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  • 1.
    Albers, Michael F
    et al.
    Department of Chemical Biology, Max Planck Institute for Molecular Physiology.
    Hedberg, Christian
    Amino acid building blocks for Fmoc solid-phase synthesis of peptides phosphocholinated at serine, threonine, and tyrosine2013In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 78, no 6, p. 2715-2719Article in journal (Refereed)
    Abstract [en]

    Phosphocholination of eukaryotic host cell proteins has recently been identified as a novel post-translational modification important for bacterial pathogenesis. Here, we describe the first straightforward synthetic strategy for peptides containing phosphocholinated serine, threonine, or tyrosine residues using preformed functional amino acid building blocks, fully compatible with standard Fmoc solid-phase peptide synthesis.

  • 2.
    Al-Smadi, Derar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry. An Najah Natl Univ, Dept Chem, Fac Sci, Nablus, Palestine.
    Enugala, Thilak Reddy
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Kessler, Vadim
    Swedish Univ Agr Sci, Dept Mol Sci, Box 7015, SE-75007 Uppsala, Sweden.
    Mhasal, Anil Rhanu
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Kamerlin, Shina Caroline Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Kihlberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Norberg, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Chemical and Biochemical Approaches for the Synthesis of Substituted Dihydroxybutanones and Di-, and Tri-Hydroxypentanones2019In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 84, no 11, p. 6982-6991Article in journal (Refereed)
    Abstract [en]

    Polyhydroxylated compounds are building blocks for the synthesis of carbohydrates and other natural products. Their synthesis is mainly achieved by different synthetic versions of aldol-coupling reactions, catalyzed either by organocatalysts, enzymes or metal-organic catalysts. We have investigated the formation of 1,4-substituted 2,3-dihydroxybutan-1-one derivatives from para- and meta-substituted phenylacetaldehydes by three distinctly different strategies. The first involved a direct aldol reaction with hydroxyacetone, dihydroxyacetone or 2-hydroxyacetophenone, catalyzed by the cinchona derivative cinchonine. The second was reductive cross-coupling with methyl or phenyl glyoxal promoted by SmI2 resulting in either 5-substituted 3,4-dihydroxypentan-2-ones or 1,4 bis-phenyl substituted butanones, respectively. Finally, in the third case, aldolase catalysis was employed for synthesis of the corresponding 1,3,4-trihydroxylated pentan-2-one derivatives. The organocatalytic route with cinchonine generated distereomerically enriched syn products (de = 60−99 %), with moderate enantiomeric excesses (ee = 43−56%), but did not produce aldols with either hydroxyacetone or dihydroxyacetone as donor ketones. The SmI2-promoted reductive cross-coupling generated product mixtures with diastereomeric and enantiomeric ratios close to unity. This route allowed for the production of both 1-methyl- and 1-phenylsubstituted 2,3-dihydroxybutanones, at yields between 40−60%. Finally, the biocatalytic approach resulted in enantiopure syn (3R,4S) 1,3,4-trihydroxypentan-2-ones.

  • 3.
    Andersson, Hanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry. University of Gothenburg, SE-412 96 Gothenburg, Sweden.
    Gräfenstein, Jürgen
    National Sun Yat-Sen University, Kaohsiung, Taiwan.
    Isobe, Minoru
    National Sun Yat-Sen University, Kaohsiung, Taiwan.
    Erdélyi, Máté
    University of Gothenburg, SE-412 96 Gothenburg, Sweden; The Swedish NMR Centre, SE-413 96 Gothenburg, Sweden.
    Sydnes, Magne O
    University of Stavanger, NO-4036 Stavanger, Norway.
    Photochemically Induced Aryl Azide Rearrangement: Solution NMR Spectroscopic Identification of the Rearrangement Product2017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 3, p. 1812-1816Article in journal (Refereed)
    Abstract [en]

    Photolysis of ethyl 3-azido-4,6-difluorobenzoate at room temperature in the presence of oxygen results in the regioselective formation of ethyl 5,7-difluoro-4-azaspiro[2.4]hepta-1,4,6-triene-1-carboxylate, presumably via the corresponding ketenimine intermediate which undergoes a photochemical four-electron electrocyclization followed by a rearrangement. The photorearrangement product was identified by multinuclear solution NMR spectroscopic techniques supported by DFT calculations.

  • 4.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Regio- and Stereoselective Deuteration of Allylic Chlorides Controlled by Neighboring Alcohol or Ether Groups1996In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 61, no 12, p. 4154-4156Article in journal (Refereed)
  • 5.
    Angelin, Marcus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Crystallization-induced secondary selection from a tandem driven dynamic combinatorial resolution process2008In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 73, no 9, p. 3593-3595Article in journal (Refereed)
    Abstract [en]

    Crystallization-induced secondary selection from a tandem driven dynamic combinatorial library is presented. In a one-pot experiment, an initial nitroaldol equilibrium was kinetically driven by a tandem reaction resulting in a subsequent dynamic library of diastereoisomers. This library was then further driven by a phase change, resulting in amplification and isolation of a highly diastereomerically enriched and synthetically interesting isoindolinone.

  • 6.
    Angelin, Marcus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Rahm, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Diastereoselective One-Pot Tandem Synthesis of 3-Substituted Isoindolinones: A Mechanistic Investigation2010In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 75, no 17, p. 5882-5887Article in journal (Refereed)
    Abstract [en]

    The mechanism of a base-catalyzed one-pot reaction of 2-cyanobenzaldehyde and primary nitroalkanes, to produce 3-substituted isoindolinones, has been investigated. A route starting with a nitroaldol (Henry) reaction, followed by a subsequent cyclization and rearrangement, was supported by intermediate analogue synthesis and DFT calculations. Direct diastereoselective crystallization from the reaction mixture was also achieved and studied for a number of substrates. Furthermore, the 3-substituted isoindolinones are an interesting group of compounds, both present important natural products, as well as being precursors to other valuable building blocks.

