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  • 1.
    Anderson, Mattias
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Afewerki, Samson
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cõrdova, Armando
    Total Synthesis of Capsaicin Analogues from Lignin-Derived Compounds by Combined Heterogeneous Metal, Organocatalytic and Enzymatic Cascades in One Pot2014In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 356, no 9, p. 2113-2118Article in journal (Refereed)
    Abstract [en]

    The total synthesis of capsaicin analogues was performed in one pot, starting from compounds that can be derived from lignin. Heterogeneous palladium nanoparticles were used to oxidise alcohols to aldehydes, which were further converted to amines by an enzyme cascade system, including an amine transaminase. It was shown that the palladium catalyst and the enzyme cascade system could be successfully combined in the same pot for conversion of alcohols to amines without any purification of intermediates. The intermediate vanillyl-amine, prepared with the enzyme cascade system, could be further converted to capsaicin analogues without any purification using either fatty acids and a lipase, or Schotten-Baumann conditions, in the same pot. An aldol compound (a simple lignin model) could also be used as starting material for the synthesis of capsaicin analogues. Using l-alanine as organocatalyst, vanillin could be obtained by a retro-aldol reaction. This could be combined with the enzyme cascade system to convert the aldol compound to vanillylamine in a one-step one-pot reaction.

  • 2.
    Bah, Juho
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Naidu, Veluru Ramesh
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Teske, Johannes
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Franzén, Johan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Carbocations as Lewis Acid Catalysts: Scope and Reactivity2015In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 357, no 1, p. 148-158Article in journal (Refereed)
    Abstract [en]

    One class of potential Lewis acids that has received negligible attention as a catalyst is the carbocation. Here we show the potential of triarylmethylium ions as highly powerful Lewis acid catalysts for organic reactions. The Lewis acidity of the triarylmethylium ion can be easily tuned by variation of the electronic properties of the aromatic rings and the catalytic activity of the carbocation is shown to correlate directly to the level of stabilization of the empty p(C)-orbital at the cationic carbon. The versatility of triarylmethylium ions as efficient Lewis acid catalysts for organic reactions is demonstrated in Diels-Alder, aza-Diels-Alder, conjugate addition, halogenation, epoxide rearrangement and intramolecular hetro-ene reactions.

  • 3.
    Borg, Tessie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Danielsson, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Mohiti, Maziar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Restorp, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Diastereoselective Nucleophilic Addition to Aldehydes with Polar alpha- and alpha,beta-Substituents2011In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 353, no 11-12, p. 2022-2036Article in journal (Refereed)
    Abstract [en]

    The stereoselectivities obtained in Lewis acid-promoted Mukaiyama aldol additions and Sakurai allylations of mono-, and syn- and anti-disubstituted aldehydes possessing various polar alpha- and beta-substituents under non-chelating conditions are presented. The stereochemical outcome in the nucleophilic addition to alpha-substituted aldehydes containing an alpha-benzyloxy, alpha-fluoro or alpha-sulfonamide substituent are accurately predicted by current stereoinduction models. In contrast, the selectivitites obtained from addition of sterically demanding nucleophiles to alpha-chloro-substituted aldehydes cannot be rationalized by the same models and an alternative is discussed. The stereochemichal outcome in the additions to alpha, beta-disubstituted aldehydes is more complex and cannot be predicted using current models.

  • 4. Deiana, Luca
    et al.
    Zhao, Gui-Ling
    Lin, Shuangzheng
    Dziedzic, Pawel
    Zhang, Qiong
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Leijonmarck, Hans
    Cordova, Armando
    Organocatalytic Enantioselective Aziridination of alpha-Substituted alpha,beta-Unsaturated Aldehydes: Asymmetric Synthesis of Terminal Aziridines2010In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 352, no 18, p. 3201-3207Article in journal (Refereed)
    Abstract [en]

    The first example of a highly enantioselective organocatalytic aziridination of alpha-substituted alpha,beta-unsaturated aldehydes is presented. The reaction is catalyzed by simple chiral amines and gives access to highly functional terminal azirdines containing an alpha-tertiary amine stereocenter in high yields and enantiomeric ratios (95.5:4.5-98:2).

