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  • 151.
    Bornschein, Christoph
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Universität Rostock, Germany.
    Gustafson, Karl P. J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Verho, Oscar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Beller, Matthias
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Evaluation of Fe and Ru Pincer-Type Complexes as Catalysts for the Racemization of Secondary Benzylic Alcohols2016In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 22, no 33, p. 11583-11586Article in journal (Refereed)
    Abstract [en]

    Fe and Ru pincer-type catalysts are used for the racemization of benzylic alcohols. Racemization with the Fe catalyst was achieved within 30 minutes under mild reaction conditions, with a catalyst loading as low as 2 mol %. This reaction constitutes the first example of an iron-catalyzed racemization of an alcohol. The efficiency for racemization of the Fe catalyst and its Ru analogue was evaluated for a wide range of sec-benzylic alcohols. The commercially available Ru complex proved to be highly robust and even tolerated the presence of water in the reaction mixture.

  • 152.
    Borén, Linnéa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantioselective Synthesis of Sec-Alcohol Derivatives and Diols via Combined Ruthenium and Enzyme Catalysis2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

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

  • 153.
    Borén, Linnéa
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Leijondahl, Karin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dynamic Kinetic Asymmetric Transformation of 1,4-diols and Preparation of Trans-2,5-Disubstituted pyrrolidines2009In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, no 26, p. 3237-3240Article in journal (Refereed)
    Abstract [en]

    Dynamic kinetic asymmetric transformation (DYKAT) of a series of 1,4-diols is carried out with Candida antarctica lipase B (CALB), Pseudomonas cepacia lipase II (PS-C II), and a ruthenium catalyst. A β-chloro-substituted 1,4-diol is successfully transformed into an optically pure 1,4-diacetate, which is a highly useful synthetic intermediate. The usefulness of the optically pure 1,4-diacetates is demonstrated by the synthesis of enantiopure 2,5-disubstituted pyrrolidines.

  • 154.
    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)
  • 155.
    Bouma, M. J.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    7.07 α-Oxygenation of Carbonyl Compounds2014In: Comprehensive Organic Synthesis II (Second Edition) / [ed] Paul Knochel and Gary A. Molander, Amsterdam: Oxford: Elsevier , 2014, 2nd, p. 213-241Chapter in book (Refereed)
    Abstract [en]

    Abstract The chapter describes synthetically useful strategies for α-oxygenation of carbonyl compounds, with special emphasis on recent methods for catalytic and asymmetric reactions. The oxidation of enolates, enols, enol ethers, and α,β-unsaturated compounds is discussed in detail. Classical oxidation reagents like metal oxides, molecular oxygen, peroxides, and peracids are covered, with asymmetric dihydroxylation of enol ethers giving the highest enantioselectivities together with organocatalytic methods using peroxides. Oxaziridines, nitrosoarenes, and hypervalent iodine compounds are more recently developed α-oxygenation alternatives that allow metal-free oxidations under mild conditions. The combination of nitrosoarenes with organocatalysis is currently the best method for enantioselective α-oxygenations. The area of asymmetric α-oxygenations with hypervalent iodine compounds is currently under development, and high enantioselectivities have only been achieved in intramolecular reactions and epoxidations.

  • 156.
    Bouma, Marinus J.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    General One-Pot Synthesis of Alkynyliodonium Salts and Alkynyl Benziodoxolones from Aryl Iodides2012In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 45, p. 14242-14245Article in journal (Refereed)
  • 157.
    Brea, Oriana
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Luna, Alberto
    Diaz, Cristina
    Corral, Ines
    Molecular Modelling of the H-2-Adsorptive Properties of Tetrazolate-Based Metal-Organic Frameworks: From the Cluster Approach to Periodic Simulations2018In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 19, no 11, p. 1349-1357Article in journal (Refereed)
    Abstract [en]

    Hydrogen has been proposed as a long-term non-fossil fuel to be used in a future ideal carbon-neutral energetic economy. However, its low volumetric energy density hinders its storage and transportation. Metal-organic frameworks (MOFs) represent very promising materials for this purpose due to their very extended surface areas. Azolates, in particular tetrazolates, are - together with carboxylate functionalities - very common organic linkers connecting metallic secondary building units in MOFs. This study addresses, from a theoretical perspective, the H-2 adsorptive properties of tetrazolate linkers at the molecular level, following a size-progressive approach. Specifically, we have investigated how the physisorption energies and geometries are affected when changing the environment of the linker by considering the azolates in the gas phase, immersed in a finite cluster, or being part of an infinite extended crystal material. Furthermore, we also study the H-2 adsorptive capacity of these linkers within the cluster model.