  • 7.
    Angles d'Ortoli, Thibault
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hamark, Christoffer
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Structure-Reactivity Relationships of Conformationally Armed Disaccharide Donors and Their Use in the Synthesis of a Hexasaccharide Related to the Capsular Polysaccharide from Streptococcus pneumoniae Type 372017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 15, p. 8123-8140Article in journal (Refereed)
    Abstract [en]

    To advance the field of glycobiology, efficient synthesis methods of oligosaccharides and glycoconjugates are a requisite. In glycosylation reactions using superarmed donors, both selectivity and reactivity issues must be considered, and we herein investigate these aspects for differently protected beta-linked 2-O-glycosylated glucosyl donors carrying bulky tert-butyldimethylsilyl groups to different extents. The acceptors in reactions being secondary alcohols presents a challenging situation with respect to steric crowding. Conformational pyranose ring equilibria of the superarmed disaccharide donors with axial-rich substituents contained skew and boat conformations, and three-state models were generally assumed. With NIS/TfOH as the promotor, 2,6-di-tert-butyl-4-methylpyridine as the base, and a dichloromethane/toluene solvent mixture, ethyl 1-thio-beta-d-glucosyl disaccharide donors having 6-O-benzyl group(s) besides tert-butyldimethylsilyl groups were efficiently coupled at -40 degrees C to the hydroxyl group at position 3 of glucopyranosyl acceptors to form beta-(1 -> 2),beta-(1 -> 3)-linked trisaccharides, isolated in excellent 95% yield. The more axial-rich donors in skew and boat conformations are thus preorganized closer to the assumed transition state in these glycosylation reactions. The developed methodology was subsequently applied in the synthesis of a multibranched hexasaccharide related to the capsular polysaccharide from Streptococcus pneumoniae type 37, which consists of a beta-(1 -> 3)-linked backbone and a beta-(1 -> 2)-linked side chain of D-glucosyl residues in disaccharide repeating units.

  • 8.
    Arefalk, Anna
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Wannberg, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Larhed, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Hallberg, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Stereoselective Synthesis of 3-Aminoindan-1-ones and Subsequent Incorporation into HIV-1 Protease Inhibitors2006In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 71, no 3, p. 1265-1268Article in journal (Refereed)
    Abstract [en]

    A new method for the stereoselective synthesis of 3-aminoindan-1-ones from triflates of salicylic sulfinyl imines and ethylene glycol vinyl ether has been developed. The reaction sequence starts with a regioselective Heck reaction followed by stereoselective Lewis acid mediated annulation. Acidic cleavage of the sulfinamides produced pure (R)- and (S)-3-aminoindan-1-ones, which were successfully isolated and incorporated into active HIV-1 protease inhibitors.

  • 9.
    Arvela, Riina K
    et al.
    Department of Chemistry, University of Connecticut.
    Leadbeater, Nicholas E
    Department of Chemistry, University of Connecticut.
    Microwave-promoted Heck coupling using ultralow metal catalyst concentrations.2005In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 70, no 5, p. 1786-1790Article in journal (Refereed)
    Abstract [en]

    We show that Heck couplings can be performed in water using microwave heating and Pd catalyst concentrations as low as 500 ppb. The methodology is simple; all that is required as the catalyst is a stock solution of palladium.

  • 10.
    Arvela, Riina K
    et al.
    University of Connecticut, Department of Chemistry.
    Leadbeater, Nicholas E
    University of Connecticut, Department of Chemistry.
    Sangi, Michael S
    University of Connecticut, Department of Chemistry.
    Williams, Victoria A
    University of Connecticut, Department of Chemistry.
    Granados, Patricia
    Saint Mary's University, Department of Chemistry.
    Singer, Robert D
    Saint Mary's University, Department of Chemistry.
    A reassessment of the transition-metal free suzuki-type coupling methodology.2005In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 70, no 1, p. 161-168Article in journal (Refereed)
    Abstract [en]

    We present here a reassessment of our transition-metal free Suzuki-type coupling protocol. We believe that, although the reaction can be run without the need for addition of a metal catalyst, palladium contaminants down to a level of 50 ppb found in commercially available sodium carbonate are responsible for the generation of the biaryl rather than, as previously suggested, an alternative non-palladium-mediated pathway. We present a revised methodology for Suzuki couplings using ultralow palladium concentrations for use with aryl and vinyl boronic acids and discuss the effects of the purity of the boronic acid on the reaction.

  • 11.
    Arvela, Riina K.
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Pasquini, Serena
    Università degli Studi di Siena, Dipartimento Farmaco Chimico Tecnologico.
    Larhed, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Highly regioselective internal heck arylation of hydroxyalkyl vinyl ethers by aryl halides in water2007In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 72, no 17, p. 6390-6396Article in journal (Refereed)
    Abstract [en]

    Highly regioselective and fast Pd(0)-catalyzed internal α-arylation of ethylene glycol vinyl ether with aryl halides was shown to be possible in water without the need for any halide scavengers or ionic liquid additives. This presents, to our knowledge, the first case of water being utilized in the selective arylation of electron-rich olefins. Resulting α-products were hydrolyzed and isolated as corresponding acetophenones in good to excellent yields when using aryl bromides and with good to moderate yields in the case of aryl iodides. Microwave irradiation was shown to be beneficial in activation of aryl chlorides toward the internal Heck arylation. The scope of the protocol was further increased to include different hydroxyalkyl vinyl ethers, these all giving selectively only branched α-products. Finally, the active role of the hydroxy group in directing the regioselectivity toward internal arylation of electron-rich olefins, even in nonpolar toluene, was revealed.

  • 12.
    Aune, Marie
    et al.
    Uppsala University.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Matsson, Olle
    Uppsala University.
    Solvent Dependence of Enantioselectivity for a Base Catalyzed 1,3-Hydron Transfer Reaction: A Kinetic Isotope Effect and NMR Spectroscopic Study.1995In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 60, no 5, p. 1356-1364p. 1356-1364Article in journal (Refereed)
    Abstract [en]

    The base-catalyzed rearrangement of 1-methylindene (1) to 3-methylindene (2) has been studied. The reaction proceeds with substrate enantioselectivity (kinetic resolution) when chiral tertiary amines are used as catalysts. When dihydroquinidine (DHQD) (3

  • 13.
    Ayub, Rabia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    El Bakouri, Ouissam
    Univ Girona, IQCC, C Maria Aurelia Capmany 6, Girona 17003, Catalonia, Spain..
    Jorner, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Sola, Miguel
    Univ Girona, IQCC, C Maria Aurelia Capmany 6, Girona 17003, Catalonia, Spain..
    Ottosson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Can Baird's and Clar's Rules Combined Explain Triplet State Energies of Polycyclic Conjugated Hydrocarbons with Fused 4n pi- and (4n+2)pi-Rings?2017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 12, p. 6327-6340Article in journal (Refereed)
    Abstract [en]

