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  • 301. Das, Biswanath
    et al.
    Daver, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Singh, Amrendra
    Singh, Reena
    Haukka, Matti
    Demeshko, Serhiy
    Meyer, Franc
    Lisensky, George
    Jarenmark, Martin
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nordlander, Ebbe
    A Heterobimetallic FeIIIMnII Complex of an Unsymmetrical Dinucleating Ligand: A Structural and Functional Model Complex for the Active Site of Purple Acid Phosphatase of Sweet Potato2014Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2014, nr 13, s. 2204-2212Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The heterodinuclear mixed-valence complex [FeMn(ICIMP)(OAc)(2)Cl] (1) {H2ICIMP = 2-(N-carboxylmethyl)-[N-(N-methylimidazolyl-2-methyl)aminomethyl]-[6-(N-isopropylmethyl)-[N-(N-methylimidazolyl-2-methyl)]aminomethyl-4-methylphenol], an unsymmetrical N4O2 donor ligand} has been synthesized and fully characterized by several spectroscopic techniques as well as by X-ray crystallography. The crystal structure of the complex reveals that both metal centers in 1 are six-coordinate with the chloride ion occupying the sixth coordination site of the Mn-II ion. The phenoxide moiety of the ICIMP ligand and both acetate ligands bridge the two metal ions of the complex. Mossbauer spectroscopy shows that the iron ion in 1 is high-spin Fe-III. Two quasi-reversible redox reactions for the complex, attributed to the (FeMnII)-Mn-III/(FeMnII)-Mn-II (at -0.67 V versus Fc/Fc(+)) and (FeMnII)-Mn-III/(FeMnIII)-Mn-III (at 0.84 V), were observed by means of cyclic voltammetry. Complex 1, with an Fe-III-Mn-II distance of 3.58 angstrom, may serve as a model for the mixed-valence oxidation state of purple acid phosphatase from sweet potato. The capability of the complex to effect organophosphate hydrolysis (phosphatase activity) has been investigated at different pH levels (5.5-11) by using bis(2,4-dinitrophenyl)phosphate (BDNPP) as the substrate. Density functional theory calculations indicate that the substrate coordinates to the Mn-II ion. In the transition state, a hydroxide ion that bridges the two metal ions becomes terminally coordinated to the Fe-III ion and acts as a nucleophile, attacking the phosphorus center of BDNPP with the concomitant dissociation of the leaving group.

  • 302. Das, Biswanath
    et al.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shatskiy, Andrey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Demeshko, Serhiy
    Liao, Rong-Zhen
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Haukka, Matti
    Zeglio, Erica
    Abdel-Magied, Ahmed F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Meyer, Franc
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nordlander, Ebbe
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Water oxidation catalyzed by molecular di- and nonanuclear Fe complexes: importance of a proper ligand framework2016Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, nr 34, s. 13289-13293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis of two molecular iron complexes, a dinuclear iron(III,III) complex and a nonanuclear iron complex, based on the di-nucleating ligand 2,2'-(2-hydroxy-5-methyl-1,3-phenylene)bis(1H-benzo[d]imidazole-4-carboxylic acid) is described. The two iron complexes were found to drive the oxidation of water by the one-electron oxidant [Ru(bpy)(3)](3+).

  • 303.
    Daver, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Quantum Chemical Modeling of Phosphoesterase Mimics and Chemistry in Confined Spaces2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In this thesis, density functional theory is employed in the study of two kinds of systems that can be considered to be biomimetic in their own ways. First, three binuclear metal complexes, synthesized by the group of Prof. Ebbe Nordlander, have been investigated. The complexes are designed to resemble the active sites of phosphatase enzymes and have been examined in complexes where either two Zn(II) ions or one Fe(III) and one Mn(II) ion are bound. These dinuclear compounds were studied as catalysts for the hydrolysis of bis(2,4-dinitrophenyl) phosphate and the transesterification of 2-hydroxypropyl p-nitrophenyl phosphate, which are model systems for the same reactions occurring in DNA or RNA. It was found that the two reactions take place in similar ways: a hydroxide ion that is terminally bound to one of the metal centers acts either as a nucleophile in the hydrolysis reaction or as a base in the transesterification. The leaving groups depart in an effectively concerted manner, and the formed catalyst-product complexes are predicted to be the resting states of the catalytic cycles. The rate-determining free energy barriers are identified from the catalyst-product complex in one catalytic cycle to the transition state of nucleophilic attack in the next.

    Another type of biomimetic modeling is made with an aim of imitating the conceptual features of selective binding of guests and screening them from solute-solvent interactions. Such features are found in so-called nanocontainers, and this thesis is concerned with studies of two capsules synthesized by the group of Prof. Julius Rebek, Jr. First, the cycloaddition of phenyl acetylene and phenyl azide has experimentally been observed to be accelerated in the presence of a capsule. Computational studies were herein performed on this system, and a previously unrecognized structure of the capsule is discovered. Two main factors are then identified as sources of the rate acceleration compared to the uncatalyzed reaction, namely the reduction of the entropic component and the selective destabilization of the reactant supercomplex over the transition state.