  • 158.
    Brea, Oriana
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mó, Otilia
    Yáñez, Manuel
    Merced Montero-Campillo, M.
    Alkorta, Ibon
    Elguero, José
    Are beryllium-containing biphenyl derivatives efficient anion sponges?2018In: Journal of Molecular Modeling, ISSN 1610-2940, E-ISSN 0948-5023, Vol. 24, no 1, article id 16Article in journal (Refereed)
    Abstract [en]

    The structures and stabilities of 2,2'-diBeX-1,1'-biphenyl (X = H, F, Cl, CN) derivatives and their affinities for F-, Cl-, and CN- were theoretically investigated using a B3LYP/6-311 + G(3df, 2p)//B3LYP/6-31 + G(d,p) model. The results obtained show that the 2,2'-diBeX-1,1'-biphenyl derivatives (X = H, F, Cl, CN) exhibit very high F-, Cl-, and CN- affinities, albeit lower than those reported before for their 1,8-diBeX-naphthalene analogs, in spite of the fact that the biphenyl derivatives are more flexible than their naphthalene counterparts. Nevertheless, some of the biphenyl derivatives investigated are predicted to have anion affinities larger than those measured for SbF5, which is considered one of the strongest anion capturers. Therefore, although weaker than their naphthalene analogs, the 2,2'-diBeX-1,1'-biphenyl derivatives can still be considered powerful anion sponges. This study supports the idea that compounds containing -BeX groups in chelating positions behave as anion sponges due to the electron-deficient nature and consequently high intrinsic Lewis acidity of these groups.

  • 159. Breistein, Palle
    et al.
    Johansson, Jonas
    Ibrahem, Ismail
    Lin, Shuangzheng
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Deiana, Luca
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Cordova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    One-Step Catalytic Enantioselective a-Quaternary 5-Hydroxyproline Synthesis: An Asymmetric Entry to Highly Functionalized a-Quaternary Proline Derivatives2012In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 354, no 6, p. 1156-1162Article in journal (Refereed)
    Abstract [en]

    The highly enantioselective cascade reaction between N-protected a-cyanoglycine esters and a,beta-unsaturated aldehydes is disclosed. The reaction represents a one-step entry to polysubstituted 5-hydroxyproline derivatives having a quaternary a-stereocenter generally in high yields with up to >95:5 dr and 99:1 er. It is also a direct catalytic two-step entry to functionalized a-quaternary proline derivatives.

  • 160.
    Bruneau, Alexandre
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Gustafson, Karl P. J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yuan, Ning
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Swedish University of Agricultural Sciences, Sweden.
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Persson, Ingmar
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Synthesis of Benzofurans and Indoles from Terminal Alkynes and Iodoaromatics Catalyzed by Recyclable Palladium Nanoparticles Immobilized on Siliceous Mesocellular Foam2017In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 52, p. 12886-12891Article in journal (Refereed)
    Abstract [en]

    Herein, we report on the utilization of a heterogeneous catalyst, consisting of Pd nanoparticles supported on a siliceous mesocellular foam (Pd-0-AmP-MCF), for the synthesis of heterocycles. Reaction of o-iodophenols and protected o-iodoanilines with acetylenes in the presence of a Pd nanocatalyst produced 2-substituted benzofurans and indoles, respectively. In general, the catalytic protocol afforded the desired products in good to excellent yields under mild reaction conditions without the addition of ligands. Moreover, the structure of the reported Pd nanocatalyst was further elucidated with extended X-ray absorption fine-structure spectroscopy, and it was proven that the catalyst could be recycled multiple times without significant loss of activity.