    Compounds that can be labeled as "aromatic chameleons" are pi-conjugated compounds that are able to adjust their pi-electron distributions so as to comply with the different rules of aromaticity in different electronic states. We used quantum chemical calculations to explore how the fusion of benzene rings onto aromatic chameleonic units represented by biphenylene, dibenbzocyclooctatetraene, and dibenzo[a,e]pentalene modifies the first triplet excited states (T-1) of the compounds. Decreases in T-1 energies are observed when going from isomers with linear connectivity of the fused benzene rings to those with cis- or transbent connectivities. The T-1 energies decreased down to those of the parent (isolated) 4n pi-electron units. Simultaneously, we observe an increased influence of triplet State aromaticity of the central 4n ring as given by Baird's rule and evidenced by geometric, magnetic, and electron density based aromaticity indices (HOMA, NICS-XY, ACID, and FLU). Because of an influence of,triplet state aromaticity in the central 4n pi-electron units,, the most stabilized, compounds, retain the triplet excitation in Baird pi-quartets or octets, enabling the outer benzene rings to adapt closed-shell singlet Clar pi-sextet character. Interestingly, the T-1 energies go down as the total number of aromatic cycles within a molecule in the T-1 state increases.

  • 14.
    Ayub, Rabia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. uppsala university.
    El Bakouri, Ouissam
    Univ Girona, IQCC, C Maria Aurelia Capmany 6, Girona 17003, Catalonia, Spain.
    Jorner, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. uppsala university.
    Sola, Miquel
    Univ Girona, IQCC, C Maria Aurelia Capmany 6, Girona 17003, Catalonia, Spain.
    Ottosson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. uppsala university.
    Can Baird’s and Clar’s Rules Combined Explain Triplet State Energies of Polycyclic Conjugated Hydrocarbons with Fused 4nπ- and (4n + 2)π-Rings?2017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 12, p. 6327-6340Article in journal (Refereed)
  • 15.
    Baeckstrom, P.
    et al.
    KTH, Sweden.
    Li, L.
    KTH, Sweden.
    Polec, I.
    Unelius, C. Rikard
    KTH, Sweden.
    Wimalasiri, W. R.
    Convenient Method for the Synthesis of Lineatin, a Pheromone Component of Trypodendron-Lineatum1991In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 56, no 10, p. 3358-3362Article in journal (Refereed)
    Abstract [en]

    Synthesis of racemic lineatin (1), a pheromone component of Trypodendron lineatum, is described. Condensation of 5-methyl-5-hexen-2-one (2) and triethyl phosphonoacetate with LiN(SiMe3)2 gave esters 3, which upon hydrolysis gave acids 4a-f. The bicyclo[3.2.0] ring compounds 5 and 6 were obtained via an intramolecular [2 + 2] addition by refluxing underivatized carboxylic acids 4a-f with NaOAc and Ac2O. Compound 5 was isomerized to the thermodynamically more stable isomer 6 using a Pd/C catalyst activated with hydrogen. Reduction of 6 with LiAlH4 gave the endo and exo isomers 7a and 7b (4:1). Isolation of the alcohol 7a followed by acetylation gave 8. Subsequent oxidation with OsO4 and methylmorpholine N-oxide gave diol 9. Cleavage of 9 with H5IO6 in diethyl ether gave keto aldehyde 10, which was converted to keto acetal 11. Treatment of 11 with MeMgBr followed by acidic workup gave 1. The overall efficiency is approximately 20%.

  • 16. Belda, O
    et al.
    Kaiser, N F
    Bremberg, U
    Larhed, M
    Hallberg, A
    Moberg, C
    Highly stereo- and regioselective allylations catalyzed by Mo-pyridylamide complexes: Electronic and steric effects of the ligand2000In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 65, no 18, p. 5868-5870Article in journal (Refereed)
  • 17. Belda, O.
    et al.
    Kaiser, N. F.
    Bremberg, U.
    Larhed, M.
    Hallberg, A.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Highly stereo- and regioselective allylations catalyzed by Mo-pyridylamide complexes: Electronic and steric effects of the ligand2000In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 65, no 18, p. 5868-5870Article in journal (Refereed)
  • 18. Bengtson, A
    et al.
    Larhed, M
    Hallberg, A
    Protected indanones by a Heck-Aldol annulation reaction2002In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 67, no 16, p. 5854-5856Article in journal (Refereed)
    Abstract [en]

    Monoprotected 3-hydroxyindan-1-ones have been prepared in moderate to good yields by a new tandem reaction involving salicylaldehyde triflates and commercially available 2-hydroxyethyl vinyl ether. This one-pot annulation reaction proceeds in the presence of a palladium bidentate catalyst and results in the formation of two new ring systems.

  • 19.
    Bengtsson, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    A Selective Intramolecular 5-exo-dig or 6-endo-dig Cyclization en Route to 2-Furanone or 2-Pyrone Containing Tricyclic Scaffolds2011In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 76, no 23, p. 9817-9825Article in journal (Refereed)
    Abstract [en]

    Ringfused bicyclic 2-pyridones exhibit interesting biological properties against pili assembly in uropathogenic E. coli1 as well as curli formation2. In the strive for new ring-fused central fragments highly selective synthetic routes to the 2-furanone or 2-pyrone containing tricyclic scaffolds 1 and 2 have been developed.

  • 20. Bergman, J.
    et al.
    Pettersson, B.
    Hasimbegovic, V.
    Svensson, Per H.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. AstraZeneca R&D, Pharmaceut Dev, Sweden.
    Thionations using a P4S10-pyridine complex in solvents such as acetonitrile and dimethyl sulfone2011In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 76, no 6, p. 1546-1553Article in journal (Refereed)
    Abstract [en]

    Tetraphosphorus decasulfide (P 4S 10) in pyridine has been used as a thionating agent for a long period of time. The moisture-sensitive reagent has now been isolated in crystalline form, and the detailed structure has been determined by X-ray crystallography. The thionating power of this storable reagent has been studied and transferred to solvents such as acetonitrile in which it has proven to be synthetically useful and exceptionally selective. Its properties have been compared with the so-called Lawesson reagent (LR). Particularly interesting are the results from thionations at relatively high temperatures (̃165 °C) in dimethyl sulfone as solvent. Under these conditions, for instance, acridone and 3-acetylindole could quickly be transformed to the corresponding thionated derivatives. Glycylglycine similarly gave piperazinedithione. At these temperatures, LR is inefficient due to rapid decomposition. The thionated products are generally cleaner and more easy to obtain because in the crystalline reagent, impurities which invariably are present in the conventional reagents, P 4S 10 in pyridine or LR, have been removed.

