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  • 1.
    Abdelhamid, Hani
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wilk-Kozubek, Magdalena
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Ahmed, M. El-Zohry
    Valiente, Alejandro
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bermejo-Gomez, Antonio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mudring, Anja-Verena
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Luminescence Properties for a Family of Highly Stable Lanthanide Metal-Organic FrameworksManuscript (preprint) (Other academic)
  • 2.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Transition metal-catalyzed epoxidation of alkenes2010In: Modern Oxidation Methods / [ed] Jan-Erling Bäckvall, Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA , 2010, 2, p. 37-84Chapter in book (Other academic)
  • 3.
    Adrian Meredith, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Björklund, Catarina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Edlund, Michael
    Jansson, Katarina
    Lindberg, Jimmy
    Vrang, Lotta
    Hallberg, Anders
    Institutionen för läkemedelskemi, Uppsala universitet.
    Rosenquist, Åsa
    Samuelsson, Bertil
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Design and Synthesis of BACE-1 Inhibitors Containing a New Hydroxyethylene (HE) Scaffold: Potent activities in a cellular assayManuscript (preprint) (Other academic)
    Abstract [en]

    In a preceding report from our group we disclosed the development of a novel HE transition state isostere with a difluorophenoxymethyl side chain in the P1 position and a methoxy group in the P1’ position furnishing highly potent inhibitors of BACE-1 (i.e. lead compound 1), which moreover exhibit very promising selectivity over cathepsin D. In a continuation of this work with the aim at improving on the cell-based activity and pharmacokinetic properties, we have further developed the SAR for the P1 side chain of inhibitor 1 whereby the P1 side chain oxygen has been substituted for an amine, a carbon or a bond. The chemistry developed for the previous HE inhibitor structure 1 has now been extended to readily accommodate the introduction of new P1 side chains into this new HE scaffold. These modifications have given rise to several highly potent inhibitors where the most potent displayed a BACE-1 Ki value of 0.2 nM and a cell-based Aβ40 IC50 value of 9 nM. Thus, regarding the enzyme inhibition in the cell assay a more than 600-fold improvement compared to compound 1 was achieved via minor structural alterations.

  • 4.
    Ahlford, Katrin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rhodium-catalyzed asymmetric transfer hydrogenation of ketones. Ligand development and mechanistic investigation2008Licentiate thesis, comprehensive summary (Other academic)
  • 5.
    Ahlford, Katrin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ryberg, Per
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Nordin, Mikael
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic investigation of enantioswitchable catalysts for asymmetric transfer hydrogenation2010In: Abstracts of Papers, 239th ACS National Meeting, San Francisco , CA, United States, March 21-25, 2010, Washington: American Chemical Society , 2010Conference paper (Other academic)
  • 6.
    Ahlsten, Nanna
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Transition metal-catalysed enol formation from allylic alcohols: Isomerisation, C−C and C−F bond formations 2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes the isomerisation of allylic alcohols into enols and enolates catalysed by transition metal complexes. The transformation has been used to prepare both unsubstituted and α-substituted carbonyl compounds. Significant attention has been given to the mechanistic aspects of the reactions.

    In the first part of this thesis, an environmentally benign procedure for the redox isomerisation of allylic alcohols into ketones is described. The reaction takes place in water and at room temperature using a cationic rhodium complex in combination with water-soluble phosphines. A variety of allylic alcohols could be isomerised in high yields using this procedure.

    The second part describes the combination of an allylic alcohol isomerisation with a C−C bond formation, catalysed by a rhodium complex. In this way, allylic alcohols were coupled with aldehydes and N-tosyl imines forming aldol and Mannich-type products. In addition, homoallylic and bishomoallylic alcohols were for the first time isomerised into the corresponding enolates and coupled using this methodology.

    In the third part of this thesis, the isomerisation of allylic alcohols was coupled with a C−F bond formation using an iridium complex and electrophilic fluorinating reagents. This novel transformation was used to convert allylic alcohols into single regioisomers of α-fluoroketones. The reaction is tolerant to air and water and takes place at room temperature.

    All of the reactions described take place under mild conditions, are operationally simple, and utilise catalysts formed in situ from commercially available metal complexes and ligands.