  • 5. Fiorati, Andrea
    et al.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Svedendahl Humble, Maria
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Tessaro, Davide
    Application of Transaminases in a Disperse System for the Bioamination of Hydrophobic Substrates2020In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 362, no 5, p. 1156-1166Article in journal (Refereed)
    Abstract [en]

    Abstract The challenging bioamination of hydrophobic substrates has been attained through the employment of a disperse system consisting of a combination of a low polarity solvent (e. g. isooctane or methyl-tert-butylether), a non-ionic surfactant and a minimal amount of water. In these conditions, amine transaminases (ATA) were shown to efficiently carry out the reductive amination of variously substituted cyclohexanones, providing good conversions often coupled with a superior stereoselectivity if compared with the corresponding chemical reductive amination. An array of synthetically useful 4-substituted aminocyclohexanes was consequentially synthesized through biocatalysis, analyzed and stereochemically characterized.

  • 6.
    Gerdin, Martin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Moberg, Christina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Enantioselective Platinum-Catalyzed Silicon-Boron Addition to 1,3-Cyclohexadiene2005In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 347, no 6, p. 749-753Article in journal (Refereed)
    Abstract [en]

    Silaboration of 1,3-cyclohexadiene in the presence of Pt(acac)(2), DIBALH, and a phosphoramidite prepared from (S)-1,1'-bi-2-naphthol and diisopropylamine led to (1R,4S)-1-(dimethylphenylsilyl)4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-cyclohexene with 70% ee. Chiral catalysts based on Ni gave no or essentially racemic product, whereas complexes containing Pd were inactive.

     

     

     

     

  • 7.
    Gerdin, Martin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Nadakudity, Sailendra Kumar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Worch, Christin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Moberg, Christina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Regioselective Preparation of Functionalized exo-Methylene-cyclopentanes and exo-Methylenepyrrolidines via Silaborative Carbocyclization of 1,6-Enynes2010In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 352, no 14-15, p. 2559-2570Article in journal (Refereed)
    Abstract [en]

    Silaborative carbocyclization of 1,6-enynes catalyzed by Pd-PEPPSI-IPr {PEPPSI=pyridine-enhanced precatalyst preparation stabilization and initiation; IPr=N,N-bis[2,6-(diisopropyl)phenyl] imidazolium} employing either (dimethylphenylsilyl) pinacolborane or (chlorodimethylsilyl)pinacolborane provides access to densely functionalized five-membered rings as single diastereomers in excellent yields. The vinylboronate functions were employed in palladium-catalyzed Suzuki cross-coupling reactions with a range of aryl bromides, containing electron-with-drawing as well as electron-donating substituents, furnishing arylated exo-methylenecyclopentanes or exo-methylenepyrrolidines in good yields. Subsequent oxidation of the isopropoxydimethylsilyl function generated via addition of (chlorodimethylsilyl)-pinacolborane provided access to hydroxymethyl derivatives of the arylated compounds. Use of a chiral ester, bismenthyl (2-propenyl)(2-propynyl)malonate, afforded two diastereomeric products which could be separated, thereby giving access to the cyclized compounds as single isomers, with opposite absolute configurations at the newly formed stereocenter.

