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  • 1.
    Ali, Tara
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Weintraub, Andrej
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Structural determination of the O-antigenic polysaccharide from the Shiga toxin-producing Escherichia coli O1712006In: Carbohydrate Research, ISSN 0008-6215, Vol. 341, p. 1878-1883Article in journal (Refereed)
  • 2.
    Anderlund, Magnus F.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zheng, J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ghiladi, M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kritikos, Mikael
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Rivière, Erik
    Sun, Licheng
    Girerd, Jean-Jaques
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    A New, Dinuclear High Spin Manganese(III) Complex with Bridging Phenoxy and Methoxy Groups. Structure and Magnetic Properties2006In: Inorganic Chemistry Communications, ISSN 1387-7003, E-ISSN 1879-0259, Vol. 9, no 12, p. 1195-1198Article in journal (Refereed)
    Abstract [en]

    A new μ-phenoxy-μ-metoxy di-manganese(III) complex with the trisphenolic ligand, 2,6-bis[((2-hydroxybenzyl)(2-pyridylmethyl)amino)methyl]-4-methylphenol, was isolated as a perchlorate salt. The X-ray structure shows that the two manganese(III) ions are in a distorted octrahedral enviroment with approximately perpendicular Jahn–Teller axes. Investigation of the molar magnetic susceptibility reveals a ferromagnetic coupling between the two high-spin manganese(III) ions. Fitting of the data led to g = 2 and J = 12.5 cm−1

  • 3.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selander, Nicklas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Strategies for fine-tuning the catalytic activity of pincer-complexes2006In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 47, no 50, p. 8999-9001Article in journal (Refereed)
    Abstract [en]

    Various methoxy substituted pincer-complexes were prepared in order to study the substituent effects on the catalytic activity in palladium catalyzed opening of vinyl epoxides and boronation of cinnamyl alcohol. The results clearly show that methoxy substitution at the para-position of the pincer-complex leads to up to fourfold acceleration of the catalytic reactions, while substitution of the side-arms does not change the activity of the complex or leads to a slight deceleration of the catalytic processes.

  • 4.
    Borén, Linnéa
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Xu, Yongmei
    Córdova, Armando
    Bäckvall, Jan-Erling
    (S)-Selective Kinetic Resolution and Chemoenzymatic Dynamic Kinetic Resolution of Secondary Alcohols2006In: Chemistry: a European Journal, ISSN 0947-6539, Vol. 12, no 1, p. 225-232Article in journal (Refereed)
  • 5. Cotton, Hanna K.
    et al.
    Norinder, Jakob
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Screening of Ligands in the Asymmetric Metallocenethiolatocopper(I)-Catalyzed Allylic Substitution with Grignard Reagents2006In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 62, no 24, p. 5632-5640Article in journal (Refereed)
    Abstract [en]

    Screening of metallocenethiolate ligands for copper(I)-catalyzed substitution of allylic acetates with Grignard reagents has been carried out. The previously used ligand, lithium (R,Sp)-2-(1-dimethylaminoethyl)ferrocenylthiolate (4a), possessing both central and planar chirality, was the starting point for the screening. It was found that the diastereomeric ligand lithium (R,Rp)-2-(1-dimethylaminoethyl)ferrocenylthiolate (4b) exhibiting reversed planar chirality gave increased enantioselectivity in the allylic substitution, at least when cinnamyl acetate was used as a substrate. The ruthenocene-based ligand lithium (R,Sp)-2-(1-dimethylaminoethyl)ruthenocenylthiolate (4c) gave an enhanced reaction rate, but lower chiral induction. The use of disulfide bis[(R,Sp)-2-(1-dimethylaminoethyl)ferrocenyl]disulfide (7a) as a ligand precursor worked well but resulted in lower enantioselectivity.