    In the second capsule study, the alkane binding trends of a water-soluble cavitand was studied. It is found that implicit solvation models fail severely in reproducing the experimental equilibrium observed between binding of n-decane by the cavitand monomer and encapsulation in the capsule dimer. A mixed explicit/implicit solvation protocol is developed to better quantify the effect of hydrating the cavitand, and a simple correction to the hydration free energy of a single water molecule is proposed to remedy this. The resulting scheme is used to predict new hydration free energies of the cavitand complexes, resulting in significant improvement vis-à-vis experiments.

    The computational results presented in this thesis show the usefulness of the quantum chemical calculations to develop understanding of experimental trends observed for substrate binding and catalysis. In particular, the methodology is shown to be versatile enough such that experimental observations can be reproduced for such diverse systems as studied herein.

  • 304.
    Daver, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Quantum Chemical Modelling of Biomimetic Phosphoesterase Complexes2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Phosphoesterases are a class of enzymes that catalyze hydrolysis of phosphoester bonds. They facilitate the modification of nucleic acid sequences, as well as the breakdown of rest products of warfare agents and insecticides. In this thesis, three biomimetic complexes that perform the same tasks are studied using density functional theory.

    Two of the catalysts contain a dizinc core while the third binds an Fe(III) ion and a Mn(II)ion. These complexes catalyze the hydrolysis of the phosphodiester substrate bis-(2,4)-dinitrophenyl phosphate (BDNPP). The substrate is analogous to the phosphoric link between two nucleotides in DNA, and the system is thus a model for cleaving bonds between nucleotides.

    By means of computational modelling, the reaction mechanisms are investigated in detail. Different binding modes of the substrates to the catalysts are considered and several mechanistic proposals are evaluated. Conclusions are drawn on the basis of free energy barriers calculated for the different mechanisms.

    In all studied reactions, a hydroxide bridging the metals becomes terminally coordinated to one of the zinc ions and then attacks the phosphorus center in a nucleophilic fashion. Leaving group dissociation takes place without a barrier.

    One of the catalysts was also studied binding a model substrate for RNA, namely hydroxy-2-isopropyl p-nitrophenyl phosphate (HPNP). The hydroxide was found to act as a base, activating the alcohol moiety of the substrate which in turn performs the nucleophilic attack on the phosphorus center.

    Common for all studied systems is that the catalyst-product complex is calculated to be the most stable species. Hence, this complex is suggested to be the resting state of the catalytic cycle. The free energy barriers of the reactions are associated with going from the catalystproduct complex of one catalytic cycle to the transition state for nucleophilic attack in the next. Calculated barriers are in good agreements with experiments.

  • 305.
    Daver, Henrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Algarra, Andrés G.
    Rebek, Jr., Julius
    Harvey, Jeremy N.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Toward Accurate Quantum Chemical Modeling of Water-Soluble Self-Assembled CapsulesManuskript (preprint) (Övrigt vetenskapligt)
  • 306.
    Daver, Henrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Algarra, Andrés G.
    Rebek, Julius
    Harvey, Jeremy N.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mixed Explicit-Implicit Solvation Approach for Modeling of Alkane Complexation in Water-Soluble Self-Assembled Capsules2018Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, nr 39, s. 12527-12537Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The host-guest binding properties of a water-soluble resorcinarene-based cavitand are examined using density functional theory methodology. Experimentally, the cavitand has been observed to self-assemble in aqueous solution into both 1:1 and 2:1 host/guest complexes with hydrophobic guests such as n-alkanes. For n-decane, equilibrium was observed between the 1:1 and 2:1 complexes, while 1:1 complexes are formed with shorter n-alkanes and 2:1 complexes are formed with longer ones. These findings are used to assess the standard quantum chemical methodology. It is first shown that a rather advanced com- putational protocol (B3LYP-D3(BJ)/6-311+G(2d,2p) with COSMO-RS and quasi-rigid-rotor-harmonic-oscillator) gives very large errors. Systematic examination of the various elements of the methodology shows that the error stems from the implicit solvation model. A mixed explicit-implicit solvation protocol is developed that involves a parametrization of the hydration free energy of water such that water cluster formation in water is predicted to be thermoneutral. This new approach is demonstrated to lead to a major improvement in the calculated binding free energies of n-alkanes, reproducing very well the 1:1 versus 2:1 host/guest binding trends.

  • 307.
    Daver, Henrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Das, Biswanath
    Nordlander, Ebbe
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Theoretical Study of Phosphodiester Hydrolysis and Transesterification Catalyzed by an Unsymmetric Biomimetic Dizinc Complex2016Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 55, nr 4, s. 1872-1882Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Density functional theory calculations have been used to investigate the reaction mechanisms of phosphodiester hydrolysis and transesterification catalyzed by a dinuclear zinc complex of the 2-(N-isopropyl-N-((2-pyridyl)methyl)-aminomethyl)-6-(N-(carboxylmethyl)-N-((2-pyridyl)methyl)amino-methyl)-4-methylphenol (IPCPMP) ligand, mimicking the active site of zinc phosphotriesterase. The substrates bis(2,4)-dinitrophenyl phosphate (BDNPP) and 2-hydroxypropyl-p-nitrophenyl phosphate (HPNP) were employed as analogues of DNA and RNA, respectively. A number of different mechanistic proposals were considered, with the active catalyst harboring either one or two hydroxide ions. It is concluded that for both reactions the catalyst has only one hydroxide bound, as this option yields lower overall energy barriers. For BDNPP hydrolysis, it is suggested that the hydroxide acts as the nucleophile in the reaction, attacking the phosphorus center of the substrate. For HPNP transesterification, on the other hand, the hydroxide is proposed to act as a Bronsted base, deprotonating the alcohol moiety of the substrate, which in turn performs the nucleophilic attack. The calculated overall barriers are in good agreement with measured rates. Both reactions are found to proceed by essentially concerted associative mechanisms, and it is demonstrated that two consecutive catalytic cycles need to be considered in order to determine the rate-determining free energy barrier.