  • 8. Grutters, Michiel M. P.
    et al.
    van der Vlugt, Jarl Ivar
    Pei, Yuxin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Mills, Allison M.
    Lutz, Martin
    Spek, Anthony L.
    Muller, Christian
    Moberg, Christina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Vogt, Dieter
    Highly Selective Cobalt-Catalyzed Hydrovinylation of Styrene2009In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 351, no 13, p. 2199-2208Article in journal (Refereed)
    Abstract [en]

    Phosphine complexes of cobalt halide salts activated by diethylaluminum chloride are shown to yield highly active catalysts in the hydrovinylation of styrene, with unprecedented high selectivity to the desired product 3-phenyl-1-butene (3P1B). Double-bond isomerization, a common problem in codimerization reactions, only occurs after full conversion with these catalyst systems, even at elevated temperature. The most active catalysts are based on cobalt halide species combined with either C-1- or C-2-bridged diphosphines, heterodonor P,N or P,O ligands, flexible bidentate phosphine ligands or monodentate phosphine ligands. Kinetic investigations show an order > 1 in catalyst, which indicates either the involvement of dinuclear species in the catalytic cycle or partial catalyst decomposition via a bimolecular pathway.

  • 9. Hallman, K.
    et al.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Palladium(II)-catalyzed oxidation of alcohols with air as reoxidant2001In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 343, no 3, p. 260-263Article in journal (Refereed)
    Abstract [en]

    Oxidation of primary and secondary aliphatic and secondary benzylic alcohols into their corresponding aldehydes and ketones was achieved in good yields with palladium catalysts using air as the reoxidant of palladium. The use of palladacycle 1 resulted in higher yields and a faster reaction than the use of Pd(OAc)(2) as the palladium source.

  • 10.
    Hammar, Peter
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Marcelli, Tommaso
    Van't Hoff Institute of Molecular Sciences, University of Amsterdam.
    Hiemstra, Henk
    Van't Hoff Institute of Molecular Sciences, University of Amsterdam.
    Himo, Fahmi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Density Functional Theory Study of the Cinchona Thiourea-Catalyzed Henry reaction: Mechanism and Enantioselectivity2007In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, no 17-18, p. 2537-2548Article in journal (Refereed)
    Abstract [en]

    We report a density functional theory investigation of the enantioselective Cinchona thiourea-catalyzed Henry reaction of aromatic aldehydes with nitromethane. We show that two pathways (differing in the binding modes of the reactants to the catalyst) are possible for the formation of the C-C bond, and that they have comparable reaction barriers. The enantioselectivity is investigated, and our results are in agreement with the experimentally observed solvent dependence of the reaction.

  • 11.
    Ibrahem, Ismail
    et al.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University.
    Hammar, Peter
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Vesely, Jan
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University.
    Rios, Ramon
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University.
    Eriksson, Lars
    Department of Structural Chemistry, Arrhenius Laboratory, Stockholm University.
    Córdova, Armando
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University.
    Organocatalytic asymmetric hydrophosphination of alpha,beta-unsaturated aldehydes: Development, mechanism and DFT calculations2008In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 350, no 11-12, p. 1875-1884Article, review/survey (Refereed)
    Abstract [en]

    The development and mechanism of the highly chemo- and enantioselective organocatalytic hydrophosphination reaction of alpha,beta-unsaturated aldehydes is presented. The reactions are catalyzed by protected chiral diarylprolinol derivatives and give access to optically active phosphine derivatives in high yields with up to 99% ee. The organocatalytic addition of other phosphorus nucleophiles was also investigated. The origin of the high enantioselectivity for the reaction with diphenylphosphine as the nucleophile is investigated by density functional theory calculations.

  • 12. Kohls, Hannes
    et al.
    Anderson, Mattias
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Dickerhoff, Jonathan
    Weisz, Klaus
    Cordova, Armando
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Brundiek, Henrike
    Bornscheuer, Uwe T.
    Hoehne, Matthias
    Selective Access to All Four Diastereomers of a 1,3-Amino Alcohol by Combination of a Keto Reductase- and an Amine Transaminase-Catalysed Reaction2015In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 357, no 8, p. 1808-1814Article in journal (Refereed)
    Abstract [en]