  • 6.
    Cumpstey, Ian
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    New oligosaccharide analogues: non-glycosidically linked thioether-bridged pseudodisaccharides2006In: Synlett, ISSN 0936-5214, no 11, p. 1711-1714Article in journal (Refereed)
  • 7.
    Dziedzic, Pawel
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Weibiao, Zou
    Hafrén, Jonas
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    The small peptide-catalyzed direct asymmetric aldol reaction in water2006In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 4, p. 38-40Article in journal (Refereed)
  • 8.
    Ekström, Jesper
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Abrahamsson, Maria
    Olson, Carol
    Bergquist, Jonas
    Kanyak, Feliz B.
    Eriksson, Lars
    Sun, Licheng
    Åkermark, Björn
    Becker, Hans-Christian
    Hammarström, Leif
    Ott, Sascha
    Bio Inspired Side-on Attachment of a Ruthenium Photo-sensitizer to an Iron Hydrogenase Active Site Model2006In: Dalton Transactions, ISSN 1477-9226, no 38, p. 4599-4606Article in journal (Refereed)
  • 9.
    Fransson, Ann-Britt L.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Xu, Yongmei
    Leijondahl, Karin
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enzymatic Resolution, Desymmetrization and Dynamic Kinetic Asym-metric Transformation of 1,3-Cycloalkanediols2006In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 71, no 17, p. 6309-6316Article in journal (Refereed)
    Abstract [en]

    An efficient desymmetrization of cis-1,3-cyclohexanediol to (1S,3R)-3-(acetoxy)-1-cyclohexanol ((R,S)-2a) was performed via Candida antarctica lipase B (CALB)-catalyzed transesterification, in high yield (up to 93%) and excellent enantioselectivity (ee's up to >99.5%). (R,R)-Diacetate ((R,R)-3a) was obtained in a DYKAT process at room temperature from (1S,3R)-3-acetoxy-1-cyclohexanol ((R,S)-2a), in a high trans/cis ratio (91:9) and in excellent enantioselectivity of >99%. Metal- and enzyme-catalyzed dynamic transformation of cis/trans-1,3-cyclohexanediol using PS-C gave a high diastereoselectivity for cis-diacetate (cis/trans = 97:3). The (1R,3S)-3-acetoxy-1-cyclohexanol (ent-(R,S)-2a) was obtained from cis-diacetate by CALB-catalyzed hydrolysis in an excellent yield (97%) and selectivity (>99% ee). By deuterium labeling it was shown that intramolecular acyl migration does not occur in the transformation of cis-monoacetate to the cis-diacetate.

  • 10. Fransson, Ann-Britt
    et al.
    Xu, Yongmei
    Leijondahl, Karin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Enzymatic resolution, desymmetrization and dynamic kinetic asymmetric transformation of 1,3-cycloalkanediols2006In: Journal of organic chemistry, ISSN 0022-3263, Vol. 71, no 17, p. 6309-6316Article in journal (Refereed)
  • 11. Gao, Weiming
    et al.
    Liu, Jianhui
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Licheng
    Bidentate phosphine ligand based Fe2S2-containing macromolecules: synthesis, characterization, and catalytic electrochemical hydrogen production2006In: Inorganic Chemistry, ISSN 0020-1669, Vol. 45, no 23, p. 9169-9171Article in journal (Refereed)
  • 12.
    Ibrahem, Ismail
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dziedzic, Pawel
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Organocatalytic asymmetric alpha-aminomethylation of cyclohexanones2006In: Synthesis, ISSN 0039-7881, no 23, p. 4060-4064Article in journal (Refereed)
  • 13.
    Ibrahem, Ismail
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zou, Weibiao
    Casas, Jesus
    Sunden, Henrik
    Cordova, Armando
    Direct Organocatalytic Enantioselective α-Aminomethylation of Ketones2006In: Tetrahedron, Vol. 62, p. 357-Article in journal (Refereed)
  • 14. Ji, Sanhao
    et al.
    Ju, Yong
    Fu, Hua
    Zhao, Yufen
    Johansson, Tommy
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stawinski, Jacek
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    The influences of a nitrogen atom position in dinucleoside 2-,3-,4-pyridylphosphonates on fragmentation patterns in electrospray ionization multistage tandem mass spectra2006In: Nucleosides, Nucleotides, and Nucleic Acids, ISSN 1525-7770, Vol. 25, p. 771-784Article in journal (Refereed)
  • 15. Johansson, Per-Ola
    et al.
    Bäck, Marcus
    Kvarnström, Ingemar
    Jansson, Katarina
    Vrang, Lotta
    Hamelink, Elizabeth
    Hallberg, Anders
    Rosenquist, Åsa
    Samuelsson, Bertil
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Potent inhibitors of the hepatitis C virus NS3 protease: use of a novel P2 cyclopentane-derived template2006In: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, Vol. 14, p. 5136-5151Article in journal (Refereed)
  • 16.
    Jonsson, K. Hanna M.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Methyl 4-O-benzoyl-2,3-O-isopropylidene-a-L-rhamnopyranoside2006In: Acta Crystallographica Section C: Crystal Structure Communications, ISSN 0108-2701, E-ISSN 1600-5759, Vol. 62, no 8, p. o447-o449Article in journal (Refereed)
    Abstract [en]