  • 21. Bergman, Jan
    et al.
    Arewang, Carl-Johan
    Svensson, Per H.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. SP Process Development, Sweden .
    Oxidative Ring Expansion of Spirocyclic Oxindole Derivatives2014In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 79, no 19, p. 9065-9073Article in journal (Refereed)
    Abstract [en]

    Oxidation of the spirocyclic oxindole derivative, isamic acid 1, led to decarboxylation and ring expansion to quinazolino[4,5-b]quinazoline-6,8-dione 7 rather than, as previously believed, its isomer 6. The structure of 7 was confirmed by X-ray crystallography. Condensation of isatin (indole-2,3-dione) and 2-aminobenzamide led to the spirocyclic molecule, spiro[3H-indole-3,2'(1H)quinazoline]-2,4'(1H,3H)dione 8, which was also identified as an intermediate in the oxidation of isamic acid. Mild hydrolysis of 7 gave the 10-membered molecule 22. Isamic acid could easily be converted to N-nitrosoisamic acid, which when heated in ethanol underwent a ring expansion to a hydroximino derivative, 38, of compound 6. The structure of 38 was confirmed by X-ray crystallography.

  • 22.
    Bielawski, Marcin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Aili, David
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Regiospecific One-Pot Synthesis of Diaryliodonium Tetrafluoroborates from Arylboronic Acids and Aryl Iodides2008In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 73, no 12, p. 4602-4607Article in journal (Refereed)
    Abstract [en]

    Diaryliodonium salts have recently received considerable attention as mild arylation reagents in organic synthesis. This paper describes a regiospecific, sequential one-pot synthesis of symmetrical and unsymmetrical diaryliodonium tetrafluoroborates, which are the most popular salts in metal-catalyzed arylations. The protocol is fast and high-yielding and has a large substrate scope. Furthermore, the corresponding diaryliodonium triflates can conveniently be obtained via an in situ anion exchange.

  • 23.
    Bjorkling, F.
    et al.
    KTH, Stockholm.
    Norin, T.
    KTH, Stockholm.
    Unelius, C. Rikard
    KTH, Stockholm.
    Miller, R. B.
    Univ. of California, Davis, USA.
    A Stereospecific Synthesis of All 4 Isomers of 9,11-Tetradecadienyl Acetate Using a General-Method Applicable to 1,3-Dienes1987In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 52, no 2, p. 292-294Article in journal (Refereed)
  • 24.
    Blid, Jan
    et al.
    KTH, Superseded Departments, Chemistry.
    Brandt, Peter
    Somfai, Peter
    KTH, Superseded Departments, Chemistry.
    Lewis Acid Mediated [2,3]-Sigmatropic Rearrangement of Allylic alpha-Amino Amides2004In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, no 9, p. 3043-3049Article in journal (Refereed)
    Abstract [en]

     Boron trifluoride and BBr3 mediated [2,3]-sigmatropic rearrangements of allylic alpha-amino amides have been developed affording secondary amines in good yields. (E)-Crotyl and (E)-cinnamyl alpha-amino amides 2b and 2c exhibit excellent syn-diastereoselectivity upon rearrangement with either Lewis acid. The allylic amine 2a forms upon treatment with BF3 or BBr3 a five-membered heterocylic complex in which a single halide anion has been displaced by the carbonyl oxygen atom. The structures of the Lewis acid-amine complexes were elucidated using NMR spectroscopy. A plausible reaction mechanism, based on DFT calculations, is presented. Thus, BF3- or BBr3-complexed allylic amines 2 are shown to preferentially proceed, after deprotonation, via an endo transition state.

  • 25.
    Blid, Jan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Panknin, Olaf
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tuzina, Pavel
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lewis acid mediated asymmetric 2,3 -sigmatropic rearrangement of allylic amines. Scope and mechanistic investigation2007In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 72, no 4, p. 1294-1300Article in journal (Refereed)
    Abstract [en]

    [GRAPHIC] The first asymmetric [2,3]-sigmatropic rearrangement of achiral allylic amines has been realized by quaternization of the amines with an enantiomerically pure diazaborolidine and subsequent treatment with Et3N. The resultant homoallylic amines were obtained in good yields and excellent ee's. The observed diastereo- and enantioselectivities were rationalized by invoking a kinetically controlled process, and support for this model was obtained from an NMR spectroscopic investigation of the chiral Lewis acid-substrate complex. The structure of the Lewis acid-product complex was established by X-ray crystallographic analysis and supported the proposed mechanism.

  • 26.
    Blomberg, David
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kreye, Paul
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sethson, Ingmar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Brickmann, Kay
    AstraZeneca R&D Mölndal, Mölndal, Sweden.
    Kihlberg, Jan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Synthesis and conformational studies of a β-turn mimetic incorporated in Leu-enkephalin2004In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, no 10, p. 3500-3508Article in journal (Refereed)
    Abstract [en]

    A β-turn mimetic in which the four amino acids of a β-turn have been replaced by a 10-membered ring has been designed, synthesized, and subjected to conformational studies. In the mimetic, the intramolecular COi − HNi+3 hydrogen bond that is often found in β-turns has been replaced by an ethylene bridge. In addition, the amide bond between residues i and i + 1 was exchanged for a methylene ether isoster. Such a β-turn mimetic, based on the first four residues of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu), was prepared in 15 steps. The synthesis relied on a β-azido alcohol prepared in five steps from Cbz-Tyr(tBu)-OH as a key, i-position building block. tert-Butyl bromoacetate, glycine, and a Phe-Leu dipetide were then used as building blocks for positions i + 1, i + 2, and i + 3, respectively. Conformational studies based on 1H NMR data showed that the β-turn mimetic was flexible, but that it resembled a type-II β-turn at low temperature. This low energy conformer closely resembled the structure determined for crystalline Leu-enkephalin.