    The biocatalytic synthesis of chiral amines has become a valuable addition to the chemists' tool-box. However, the efficient asymmetric synthesis of functionalised amines bearing more than one stereocentre, such as 1,3-amino alcohols, remains challenging. By employing a keto reductase (KRED) and two enantiocomplementary amine transaminases (ATA), we developed a biocatalytic route towards all four diastereomers of 4-amino-1-phenylpentane-2-ol as a representative molecule bearing the 1,3-amino alcohol functionality. Starting from a racemic hydroxy ketone, a kinetic resolution using an (S)-selective KRED provided optically active hydroxy ketone (86% ee) and the corresponding diketone. Further transamination of the hydroxy ketone was performed by either an (R)- or an (S)-selective ATA, yielding the (2R,4R)- and (2R,4S)-1,3-amino alcohol diastereomers. The remaining two diastereomers were accessible in two subsequent asymmetric steps: the diketone was reduced regio- and enantioselectively by the same KRED, which yielded the (S)-configured hydroxy ketone. Eventually, the subsequent transamination of the crude product with (R)- and (S)-selective ATAs yielded the remaining (2S,4R)and (2S,4S)-diastereomers, respectively.

  • 13.
    Land, Henrik
    et al.
    Uppsala University.
    Ruggieri, Federica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Szekrenyi, Anna
    Fessner, Wolf-Dieter
    Berglund, Per
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Engineering the Active Site of an (S)-Selective Amine Transaminase for Acceptance of Doubly Bulky Primary Amines2020In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 362, no 4, p. 812-821Article in journal (Refereed)
    Abstract [en]

    A protein engineering approach for expanding the substrate scope of the (S)-selective Chromobacterium violaceum amine transaminase is presented. Amino acid residues in the small binding pocket of the active site were targeted in order to increase the pocket size for acceptance of primary amines bearing two bulky groups. A highly sensitive fluorescence assay was then used to evaluate the generated enzyme variants for their activity towards propyl- and benzyl-substituted screening substrates. The best variant, L59A/F88A, was successfully applied in the kinetic resolution of 1,2-diphenylethylamine using different conditions and substrate loadings. The variant L59A/F88A generated enantiomerically pure (R)-1,2-diphenylethylamine with ee >99 % under all tested conditions. The variant also holds great promise for synthesis of hydrophobic compounds as it shows optimum activity when 20 % (v/v) DMSO is applied as cosolvent. The variant L59A/F88A provides a great addition to the available catalyst toolbox for synthesis of chiral amines, as it is the first published (S)-selective amine transaminase showing activity towards benzyl-substituted primary amines.

  • 14.
    Lundgren, Stina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Wingstrand, Erica
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Moberg, Christina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lewis acid-Lewis base-catalysed enantioselective addition of alpha-ketonitriles to aldehydes2007In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, no 3, p. 364-372Article in journal (Refereed)
    Abstract [en]

    Additions of structurally diverse alpha-ketonitriles to aromatic and aliphatic prochiral aldehydes yielding highly enantioenriched acylated cyanohydrins were achieved using a combination of a titanium salen dimer and an achiral or chiral Lewis base. In most cases high yields and high enantioselectivities were observed. The ee was moderate in the initial part of the reaction but increased over time. This could be avoided, and higher ees obtained, by keeping the titanium complex, in the presence or absence of aldehyde and ketonitrile, at -40 degrees C prior to the addition of the Lewis base. A mechanism initiated by nucleophilic attack of the tertiary amine at the carbonyl carbon atom of the ketonitile is supported by C-13 labelling experiments.

  • 15.
    Marcelli, Tommaso
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Hammar, Peter
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Himo, Fahmi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Origin of Enantioselectivity in the Organocatalytic Reductive Amination of α-Branched Aldehydes2009In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 351, no 4, p. 525-529Article in journal (Refereed)
    Abstract [en]

    The reason for enantioselectivity in thereductive amination of α-branched aldehydes wasinvestigated. The relative energies of all the diastereomeric transition states for hydride transfer of a suitable computational model were calculated at the B3LYP/6-311+(2d,2p) level of theory. Our calculations successfully reproduce and rationalize the experimentally observed stereochemical outcome of the reaction.