  • 308.
    Daver, Henrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Harvey, Jeremy N.
    Rebek, Jr., Julius
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Quantum Chemical Modeling of Cycloaddition Reaction in a Self-Assembled Capsule2017Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 139, nr 43, s. 15494-15503Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dispersion-corrected density functional theory is used to study the cycloaddition reaction between phenyl acetylene and phenyl azide inside a synthetic, self-assembled capsule. The capsule is first characterized computationally and a previously unrecognized structure is identified as being the most stable. Next, an examination of the free energies of host-guest complexes is conducted, considering all possible reagent, solvent and solvent impurity combinations as guests. The experimentally observed relative stabilities of host-guest complexes are quite well reproduced, when the experimental concentrations are taken into account. Experimentally, the presence of the host capsule has been shown to accelerate the cycloaddition reaction and to yield exclusively the 1,4-regioisomer product. Both these observations are reproduced by the calculations. A detailed energy decomposition analysis shows that reduction of the entropic cost of bringing together the reactants along with a geometric destabilization of the reactant supercomplex are the major contributors to the rate acceleration compared to the background reaction. Finally, a sensitivity analysis is conducted to assess the stability of the results with respect to the choice of methodology.

  • 309.
    Davies, Ronnie
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Rydberg, Per
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Westberg, Emelie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Motwani, Hitesh V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnstone, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Törnqvist, Margareta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    A New General Pathway for Synthesis of Reference Compounds of N-Terminal Valine-Isocyanate Adducts2010Ingår i: Chemical Research in Toxicology, ISSN 0893-228X, E-ISSN 1520-5010, Vol. 23, nr 3, s. 540-546Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adducts to Hb could be used as biomarkers to monitor exposure to isocyanates. Particularly useful is the measurement of carbamoylation of N-terminal valines in Hb, after detachment as hydantoins. The synthesis of references from the reactive isocyanates, especially diisocyanates, has been problematic due to side reactions and polymerization of the isocyanate starting material. A simpler, safer, and more general method for the synthesis of valine adducts of isocyanates has been developed using N-[(4-nitrophenyl)-carbamate]valine methylamide (NPCVMA) as the key precursor to adducts of various mono- and diisocyanates of interest. By reacting NPCVMA with a range of isocyanate-related amines, carbamoylated valines are formed without the use of the reactive isocyanates. The carbamoylated products synthesized here were cyclized with good yields of the formed hydantoins. The carbamoylated derivative from phenyl isocyanate also showed quantitative yield in a test with cyclization tinder the conditions used in blood. This new pathway for the preparation of N-carbamoylated model compounds overcomes the above-mentioned problems in the synthesis and is a general and simplified approach, which could make such reference compounds of adducts to N-terminal valine from isocyanates accessible for biomonitoring purposes. The synthesized hydantoins corresponding to adducts from isocyanic acid, methyl isocyanate, phenyl isocyanate, and 2,6-toluene diisocyanate were characterized by LC-MS analysis. The background level of the hydantoin from isocyanic acid in human blood was analyzed with the LC-MS conditions developed.

  • 310.
    Deiana, Luca
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Development of Catalytic Enantioselective Approaches for the Synthesis of Carbocycles and Heterocycles2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In biological systems, most of the active organic molecules are chiral. Some of the main constituents of living organisms are amino acids and sugars. They exist predominantly in only one enantiomerically pure form. For example, our proteins are built-up by L-amino acids and as a consequence they are enatiomerically pure and will interact in different ways with enantiomers of chiral molecules. Indeed, different enantiomers or diastereomers of a molecule could often have a drastically different biological activity. It is of paramount importance in organic synthesis to develop new routes to control and direct the stereochemical outcome of reactions. The aim of this thesis is to investigate new protocols for the synthesis of complex chiral molecules using simple, environmentally friendly proline-based organocatalysts. We have investigated, the aziridination of linear and branched enals, the stereoselective synthesis of β-amino acids with a carbene co-catalyst, the synthesis of pyrazolidines, the combination of heterogeneous transition metal catalysis and amine catalysis to deliver cyclopentenes bearing an all-carbon quaternary stereocenter and a new heterogeneous dual catalyst system for the carbocyclization of enals. The reactions presented in this thesis afforded the corresponding products with high levels of chemo-, diastero- and enantioselectivity.