    The title compound, C17H22O6, having an ester group at O4 of the hexopyranosyl sugar residue shows for the exo-cyclic C=O bond a conformation that is eclipsed to the C4-H4 bond. The two related torsion angles are denoted by syn and cis conformations. The q1 torsion angle (H4-C4-O4-C10) is indicated to have a similar conformation in solution as analyzed by NMR spectroscopy and a Karplus-type relationship.

  • 17.
    Jonsson, K. Hanna M.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Weintraub, Andrej
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Structural studies of the O-antigenic polysaccharide from Shigella dysenteriae type 3 and Escherichia coli O124, a reinvestigation2006In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 341, p. 2986-2989Article in journal (Refereed)
  • 18.
    Landersjö, Clas
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stevensson, Baltzar
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Eklund, Robert
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Östervall, Jennie
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Maliniak, Arnold
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Söderman, Peter
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Molecular conformations of a disaccharide investigated using NMR spectroscopy2006In: Journal of Biomolecular NMR, ISSN 0925-2738, E-ISSN 1573-5001, Vol. 35, p. 89-101Article in journal (Refereed)
    Abstract [en]

    The molecular structure of -l-Rhap-(1→ 2)--l-Rhap-OMe has been investigated using conformation sensitive NMR parameters: cross-relaxation rates, scalar 3 J CH couplings and residual dipolar couplings obtained in a dilute liquid crystalline phase. The order matrices of the two sugar residues are different, which indicates that the molecule cannot exist in a single conformation. The conformational distribution function, , related to the two glycosidic linkage torsion angles and was constructed using the APME method, valid in the low orientational order limit. The APME approach is based on the additive potential (AP) and maximum entropy (ME) models. The analyses of the trajectories generated in molecular dynamics and Langevin dynamics (LD) computer simulations gave support to the distribution functions constructed from the experimental NMR parameters. It is shown that at least two conformational regions are populated on the Ramachandran map and that these regions exhibit very different molecular order. Electronic Supplementary Material  Supplementary material is available for this article at http://www.dx.doi.org/10.1007/s10858-006-9006-0 and is accessible for authorized users.