  • 161.
    Buitrago, Elina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Transition metal catalyzed reduction of ketones2010Licentiate thesis, comprehensive summary (Other academic)
  • 162.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Andersson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ryberg, Per
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    High Throughput Screening of a Catalyst Library for the Asymmetric Transfer Hydrogenation of Heteroaromatic Ketones: Formal Syntheses of (R)-Fluoxetine and (S)-Duloxetine2012In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 4, no 12, p. 2082-2089Article in journal (Refereed)
    Abstract [en]

    A total of 21 amino acid based ligands including hydroxy amide, thioamide, and hydroxamic acid functionalities, respectively, were combined with [Ru(p-cymene)Cl2]2 and [RhCp*Cl2]2, and used as catalysts for the asymmetric transfer hydrogenation of four different heteroaromatic ketones in 2-propanol. The reactions were performed on a Chemspeed automated high-throughput screening robotic platform. Optimal catalysts were identified for the individual heterocyclic substrate classes. Based on these results, the formal syntheses of the antidepressant drugs (R)-fluoxetine and (S)-duloxetine were conducted by using the found catalysts in the key reaction step, which results in high isolated yields (94?%) and excellent product enantioselectivities (>99?% ee) of the formed 1,3-amino alcohols.

  • 163.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Andersson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ryberg, Per
    Aztra Zeneca, Global Process R&D, Södertälje, Sweden.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selective reduction of heteroaromatic ketones: A combinatorial approach2011Conference paper (Other academic)
    Abstract [en]

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

  • 164.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tinnis, Fredrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Efficient and Selective Hydrosilylation of Carbonyls Catalyzed by Iron Acetate and N-Hydroxyethylimidazolium Salts2012In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 354, no 1, p. 217-222Article in journal (Refereed)
    Abstract [en]

    Aromatic aldehydes, along with aryl alkyl, heteroaryl alkyl, and dialkyl ketones were efficiently reduced to their corresponding primary and secondary alcohols, respectively, in high yields, using the commercially available and inexpensive polymeric silane, polymethylhydrosiloxane (PMHS), as reducing agent. The reaction is catalyzed by in situ generated iron complexes containing hydroxyethyl-functionalized NHC ligands. Turnover frequencies up to 600 h−1 were obtained

  • 165.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zani, Lorenzo
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Fe/NHC-catalyzed hydrosilylation of aromatic ketones2009In: Abstracts of Papers, 238th ACS National Meeting, Washington, DC, United States, August 16-20, 2009, Washington, DC: American Chemical Society , 2009Conference paper (Other academic)
  • 166.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zani, Lorenzo
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selective hydrosilylation of ketones catalyzed by in situ-generated iron NHC complexes2011In: Applied organometallic chemistry, ISSN 0268-2605, E-ISSN 1099-0739, Vol. 25, no 10, p. 748-752Article in journal (Refereed)
    Abstract [en]

    Aryl alkyl-, heteroaryl alkyl- and dialkyl ketones were readily reduced to their corresponding secondary alcohols in high yields, using the commercially available and inexpensive polymeric silane polymethylhydrosiloxane (PMHS), as reducing agent. The reaction is catalyzed by an in situ-generated iron complex, conveniently generated from iron(II) acetate and the commercially available N-heterocyclic carbene (NHC) precursor IPr·HCl.

  • 167. Bunrit, Anon
    et al.
    Dahlstrand, Christian
    Olsson, Sandra K.
    Srifa, Pemikar
    Huang, Genping
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Orthaber, Andreas
    Sjöberg, Per J. R.
    Biswas, Srijit
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Samec, Joseph S. M.
    Brønsted Acid-Catalyzed Intramolecular Nucleophilic Substitution of the Hydroxyl Group in Stereogenic Alcohols with Chirality Transfer2015In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 137, no 14, p. 4646-4649Article in journal (Refereed)
    Abstract [en]

    The hydroxyl group of enantioenriched benzyl, propargyl, allyl, and alkyl alcohols has been intramolecularly displaced by uncharged O-, N-, and S-centered nucleophiles to yield enantioenriched tetrahydrofuran, pyrrolidine, and tetrahydrothiophene derivatives with phosphinic acid catalysis. The five-membered heterocyclic products are generated in good to excellent yields, with high degree of chirality transfer, and water as the only side-product. Racemization experiments show that phosphinic acid does not promote S(N)1 reactivity. Density functional theory calculations corroborate a reaction pathway where the phosphinic acid operates as a bifunctional catalyst in the intramolecular substitution reaction. In this mechanism, the acidic proton of the phosphinic acid protonates the hydroxyl group, enhancing the leaving group ability. Simultaneously, the oxo group of phosphinic acid operates as a base abstracting the nucleophilic proton and thus enhancing the nucleophilicity. This reaction will open up new atom efficient techniques that enable alcohols to be used as nucleofuges in substitution reactions in the future.