  • 311.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Afewerki, Samson
    Palo-Nieto, Carlos
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cordova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Mid Sweden University.
    Highly Enantioselective Cascade Transformations by Merging Heterogeneous Transition Metal Catalysis with Asymmetric Aminocatalysis2012Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 2, s. 851-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The concept of combining heterogeneous transition metal and amine catalysis for enantioselective cascade reactions has not yet been realized. This is of great advantage since it would allow for the recycling of expensive and non-environmentally friendly transition metals. We disclose that the use of a heterogeneous Pd-catalyst in combination with a simple chiral amine co-catalyst allows for highly enantioselective cascade transformations. The preparative power of this process has been demonstrated in the context of asymmetric cascade Michael/carbocyclization transformations that delivers cyclopentenes bearing an all carbon quaternary stereocenters in high yields with up to 30: 1 dr and 99% ee. Moreover, a variety of highly enantioselective cascade hetero-Michael/carbocyclizations were developed for the one-pot synthesis of valuable dihydrofurans and pyrrolidines (up to 98% ee) by using bench-stable heterogeneous Pd and chiral amines as co-catalysts.

  • 312.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ibrahem, Ismail
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rios, Ramon
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic asymmetric aziridination of α, β- unsaturated aldehydes2011Ingår i: Abstracts of Papers, 242nd ACS National Meeting & Exposition, Denver, CO, United States, August 28-September 1, 2011, American Chemical Society , 2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The development, scope and application of the highly enantioselective organocatalytic aziridination of a, b- unsaturated aldehydes is presented. The aminocatalytic aziridination of a, b- unsaturated aldehydes enables the asymmetric formation of b-formylaziridines with up to >19:1 dr and 99% ee. The aminocatalytic aziridination of a-monosobstituted enals gives access to terminal a-substituted-a-formyl aziridines in high yields and up to 99% ee. In the case of the organocatalytic aziridination of disubstituted a, b-unsaturated aldehydes, the transformations gives nearly enantiomeric pure b-formyl-functionalized aziridine products. A higly enantioselective one-pot cascade sequence based on combination of asymmetric amine and N-heterocyclic carbene catalysis is also disclosed. This transformation gives the corresponding N-Boc and N-Cbz protected b-amino acid esters with ee´s ranging from 92-99%.

  • 313.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dziedzic, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ullah, Farman
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lin, Shuangzheng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dynamic kinetic asymmetric transformation (DYKAT) by combination of amine and transition metal cascade catalysis2010Ingår i: Abstracts of Papers, 239th ACS National Meeting, San Francisco, CA, United States, March 21-25, 2010, Washington, D C: American Chemical Society , 2010Konferensbidrag (Övrigt vetenskapligt)
  • 314.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dziedzic, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vesely, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ibrahem, Ismail
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rios, Ramón
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic asymmetric aziridination of α,β-unsaturated aldehydes2011Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, nr 28, s. 7904-7917Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development, scope, and application of the highly enantioselective organocatalytic aziridination of α,β-unsaturated aldehydes is presented. The aminocatalytic azirdination of α,β-unsaturated aldehydes enables the asymmetric formation of β-formyl aziridines with up to >19:1 d.r. and 99% ee. The aminocatalytic aziridination of α-monosubstituted enals gives access to terminal α-substituted-α-formyl aziridines in high yields and upto 99% ee. In the case of the organocatalytic aziridination of disubstituted α,β-unsaturated aldehydes, the transformations were highly diastereo- and enantioselective and give nearly enantiomerically pure β-formyl-functionalized aziridine products (99% ee). A highly enantioselective one-pot cascade sequence based on the combination of asymmetric amine and N-heterocycliccarbene catalysis (AHCC) is also disclosed. This one-pot three-component co-catalytic transformation between α,β-unsaturated aldehydes, hydroxylamine derivatives, and alcohols gives the corresponding N-tert-butoxycarbonyl and N-carbobenzyloxy-protected β-amino acid esters with ee values ranging from 92–99%. The mechanisms and stereochemistry of all these catalytic transformations are also discussed.

  • 315.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ghisu, Lorenza
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Afewerki, Samson
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hedin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bacsik, Zoltan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Mid-Sweden University, Sweden.
    Enantioselective Heterogeneous Synergistic Catalysis for Asymmetric Cascade Transformations2014Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 356, nr 11-12, s. 2485-2492Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A modular design for a novel heterogeneous synergistic catalytic system, which simultaneously activates the electrophile and nucleophile by the combined activation modes of a separate metal and non-metal catalyst, for asymmetric cascade transformations on a solid surface is disclosed. This modular catalysis strategy generates carbocycles (up to 97.5: 2.5 er) as well as spirocyclic oxindoles (97.5: 2.5 to > 99: 0.5 er), containing all-carbon quaternary centers, in a highly enantioselective fashion via a one-pot dynamic relay process.

  • 316.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ghisu, Lorenza
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cordova, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Afewerki, Samson
    Zhang, Renyun
    Cordova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Mittuniversitetet, Sundsvall.
    Efficient and Highly Enantioselective Aerobic Oxidation-Michael-Carbocyclization Cascade Transformations by Integrated Pd(0)-CPG Nanoparticle/Chiral Amine Relay Catalysis2014Ingår i: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, Vol. 46, nr 10, s. 1303-1310Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of highly diastereo- and enantioselective aerobic oxidation-Michael-carbocyclization cascade transformations by integrated heterogeneous Pd(0)-CPG nanoparticle/chiral amine relay catalysis are disclosed. The heterogeneous Pd(0)-CPG nanoparticle catalysts were efficient for both the sequential aerobic oxidation and dynamic kinetic asymmetric Michael-carbocyclization transformations, resulting in 1) oxidation of a variety of allylic alcohols to enals and 2) formation of cyclopentenes containing an all-carbon quaternary stereocenter in good to high yields with up to 20:1 dr and 99.5:0.5 er.