  • 16.
    Marx, Lisa
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Rios-Lombardia, Nicolas
    Farnberger, Judith F.
    Kroutil, Wolfgang
    Benitez-Mateos, Ana I.
    Lopez-Gallego, Fernando
    Moris, Francisco
    Gonzalez-Sabin, Javier
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Chemoenzymatic Approaches to the Synthesis of the Calcimimetic Agent Cinacalcet Employing Transaminases and Ketoreductases2018In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 360, no 11, p. 2157-2165Article in journal (Refereed)
    Abstract [en]

    Abstract Several chemoenzymatic routes have been explored for the preparation of cinacalcet, a calcimimetic agent. Transaminases (TAs) and ketoreductases (KREDs) turned out to be useful biocatalysts for the preparation of key optically active precursors. Thus, the asymmetric amination of 1‐acetonaphthone yielded an enantiopure (R)‐amine, which can be alkylated in one step to yield cinacalcet. Alternatively, the bioreduction of the same ketone resulted in an enantiopure (S)‐alcohol, which was easily converted into the previous (R)‐amine. In addition, the reduction was efficiently performed with the KRED and its cofactor co‐immobilized on the same porous surface. This self‐sufficient heterogeneous biocatalyst presented an accumulated total turnover number (TTN) for the cofactor of 675 after 5 consecutive operational cycles. Finally, in a preparative scale synthesis the TA‐based approach was performed in aqueous medium and led to enantiopure cinacalcet in two steps and 50% overall yield.

  • 17. Marzorati, Mattia
    et al.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Riva, Sergio
    Danieli, Bruno
    Incorporation of primary amines into a polyester chain by a combination of chemical and lipase-catalyzed epsilon-caprolactone ring-opening processes2007In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, no 12-nov, p. 1963-1968Article in journal (Refereed)
    Abstract [en]

    A simple chemoenzymatic strategy for the incorporation of bioactive and suitably functionalized molecules into a polyester chain has been developed. The protocol involves first the reaction of a primary amine with E-caprolactone to give an amide carrying a terminal primary hydroxy group, followed by the enzymatic growth of the polymeric chain triggered by Novozym 435. This method is versatile and of different amines into polyesters, as has been shown with the model compounds benzylamine and tryptamine, the bioactive compound N-deacetylthiocolchicine and the functionalized propargylamine and tyramine.

  • 18.
    Ni, Shengjun
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Abd El Aleem Ali Ali El Remaily, Mahmoud
    Franzén, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Carbocation Catalyzed Bromination of Alkyl Arenes, a Chemoselective sp3 vs. sp2 C−H Functionalization2018In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 360, no 21, p. 4197-4204Article in journal (Refereed)
    Abstract [en]

    The versatility of the trityl cation (TrBF4) as a highly efficient Lewis acid organocatalyst isdemonstrated in a light induced benzylic brominaion of alkyl-arenes under mild conditions. The reaction wasconducted at ambient temperature under common hood light (55 W fluorescent light) with catalyst loadingsdown to 2.0 mol% using N-bromosuccinimide (NBS) as the brominating agent. The protocol is applicable toan extensive number of substrates to give benzyl bromides in good to excellent yields. In contrast to mostpreviously reported strategies, this protocol does not require any radical initiator or extensive heating. Forelectron-rich alkyl-arenes, the trityl ion catalyzed bromination could be easily switched between benzylic sp3CH functionalization and arene sp2 CH functionalization by simply alternating the solvent. Thischemoselective switch allows for high substrate control and easy preparation of benzyl bromides andbromoarenes, respectively. The chemoselective switch was also applied in a one-pot reaction of 1-methylnaphthalene for direct introduction of both sp3 CBr and sp2 CBr functionality.