  • 7.
    Ahlsten, Nanna
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Transition metal-catalysed isomerisation of allylic alcohols: Applications to C−C, C−F and C−Cl bond formation2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The focus of this thesis has been to develop selective and atom-economical methods for carbon-carbon and carbon-heteroatom bond formation, and to some extent improve on existing findings in this area. More specifically, methods for the catalytic generation of enolates from allylic alcohols and their in situ functionalisation with electrophilic reagents are described.  

    In the first part of this thesis, a method for the Rh-catalysed redox-isomerisation of allylic alcohols into carbonyl compounds under environmentally benign conditions is described. The reaction takes place at room temperature, in the absence of acids or bases, using water as the only solvent, and it is applicable to both primary and secondary allylic alcohols.

    The second part describes the combination of an isomerisation reaction of allylic alcohols with a C−C bond formation, catalysed by a rhodium complex. In this way, allylic alcohols were coupled with aldehydes and N-tosylimines to give aldol and Mannich-type products. In addition to allylic alcohols, homoallylic and bishomoallylic alcohols could be used as enolate precursors, and this is the first report where the latter two substrate types have been used in such a reaction.       

    In the remaining parts of the thesis, an iridium-catalysed isomerisation of allylic alcohols has been combined with an electrophilic halogenation step to provide a conceptually new method for the synthesis of α-halogenated carbonyl compounds. In this way, α-fluoro and α-chloroketones have been synthesised as single constitutional isomers, with the regiochemistry of the final products determined by the position of the double bond in the allylic alcohols. The reactions are tolerant to air, run in water-organic solvent mixtures, and proceed at room temperature.

  • 8.
    Ahlsten, Nanna
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bermejo-Gómez, Antonio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of α-chlorinated ketones and aldehydes: Iridium-catalyzed tandem 1,3-H shift/chlorination of allylic alcoholsManuscript (preprint) (Other academic)
  • 9.
    Ahlsten, Nanna
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rhodium-catalysed coupling of allylic, homoallylic, and bishomoallylic alcohols with aldehydes and N-tosylimines2010In: Abstracts of Papers, 239th ACS National Meeting, San Francisco, CA, United States, March 21-25, 2010, American Chemical Society , 2010Conference paper (Other academic)
  • 10.
    Alam, Rauful
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium-catalyzed Allylic C-H and C-OH Functionalization. Reactions of the Obtained Allylboronic Acids2014Licentiate thesis, monograph (Other academic)
    Abstract [en]

    This thesis is focused on the studies of two major transformations. The first transformation deals with the development of palladium-catalyzed selective allylic trifluoroacetoxylation reactions based on C-H functionalization, whereas the second comprises the synthesis and isolation of allylboronic acids using diboronic acid B2(OH)4 as boron source. Both reactions proceed with a very high regio- and stereoselectivity. The mechanistic studies of the allylic C-H trifluoroacetoxylation indicate that the reaction proceeds via (η3-allyl)palladium intermediate.

    The reactivity of the allylboronic acids was studied with ketone and imine substrates. Unlikeother boronates (such as allyl-Bpin derivatives), allylboronic acids react with ketones and imines without any additives under neutral and mild conditions (typically at room temperature). The regio- and stereoselectivity of this reaction is remarkably high. Using functionalized allylboronic acids (prepared in the above mentioned Pd-catalyzed reactions) homoallylic alcohols and amines with adjacent tertiary and quaternary centers could be obtained with high selectivity. Interestingly, both the ketones and the imines reacted with anti-stereoselectivity. This was surprising for the imines. Our mechanistic study has shown that the acyclic aldimines undergo cis/trans isomerization prior to the allylation reaction.

  • 11.
    Ali, Tara
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Structural Studies of O-Polysaccharides from Diarrhoeal Escherichia coli2007Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis describes the structural analysis of O-polysaccharides from the Gram-negative bacterium Escherichia coli that is a diarrhoeal pathogen. The Escherichia coli serotypes investigated were O178, O171, O166 and O128. The methods used in these studies were nuclear magnetic resonance spectroscopy and component analysis.

    All analysed serotypes had pentasaccharide repeating units. E. coli strain O128 and O166 was shown to have the topology of four carbohydrate residues in the backbone while the 5-residue backbone is found in E. coli O178 and O171.