  • 317.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jiang, Yan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palo-Nieto, Carlos
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Afewerki, Samson
    Incerti-Pradillos, Celia A.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Mid Sweden University, Sweden.
    Combined Heterogeneous Metal/Chiral Amine: Multiple Relay Catalysis for Versatile Eco-Friendly Synthesis2014Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 53, nr 13, s. 3447-3451Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein is described a versatile and broad synergistic strategy for expansion of chemical space and the synthesis of valuable molecules (e.g. carbocycles and heterocycles), with up to three quaternary stereocenters, in a highly enantioselective fashion from simple alcohols (31examples, 95:5 to >99.5:0.5 e.r.) using integrated heterogeneous metal/chiral amine multiple relay catalysis and air/O-2 as the terminal oxidant. A novel highly 1,4-selective heterogeneous metal/amine co-catalyzed hydrogenation of enals was also added to the relay catalysis sequences.

  • 318.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dziedzik, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rios, Ramón
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vesely, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    One-pot highly enantioselective catalytic Mannich-type reactions between aldehydes and stable α-amido sulfones: asymmetric synthesis of β-amino aldehydes and β-amino acids2010Ingår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, nr 2, s. 234-237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A highly enantioselective catalytic route to carbamate- and benzoate-protected beta-amino aldehydes and beta-amino acids is presented. The amino acid-catalyzed one-pot asymmetric reaction between unmodified aldehydes and alpha-amido sulfones gives the corresponding beta-amino compounds with up to 95:5 dr and 97-99%

  • 319.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Leijonmarck, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lehmann, Christian
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Lehmann, Christian W.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Mid Sweden University.
    Direct Catalytic Asymmetric Synthesis of Pyrazolidine Derivatives2012Ingår i: ChemistryOpen, ISSN 2191-1363, Vol. 1, nr 3, s. 134-139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A highly enantioselective, metal-free cascade reaction between di-1,2-N-protected hydrazine and α,β-unsaturated aldehydes is disclosed. The catalytic, asymmetric cascade transformation is a direct entry to 3-hydroxypyrazolidine and 3-allylpyrazolidine derivatives in one step and two steps, respectively, with >19:1 d.r. and 98–99 % ee using simple chiral pyrrolidines as catalysts.

  • 320.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lin, Shuangzheng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dziedzic, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhang, Qiong
    Leijonmarck, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Organocatalytic enantioselective aziridination of α-substituted α,β-unsaturated aldehydes: asymmetric synthesis ot terminal aziridines2010Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 352, nr 18, s. 3201-3207Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 321.
    Deng, Hong-Ping
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Allylic sp (3) C-H borylation of alkenes via allyl-Pd intermediates: an efficient route to allylboronates2014Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 50, nr 65, s. 9207-9210Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Palladium catalyzed allylic C-H functionalization was performed using exocyclic alkene substrates. Multi-component synthesis of stereodefined homoallylic alcohols could be performed using a reaction sequence involving allylic C-H borylation and allylation of aldehydes.

  • 322.
    Deng, Hong-Ping
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wang, Dong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Direct Allylation of Quinones with Allylboronates2015Ingår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 80, nr 6, s. 3343-3348Artikel i tidskrift (Refereegranskat)
    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.

  • 323.
    Deng, Youqian
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bartholomeyzik, Teresa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Persson, Andreas K. A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium-Catalyzed Oxidative Arylating Carbocyclization of Allenynes2012Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 51, nr 11, s. 2703-2707Artikel i tidskrift (Refereegranskat)
  • 324.
    Deng, Youqian
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium-Catalyzed Oxidative Acyloxylation/Carbocyclization of Allenynes2013Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, nr 11, s. 3217-3221Artikel i tidskrift (Refereegranskat)
  • 325.
    Deng, Youqian
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Persson, Andreas K. A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium-Catalyzed Oxidative Carbocyclizations2012Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 37, s. 11498-11523Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Palladium-catalyzed oxidative carboncarbon bond-forming annulations, that is, carbocyclization reactions, have recently emerged as efficient and atom-economical routes to carbo- and heterocycles, whereby less functionalized substrates and fewer synthetic steps are needed to obtain a target molecule compared with traditional non-oxidative carboncarbon bond-forming reactions. In this review, the synthetic efforts in palladium-catalyzed oxidative carbocyclization reactions are summarized.

  • 326.
    Deng, Youqian
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Teresa, Bartholomeyzik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Control of Selectivity in Palladium-Catalyzed Oxidative Carbocyclization/Borylation of Allenynes2013Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, nr 24, s. 6283-6287Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In control: A highly selective carbocyclization/borylation of allenynes with bis(pinacolato)diboron (B2pin2) under palladium catalysis and with p-benzoquinone (BQ) as the oxidant was developed. The use of either LiOAc⋅2 H2O with 1,2-dichloroethane (DCE) as the solvent or BF3⋅Et2O together with THF is crucial for the selective formation of borylated trienes and vinylallenes, respectively.