  • 19.
    Paavola, Sari
    et al.
    KTH, Superseded Departments, Chemistry.
    Zetterberg, Krister
    KTH, Superseded Departments, Chemistry.
    Privalov, Timofei
    KTH, Superseded Departments, Chemistry.
    Csoregh, I.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Aerobic oxidation of 1-phenylethanol catalyzed by palladaheterocycles2004In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 346, no 2-3, p. 237-244Article in journal (Refereed)
    Abstract [en]

    Cyclometallated palladium compounds with pyridine were shown to serve as more efficient catalysts for the aerobic oxidation of 1-phenylethanol than a previously investigated analogue with an oxazoline ring. Substituents with different electronic properties in the phenyl ring were shown to exhibit an only minor influence on the reactivity of the catalytic system. The first step in the reaction consists of the splitting of the acetate bridge in the dimeric starting complex and coordination of a ligand to palladium. By ab initio calculations it was shown that, in the presence of solvent, a complex with pyridine was more stable than that with the alcohol, whereas the opposite situation was found in the gas phase. The complex with coordinated alcohol was stabilized by hydrogen bonding. Good agreement was found between the computed structure and the X-ray structure of the initial palladaheterocycle 1.

  • 20. Scheidt, Thomas
    et al.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Anderson, Mattias
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Chen, Yujie
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Yi, Dong
    Fessner, Wolf-Dieter
    Fluorescence-Based Kinetic Assay for High-Throughput Discovery and Engineering of Stereoselective omega-Transaminases2015In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 357, no 8, p. 1721-1731Article in journal (Refereed)
    Abstract [en]

    omega-Transaminases are a valuable class of enzymes for the production of chiral amines with either (R)- or (S)-configuration in high optical purity and 100% yield by the biocatalytic reductive amination of prochiral ketones. A versatile new assay was developed to quantify omega-transaminase activity for the kinetic characterization and enantioselectivity typing of novel or engineered enzymes based on the conversion of 1-(6-methoxynaphth-2-yl)alkylamines. The associated release of the acetonaphthone product can be monitored by the development of its bright fluorescence at 450 nm with very high sensitivity and selectivity. The assay principle can be used to quantify omega-transaminase catalysis over a very broad range of enzyme activity. Because of its simplicity and low substrate consumption in microtiter plate format the assay seems suitable for liquid screening campaigns with large library sizes in the directed evolution of optimized transaminases. For assay substrates that incorporate structural variations, an efficient modular synthetic route was developed. This includes racemate resolution by lipase-catalyzed transacylation to furnish enantiomerically pure (R)and (S)-configured amines. The latter are instrumental for the rapid enantioselectivity typing of omega-transaminases. This method was used to characterize two novel (S)-selective taurine-pyruvate transaminases of the subtype 6a from thermophilic Geobacillus thermodenitrificans and G. thermoleovorans.

  • 21.
    Seashore-Ludlow, Brinton
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Danielsson, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Domino Carbopalladation-Carbonylation: Investigation of Substrate Scope2012In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 354, no 1, p. 205-216Article in journal (Refereed)
    Abstract [en]

    This work gives an in depth account of our domino carbopalladation-carbonylation method for substrates possessing beta-hydrogens. The scope of the method is examined for allylic amines containing trisubstituted olefins and we detail our attempts toward the diastereospecific synthesis of contiguous quaternary centers using this technology. The results give key insights into the relative rates of the competing reactions of the alkyl palladium intermediates, which is crucial for the understanding and development of new domino processes.

  • 22.
    Tilliet, Mélanie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lundgren, Stina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Moberg, Christina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Levacher, Vincent
    Laboratoire de Chimie Organique Fine et Hétérocyclique, UMR 6014, Université et INSA de Rouen.
    Polymer-Bound Pyridine-Bis(oxazoline). Preparation through Click Chemistry and Evaluation in Asymmetric Catalysis2007In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, no 13, p. 2079-2084Article in journal (Refereed)
    Abstract [en]

    A pyridine-bis(oxazoline) ligand was efficiently immobilized by copper(I)-catalyzed azide-alkyne cycloaddition onto a polystyrene resin. The so obtained click-pybox resin 1a was associated with various metal salts (YbCl3, LuCl3, CuOTf) and the resulting resin-bound catalysts were explored in ring-opening of cyclohexene oxide, silylcyanation of benzaldehyde and alkynylation of imines. These new polymer-supported catalysts exhibit good to excellent performances in terms of catalytic activity, enantioselectivity and recyclability.