    The biological repeating units have been determined for the analysed polysaccharides and it was shown that all of the serotypes studied had a 3-substituted N-acetylgalactosamine residue at the reducing end. From this it was deduced that the terminal end of E. coli O171 and O128 have sialic acid and blood type antigens, respectively. This should make E. coli O171 and O128 less recognizable to the immune system as a foreign invader. This can result in that E. coli O171 and O128 may evade the immune system more easily.

  • 12.
    Alpe, Marianne
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of oligosaccharides related to the capsular polysaccharides of Streptococcus pneumoniae serotype 9 and of Cryptococcus neoformans2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the present investigation, synthesis of oligosaccharides corresponding to structural elements present in the capsular polysaccharides of Streptococcus pneumoniae and Cryptococcus neoformans has been achieved. The first two sections describe the synthesis of spacer-equipped oligosaccharides corresponding to structures from the CPS of Streptococcus pneumoniae serotypes 9N, 9A and 9L, the production of which involved synthetic challenges such as the construction of β-ManNAc and α-GlcA linkages. The former challenge was met by employing azide displacement of a 2-O-triflate substituent on a β-glucoside, whereas the latter task was accomplished utilizing thioethyl glucuronic acid donors in the presence of various promoters. The pentasaccharide product obtained correspond to the complete repeating unit of the CPS of serotype 9A.

    The last two sections of this thesis describe the construction of thioglycoside di- and trisaccharide building blocks containing α-Man, β-Xyl, β-GlcA and 6-O-acetyl motifs, as well as subsequent assembly of these building blocks into oligosaccharides corresponding to the repeating units of the capsular polysaccharide of the yeast Cryptococcus neoformans. The GlcA moiety was introduced via trichloroacetimidate coupling involving the peracetylated glucuronic acid methyl ester donor, after which the subsequent necessary benzylation was performed with the di- and trisaccharides. All of the target oligosaccharides were synthesized as amino-spacer glycosides in order to make conjugation to a carrier protein possible.

  • 13.
    Anderlund, Magnus F.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Högblom, Joakim
    Shi, Wei
    Huang, Ping
    Eriksson, Lars
    Weihe, Högni
    Styring, Stenbjörn
    Åkermark, Björn
    Magnuson, Ann
    Synthesis, Structure and Redox Chemistry of a Dinuclear Manganese Complex with a Novel Unsymmetric N5O2 LigandManuscript (Other academic)
  • 14.
    Angles d'Ortoli, Thibault
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mobarak, Hani
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ståhle, Jonas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hamark, Christoffer
    Fontana, Carolina
    Engström, Olof
    Apostolica, Patricia
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Complete 1H and 13C NMR chemical shift assignments of mono- to tetrasaccharides as basis for NMR chemical shift predictions of oligo- and polysaccharides using the computer program CASPERManuscript (preprint) (Other academic)
  • 15.
    Aydin, Juhanes
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Fine-tuning of the catalytic activity and selectivity of palladium pincer complexes2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is focused on optimization of the catalytic properties of so-called pincer complexes. This work involved synthesis of a large variety of palladium pincer complexes, which were applied in various organic transformations. Optimization of the catalytic properties (also called fine-tuning) was directed to increase the catalytic activity as well as the chemo- and stereo-selectivity of the complexes. This could be achieved by varying the heteroatoms in the terdentate pincer ligand, by changing the electronic properties of the coordinated aryl moiety and by implementing chiral functionalities in the pincer complexes.

    In the cross-coupling reaction of vinyl epoxides and aziridines with organoboronic acids the chemoselectivity of the reaction could be increased by employment of pincer complexes instead of commonly used palladium(0) catalysts. Furthermore, application of a methoxy substituent in the aromatic subunit of the complex considerably increased the activity of the pincer complex catalyst.

    Fine-tuning of the stereoselectivity in electrophilic allylation reactions was achieved using a wide variety of BINOL and biphenanthrol based pincer complexes. The synthesis of these highly stable chiral palladium complexes was accomplished by using an efficient modular approach. The highest enantioselectivity (85% ee) was obtained by applying biphenanthrol based pincer complexes.

    We have presented the first palladium pincer complex catalyzed condensation of sulfonimines with isocyanoacetate. Variation of the heteroatoms in the terdentate ligand of the complex strongly influenced the stereoselectivity of the catalytic transformation. The highest stereoselectivity was obtained by using phosphine based pincer complexes. We have also succeeded to isolate and fully characterize the key intermediate of this reaction.