  • 327.
    Deska, Jan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Enzymatic kinetic resolution of primary allenic alcohols. Application to the total synthesis and stereochemical assignment of striatisporolide A2009Ingår i: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 7, nr 17, s. 3379-3381Artikel i tidskrift (Refereegranskat)
  • 328.
    Deska, Jan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    del Pozo Ochoa, Carolina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Chemoenzymatic dynamic kinetic resolution of axially chiral allenes2010Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, nr 15, s. 4447-4451Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dimeric palladium bromide complexes bearing monodentate N-heterocyclic carbene ligands have been identified as efficient catalysts for the chemoselective racemization of axially chiral allenyl alcohols. In combination with porcine pancreatic lipase as biocatalyst, a dynamic kinetic resolution has been developed, giving access to optically active allenes in good yield and high enantiomeric purity (

  • 329.
    Dey, Chandan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lindstedt, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Olofsson, Berit
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Wallenberg Research Centre at Stellenbosch University, South Africa.
    Metal-Free C-Arylation of Nitro Compounds with Diaryliodonium Salts2015Ingår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 17, nr 18, s. 4554-4557Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An efficient, mild, and metal-free arylation of nitro-alkanes with diaryliodonium salts has been developed, giving easy access to tertiary nitro compounds. The reaction proceeds in high yields without the need for excess reagents and can be extended to alpha-arylation of nitroesters. Nitroalkanes were selectively C-arylated in the presence of other easily arylated functional groups, such as phenols and aliphatic alcohols.

  • 330.
    Di Francesco, Davide
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Subbotina, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rautiainen, Sari
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Samec, Joseph S. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ductile Pd-Catalysed Hydrodearomatization of Phenol-Containing Bio-Oils Into Either Ketones or Alcohols using PMHS and H2O as Hydrogen Source2018Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 360, nr 20, s. 3924-3929Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of phenolic bio-oil components were selectively hydrodearomatized by palladium on carbon into the corresponding ketones or alcohols in excellent yields using polymethylhydrosiloxane and water as reducing agent. The selectivity of the reaction was governed by the water concentration where selectivity to alcohol was favoured at higher water concentrations. As phenolic bio-oil examples cardanol and beech wood tar creosote were studied as substrate to the developed reaction conditions. Cardanol was hydrodearomatized into 3-pentadecylcyclohexanone in excellent yield. From beech wood tar creosote, a mixture of cyclohexanols was produced. No hydrodeoxygenation occurred, suggesting the applicability of the reported method for the production of ketone-alcohol oil from biomass.

  • 331.
    Diner, Colin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Recent Advances in the Preparation and Application of Allylboron Species in Organic Synthesis2017Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 139, nr 1, s. 2-14Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    In this Perspective we will highlight the most important recent breakthroughs in selective allylboron chemistry (both the synthesis and application of these species). In addition we will provide an outlook toward the future of this promising subfield of organic synthesis.

  • 332. Dorange, Ismet
    et al.
    Löfstedt, Joakim
    Franzén, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Närhi, Katja
    Bäckvall, Jan E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Allenes as Carbon Nucleophiles in Intramolecular Attack on (π-1,3-diene)Palladium Complexes: Evidence for trans-Carbopalladation of the 1,3-Diene2003Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 9, nr 14, s. 3445-3449Artikel i tidskrift (Refereegranskat)
  • 333. Dorau, Robin
    et al.
    Görbe, Tamás
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Svedendahl Humble, Maria
    Improved Enantioselectivity of Subtilisin Carlsberg Towards Secondary Alcohols by Protein Engineering2018Ingår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 19, nr 4, s. 338-346Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Generally, the catalytic activity of subtilisin Carlsberg (SC) for transacylation reactions with secondary alcohols in organic solvent is low. Enzyme immobilization and protein engineering was performed to improve the enantioselectivity of SC towards secondary alcohols. Possible amino-acid residues for mutagenesis were found by combining available literature data with molecular modeling. SC variants were created by site-directed mutagenesis and were evaluated for a model transacylation reaction containing 1-phenylethanol in THF. Variants showing high E values (>100) were found. However, the conversions were still low. A second mutation was made, and both the E values and conversions were increased. Relative to that shown by the wild type, the most successful variant, G165L/M221F, showed increased conversion (up to 36 %), enantioselectivity (E values up to 400), substrate scope, and stability in THF.

  • 334. Duan, Lele
    et al.
    Bozoglian, Fernando
    Mandal, Sukanta
    Stewart, Beverly
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Privalov, Timofei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Llobet, Antoni
    Sun, Licheng
    A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem II2012Ingår i: Nature Chemistry, ISSN 1755-4330, E-ISSN 1755-4349, Vol. 4, nr 5, s. 418-423Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Across chemical disciplines, an interest in developing artificial water splitting to O-2 and H-2, driven by sunlight, has been motivated by the need for practical and environmentally friendly power generation without the consumption of fossil fuels. The central issue in light-driven water splitting is the efficiency of the water oxidation, which in the best-known catalysts falls short of the desired level by approximately two orders of magnitude. Here, we show that it is possible to close that 'two orders of magnitude' gap with a rationally designed molecular catalyst [Ru(bda)(isoq)(2)] (H(2)bda = 2,2'-bipyridine-6,6'-dicarboxylic acid; isoq = isoquinoline). This speeds up the water oxidation to an unprecedentedly high reaction rate with a turnover frequency of >300 s(-1). This value is, for the first time, moderately comparable with the reaction rate of 100-400 s(-1) of the oxygen-evolving complex of photosystem II in vivo.