  • 168. Bunrit, Anon
    et al.
    Dahlstrand, Christian
    Srifa, Pemikar
    Olsson, Sandra K.
    Huang, Genping
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Tianjin University, China.
    Biswas, Srijit
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Samec, Joseph S. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Uppsala University, Sweden.
    Nucleophilic Substitution of the Hydroxyl Group in Stereogenic Alcohols with Chirality Transfer2016In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, Vol. 27, no 2, p. 173-176Article in journal (Refereed)
    Abstract [en]

    A brief overview of the development of direct substitution of the hydroxyl (OH) group of alcohols in our research group is presented. By applying a BrOnsted acid, an intramolecular substitution of the OH group in stereogenic alcohols with chirality transfer was achieved. Noteworthy, the intramolecular substitution has a wide scope in respect to both the nucleophile and also the nucleofuge. A mechanistic study by both experiments and DFT calculations revealed a unique reaction pathway in which the BrOnsted acid operates in a bifunctional manner to promote an S(N)2-type reaction mechanism.

  • 169.
    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.

  • 170.
    Bunrit, Anon
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Srifa, Pemikar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dahlstrand, Christian
    Huang, Genping
    Biswas, Srijit
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Watile, Rahul
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Samec, Joseph
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    H3PO2-Catalyzed Intramolecular Stereospecific Substitution of the Hydroxyl Group in Stereogenic Secondary Alcohols by N-, O-, and S-centered Nucleophiles to Generate HeterocyclesManuscript (preprint) (Other academic)
    Abstract [en]

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

  • 171.
    Bunrit, Anon
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Watile, Rahul
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lagerspets, Emi
    Lanekoff, Ingela
    Biswas, Srijit
    Repo, Timo
    Samec, Joseph
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Iron (III)-Catalyzed Intramolecular Stereospecific Substitution of the OH Group in Stereogenic Secondary and Tertiary AlcoholsManuscript (preprint) (Other academic)
    Abstract [en]

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

  • 172.
    Burkhardt, Anja
    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, Department of Structural Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Cumpstey, Ian
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    (Z)-1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose O-benzyloxime2009In: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. E65, no Part 3, p. o633-o633Article in journal (Refereed)
  • 173. Bustelo, Emilio
    et al.
    Gushchin, Artem L.
    Fernandez-Trujillo, M. Jesus
    Basallote, Manuel G.
    Algarra, Andres G.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    On the Critical Effect of the Metal (Mo vs. W) on the [3+2] Cycloaddition Reaction of M3S4 Clusters with Alkynes: Insights from Experiment and Theory2015In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, no 42, p. 14823-14833Article in journal (Refereed)
    Abstract [en]

    Whereas the cluster [Mo3S4(acac)(3)(py)(3)](+) ([1](+), acac=acetylacetonate, py=pyridine) reacts with a variety of alkynes, the cluster [W3S4(acac)(3)(py)(3)](+) ([2](+)) remains unaffected under the same conditions. The reactions of cluster [1]+ show polyphasic kinetics, and in all cases clusters bearing a bridging dithiolene moiety are formed in the first step through the concerted [3+2] cycloaddition between the C equivalent to C atoms of the alkyne and a Mo(mu-S)(2) moiety of the cluster. A computational study has been conducted to analyze the effect of the metal on these concerted [3+ 2] cycloaddition reactions. The calculations suggest that the reactions of cluster [2](+) with alkynes feature Delta G(+) values only slightly larger than its molybdenum analogue, however, the differences in the reaction free energies between both metal clusters and the same alkyne reach up to approximately 10 kcal mol(-1), therefore indicating that the differences in the reactivity are essentially thermodynamic. The activation strain model (ASM) has been used to get more insights into the critical effect of the metal center in these cycloadditions, and the results reveal that the change in reactivity is entirely explained on the basis of the differences in the interaction energies E-int between the cluster and the alkyne. Further decomposition of the E-int values through the localized molecular orbital-energy decomposition analysis (LMO-EDA) indicates that substitution of the Mo atoms in cluster [1](+) by W induces changes in the electronic structure of the cluster that result in weaker intra-and inter-fragment orbital interactions.