  • 19.
    Leijondahl, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Fransson, Ann-Britt
    Bäckvall, Jan-Erling
    Ruthenium-catalyzed transfer hydrogenation/hydrogenation of 1,3-cycloalkanediones to 1,3-cycloalkanediols using microwave heating2006In: Journal of organic chemistry, ISSN 0022-3263, Vol. 71, no 22, p. 8622-8625Article in journal (Refereed)
  • 20. Li, Chun-Yan
    et al.
    Zhang, Xiao-Bing
    Han, Zhi-Xiang
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Licheng
    Shen, Guo-Li
    Yu, Ru-Qin
    A wide pH range optical sensing system based on a sol-gel encapsulated amino-functionalised corrole2006In: The Analyst, ISSN 0003-2654, Vol. 131, p. 388-393Article in journal (Refereed)
  • 21. Lindén, Auri A.
    et al.
    Johansson, Mikael
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hermanns, Nina
    Bäckvall, Jan-E.
    Efficient and Selective Sulfoxidation by Hydrogen Peroxide, Using a Recyclable Flavin-[bmim]PF6 Catalytic System2006In: Journal of organic chemistry, ISSN 0022-3263, Vol. 71, no 10, p. 3849 -3853Article in journal (Refereed)
  • 22.
    Norinder, Jakob
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yoshikai, Naohiko
    Bäckvall, Jan-Erling
    Nakamura, Eiichi
    Unusual Homocoupling in the Reaction of Diorganocuprates with an Allylic Halide2006In: Organometallics, Vol. 25, no 9, p. 2129 -2132Article in journal (Refereed)
  • 23.
    Närhi, Katja
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Franzén, Johan
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    An unexpectedly mild thermal alder-ene-type cyclization of enallenes2006In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, ISSN 0022-3263, Vol. 71, no 7, p. 2914-2917Article in journal (Refereed)
    Abstract [en]

    A mild, thermal Alder-ene reaction of enallenes has been developed. The allenic double bond acts as the "ene" and generates a carbon-carbon bond to an unactivated olefinic "enophile" in DMF at 120 degrees C to give [n.3.0] bicyclic systems (n = 3-5) in good yields. Except for a minor [2 + 2] cycloaddition byproduct, the reaction proceeded with complete atom economy, as there is no requirement of a catalyst or additional reactants, and no waste products are formed in the process.

  • 24. Olofsson, B.
    et al.
    Bogár, Krisztián
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Fransson, A.-B.L.
    Bäckvall, Jan-E.
    Divergent Asymmetric Synthesis of 3,5-Disubstituted Piperidines2006In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 71, no 21, p. 8256-8260Article in journal (Refereed)
  • 25.
    Olofsson, Berit
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bogár, Krisztián
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Fransson, Ann-Britt L
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Divergent asymmetric synthesis of 3,5-disubstituted piperidines.2006In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 71, no 21, p. 8256-60Article in journal (Refereed)
    Abstract [en]

    A divergent synthesis of various 3,5-dioxygenated piperidines with interesting pharmacological properties is described. A mixture of the achiral cis- and racemic trans-3,5-piperidine diol could be efficiently obtained from N-benzylglycinate in five steps by the use of chemoenzymatic methods. In the subsequent enzyme- and Ru-catalyzed reaction, the rac/meso diol mixture was efficiently transformed to the cis-(3R,5S)-diacetate with excellent diastereoselectivity and in high yield. Further transformations of the cis-diacetate selectively delivered the cis-piperidine diol and the cis-(3R,5S)-hydroxy acetate. Alternatively, the DYKAT could be stopped at the monoacetate stage to give the trans-(3R,5R)-hydroxy acetate.

  • 26.
    Olsson, Vilhelm
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sebelius, Sara
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selander, Nicklas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Direct Boronation of Allyl Alcohols with Diboronic Acid Using Palladium Pincer-Complex Catalysis. A Remarkably Facile Allylic Displacement of the Hydroxy Group under Mild Reaction Conditions2006In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 128, no 14, p. 4588-4589Article in journal (Refereed)
    Abstract [en]

    Allyl alcohols were converted to allyl boronic acids and subsequently to trifluoro(allyl)borates with tetrahydroxy diboron using palladium pincer-complex catalysis. These reactions are regio- and stereoselective proceeding with high isolated yields. Competitive boronation experiments indicate that under the applied reaction conditions the allylic displacement of a hydroxy group is faster than the displacement of an acetate leaving group. It is assumed that the hydroxy group of the allyl alcohol is converted to a diboronic acid ester functionality, which can easily be substituted.