  • 335.
    Duan, Lele
    et al.
    Department of Chemistry, Royal Institute of Technology .
    Nyhlén, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Fischer, Andreas
    Department of Chemistry, Royal Institute of Technology .
    Xu, Yunhua
    Department of Chemistry, Royal Institute of Technology .
    Privalov, Timofei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Department of Chemistry, Royal Institute of Technology .
    Highly Active Mononuclear Ru Catalysts for Water Oxidation: O-O Bond Formation via Direct Radical CouplingIngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126Artikel i tidskrift (Refereegranskat)
  • 336. Dutheuil, Guillaume
    et al.
    Selander, Nicklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Aggarwal, Varinder K.
    Direct synthesis of functionalized allylic boronic esters from allylic alcohols and inexpensive reagents and catalysts2008Ingår i: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, nr 14, s. 2293-2297Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A remarkably simple and effective system for the direct conversion of allylic alcohols into high value allylic boronic esters using commercially available reagents and catalysts is described.

  • 337.
    Dziedzic, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Amino acid-catalyzed synthesis of amino acid derivatives: Application and semi-synthesis of Paclitaxel, Docetaxel and their derivatives2010Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis deals with different applications of organocatalysis, where amino acid derivatives and small peptides are applied as catalysts. First, the development of environmentally friendly aldol reactions, carried out in aqueous media is illustrated. The corresponding β-hydroxy ketones are formed with ee´s up to 99%. Chapter 3 describes the ability of β3-amino acids to selectively catalyze Mannich-type reactions and govern the formation of products with high anti-selectivity (up to >19:1) and ee´s up to 99%. In the following chapter, an amino acid-catalyzed one-pot three component Mannich reaction between dihydroxyacetone and PMP-protected imines, is presented. The corresponding a,a’-dihydroxy-b-aminoketones are obtained in high yields and with 82-95% ee. Next, an aza-Morita-Baylis-Hillman reaction was investigated where L-proline is the catalyst. The reaction proceeds with excellent chemo- and enantioselectivity to give the corresponding compounds in good yields and with 97-99% ee. Finally, the last part describes development of a proline-catalyzed Mannich reation between N-acyl imines and protected α-hydroxyaldehyes, providing access to different α-hydroxy-β-amino acids in good yields and high enantioselctivity (92-99% ee). The obtained amino acids were further applied in the semisynthesis of paclitaxel and docetaxel derivatives.

  • 338.
    Dziedzic, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Asymmetric Organocatalytic Aldol and Mannich Reactions Catalyzed by Amino Acid-Derivatives and Small Peptides with a Primary Amine Functionality2008Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 339.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bartoszewicz, Agnieszka
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Inorganic ammonium salts as catalysts for direct aldol reactions in the presence of water2009Ingår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 52, s. 7242-7245Artikel i tidskrift (Refereegranskat)
  • 340.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Acyclic beta-amino acid catalyzed asymmetric anti-selective Mannich-type reactions2007Ingår i: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 18, nr 9, s. 1033-1037Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     The ability of a primary amine containing acyclic beta(3)-amino acids to catalyze direct asymmetric anti-selective Mannich-type reactions is presented. The reactions are generally highly diastereo- and enantioselective to give the corresponding Mannich products with up to >19:1 dr (anti/syn) and 88-99% ee.

  • 341.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ibrahem, Ismail
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Direct catalytic asymmetric three-component Mannich reactions with dihydroxyacetone: enantioselective synthesis of amino sugar derivatives2008Ingår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, nr 5, s. 803-807Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Highly enantioselective, amino acid-catalyzed, one-pot three-component asymmetric Mannich reactions between dihydroxyacetone, p-anisidine, and aldehydes are presented. The reactions proceeded with high chemo- and stereoselectivity and furnished the corresponding α,α′-dihydroxy-β-aminoketones in high yields with 82–95% ee.

  • 342.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Schyman, Patric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kullberg, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Highly enantioselective organocatalytic addition of aldehydes to acylimines: Asymmetric syntheses of the paclitaxel and docetaxel side-chains and their analogs2010Ingår i: Abstracts of Papers, 239th ACS National Meeting, San Francisco, CA, United States, March 21-25, 2010, Washington, D C: American Chemical Society , 2010Konferensbidrag (Övrigt vetenskapligt)
  • 343.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Schyman, Patric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för fysikalisk kemi.
    Kullberg, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Highly enantioselective organocatalytic addition of aldehydes to N-(phenylmethylene)benzamides: Asymmetric synthesis of the paclitaxel side chain and its analogues2009Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, nr 16, s. 4044-4048Artikel i tidskrift (Refereegranskat)
  • 344.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vesely, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic asymmetric synthesis of the docetaxel (Taxotere) side chain: organocatalytic highly enantioselective synthesis of esterification-ready alpha-hydroxy-beta-amino acids2008Ingår i: Tetrahedron Letters, ISSN 0040-4039, Vol. 49, nr 47, s. 6631-6634Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A highly enantioselective catalytic route to protected β-amino-α-hydroxy acids, such as the side chain of Taxotere, is presented. The organocatalytic asymmetric reactions between unmodified protected α-oxyaldehydes and N-Boc-protected aryl imines give the corresponding compound with up to >19:1 dr and 99–99% ee.

