complexes2009In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, no 23, p. 5709-5718Article in journal (Refereed)
  • 1547.
    Wettergren, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bøgevig, Anders
    Portier, Maude
    Adolfsson, Hans
    Ruthenium-Catalyzed Enantioselective Reduction of Electron-Rich Aryl Alkyl Ketones2006In: Advanced Synthesis and Catalysis, ISSN 1615-4150, Vol. 348, no 10-11, p. 1277-1282Article in journal (Refereed)
  • 1548.
    Wettergren, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zaitsev, Alexey
    Adolfsson, Hans
    Rhodium-Catalyzed Asymmetric Transfer Hydrogenation of Aryl Alkyl Ketones Employing Ligands Derived from Amino Acids2007In: Advanced Synthesis and Catalysis, ISSN 1615-4150, Vol. 349, no 17-18, p. 2556-2562Article in journal (Refereed)
  • 1549.
    Wettergren, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zaitsev, Alexey B.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Asymmetric transfer hydrogenation of ketones: development of amino acid derived transition metal catalysts2008In: Abstracts of Papers, 235th ACS National Meeting, New Orleans, LA, United States, April 6-10, 2008, 2008Conference paper (Other academic)
  • 1550.
    Wettergren, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zaitsev, Alexey B.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rhodium-catalyzed asymmetric transfer hydrogenation of aryl alkyl ketones employing ligands derived from amino acids2007In: Advanced Synthesis & Catalysis, ISSN 1615-4150, Vol. 349, p. 2556-2562Article in journal (Refereed)
28293031323334 1501 - 1550 of 1666
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