  • 174. Bäck, Marcus
    et al.
    Johansson, Per-Ola
    Wångsell, Fredrik
    Thorstensson, Fredrik
    Kvarnström, Ingemar
    Ayesa, Susana
    Wähling, Horst
    Pelcman, Mikael
    Jansson, Katarina
    Lindström, Stefan
    Wallberg, Hans
    Classon, Björn
    Rydergård, Christina
    Vrang, Lotta
    Hamelink, Elizabeth
    Hallberg, Anders
    Rosenquist, Åsa
    Samuelsson, Bertil
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Novel potent macrocyclic inhibitors of the hepatitis C virus NS3 protease: use of cyclopentane and cyclopentene P2-motifs2007In: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, Vol. 15, no 22, p. 7184-7202Article in journal (Refereed)
  • 175.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry. -.
    Asymmetric Catalysis via Dynamic Kinetic Resolution2007In: Asymmetric Synthesis - The Essentials, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim , 2007, p. 171-175Chapter in book (Refereed)
    Abstract [en]

    -

  • 176.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Catalytic asymmetric synthesis via combined metal and enzyme catalysis2009In: 3rd Hellenic Symposium on Organic Synthesis, October 15-17, 2009, Athens, Greece: Abstracts of papers, Athens, 2009Conference paper (Other academic)
  • 177.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Modern Oxidation Methods2010Collection (editor) (Other academic)
  • 178.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium- and ruthenium-catalyzed redox reactions in selective organic synthesis2009In: Abstract of LOST II Symposium in honour of Prof. Alain Krief, March 18-20, 2009, Namur, Belgium, 2009Conference paper (Other academic)
  • 179.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pd- and Ru-catalyzed redox reactions in catalysis. Application to the combination with enzyme catalysis2009In: Abstract of 42nd Jahrestreffen Deutscher Katalytiker, March 11-13, 2009, Weimar, Germany, 2009Conference paper (Other academic)
  • 180.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Preface2010In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 53, no 13-14, p. 831-831Article in journal (Refereed)
  • 181.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Recent advances in the combination of metal and enzyme catalysis2009In: Abstract of the 10th Netherlands Catalysis and Chemistry Conference (NCCC-X), March 2-4, 2009, Noordwijkerhout, the Netherlands, 2009Conference paper (Other academic)
  • 182.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selective oxidation of amines and sulfides2010In: Modern Oxidation Methods / [ed] Jan-Erling Bäckvall, Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA , 2010, 2, p. 277-313Chapter in book (Other academic)
  • 183. Carballeira, José Daniel
    et al.
    Krumlinde, Patrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bocola, Marco
    Vogel, Andreas
    Reetz, Manfred T.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Directed evolution and axial chirality: optimization of the enantioselectivity of Pseudomonas aeruginosa lipase towards the kinetic resolution of a racemic allene2007In: Chemical Communications, ISSN 1359-7345, Vol. 20, p. 1913-1915Article in journal (Refereed)
  • 184.
    Carson, Fabian
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Agrawal, Santosh
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Gustafsson, Mikaela
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bartoszewicz, Agnieszka
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Moraga, Francisca
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ruthenium Complexation in an Aluminium Metal-Organic Framework and its Application in Alcohol Oxidation Catalysis2012In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 48, p. 15337-15344Article, review/survey (Refereed)
    Abstract [en]

    A ruthenium trichloride complex has been loaded into an aluminium metalorganic framework (MOF), MOF-253, by post-synthetic modification to give MOF-253-Ru. MOF-253 contains open bipyridine sites that are available to bind with the ruthenium complex. MOF-253-Ru was characterised by elemental analysis, N2 sorption and X-ray powder diffraction. This is the first time that a Ru complex has been coordinated to a MOF through post-synthetic modification and used as a heterogeneous catalyst. MOF-253-Ru catalysed the oxidation of primary and secondary alcohols, including allylic alcohols, with PhI(OAc)2 as the oxidant under very mild reaction conditions (ambient temperature to 40 degrees C). High conversions (up to >99%) were achieved in short reaction times (13 h) by using low catalyst loadings (0.5 mol% Ru). In addition, high selectivities (>90%) for aldehydes were obtained at room temperature. MOF-253-Ru can be recycled up to six times with only a moderate decrease in substrate conversion.