  • 27.
    Borg, Tessie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tuzina, Pavel
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lewis Acid-Promoted Addition of 1,3-Bis(silyl)propenes to Aldehydes: A Route to 1,3-Dienes2011In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 76, no 19, p. 8070-8075Article in journal (Refereed)
    Abstract [en]

    The Lewis acid-promoted addition of 1,3-bis(silyl)-propenes to aldehydes to provide the corresponding (E)-1,3-dienes in excellent stereoselectivity and good to excellent yields is reported. The procedure is mild, base-free, and operationally straightforward.

  • 28.
    Bornhof, Anna-Bea
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Xiong, Ruisheng
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Rational Synthesis of 2-Bromoporphyrins and 2,12-Dibromoporphyrins2017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 23, p. 12908-12913Article in journal (Refereed)
    Abstract [en]

    Bromoporphyrins were prepared by the metal-mediated self-condensation of brominated 1-formyldipyrromethanes. Depending on the conditions, Mg(II)-2,12-dibromoporphyrin and Mg(II)-2-bromoporphyrin could be obtained in up to 11% and 17% isolated yield, respectively. Zn(II) was also a viable templating metal. The positions of the bromine substituents were confirmed by 2D-NMR spectroscopic analysis and the X-ray crystal structure of a derivative. Suzuki and Sonogashira reactions of the bromoporphyrins yielded 2-substituted or 2,12-disubstituted porphyrins with red-shifted absorption and emission spectra. This method provides access to the minimalist core of beta-mono- and beta,beta'-disubstituted porphyrins from readily available starting materials.

  • 29.
    Bouchet, Aude
    et al.
    University of Bordeaux 1.
    Brotin, Thierry
    Ecole Normale Super Lyon.
    Linares, Mathieu
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics . Linköping University, The Institute of Technology.
    Cavagnat, Dominique
    University of Bordeaux 1.
    Buffeteau, Thierry
    University of Bordeaux 1.
    Influence of the Chemical Structure of Water-Soluble Cryptophanes on Their Overall Chiroptical and Binding Properties2011In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 76, no 19, p. 7816-7825Article in journal (Refereed)
    Abstract [en]

    The synthesis and the chiroptical properties of the two enantiomers of the hexacarboxylic acid cryptophane-A derivative, 1, are described in this article. The chiroptical and binding properties of 1 toward achiral and chiral guests have been investigated in water under basic conditions by polarimetry, electronic circular dichroism (ECD), vibrational circular dichroism (VCD), and (1)H NMR spectroscopy. These experiments reveal that the (1)H NMR spectra of 1 are very sensitive to the nature of the guest trapped in its cavity whereas ECD and VCD spectra remain unchanged. We also show that the two enantiomers of 1 are able to distinguish between the two enantiomers of a series of small chiral epoxides. The enantiodiscrimination increases with the size of the chiral guest whereas the corresponding binding constants decrease. In contrast to what was observed for other water-soluble cryptophanes, the molecular recognition process is found independent of the nature of the counterions surrounding host 1, shedding light on the importance of the chemical structure of cryptophanes on their binding and chiroptical properties.

  • 30. Bouchet, Aude
    et al.
    Brotin, Thierry
    Linares, Mathieu
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Cavagnat, Dominique
    Buffeteaeu, Thierry
    Enantioselective Complexation of Chiral Propylene Oxide by an Enantiopure Water-Soluble Cryptophane2011In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 76, no 10, p. 4178-4181Article in journal (Refereed)
    Abstract [en]

    ECD and NMR experiments show that the complexation of propylene oxide (PrO) within the cavity of an enantiopure water-soluble cryptophane 1 in NaOH solution is enantioselective and that the (R)-PrO@PP-1 diastereomer is more stable than the (S)-PrO@PP-1 diastereomer with a free energy difference of 1.7 kJ/mol. This result has been confirmed to by molecular dynamics (MD) and ab initio calculations. The enantioselectivity is preserved in LiOH and KOH solutions even though the binding constants decrease, whereas PrO is not complexed in CsOH solution.

  • 31. Bouchet, Aude
    et al.
    Brotin, Thierry
    Linares, Mathieu
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Cavagnat, Dominique
    Buffeteau, Thierry
    Conformational Effects Induced by Guest Encapsulation in an Enantiopure Water-Soluble Cryptophane2011In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 76, no 5, p. 1372-1383Article in journal (Refereed)
    Abstract [en]

    A new water-soluble cryptophane 1 derivative (penta-hydroxyl cryptophane-A) has been synthesized from cryptophanol-A and the chiroptical properties of its two enantiomers M M-1 and P P-1 have been studied by polarimetry, electronic circular dichroism (ECD), and vibrational circular dichroism (VCD). Cryptophane 1 shows specific circular dichroism responses upon complexation that depend on the size of the guest and on the nature of the counterion (Li+, Na+, K+, Cs+) present in the solution. In LiOH and NaOH solutions, chiroptical changes induced by the encapsulation of guests and by the presence of cations in the vicinity of hosts can be interpreted from molecular dynamics (MD) and ab initio calculations by subtle conformational changes of the bridges. In KOH solution, the exchange dynamics is dependent on the size of the guest molecules, whereas in CsOH solution no encapsulation effect is observed whatever the size of the guest molecule. This last behavior comes from the fact that host 1 exhibits a very high affinity for cesium cations.

  • 32. Bratt, Emma
    et al.
    Verho, Oscar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Johansson, Magnus J.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    A General Suzuki Cross-Coupling Reaction of Heteroaromatics Catalyzed by Nanopalladium on Amino-Functionalized Siliceous Mesocellular Foam2014In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 79, no 9, p. 3946-3954Article in journal (Refereed)
    Abstract [en]

    Suzuki-Miyaura cross-coupling reactions of heteroaromatics catalyzed by palladium supported in the cavities of amino-functionalized siliceous mesocellular foam are presented. The nanopalladium catalyst effectively couples not only heteroaryl halides with boronic acids but also heteroaryl halides with boronate esters, potassium trifluoroborates, MIDA boronates, and triolborates, producing a wide range of heterobiaryls in good to excellent yields. Furthermore, the heterogeneous palladium nanocatalyst can easily be removed from the reaction mixture by filtration and recycled several times with minimal loss in activity. This catalyst provides an alternative, environmentally friendly, low-leaching process for the preparation of heterobiaryls.