  • 16.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Senthil Kumar, Kuppusamy
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic studies of the palladium pincer complex-catalyzed condensation of sulfonimines and isocyanoacetate to imidazoline derivatives2008In: Abstracts of Papers, 235th ACS National Meeting, New Orleans, LA, United States, April 6-10, 2008, 2008Conference paper (Other academic)
  • 17.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantioselective palladium pincer complex catalyzed carbon carbon coupling reactions between tosylimines and various nucleophiles2008In: Abstracts of Papers, 236th ACS National Meeting, Philadelphia, PA, United States, August 17-21, 2008, Washington, DC: American Chemical Society , 2008Conference paper (Other academic)
  • 18.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic considerations for the enantioselective palladium pincer complex catalyzed carbon-carbon coupling reactions2008In: Abstracts of Papers, 236th ACS National Meeting, Philadelphia, PA, United States, August 17-21, 2008, Washington, DC: American Chemical Society , 2008Conference paper (Other academic)
  • 19.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Wallner, Olov A.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olsson, Vilhelm J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Application of BINOL based pincer-complexes for palladium-catalyzed transformations2007In: Abstracts of Papers, 233rd ACS National Meeting, Chicago, IL, United States, March 25-29, 2007, 2007Conference paper (Other academic)
  • 20.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Wallner, Olov A.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olsson, Vilhelm J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium pincer complex catalyzed asymmetric transformations of sulfonimines2007In: Abstracts of Papers, 233rd ACS National Meeting, Chicago, IL, United States, March 25-29, 2007, 2007Conference paper (Other academic)
  • 21.
    Ayesa, Susana
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Maltseva, Tatiana
    Rakos, Laszlo
    Hamelink, Elisabeth
    Classon, Björn
    Samuelsson, Bertil
    Investigation of Allylic Alcohols in the P1 Position of Inhibitors of Hepatitis C Virus NS3 ProteaseManuscript (Other academic)
  • 22. Back, Marcus
    et al.
    Nyhlén, Jonas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kvarnström, Ingemar
    Rosenquist, Åsa
    Samuelsson, Bertil
    Design, synthesis and SAR of potent statin-based β-secretase inhibitors: Exploration of P1 phenoxy and benzyloxy residues2007Conference paper (Other academic)
  • 23.
    Balan, Daniela
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    The three-component aza-Baylis-Hillman reaction: development and application2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The current thesis presents the optimization and generalization of the Baylis-Hillman reaction applied to in situ generated imines, i.e. a three-component aza- Baylis-Hillman reaction. We found that the title reaction proceeds most efficiently in the presence of a combination of catalysts, i.e. 3-hydroxyquinuclidine (0.15 equiv) and titanium isopropoxide (0.02 equiv), together with molecular sieves (4 Å; activated powder; 200 mg/mmol substrate) at ambient temperature.

    Our study of the scope and limitations of this reaction, revealed that arylaldehydes and sulfonamides are the only imine precursors which both generate the corresponding imines in situ and facilitate a further reaction with the Michael acceptor in a Baylis-Hillman fashion. Among the Michael acceptors tested, acrylates and acrylonitrile demonstrate high reactivity, while acrylamides and β-substituted acrylates do not participate in the reaction.

    The optimized conditions applied to the above range of substrates results in good-to-excellent yields of the desired amine-products (53-94%) and very high chemoselectivity (83- >99%). Furthermore, the reaction times observed under these conditions are considerably shorter than those previously reported for the aza-Baylis-Hillman reaction.

    In the development of a stereoselective version of the title reaction, the use of a chiral catalyst proved to be most effective. Thus, an enantiomeric excess up to 74% can be obtained with β-Isocupreidine. With chiral imine precursors or chiral acrylates, the diastereoselectivity attained was poor. No asymmetric induction was observed when chiral Lewis acids were employed as a co-catalyst.

    The α-methylene-β-amino acid derivatives obtained via the three-component aza-Baylis-Hillman reaction were subjected to further transformation. Carbon chain elongation at the olefinic end of the amine-adduct was attempted. For this purpose, the Miyaura borylation protocol could be successfully applied. The subsequent Suzuki-type cross-coupling reaction resulted predominantly in hydrolysis of the boronate intermediate, together with formation of the amine-adduct via β-hydride elimination. The optimal conditions for this latter reaction remain to be found.