  • 23.
    Torssell, Staffan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    1,3-Dipolar Cycloadditions of Carbonyl Ylides to Aldimines:  Scope, Limitations and Asymmetric Cycloadditions2006In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 348, no 16-17, p. 2421-2430Article in journal (Refereed)
    Abstract [en]

    The development of a diastereoselective 1,3-dipolar cycloaddition of carbonyl ylides and imines for the synthesis of alpha-hydroxy-beta-amino esters is described. The methodology is successfully applied to chiral alpha-methylbenzylimines affording enantiomerically pure syn-beta-amino alcohols, which is exemplified with a short asymmetric synthesis of the paclitaxel side-chain. The use of chiral Rh(11) carboxylate catalysts for the development of a catalytic enantioselective 1,3-dipolar cycloaddition is also described, affording syn-beta-amino alcohols in modest enantiomeric purity (e.r. up to 82:18).

  • 24.
    Vongvilai, Pornrapee
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Larsson, Rikard
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Direct Asymmetric Dynamic Kinetic Resolution by Combined Lipase Catalysis and Nitroaldol (Henry) Reaction2008In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 350, no 3, p. 448-452Article in journal (Refereed)
    Abstract [en]

    The asymmetric synthesis of β-nitroalkanol derivatives was simply achieved by a combined nitroaldol (Henry) reaction with lipase-catalyzed transesterification in high yield and enantiomeric purity (up to 92% and 99% ee) through a direct one-pot procedure.

  • 25.
    Zhang, Wei
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Franzén, Johan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Diverse Asymmetric Quinolizidine Synthesis: A Stereodivergent One-Pot Approach2010In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 352, no 2-3, p. 499-518Article in journal (Refereed)
    Abstract [en]

    A diverse stereodivergent organocatalytic one-pot addition/cyclization/annulation sequence to optically active quinolizidine derivatives from easily available starting materials is presented. The one-pot sequence relies on a pyrrolidine-catalyzed enantioselective Conjugate addition of electron-deficient amide alpha-carbons to alpha,beta-unsaturated aldehydes, spontaneous hemiaminal formation and acid-catalyzed/mediated N-acyliminium ion cyclization to give the quinolizidine framework. Simple tuning of the reaction conditions in the N-acyliminuim ion cyclization step provides a diastereomeric switch, which gives access to both of the two bridgehead epimers through kinetic, thermodynamic or chelation control. The methodology display a broad substrate scope that is demonstrated by the stereoselective formation of indolo-, thieno-, benzofuro-, furo- and different benzoquinolizidine derivatives with high atom efficiency, up to >99% ee and up to >95:5 dr. Due to its efficiency, synthetic diversity and operational simplicity, this protocol has the potential to find important use as a key step in natural product Synthesis, biochemistry and pharmaceutical science. The stereochemical Outcome of the one-pot sequence was investigated. and the mechanism and origin of stereoselectivity of the different steps is discussed.

  • 26.
    Zhang, Yan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Vongvilai, Pornrapee
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Sakulsombat, Morakot
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Asymmetric Synthesis of Substituted Thiolanes through Domino Thia-Michael-Henry Dynamic Covalent Systemic Resolution using Lipase Catalysis2014In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 356, no 5, p. 987-992Article in journal (Refereed)
    Abstract [en]

    Dynamic systems based on consecutive thia-Michael and Henry reactions were generated and transformed using lipase-catalyzed asymmetric transformation. Substituted thiolane structures with three contiguous stereocenters were resolved in the process in high yields and high enantiomeric excesses.

1 - 26 of 26
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