  • 33.
    Brea, Oriana
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Daver, Henrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rebek, Julius
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Modeling Decomposition of N-Nitrosoamides in a Self-Assembled Capsule2019In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 84, no 11, p. 7354-7361Article in journal (Refereed)
    Abstract [en]

    Density functional theory calculations are employed to investigate the mechanism and energies of the decomposition of N-nitrosoamides in the presence of a resorcinarene-based self-assembled nanocapsule. From experiments, it is known that confinement in the capsule inhibits the thermal decomposition of these compounds. N-Nitrosoamides with both aromatic and aliphatic substituents are considered here and the calculations show that, for both kinds, binding to the capsule leads to a significant increase in the energy barrier of the rate-determining step, the 1,3 N -> O acyl transfer reaction. A distortion-interaction analysis is conducted to probe the reasons behind the inhibition of the reaction. In addition, we characterized hypothetical intermediates that might be involved in the formation of the decomposition products inside the capsule. Interestingly, it is found that the capsule stabilizes ion-pair species that are unstable in mesitylene solution. Finally, a possible explanation is proposed for the observed encapsulation of the decomposition product of only one of the substrates.

  • 34. Bremberg, U
    et al.
    Larhed, M
    Moberg, C
    Hallberg, A
    Rapid microwave-induced palladium-catalyzed asymmetric allylic alkylation1999In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 64, no 4, p. 1082-1083Article in journal (Refereed)
  • 35. Brotin, Thierry
    et al.
    Montserret, Roland
    Bouchet, Aude
    Cavagnat, Dominique
    Linares, Mathieu
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Buffeteau, Thierry
    High Affinity of Water-Soluble Cryptophanes for Cesium Cations2012In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 77, no 2, p. 1198-1201Article in journal (Refereed)
    Abstract [en]

    Exceptionally high affinity for cesium cations was achieved in aqueous solution using two enantiopure cryptophanes. Complexation of cesium was evidenced by Cs-133 NMR spectroscopy and by electronic circular dichroism (ECD). Binding constants as high as 6 X 10(9) M-1 have been measured by isothermal titration calorimetry (ITC). Very strong complexation of rubidium cations (K similar to 10(6) M-1) has also been measured. Chiral hosts allowed the detection of the two cations at low concentrations (mu M) using ECD.

  • 36.
    Bunrit, Anon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC. Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Sawadjoon, Supaporn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Tsupova, Svetlana
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Sjöberg, Per J. R.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Samec, Joseph S. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC. Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    A General Route to beta-Substituted Pyrroles by Transition-Metal Catalysis2016In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 81, no 4, p. 1450-1460Article in journal (Refereed)
    Abstract [en]

    An atom-efficient route to pyrroles substituted in the beta-position has been achieved in four high yielding steps by a combination of Pd, Ru, and Fe catalysis with only water and ethene as side-products. The reaction is general and gives pyrroles substituted in the beta-position with linear and branched alkyl, benzyl, or aryl groups in overall good yields. The synthetic route includes a Pd-catalyzed monoallylation step of amines with substituted allylic alcohols that proceeds to yield the monoallylated products in moderate to excellent yields. In a second step, unsymmetrical diallylated aromatic amines are generated from the reaction of a second allylic alcohol with high selectivity in moderate to good yields by control of the reaction temperature. Ru-catalyzed ring-closing metathesis performed on the diallylated aromatic amines yields the pyrrolines substituted in the beta-position in excellent yields. By addition of ferric chloride to the reaction mixture, a selective aromatization to yield the corresponding pyrroles substituted in the beta-position was achieved. A reaction mechanism involving a palladium hydride, generated from insertion of palladium to O-H of an allyl alcohol, that is responsible for the C-O bond cleavage to generate the pi-allyl intermediate is proposed.

  • 37.
    Bunrit, Anon
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Uppsala University, Sweden.
    Sawadjoon, Supaporn
    Tšupova, Svetlana
    Sjöberg, Per J. R.
    Samec, Joseph S. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Uppsala University, Sweden.
    A General Route to beta-Substituted Pyrroles by Transition-Metal Catalysis2016In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 81, no 4, p. 1450-1460Article in journal (Refereed)
    Abstract [en]

    An atom-efficient route to pyrroles substituted in the beta-position has been achieved in four high yielding steps by a combination of Pd, Ru, and Fe catalysis with only water and ethene as side-products. The reaction is general and gives pyrroles substituted in the beta-position with linear and branched alkyl, benzyl, or aryl groups in overall good yields. The synthetic route includes a Pd-catalyzed monoallylation step of amines with substituted allylic alcohols that proceeds to yield the monoallylated products in moderate to excellent yields. In a second step, unsymmetrical diallylated aromatic amines are generated from the reaction of a second allylic alcohol with high selectivity in moderate to good yields by control of the reaction temperature. Ru-catalyzed ring-closing metathesis performed on the diallylated aromatic amines yields the pyrrolines substituted in the beta-position in excellent yields. By addition of ferric chloride to the reaction mixture, a selective aromatization to yield the corresponding pyrroles substituted in the beta-position was achieved. A reaction mechanism involving a palladium hydride, generated from insertion of palladium to O-H of an allyl alcohol, that is responsible for the C-O bond cleavage to generate the pi-allyl intermediate is proposed.

  • 38.
    Buskas, T.
    et al.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
    Soderberg, E.
    Söderberg, E., Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Fraser-Reid, B.
    NPG Research Institute, 710 West Main Street, Durham, NC 27701, United States.
    Use of n-pentenyl glycosides as precursors to various spacer functionalities2000In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 65, no 4, p. 958-963Article in journal (Refereed)
    Abstract [en]

    Pent-4-enyl ß-D-glucopyranoside and its peracetylated and perbenzylated derivatives are shown to be excellent substrates for preparation of a wide variety of spacer functionalities. The spacer derivatives so obtained are promising substrates for preparing agents such as neo-glycoconjugates, micelies, and liquid crystalline phases, which are of interest for studying various biological and physiological phenomena of carbohydrates.