    Finally, 2,5-dihydropyrroles have been synthesized from aza-Baylis-Hillman adducts, via a short and efficient route in which the key step is a microwave-assisted ring-closing metathesis of the N-allylated amine-adducts.

  • 24.
    Bartholomeyzik, Teresa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Investigation of Selectivity in Palladium-Catalyzed Oxidative Arylating Carbocyclization of Allenynes.Manuscript (preprint) (Other academic)
  • 25.
    Bartholomeyzik, Teresa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium(II)-Catalyzed Oxidative Carbocyclization/Functionalization of Allenynes2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The selective formation of carbon-carbon bonds constitutes a key transformation in organic synthesis with useful applications in pharmaceutical or material industry. A particularly versatile tool for carbon-carbon as well as carbon-heteroatom bond formation is palladium catalysis, which allows for mild and selective routes even towards complex structures.

    The work in this thesis describes the development and the mechanistic investigation of a palladium(II)-catalyzed oxidative carbocyclization/functionalization methodology, which converts 1,5-allenynes into either arylated or borylated carbocycles. To this end, either boronic acids or B2pin2 are employed and 1,4-benzoquinone serves as the stoichiometric oxidant. These protocols provide access to two products, a cyclic triene and a cyclic vinylallene. Their formation is dependent on the substrate structure as the latter product requires a propargylic C–H bond to be present in the substrate. Based on kinetic isotope effects, mechanisms involving either an initial allenic or propargylic C–H abstraction, respectively, were proposed. Full control of product selectivity to give either trienes or vinylallenes was achieved by modifying the reaction conditions with additives. Using substoichiometric amounts of BF3·OEt2 leads selectively to borylated or arylated vinylallenes. Under arylating conditions the reaction is zero order in allenyne and oxidant, and first order in phenylboronic acid. Transmetalation and, to some extent, propargylic C–H cleavage were found to be turnover-limiting. The selective reaction towards functionalized trienes was achieved by addition of either substoichiometric LiOAc·2H2O (borylation) or excess amounts of H2O (arylation). For the latter case, a kinetic study revealed an unusually slow catalyst activation. Lower concentrations of H2O gave product mixtures, and it was shown that vinylallenes are formed with either boronic acid or boroxine, whereas the formation of trienes requires boronic acid.

  • 26.
    Bartholomeyzik, Teresa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium(II)-Catalyzed Oxidative Carbocyclization/Functionalization of Allenynes2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Palladium catalysis has emerged as an outstanding tool in synthetic organic chemistry for the mild and selective formation of carbon-carbon and carbon-heteroatom bonds. This thesis has been directed towards the extension of palladium(II)-catalyzed carbocyclization chemistry under oxidative conditions. An oxidative carbocyclization/functionalization methodology utilizing boron-containing transmetalation reagents was exploited to convert 1,5-allenynes into either arylated or borylated carbocycles. Two protocols were developed that use minimal amounts of Pd(OAc)2, stoichiometric para-benzoquinone as the oxidant and either bis(pinacolato)diboron or different arylboronic acids under mild conditions. A wide substrate scope is applicable to both methods. When the allenyne substrate bears a propargylic hydrogen, two isomeric functionalized carbocycles can be formed. By controlling the reaction conditions the reaction can be directed towards either of these two isomeric products. Kinetic isotope effect studies suggest that the mechanism leading to the different products proceeds through allylic or propargylic C-H bond cleavage, respectively. Moreover, it was observed that water has an interesting effect on the product selectivity when arylboronic acids are used in the oxidative carbocyclization of allenynes.