  • 27.
    Rios, Ramón
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sundén, Henrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ibrahem, Ismail
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zhao, Gui-Ling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    A one-pot organocatalytic asymmetric entry to tetrahydrothioxanthenones2006In: Tetrahedron Letters, Vol. 47, no 49, p. 8679-8682Article in journal (Refereed)
  • 28.
    Samec, Joseph S. M.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Éll, Alida H.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Åberg, Jenny B.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Privalov, Timofei
    Kungliga Tekniska Högskolan.
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Department of Structural Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic Study of Hydrogen Transfer to Imines from a Hydroxycyclopentadienyl Ruthenium Hydride. Experimental Support for a Mechanism Involving Coordination of Imine to Ruthenium Prior to Hydrogen Transfer2006In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 128, no 44, p. 14293-14305Article in journal (Refereed)
    Abstract [en]

    Reaction of [2,3,4,5-Ph4(η5-C4COH)Ru(CO)2H] (2) with different imines afforded ruthenium amine complexes at low temperatures. At higher temperatures in the presence of 2, the complexes decomposed to give [Ru2(CO)4(μ-H)(C4Ph4COHOCC4Ph4)] (1) and free amine. Electron-rich imines gave ruthenium amine complexes with 2 at a lower temperature than did electron-deficient imines. The negligible deuterium isotope effect (kRuHOH/kRuDOD = 1.05) observed in the reaction of 2 with N-phenyl[1-(4-methoxyphenyl)ethylidene]amine (12) shows that neither hydride (RuH) nor proton (OH) is transferred to the imine in the rate-determining step. In the dehydrogenation of N-phenyl-1-phenylethylamine (4) to the corresponding imine 8 by [2,3,4,5-Ph4(η4-C4CO)Ru(CO)2] (A), the kinetic isotope effects observed support a stepwise hydrogen transfer where the isotope effect for C−H cleavage (kCHNH/kCDNH = 3.24) is equal to the combined (C−H, N−H) isotope effect (kCHNH/kCDND = 3.26). Hydrogenation of N-methyl(1-phenylethylidene)amine (14) by 2 in the presence of the external amine trap N-methyl-1-(4-methoxyphenyl)ethylamine (16) afforded 90−100% of complex [2,3,4,5-Ph4(η4-C4CO)]Ru(CO)2NH(CH3)(CHPhCH3) (15), which is the complex between ruthenium and the amine newly generated from the imine. At −80 °C the reaction of hydride 2 with 4-BnNH-C6H9=NPh (18), with an internal amine trap, only afforded [2,3,4,5-Ph44-C4CO)](CO)2RuNH(Ph)(C6H10-4-NHBn) (19), where the ruthenium binds to the amine originating from the imine, showing that neither complex A nor the diamine is formed. Above −8 °C complex 19 rearranged to the thermodynamically more stable [Ph4(η4-C4CO)](CO)2RuNH(Bn)(C6H10-4-NHPh) (20). These results are consistent with an inner sphere mechanism in which the substrate coordinates to ruthenium prior to hydrogen transfer and are difficult to explain with the outer sphere pathway previously proposed.

  • 29. Schwartz, Lennart
    et al.
    Ekström, Jesper
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lomoth, Reiner
    Ott, Sascha
    Dynamic Ligation at the First Amine-coordinated Iron Hydrogenase Active Site Mimic2006In: Chemical Communications, ISSN 1359-7345, no 40, p. 4206-4208Article in journal (Refereed)
  • 30.
    Sebelius, Sara
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olsson, Vilhelm J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Wallner, Olov A.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium-Catalyzed Coupling of Allylboronic Acids with Iodobenzenes. Selective Formation of the Branched Allylic Product in the Absence of Directing Groups2006In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 128, no 25, p. 8150-8151Article in journal (Refereed)
    Abstract [en]