  • 39.
    Bäckvall, Jan-E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Granberg, Kennth L.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Gatti, Roberto
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Stereocontrolled Lactonization Reactions via Palladium-Catalyzed 1,4-Addittion to Conjugated Dienes1993In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 58, no 20, p. 5445-5451Article in journal (Refereed)
    Abstract [en]

    Stereocontrolledp alladium(I1)-catalyzed1 ,4-chloro-and 1,4-acetoxylactonizations o f conjugated cyclic dienes have been developed to give stereodefined fused lactones. The stereochemistry of the 1,4- acetoxylactonization was controlled by the ligand on the metal catalyst, and in this way either a cisor truns-acetoxylactonization was obtained. This dual stereoselectivity is explained by a stereocontrolled acetate attack (trans or cis, respectively) on the allyl group in the catalytic (π-allyl)- palladium intermediate. To further strengthen the mechanism the intermediate (π-ally1)palladium complex was isolated and fully characterized. A stereospecific synthesis of cis-  and truns-2-[6- (benzyloxy)-2,4-heptadien-l-yllacetic a cid (cis-  and truns-9) followed by stereoselective Pd(I1)- catalyzed chloro- and acetoxylactonization in acetonelacetic acid resulted in highly functionalized fused lactones with control of the relative stereochemistry at four different carbons.

  • 40.
    Bäckvall, Jan-Erling
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Stone, Guy
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Syntheses of (±)-α- and (±)- γ- Lycorane via a Stereocontrolled Organopalladium Route1991In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 56, no 9, p. 2988-2993Article in journal (Refereed)
    Abstract [en]

    Total syntheses of (+/-)-alpha-and (+/-)-gamma-lycorane are described. The key steps in the syntheses are the stereocontrolled palladium-catalyzed intramolecular 1,4-chloroamidation of 12 to 13 and the subsequent anti-stereoselective copper-catalyzed S(N)2' reaction of allylic chloride 13 with [3,4-(methylenedioxy)phenyl]magnesium bromide to give 14. Hexahydroindole 14 has the required relative stereochemistry between carbons 3a, 7, and 7a for alpha-lycorane (1a) and was transformed to the latter via 15 and 16. The epimeric gamma-lycorane (2) was obtained by performing the Bischler-Napieralski cyclization on 14, which led to a highly stereoselective isomerization to give exclusively 17. Compound 17 was subsequently transformed to 2. The overall yield from ester 8 to (+/-)-alpha- and (+/-)-gamma-lycorane was 40 and 36%, respectively.

  • 41.
    Caraballo, Rémi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Deng, Lingquan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Amorim, Luis
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    pH-Dependent Mutarotation of 1-Thioaldoses in Water. Unexpected Behavior of (2S)-D-Aldopyranoses2010In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 75, no 18, p. 6115-6121Article in journal (Refereed)
    Abstract [en]

    The pH-dependent mutarotation of 1-thioaldopyranoses in aqueous media has been investigated. Anomerization readily occurred at lower and neutral pH for all aldopyranoses studied, whereas mainly for (2S)-D-aldopyranoses at higher pH. 1-Thio-D-mannopyranose and 1-thio-D-altropyranose showed very strong pH dependence where the anomeric equilibrium ratios changed dramatically from a preference for the beta-anomer at lower pH to the alpha-anomer at higher pH.

  • 42. Carlqvist, P.
    et al.
    Eklund, R.
    Brinck, Tore
    KTH, Superseded Departments, Chemistry.
    A theoretical study of the uncatalyzed and BF3-assisted Baeyer-Villiger reactions2001In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 66, no 4, p. 1193-1199Article in journal (Refereed)
    Abstract [en]

    The mechanisms for the uncatalyzed and boron trifluoride (BF3) assisted Baeyer-Villiger reactions between acetone and hydrogen peroxide have been investigated using high level ab initio [MP2 and CCSD(T)] and density functional theory (B3LYP) methods. Both steps in the uncatalyzed reaction are found to have very high transition state energies. It is clear that detectable amounts of the Crieege intermediate or the products cannot be formed without the aid of a catalyst. The main function of BF3 in both the addition step and the rearrangement (migration) step is to facilitate proton transfer. In the addition step the complexation of hydrogen peroxide with BF3 leads to an increased acidity of the attacking OH group, while in the rearrangement step BF3 takes active part in the proton-transfer process. This latter step is found to be rate determining with an activation free energy of 17.7 kcal/mol in organic solution. The products of the reaction are BF2OH, hydrogen fluoride, and methyl acetate. Thus, BF3 is not directly regenerated from the reaction.

  • 43.
    Carlqvist, Peter
    et al.
    KTH, Superseded Departments, Chemistry.
    Ostmark, H.
    Brinck, Tore
    KTH, Superseded Departments, Chemistry.
    Computational study of the amination of halobenzenes and phenylpentazole. A viable route to isolate the pentazolate anion?2004In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, no 9, p. 3222-3225Article in journal (Refereed)
    Abstract [en]

    Amination of halobenzenes, which proceeds via the benzyne intermediate (1), has been studied using quantum chemical methods. The computational data are in agreement with experimentally observed trends in reactivity and provide a qualitative explanation for the observed hydrogen isotope effects. To investigate if this is a viable way to isolate the pentazolate anion (2), the reactivities of the halobenzenes have been compared to phenylpentazole (3). The reaction energetics for phenylpentazole become favorable after complexation with Zn2+.

  • 44.
    Chorell, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Das, Pralay
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Diverse functionalization of Thiazolo ring-fused 2-Pyridones2007In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 72, no 13, p. 4917-4924Article in journal (Refereed)
    Abstract [en]

    Thiazolo ring-fused 2-pyridones have proven to be highly interesting scaffolds for the development of biologically active compounds. Many methods are today available to introduce a variety of substituents in the 2-pyridone part of the heterocycle. Herein we disclose how a diverse set of substituents can be introduced in the thiazolo ring, with possibilities to vary also the spatial arrangement of the substituents. A key intermediate is the oxidized framework 9 for which an effective synthesis is described. The thiazolo part of this system can be substituted either via conjugate additions, resulting in trans selectivity, or via microwave-assisted Heck couplings that result in unsaturated aryl-substituted analogues. The scaffold can also be lithiated followed by the addition of various electrophiles, which increases the diversification potential substantially, as exemplified with the introduction of halogens, alkyl, acyl, and amide substituents.