  • 27.
    Bartholomeyzik, Teresa
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Deng, Youqian
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selective Palladium-catalyzed oxidative carbocyclization of allenynes2013In: Abstracts of Papers of The American Chemical Society, American Chemical Society (ACS), 2013Conference paper (Other academic)
  • 28.
    Bartholomeyzik, Teresa
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pendrill, Robert
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Jiang, Tuo
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Complex Kinetics in a Palladium(II)-Catalyzed Oxidative Carbocyclization: Untangling of Competing Pathways, Pre-Catalyst Activation, and Product MixturesManuscript (preprint) (Other academic)
  • 29.
    Bartoszewicz, Agnieszka
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Building molecular complexity via tandem Ru-catalyzed reactions of allylic alcohols2009Licentiate thesis, comprehensive summary (Other academic)
  • 30.
    Bartoszewicz, Agnieszka
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kalek, Marcin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stawinski, Jacek
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of nucleoside phosphorothio-, phosphorodithio- and phophoroselenoate diesters via oxidative esterification of the corresponding H-phosphonate analogues2008In: Collection Symposium Series, Vol. 10, 2008, p. 219-223Conference paper (Other academic)
  • 31.
    Bermejo-Gómez, Antonio
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ahlsten, Nanna
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of 4,5-disubstituted 2-amino-1,3-thiazoles from α,β-unsaturated ketones: Preparation of 5-Benzyl-4-methyl-1,3-thiazol-2-amine hydrochlorideManuscript (preprint) (Other academic)
  • 32.
    Björklund, Catarina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Design and Synthesis of BACE-1 Inhibitors: Novel Compounds Targeting an Aspartic Protease Important in the Pathogenesis of Alzheimer’s Disease2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the design and synthesis of protease inhibitors targeting the aspartic protease BACE-1 (β-site APP cleaving enzyme-1), an enzyme important in the pathogenesis of Alzheimer’s disease. The inhibitors are evaluated with respect to inhibition data, in a structure-activity relationship part.

    Alzheimer’s disease is a disabling, progressive and ultimately fatal form of dementia afflicting approximately 40 percent of the population over 80 years, with over 30 million people suffering from Alzheimer’s disease worldwide. This makes Alzheimer’s disease the most common form of dementia. The identification of the amyloid-β peptide (Aβ) as the main constituent of extracellular plaques, which characterize Alzheimer’s disease, suggests that Aβ plays a vital role in the pathology of Alzheimer’s disease. The formation of Aβ occurs when amyloid-β precursor protein (APP) is cleaved by β-secretase (BACE-1) and γ-secretase, which differ in length by 39-42 amino acids. This suggests that β-secretase is a suitable target for the development of therapeutics against Alzheimer’s disease.

    The synthetic work of this thesis comprises development of BACE-1 inhibitors containing a hydroxyethylene (HE) central core transition state isostere. The target molecules were readily synthesized from chiral carbohydrate starting materials. Highly potent inhibitors were produced by varying the substituents coupled to the HE central core. Selecting an aryloxymethyl P1 side-chain and a methoxy P1’ side-chain resulted in exceptionally potent BACE-1 inhibitors that also exhibit high selectivity over cathepsin D. In a further development, the ether oxygen linkage in the P1 side-chain was removed, resulting in a carba analogue, providing improved potency in a cell-based assay.

  • 33.
    Bogár, Krisztián
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthetic Transformations via Metal- and Enzyme-Catalyzed Dynamic Kinetic Resolution2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the preparation of a new half-sandwich type ruthenium(II)- catalyst for racemization of optically active secondary alcohols and the development of a highly efficient method in combination with lipases such as Candida antarctica lipase B and Pseudomonas cepacia lipase for dynamic kinetic resolution of various functionalized alcohols under mild reaction conditions.

    It was shown that the RuCl(CO)25-C5Ph5) complex can racemize optically active aliphatic and aromatic secondary alcohols at room temperature in rather short times. Different parameters, such as the nature of the catalyst, catalyst loading and solvent effect were studied. After the optimization steps, the Ru-catalyzed racemization of (S)-1-phenylethanol in the presence of Candida antarctica lipase B was also investigated. The compatibility of the metal- and enzyme-catalyzed reactions led to a highly efficient coupled catalytic system for transformation of racemic alcohols to their enantiomerically pure acetates. This protocol was applied for a wide range of secondary alcohols. It was shown that in the case of allylic alcohols the obtained enantiopure allylic acetates are useful compounds for synthesis of α-methyl carboxylic acids such as (R)-Flurbiprofen and acyloin acetates. Highly selective dynamic kinetic asymmetric transformation of 3,5-piperidine diol to deliver various 3,5-dioxygenated piperidines is also described.