    Palladium-catalyzed coupling reactions of functionalized allylboronic acids with iodobenzenes were achieved under standard Suzuki−Miyaura coupling conditions. The coupling reactions afforded selectively the branched allylic products in high to excellent yields. In contrast to palladium-catalyzed nucleophilic substitution reactions proceeding via (η3-allyl)palladium intermediates, this process does not require directing groups in the allyl moiety to achieve substitution at the congested allylic terminus. The regioselectivity of the process was largely unaffected by the substituent effects of the iodobenzenes and the allylic substrates.

  • 31.
    Selander, Nicklas
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sebelius, Sara
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Estay, Cesar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Highly Selective and Robust Palladium-Catalysed Carbon-Carbon Coupling between Allyl Alcohols and Aldehydes via Transient Allylboronic Acids2006In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 18, p. 4085-4087Article in journal (Refereed)
    Abstract [en]

    The highly regio- and stereoselective coupling of allyl alcohols with aldehydes could be achieved with 5 mol-% of SeCSe pincer complex catalyst and p-toluenesulfonic acid in the presence of diboronic acid. The transformations have a broad synthetic scope, and the high yields were obtained without the use of an inert atmosphere and carefully dried solvents.

  • 32. Sjödin, Martin
    et al.
    Irebo, Tania
    Utas, Josefin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lind, Johan
    Merényi, Gabor
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hammarström, Leif
    Kinetic Effects of Hydrogen-bonds on Proton-Coupled Electron Transfer from Phenols2006In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 128, no 40, p. 13076-13083Article in journal (Refereed)
    Abstract [en]

    The kinetics and mechanism of proton-coupled electron transfer (PCET) from a series of phenols to a laser flash generated [Ru(bpy)3]3+ oxidant in aqueous solution was investigated. The reaction followed a concerted electron−proton transfer mechanism (CEP), both for the substituted phenols with an intramolecular hydrogen bond to a carboxylate group and for those where the proton was directly transferred to water. Without internal hydrogen bonds the concerted mechanism gave a characteristic pH-dependent rate for the phenol form that followed a Marcus free energy dependence, first reported for an intramolecular PCET in Sjödin, M. et al. J. Am. Chem. Soc. 2000, 122, 3932−3962 and now demonstrated also for a bimolecular oxidation of unsubstituted phenol. With internal hydrogen bonds instead, the rate was no longer pH-dependent, because the proton was transferred to the carboxylate base. The results suggest that while a concerted reaction has a relatively high reorganization energy (λ), this may be significantly reduced by the hydrogen bonds, allowing for a lower barrier reaction path. It is further suggested that this is a general mechanism by which proton-coupled electron transfer in radical enzymes and model complexes may be promoted by hydrogen bonding. This is different from, and possibly in addition to, the generally suggested effect of hydrogen bonds on PCET in enhancing the proton vibrational wave function overlap between the reactant and donor states. In addition we demonstrate how the mechanism for phenol oxidation changes from a stepwise electron transfer−proton transfer with a stronger oxidant to a CEP with a weaker oxidant, for the same series of phenols. The hydrogen bonded CEP reaction may thus allow for a low energy barrier path that can operate efficiently at low driving forces, which is ideal for PCET reactions in biological systems.