  • 185.
    Carson, Fabian
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martínez-Castro, Elisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Marcos, Rocío
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Jansson, Kjell
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Introduction of an N-heterocyclic Carbene Iridium Complex into a Zirconium Metal–Organic Framework for CatalysisManuscript (preprint) (Other academic)
  • 186. Casas, J
    et al.
    Engqvist, Magnus
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ibrahem, I
    Kaynak, B
    Córdova, A
    Direct Amino Acid-Catalyzed Asymmetric Synthesis of Polyketide Sugars2005In: Angewandte Chemie International ed., ISSN 1433-7851, Vol. 44, no 9, p. 1343-1345Article in journal (Refereed)
  • 187. Casillo, Angela
    et al.
    Ståhle, Jonas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Parrilli, Ermenegilda
    Sannino, Filomena
    Mitchell, Daniel E.
    Pieretti, Giuseppina
    Gibson, Matthew I.
    Marino, Gennaro
    Lanzetta, Rosa
    Parrilli, Michelangelo
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tutino, Maria L.
    Corsaro, Maria M.
    Structural characterization of an all-aminosugar-containing capsular polysaccharide from Colwellia psychrerythraea 34H2017In: Antonie van Leeuwenhoek. International Journal of General and Molecular Microbiology, ISSN 0003-6072, E-ISSN 1572-9699, Vol. 110, no 11, p. 1377-1387Article in journal (Refereed)
    Abstract [en]

    Colwellia psychrerythraea strain 34H, a Gram-negative bacterium isolated from Arctic marine sediments, is considered a model to study the adaptation to cold environments. Recently, we demonstrated that C. psychrerythraea 34H produces two different extracellular polysaccharides, a capsular polysaccharide and a medium released polysaccharide, which confer cryoprotection to the bacterium. In this study, we report the structure of an additional capsular polysaccharide produced by Colwellia grown at a different temperature. The structure was determined using chemical methods, and one- and two-dimensional NMR spectroscopy. The results showed a trisaccharide repeating unit made up of only amino-sugar residues: N-acetyl-galactosamine, 2,4-diacetamido-2,4,6-trideoxy-glucose (bacillosamine), and 2-acetamido-2-deoxyglucuronic acid with the following structure: -> 4)-beta-d-GlcpNAcA-(1 -> 3)-beta-d-QuipNAc4NAc-(1 -> 3)-beta-d-GalpNAc-(1 ->. The 3D model, generated in accordance with H-1,H-1-NOE NMR correlations and consisting of ten repeating units, shows a helical structure. In contrast with the other extracellular polysaccharides produced from Colwellia at 4 A degrees C, this molecule displays only a low ice recrystallization inhibition activity.

  • 188. Castro, Vasco
    et al.
    Dvinskikh, Sergey V.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sandström, Dick
    Maliniak, Arnold
    NMR studies of membranes composed of glycolipids and phospholipids2007In: Biochimica et Biophysica Acta, Vol. 1768, no -, p. 2432-2437Article in journal (Refereed)
  • 189.
    Chen, Hong
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Deng, Youqian
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yu, Zhengbao
    Zhao, Huishuang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yao, Qingxia
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    3D Open-Framework Vanadoborate as a Highly Effective Heterogeneous Pre-catalyst for the Oxidation of Alkylbenzenes2013In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 25, no 24, p. 5031-5036Article in journal (Refereed)
    Abstract [en]

    Three three-dimensional (3D) open-framework vanadoborates, denoted as SUT-6-Zn, SUT-6-Mn, and SUT-6-Ni, were synthesized using diethylenetriamine as a template. SUT-6-Zn, SUT-6-Mn, and SUT-6-Ni are isostructural and built from (VO)(12)O-6 B18O36(OH)(6) clusters bridged by ZnO5, MnO6, and NiO6 polyhedra, respectively, to form the 3D frameworks. SUT-6 is the first vanadoborate with a 3D framework. The framework follows a semiregular hxg net topology with a 2-fold interpenetrated diamond-like channel system. The amount of template used in the synthesis played an important role in the dimensionality of the resulting vanadoborate structures. A small amount of diethylenetriamine led to the formation of this first 3D vanadoborate framework, while an increased amount of diethylenetriamine resulted in vanadoborates with zero-dimensional (0D) and one-dimensional (1D) structures. SUT-6-Zn was proved to be an efficient heterogeneous precatalyst for the oxidation of alkylbenzenes.