  • 345.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Weibiao, Zou
    Hafrén, Jonas
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    The small peptide-catalyzed direct asymmetric aldol reaction in water2006Ingår i: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 4, s. 38-40Artikel i tidskrift (Refereegranskat)
  • 346.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Practical amino acid-catalyzed asymmetric synthesis pf protected α-hydroxy-amino aldehydes and acidsManuskript (preprint) (Övrigt vetenskapligt)
  • 347. Edgar, Rebecca J.
    et al.
    van Hensbergen, Vincent P.
    Ruda, Alessandro
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Turner, Andrew G.
    Deng, Pan
    Le Breton, Yoann
    El-Sayed, Najib M.
    Belew, Ashton T.
    McIver, Kevin S.
    McEwan, Alastair G.
    Morris, Andrew J.
    Lambeau, Gérard
    Walker, Markj
    Rush, Jeffrey S.
    Korotkov, Konstantin
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    van Sorge, Nina M.
    Korotkova, Natalia
    Discovery of glycerol phosphate modification on streptococcal rhamnose polysaccharides2019Ingår i: Nature Chemical Biology, ISSN 1552-4450, E-ISSN 1552-4469, Vol. 15, nr 5, s. 463-+Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cell wall glycopolymers on the surface of Gram-positive bacteria are fundamental to bacterial physiology and infection biology. Here we identify gacH, a gene in the Streptococcus pyogenes group A carbohydrate (GAC) biosynthetic cluster, in two independent transposon library screens for its ability to confer resistance to zinc and susceptibility to the bactericidal enzyme human group IIA-secreted phospholipase A(2). Subsequent structural and phylogenetic analysis of the GacH extracellular domain revealed that GacH represents an alternative class of glycerol phosphate transferase. We detected the presence of glycerol phosphate in the GAC, as well as the serotype c carbohydrate from Streptococcus mutans, which depended on the presence of the respective gacH homologs. Finally, nuclear magnetic resonance analysis of GAC confirmed that glycerol phosphate is attached to approximately 25% of the GAC N-acetylglucosamine side-chains at the C6 hydroxyl group. This previously unrecognized structural modification impacts host-pathogen interaction and has implications for vaccine design.

  • 348.
    Edin, Michaela
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols2005Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The major part of this thesis describes the synthesis of enantiopure alcohols and diols by combining ruthenium-catalyzed redox reactions that lead to racemization or epimerization and lipase-catalyzed asymmetric trans-formations in one-pot.

    A mechanistic study of the unexpected facile formation of meso-diacetate products found in enzyme-catalyzed acetylations of alkanediols with Candida antarctica lipase B (CALB) was first performed. By deuterium labeling it was found that the formation of meso-diacetates proceeds via different mechanisms for 2,4-pentanediol and 2,5-hexanediol. Whereas the first reacts via an intramolecular acyl migration, the latter proceeds via a direct, anomalous S-acylation of the alcohol. The acyl migration occurring in the 2,4-pentanediol monoacetate was taken advantage of in asymmetric transformations of substituted 1,3-diols by combining it with a ruthenium-catalyzed epimerization and an enzymatic transesterification using CALB. The in situ coupling of these three processes results in de-epimerization and deracemization of acyclic, unsymmetrical 1,3-diols and constitutes a novel dynamic kinetic asymmetric transformation (DYKAT) concept.

    Racemization of secondary alcohols effected by a new ruthenium complex was combined in one-pot with an enzyme-catalyzed transesterification, leading to a chemoenzymatic dynamic kinetic resolution (DKR) operating at room temperature. Aromatic, aliphatic, heterocyclic and functionalized alcohols were subjected to the procedure. A mechanism for racemization by this ruthenium complex has been proposed and experimental indications for hydrogen transfer within the coordination sphere of ruthenium were found. The same ruthenium catalyst was used for epimerization in DYKAT of 1,2-diols, and a very similar complex was employed in isomerization of allylic alcohols to saturated ketones. The former method is a substrate extension of the above principle applied for DYKAT of 1,3-diols. The combination of a lipase and an organocatalyst was demonstrated by linking a lipase-catalyzed transesterification to a proline-mediated aldol reaction for the production of enantiopure (S)-β-hydroxy ketones and acetylated (R)-aldols.

  • 349.
    Edin, Michaela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    On the mechanism of the unexpected facile formation of meso-diacetate products in enzymatic acetylation of alkanediols2003Ingår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 68, s. 2216-2222Artikel i tidskrift (Refereegranskat)
  • 350.
    Edin, Michaela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Córdova, Armando
    Tandem enantioselective organo- and biocatalysis: a direct entry for the synthesis of enantiomerically pure aldols2004Ingår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 45, s. 7697-7701Artikel i tidskrift (Refereegranskat)
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