  • 33. Teodorovic, Peter
    et al.
    Slättegård, Rikard
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Oscarson, Stefan
    Synthesis of stable C-phosphonate analogues of Neisseria meningitidis group A capsular polysaccharide structures using modified Mitsunobu reaction2006In: Organic and biomolecular chemistry, Vol. 4, no 4, p. 4485-4490Article in journal (Refereed)
  • 34.
    Teodorovic, Peter
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Slättegård, Rikard
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Oscarson, Stefan
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of stable C-phosphonate analogues of Neisseria meningitidis group A capsular polysaccharide structures using modified Mitsunobu reaction2006In: Organic & Biomolecular Chemistry, ISSN 1477-0520, Vol. 4, p. 4485-4490Article in journal (Refereed)
  • 35.
    Utas, Josefin E.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kritikos, Mikael
    Sandström, Dick
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Water as a hydrogen bonding bridge between a phenol and imidazole. A simple model for water binding in enzymes.2006In: Biochimica et Biophysica Acta, ISSN 0006-3002, Vol. 1757, p. 1592-1596Article in journal (Refereed)
  • 36.
    Utas, Josefin E.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Efficient Synthesis of 2-Substituted Imidazoles by Palladium-Catalyzed Cross-Coupling with Benzylzinc Reagents2006In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, no 12, p. 1965-1967Article in journal (Refereed)
    Abstract [en]

    Substituted benzylzinc reagents have been used in novel cross-coupling reactions with 2-iodo imidazoles to form compounds containing both a phenol and an imidazole moiety. The ­intramolecular hydrogen-bonding properties of these compounds were subsequently studied.

  • 37.
    Utas, Josefin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kritikos, Mikael
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Sandström, Dick
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Water as a Hydrogen Bonding Bridge between a Phenol and Imida-zole. A Simple Model for Water Binding in Enzymes2006In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1757, no 12, p. 1592-1596Article in journal (Refereed)
    Abstract [en]

    The X-ray crystal structure of the mono-hydrate of 2,2-bis(imidazol-1-ylmethyl)-4-methylphenol has been determined. Three hydrogen bonds hold water very tightly in the crystal, as determined by deuterium solid-state NMR. The hydrogen bond between the phenolic hydroxyl and water appears to have about the same strength as the direct hydrogen bond to imidazole, suggesting that the structure can be a good model for hydrogen bonds that are mediated by a water molecule in enzymes.

  • 38. 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)
  • 39.
    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.

  • 40.
    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)
  • 41.
    Zhao, Gui-Ling
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dziedzic, Pawel
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ibrahem, Ismail
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Organocatalytic asymmetric synthesis of 1,2,3-prim,sec,sec-triols2006In: Synlett, ISSN 0936-5214, no 20, p. 3521-3524Article in journal (Refereed)
  • 42.
    Åberg, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Samec, Joseph S. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic Investigation on the Hydrogenation of Imines by [p-(Me2CH)C6H4Me]RuH(NH2CHPhCHPhNSO2C6H4-p-CH3). Experimental support for an  Ionic Pathway2006In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 26, p. 2771-2773Article in journal (Refereed)
    Abstract [en]

    The need for acidic activation in the stoichiometric hydrogenation of benzyl-[1-phenyl-ethylidene]-amine ( 6a) or [1-(4-methoxy-phenyl)-ethylidene]-methyl-amine ( 6b) by Noyori's catalyst [p-(Me2CH)C6H4Me]RuH(NH2CHPhCHPhNSO2C6H4-p-CH3)( 2) is inconsistent with the proposed concerted mechanism and supports an ionic mechanism.

  • 43.
    Éll, Alida H
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Csjernyik, Gábor
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Slagt, Vincent F
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Berner, Simon
    Puglia, Carla
    Greger, Ledung
    Oscarsson, Sven
    Synthesis os S-Thioacetate Functionalized Cobalt(II) Porphyrins and Heterogenization on gold Surface2006In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 5, p. 1193-1199Article in journal (Refereed)
    Abstract [en]

    Cobalt tetraarylporphyrins 1-Co and 2-Co with thioacetate-functionalized carbon chains on the aryl groups were synthesized. The cobalt porphyrin 2-Co was immobilized on a gold surface after deprotection of the S-acetyl group. The immobilized porphyrin was studied by X-ray Photoelectron Spectroscopy (XPS) and the results suggest that a complete monolayer of porphyrins is formed.

1 - 43 of 43
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