  • 190. Chen, Shi-Lu
    et al.
    Blomberg, Margareta R. A.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Siegbahn, Per E. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    An investigation of possible competing mechanisms for Ni-containing methyl-coenzyme M reductase2014In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 27, p. 14029-14035Article in journal (Refereed)
    Abstract [en]

    Ni-containing methyl-coenzyme M reductase (MCR) is capable of catalyzing methane formation from methyl-coenzyme M (CH3-SCoM) and coenzyme B (CoB-SH), and also its reverse reaction (methane oxidation). Based on extensive experimental and theoretical investigations, it has turned out that a mechanism including an organometallic methyl-Ni(III)F-430 intermediate is inaccessible, while another mechanism involving a methyl radical and a Ni(II)-SCoM species currently appears to be the most acceptable one for MCR. In the present paper, using hybrid density functional theory and an active-site model based on the X-ray crystal structure, two other mechanisms were studied and finally also ruled out. One of them, involving proton binding on the CH3-SCoM substrate, which should facilitate methyl-Ni(III)F-430 formation, is demonstrated to be quite unfavorable since the substrate has a much smaller proton affinity than the F-430 cofactor. Another one (oxidative addition mechanism) is also shown to be unfavorable for the MCR reaction, due to the large endothermicity for the formation of the ternary intermediate with side-on C-S (for CH3-SCoM) or C-H (for methane) coordination to Ni.

  • 191. Chen, Shi-Lu
    et al.
    Liao, Rong-Zhen
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Phosphate Monoester Hydrolysis by Trinuclear Alkaline Phosphatase; DFT Study of Transition States and Reaction Mechanism2014In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 15, no 11, p. 2321-2330Article in journal (Refereed)
    Abstract [en]

    Alkaline phosphatase (AP) is a trinuclear metalloenzyme that catalyzes the hydrolysis of a broad range of phosphate monoesters to form inorganic phosphate and alcohol (or phenol). In this paper, by using density functional theory with a model based on a crystal structure, the AP-catalyzed hydrolysis of phosphate monoesters is investigated by calculating two substrates, that is, methyl and p-nitrophenyl phosphates, which represent alkyl and aryl phosphates, respectively. The calculations confirm that the AP reaction employs a ping-pong mechanism involving two chemical displacement steps, that is, the displacement of the substrate leaving group by a Ser102 alkoxide and the hydrolysis of the phosphoseryl intermediate by a Zn2-bound hydroxide. Both displacement steps proceed via a concerted associative pathway no matter which substrate is used. Other mechanistic aspects are also studied. Comparison of our calculations with linear free energy relationships experiments shows good agreement.

  • 192. Chojnacka, Kinga
    et al.
    Santoro, Stefano
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Awartani, Radi
    Richards, Nigel G. J.
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Aponick, Aaron
    Synthetic studies on the solanacol ABC ring system by cation-initiated cascade cyclization: implications for strigolactone biosynthesis2011In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 9, no 15, p. 5350-5353Article in journal (Refereed)
    Abstract [en]

    We report a new method for constructing the ABC ringsystem of strigolactones, in a single step from a simple linearprecursor by acid-catalyzed double cyclization. The reactionproceeds with a high degree of stereochemical control, whichcan be qualitatively rationalized usingDFT calculations. Ourconcise synthetic approach offers a new model for thinkingabout the (as yet) unknown chemistry that is employed in thebiosynthetic pathways leading to this class of plant hormones.

  • 193. Chow, Winnie W. Y.
    et al.
    Herwik, Stanislav
    Kisban, Sebastian
    Ruther, Patrick
    Neves, Herc
    Oscarsson, Sven
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Gothelid, Emmanuelle
    Influence of bio-coatings on the recording performance of neural electrodes2014In: Biomedizinische Technik (Berlin. Zeitschrift), ISSN 1862-278X, E-ISSN 0013-5585, Vol. 59, no 4, p. 315-322Article in journal (Refereed)
    Abstract [en]

    Neural probes are complex devices consisting of metallic (often Pt based) electrodes, spread over an insolating/dielectric backbone. Their functionality is often limited in time because of the formation of scaring tissues around the implantation tracks. Functionalization of the probes surface can be used to limit the glial scar reaction. This is however challenging, as this treatment has to be equally efficient on all probe surfaces (metallic as well as dielectric) and should not influence the electrodes performances. This paper presents a novel technique to functionalize recording neural probes with hyaluronic acid (HyA), a major component of the extracellular matrix (ECM). HyA and the probe surface are both modified to make the reaction feasible: HyA is chemically functionalized with SS-pyridine groups while the probe surfaces are silanized. The thiol groups thus introduced on the probe surface can then react with the HyA SS-pyridine group, resulting in a covalent bonding of the latter on the former. The electrodes are protected by introducing a pretreatment step, namely an additional hyaluronic acid layer on the platinum electrode, prior to the silanization process, which was found to be effective in reducing electrode impedance under optimized conditions.