  • 34. Bogár, Krisztián
    et al.
    Krumlinde, Patrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hydrogenized Wilkinson´s Catalyst for Transfer Hydrogenation of Carbonyl CompoundsManuscript (preprint) (Other academic)
    Abstract [en]

    Combining the advantages of homogeneous and heterogeneous catalysis is possible by heterogenization of homogeneous transition metal complexes based on a grafting/anchoring technique. Wilkinson’s catalyst ((RhCl(PPh3)3) immobilized on common silica showed high activity and selectivity in transfer hydrogenation reactions of different carbonyl compounds in isopropanol. Reactions conducted at reflux in isopropanol afforded the corresponding carbinols in high yields in short reaction times. The heterogeneous feature of the catalyst allows easy recovery and efficient reuse in the same reaction up to 5 times without loss of catalytic activity.

  • 35.
    Bogár, Krisztián
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, B.
    Bäckvall, Jan-E.
    Large Scale Metalloenzymatic Dynamic Kinetic Resolution of (rac)-1-PhenylethanolManuscript (Other academic)
  • 36. Borgström, Magnus
    et al.
    Shaikh, Nizamuddin
    Johansson, Olof
    Anderlund, Magnus F.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Styring, Stenbjörn
    Åkermark, Björn
    Magnuson, Ann
    Hammarström, Leif
    Light Induced Magnanese Oxidation and Long-lived Charge Separation in a Mn2II,II-RuII-acceptor triadManuscript (Other academic)
  • 37.
    Borén, Linnéa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantioselective Synthesis of Sec-Alcohol Derivatives and Diols via Combined Ruthenium and Enzyme Catalysis2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The first part of this thesis describes the synthesis of enantiopure secondary alcohol derivatives. These syntheses are carried out via the combination of an enzyme as a resolution catalyst and a ruthenium catalyst as a racemization catalyst, in what is called dynamic kinetic resolution (DKR). By varying the resolution catalyst enantio-complementary processes can be obtained. A lipase (PS-C II) catalyzed DKR of γ-hydroxyamides gave the corresponding (R)-acetates in high yields and with high enantioselectivity. The synthetic usefulness of these obtained (R)-acetates was demonstrated by the synthesis of (R)-5-methyltetrahydrofurane-2-one. A protease (Subtilisin Carlsberg) catalyzed DKR of various secondary alcohols gave the corresponding (S)-acetates in high yields and with high enantioselectivity. In the second part of this thesis the DKR process has been extended into a dynamic kinetic asymmetric transformation (DYKAT) of diols. Various 1,5- and 1,4-diols were transformed into enantiopure diacetates in a lipase (CALB and PS-C II) catalyzed DYKAT. The synthetic utility of the obtained enantiopure diacetates were demonstrated by the synthesis of various enantiopure disubstituted heterocycles.

  • 38.
    Buitrago, Elina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Transition metal catalyzed reduction of ketones2010Licentiate thesis, comprehensive summary (Other academic)
  • 39.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Andersson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ryberg, Per
    Aztra Zeneca, Global Process R&D, Södertälje, Sweden.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selective reduction of heteroaromatic ketones: A combinatorial approach2011Conference paper (Other academic)
    Abstract [en]

    The enantioselective reduction of prochiral ketones is a most productiveway towards enantio enriched secondary alcohols used in the preparation of biologically active compounds. There are numerous transition metal catalyzed methods for this transformation, particularly based on Ru(II)-and Rh(I)-complexes, but there is a demand for a larger substrate scope. Heteroaromatic ketones are traditionally more challenging substrates. Normally a catalyst is developed for one benchmark substrate, and asubstrate screen is made with the best performing catalyst. Using this methodology, there is a high probability that for different substrates, another catalyst could outperform the one used. We have executed a multiple screen, containing a variety of different ligands together with both Ru and Rh, and heteroaromatic ketones to fine-tune, and find the optimum catalyst depending on the substrate. The acquired information was used to synthesize known, biologically active compounds, where the key reduction steps were performed with high enantioselectivities and yields.