  • 45.
    Chow, Shiao
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Stevens, Marc
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Odell, Luke
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Sulfonyl Azides as Precursors in Ligand-free Palladium-Catalyzed Synthesis of Sulfonyl Carbamates and Sulfonyl Ureas and Synthesis of Sulfonamides2016In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 81, no 7, p. 2681-2691Article in journal (Refereed)
    Abstract [en]

    An efficient synthesis of sulfonyl carbamates and sulfonyl ureas from sulfonyl azides employing a palladium-catalyzed carbonylation protocol has been developed. Using a two-chamber system, sulfonyl azides, PdCl2, and CO gas, released ex situ from Mo(CO)(6), were assembled to generate sulfonyl isocyanates in situ, and alcohols and aryl amines were exploited as nucleophiles to afford a broad range of sulfonyl carbamates and sulfonyl ureas. A protocol for the direct formation of substituted sulfonamides from sulfonyl azides and amines via nucleophilic substitution was also developed.

  • 46.
    Chow, Shiao Y.
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Odell, Luke R.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Synthesis of N-Sulfonyl Amidines and Acyl Sulfonyl Ureas from Sulfonyl Azides, Carbon Monoxide, and Amides2017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 5, p. 2515-2522Article in journal (Refereed)
    Abstract [en]

    A Pd-catalyzed and ligand-free carbonylation/cycloaddition/decarboxylation cascade synthesis of sulfonyl amidines from sulfonyl azides and substituted amides at low CO pressure is reported. The reaction proceeds via an initial Pd-catalyzed carbonylative generation of sulfonyl isocyanates from sulfonyl azides, followed by a [2 + 2] cycloaddition with amides and subsequent decarboxylation, which liberates the desired sulfonyl amidines, generating N-2 and CO2 as the only reaction byproducts. Using this simple protocol, a diverse range of sulfonyl amidines was obtained in moderate to excellent yields. In addition, the reaction can also be directed through a more conventional amidocarbonylation pathway by employing N-monosubstituted amide nucleophiles to afford acyl sulfonyl ureas in good yields.

  • 47.
    Dahlstrand, Christian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Yamazaki, Kaoru
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Kilså, Kristine
    Ottosson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Substituent Effects on the Electron Affinities and Ionization Energies of Tria-, Penta-, and Heptafulvenes: A Computational Investigation2010In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 75, no 23, p. 8060-8068Article in journal (Refereed)
    Abstract [en]

    The extent of substituent influence on the vertical electron affinities (EAs) and ionization energies (IEs) of 43 substituted tria-, penta-, and heptafulvenes was examined computationally at the OVGF/6-311G(d)//B3LYP/6-311G(d) level of theory and compared with those of tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene (TTF) as representing strong electron-acceptor and -donor compounds, respectively. The substituents X at the exocyclic positions of the fulvenes were either NH2, H, or CN, while the substituents Y at the ring positions were H, CI, F, CN, or NH2. The variations of the EAs and lEs were rationalized by qualitative arguments based on frontier orbital symmetries for the different fulvene classes with either X or Y being constant. The minimum and maximum values found for the calculated EAs of the tria-, penta-, and heptafulvenes were 0.51-2.05, 0.24-3.63, and 0.53-3.14 eV, respectively, and for the IEs 5.27-9.96, 7.07-10.31, and 6.35-10.59 eV, respectively. Two of the investigated fulvenes outperform TCNQ (calcd EA = 2.63 eV) and one outperforms TTF (calcd IE = 6.25 eV) with regard to acceptor and donor abilities, respectively. We also evaluated the properties of bis(fulvene)s, i.e., compounds composed of a donor-type heptafulvene fused with an acceptor-type pentafulvene, and it was revealed that these bis(fulvene)s can be designed so that the IE and EA of the two separate fulvene segments are retained, potentially allowing for the design of compact donor-acceptor dyads.

  • 48.
    Deng, Hong-Ping
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Wang, Dong
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Direct Allylation of Quinones with Allylboronates2015In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 80, no 6, p. 3343-3348Article in journal (Refereed)
    Abstract [en]

    Allylboronates undergo C-H allylation of unsubstituted or monosubstituted benzoquinone and naphthoquinone substrates. In the case of 2,5- or 2,6-disubstituted quinones addition involving the substituted carbon takes place. Allylation with stereodefined allylboronates occurs with retention of the configuration.

  • 49.
    Devaraj, Karthik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Ingner, Fredric
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Sollert, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Gates, Paul J.
    Univ Bristol, Sch Chem, Cantocks Close, Bristol BS8 1TS, Avon, England.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Pilarski, Lukasz T.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Arynes and Their Precursors from Arylboronic Acids via Catalytic C-H Silylation2019In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 84, no 9, p. 5863-5871Article in journal (Refereed)
    Abstract [en]

    A new, operationally simple approach is presented to access arynes and their fluoride-activated precursors based on Ru-catalyzed C-H silylation of arylboronates. Chromatographic purification may be deferred until after aryne capture, rendering the arylboronates de facto precursors. Access to various new arynes and their derivatives is demonstrated, including, for the first time, those based on a 2,3-carbazolyne and 2,3-fluorenyne core, which pave the way for novel derivatizations of motifs relevant to materials chemistry.

  • 50. Ding, Yubin
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Li, Tong
    Zhu, Weihong
    Xie, Yongshu
    alpha-Monoacylated and alpha,alpha '- and alpha,beta '-Diacylated Dipyrrins as Highly Sensitive Fluorescence "Turn-on" Zn2+ Probes2013In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 78, no 11, p. 5328-5338Article in journal (Refereed)
    Abstract [en]

    With the purpose of developing readily synthesized CHEF (chelation-enhanced fluorescence) type Zn2+ probes with relatively simple molecular structures and excellent sensing behavior, p-anisoyl chloride was used for the acylation of 5-(pentafluorophenyl)dipyrromethane. Interestingly, the alpha,beta'-diacylated product PS2 with a unique substitution mode was obtained in high yield in addition to the normal a-substituted mono- and diacylated products PSI and PS3. Further oxidation of PS1-PS3 afforded dipyrrins S1-S3. Crystal structure and H-1 NMR measurements of S2 demonstrate the existence of a pure tautomer, which is consistent with DFT calculations. S1-S3 show highly Zn2+ selective "turn-on" fluorescence based on a CHEF mechanism by the formation of 2:1 (probe:metal) Zn2+ complexes. The emission colors can be easily tuned from green to red by changing the dipyrrin substitution modes. Furthermore, these probes demonstrate fast responses and wide applicable pH ranges. Among them, S2 shows the highest Zn2+ sensitivity, with a detection limit of 4.4 x 10(-8) M.

12345 1 - 50 of 227
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