  • 194. Chow, Winnie W. Y.
    et al.
    Herwik, Stanislav
    Ruther, Patrick
    Gothelid, Emmanuelle
    Oscarsson, Sven
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bio-polymer coatings on neural probe surfaces: Influence of the initial sample composition2012In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 258, no 20, p. 7864-7871Article in journal (Refereed)
    Abstract [en]

    This paper presents the results of the study of hyaluronic acid (HyA) coating on two structural materials, silicon oxide (dielectric) surface and platinum (Pt) surface used for fabrication of probes developed for neurological investigations in the framework of the EU-project NeuroProbes. The silicon-based neural probes consist of multiple Pt electrodes on the probe shafts for neural recording applications. HyA coatings were proposed to apply on the probe surfaces to enhance the biocompatibility [1]. This study aims at understanding the influence of the initial composition of the probe surface on the structure and morphology of HyA coating. HyA was chemically functionalized by SS-pyridin using (N-Succinimidyl 3-[2-pyridyldithio]-propionate) (SPDP) and was immobilized on the surfaces via a covalent bond. The dielectric and Pt surfaces were derivatized by use of (3-mercaptopropyl) methyldimethoxysilane (MPMDMS). The silanol groups in MPMDMS bind to the dielectric surface, leaving the thiol groups at the uppermost surface and the thiol groups then bind covalently to the functionalized HyA. On the Pt surface, it is the thiol group which binds on the Pt surface. The coated surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). A well-defined HyA layer was observed on both dielectric and Pt surfaces. The coating of two molecular weights (340 kDa and 1.3 MDa) of HyA was examined. The influence of the silanized layer on the HyA coating was also investigated.

  • 195. Chowdhury, Sugata
    et al.
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Russo, Nino
    Sicilia, Emilia
    Mechanistic investigation of the hydrogenation of O2 by a transfer hydrogenation catalyst2010In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 12, p. 4178-4190Article in journal (Refereed)
  • 196. Closson, Adam
    et al.
    Johansson, Mikael
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Ionic liquid-immobilized catalytic system for biomimetic dihydroxylation of olefins2004In: Chemical Communication, ISSN 0366-5607, no 13, p. 1494-1495Article in journal (Refereed)
  • 197.
    Colas, Kilian
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Montero, Raúl
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mendoza, Abraham
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Intermolecular Pummerer Coupling with Carbon Nucleophiles in Non-Electrophilic Media2017In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 56, no 50, p. 16042-16046Article in journal (Refereed)
    Abstract [en]

    A new Pummerer-type C-C coupling protocol is introduced based on turbo-organomagnesium amides, which unlike traditional Pummerer reactions, does not require strong electrophilic activators, engages a broad range of C(sp(3))-, C(sp(2))-, and C(sp)-nucleophiles, and seamlessly integrates with C-H and C-X magnesiation. Given the central character of sulfur compounds in organic chemistry, this protocol allows access to unrelated carbonyls, olefins, organometallics, halides, and boronic esters through a single strategy.

  • 198.
    Colas, Kilian
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mendoza, Abraham
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Iterative Synthesis of Pluripotent Thioethers through Controlled Redox Fluctuation of Sulfur2018In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, Vol. 29, no 10, p. 1329-1333Article in journal (Refereed)
    Abstract [en]

    Target- and diversity-oriented syntheses are based on diverse building blocks, whose preparation requires discrete design and constructive alignment of different chemistries. To enable future automation of the synthesis of small molecules, we have devised a unified strategy that serves the divergent synthesis of unrelated scaffolds such as carbonyls, olefins, organometallics, halides, and boronic esters. It is based on iterations of a nonelectrophilic Pummerer-type C-C coupling enabled by turbo -organomagnesium amides that we have recently reported. The pluripotency of sulfur allows the central building blocks to be obtained by regulating C-C bond formation through control of its redox state.

  • 199.
    Colas, Kilian
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Vieira Dias dos Santos, Ana Catarina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mendoza, Abraham
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    One-pot Synthesis of Ketones from Aliphatic Carboxylic Acids Using Grignard Reagents and an in situ generated turbo-Hauser BaseManuscript (preprint) (Other academic)
  • 200.
    Colas, Kilian
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Vieira Dias dos Santos, Ana Catarina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mendoza, Abraham
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of Ketones from Carboxylic Acids Using Grignard Reagents and turbo-Hauser BasesManuscript (preprint) (Other academic)
1234567 151 - 200 of 1371
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