  • 40.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zani, Lorenzo
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Fe/NHC-catalyzed hydrosilylation of aromatic ketones2009In: Abstracts of Papers, 238th ACS National Meeting, Washington, DC, United States, August 16-20, 2009, Washington, DC: American Chemical Society , 2009Conference paper (Other academic)
  • 41.
    Bunrit, Anon
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Srifa, Pemikar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dahlstrand, Christian
    Huang, Genping
    Biswas, Srijit
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Watile, Rahul
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Samec, Joseph
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    H3PO2-Catalyzed Intramolecular Stereospecific Substitution of the Hydroxyl Group in Stereogenic Secondary Alcohols by N-, O-, and S-centered Nucleophiles to Generate HeterocyclesManuscript (preprint) (Other academic)
    Abstract [en]

    The direct intramolecular stereospecific substitution of the hydroxyl group in stereogenic secondary alcohols was successfully accomplished by phosphinic acid catalysis. The hydroxyl group was displaced by O-, S-, and N-centered nucleophiles to provide enantioenriched five- and six-membered heterocycles in good to excellent yields and high enantiospecificity with water as the only by product. Mechanistic studies using both experiments and calculations have been performed. Rate order determination shows first-order dependences in catalyst, internal nucleophile, and electrophile concentrations, however, independence on external nucleophile and electrophile. Furthermore, phosphinic acid does not promote SN1 reactivity. Computational studies support a bifunctional role of the phosphinic acid in which activations of both nucleofuge and nucleophile occur in a bridging SN2-type transition state. 

  • 42.
    Bunrit, Anon
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Watile, Rahul
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lagerspets, Emi
    Lanekoff, Ingela
    Biswas, Srijit
    Repo, Timo
    Samec, Joseph
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Iron (III)-Catalyzed Intramolecular Stereospecific Substitution of the OH Group in Stereogenic Secondary and Tertiary AlcoholsManuscript (preprint) (Other academic)
    Abstract [en]

    We herein report a Fe(OTf)3-catalyzed stereospecific substitution of the hydroxyl (OH) group in secondary and tertiary alcohols by N-, and O-centered nucleophiles to generate synthetically precious enantioenriched pyrrolidines, tetrahydrofuran, 1,2,3,4-tetra-hydroquinolines, and chromanes. The substitution of the OH group in benzylic, allylic, and aliphatic alcohols proceed with high yields and high degree of enantiospecificity to give saturated five- and six-membered heterocyclic products and water as the only by-product. Mechanistic studies revealed that the intramolecular substitution reaction proceeds through an SN2 reaction with secondary alcohols and an SN1 reaction, comprising a tight ion pair, with tertiary alcohols giving products with inversion of configuration at the stereogenic carbon in both cases. The iron interacts with both nucleofile and nucloefuge, where the latter leads to a controlled carbon−oxygen (C–O) bond cleavage. The procedure opens up new atom efficient technique for catalytic stereospecific reactions that allow easily accessible stereogenic secondary and tertiary alcohols to be considered as substrates in substitution reactions. 

  • 43.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Catalytic asymmetric synthesis via combined metal and enzyme catalysis2009In: 3rd Hellenic Symposium on Organic Synthesis, October 15-17, 2009, Athens, Greece: Abstracts of papers, Athens, 2009Conference paper (Other academic)
  • 44.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Modern Oxidation Methods2010Collection (editor) (Other academic)
  • 45.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium- and ruthenium-catalyzed redox reactions in selective organic synthesis2009In: Abstract of LOST II Symposium in honour of Prof. Alain Krief, March 18-20, 2009, Namur, Belgium, 2009Conference paper (Other academic)
  • 46.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pd- and Ru-catalyzed redox reactions in catalysis. Application to the combination with enzyme catalysis2009In: Abstract of 42nd Jahrestreffen Deutscher Katalytiker, March 11-13, 2009, Weimar, Germany, 2009Conference paper (Other academic)
  • 47.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Recent advances in the combination of metal and enzyme catalysis2009In: Abstract of the 10th Netherlands Catalysis and Chemistry Conference (NCCC-X), March 2-4, 2009, Noordwijkerhout, the Netherlands, 2009Conference paper (Other academic)
  • 48.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selective oxidation of amines and sulfides2010In: Modern Oxidation Methods / [ed] Jan-Erling Bäckvall, Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA , 2010, 2, p. 277-313Chapter in book (Other academic)
  • 49.
    Carson, Fabian
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martínez-Castro, Elisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Marcos, Rocío
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Jansson, Kjell
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Introduction of an N-heterocyclic Carbene Iridium Complex into a Zirconium Metal–Organic Framework for CatalysisManuscript (preprint) (Other academic)
  • 50.
    Cotton, Hanna
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Chiral metallocene ligands for transition metal-catalysed reactions2004Doctoral thesis, comprehensive summary (Other academic)
123456 1 - 50 of 293
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