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  • 1.
    Alam, Rauful
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Das, Arindam
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Huang, Genping
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stereoselective allylboration of imines and indoles under mild conditions. An in situ E/Z isomerization of imines by allylboroxines2014In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 5, no 7, p. 2732-2738Article in journal (Refereed)
    Abstract [en]

    Direct allylboration of various acyclic and cyclic aldimine, ketimine and indole substrates was performed using allylboronic acids. The reaction proceeds with very high anti-stereoselectivity for both E and Z imines. The allylboroxines formed by dehydration of allylboronic acids have a dual effect: promoting E/Z isomerization of aldimines and triggering the allylation by efficient electron withdrawal from the imine substrate.

  • 2.
    Baldassarre, Maurizio
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Baronio, Cesare M.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Morozova-Roche, Ludmilla A.
    Barth, Andreas
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Amyloid beta-peptides 1-40 and 1-42 form oligomers with mixed beta-sheets2017In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 8, no 12, p. 8247-8254Article in journal (Refereed)
    Abstract [en]

    Two main amyloid-beta peptides of different length (A beta(40) and A beta(42)) are involved in Alzheimer's disease. Their relative abundance is decisive for the severity of the disease and mixed oligomers may contribute to the toxic species. However, little is know about the extent of mixing. To study whether A beta(40) and A beta(42) co-aggregate, we used Fourier transform infrared spectroscopy in combination with C-13-labeling and spectrum calculation and focused on the amide I vibration, which is sensitive to backbone structure. Mixtures of monomeric labeled A beta(40) and unlabeled A beta(42) (and vice versa) were co-incubated for similar to 20 min and their infrared spectrum recorded. The position of the main C-13-amide I' band shifted to higher wavenumbers with increasing admixture of C-12-peptide due to the presence of C-12-amides in the vicinity of C-13-amides. The results indicate that A beta(40) and A beta(42) form mixed oligomers with a largely random distribution of A beta(40) and A beta(42) strands in their beta-sheets. The structures of the mixed oligomers are intermediate between those of the pure oligomers. There is no indication that one of the peptides forces the backbone structure of its oligomers on the other peptide when they are mixed as monomers. We also demonstrate that isotope-edited infrared spectroscopy can distinguish aggregation modulators that integrate into the backbone structure of their interaction partner from those that do not. As an example for the latter case, the pro-inflammatory calcium binding protein S100A9 is shown not to incorporate into the b-sheets of A beta(42).

  • 3. Bueken, Bart
    et al.
    Van Velthoven, Niels
    Willhammar, Tom
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). University of Antwerp, Belgium.
    Stassin, Timothee
    Stassen, Ivo
    Keen, David A.
    Baron, Gino V.
    Denayer, Joeri F. M.
    Ameloot, Rob
    Bals, Sara
    De Vos, Dirk
    Bennett, Thomas D.
    Gel-based morphological design of zirconium metal-organic frameworks2017In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 8, no 5, p. 3939-3948Article in journal (Refereed)
    Abstract [en]

    The ability of metal-organic frameworks (MOFs) to gelate under specific synthetic conditions opens up new opportunities in the preparation and shaping of hierarchically porous MOF monoliths, which could be directly implemented for catalytic and adsorptive applications. In this work, we present the first examples of xero-or aerogel monoliths consisting solely of nanoparticles of several prototypical Zr4+-based MOFs: UiO-66-X (X - H, NH2, NO2, (OH)(2)), UiO-67, MOF-801, MOF-808 and NU-1000. High reactant and water concentrations during synthesis were observed to induce the formation of gels, which were converted to monolithic materials by drying in air or supercritical CO2. Electron microscopy, combined with N-2 physisorption experiments, was used to show that irregular nanoparticle packing leads to pure MOF monoliths with hierarchical pore systems, featuring both intraparticle micropores and interparticle mesopores. Finally, UiO-66 gels were shaped into monolithic spheres of 600 mm diameter using an oil-drop method, creating promising candidates for packed-bed catalytic or adsorptive applications, where hierarchical pore systems can greatly mitigate mass transfer limitations.

  • 4.
    Huang, Genping
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kalek, Marcin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Liao, Rong-Zhen
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanism, reactivity, and selectivity of the iridium-catalyzed C(sp(3))-H borylation of chlorosilanes2015In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 6, no 3, p. 1735-1746Article in journal (Refereed)
    Abstract [en]

    The iridium-catalyzed C(sp(3))-H borylation of methylchlorosilanes is investigated by means of density functional theory, using the B3LYP and M06 functionals. The calculations establish that the resting state of the catalyst is a seven-coordinate Ir(V) species that has to be converted into an Ir(III)tris(boryl) complex in order to effect the oxidative addition of the C-H bond. This is then followed by a C-B reductive elimination to yield the borylated product, and the catalytic cycle is finally completed by the regeneration of the active catalyst over two facile steps. The two employed functionals give somewhat different conclusions concerning the nature of the rate-determining step, and whether reductive elimination occurs directly or after a prior isomerization of the Ir(V) hydride intermediate complex. The calculations reproduce quite well the experimentally-observed trends in the reactivities of substrates with different substituents. It is demonstrated that the reactivity can be correlated to the Ir-C bond dissociation energies of the corresponding Ir(V) hydride intermediates. The effect of the chlorosilyl group is identified to originate from the alpha-carbanion-stabilizing effect of the silicon, which is further reinforced by the presence of an electron-withdrawing chlorine substituent. Furthermore, the source of selectivity for the borylation of primary over secondary C(sp(3))-H can be explained on a steric basis, by repulsion between the alkyl group and the Ir/ligand moiety. Finally, the difference in the reactivity between C(sp(3))-H and C(sp(2))-H borylation is investigated and rationalized in terms of distortion/interaction analysis.

  • 5. Jiang, Jiuxing
    et al.
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Jorda, Jose Luis
    Corma, Avelino
    ITQ-54: a multi-dimensional extra-large pore zeolite with 20 [times] 14 [times] 12-ring channels2015In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 6, p. 480-485Article in journal (Refereed)
    Abstract [en]

    A multi-dimensional extra-large pore silicogermanate zeolite, named ITQ-54, has been synthesised by in situ decomposition of the N,N-dicyclohexylisoindolinium cation into the N-cyclohexylisoindolinium cation. Its structure was solved by 3D rotation electron diffraction (RED) from crystals of ca. 1 [small mu ]m in size. The structure of ITQ-54 contains straight intersecting 20 [times] 14 [times] 12-ring channels along the three crystallographic axes and it is one of the few zeolites with extra-large channels in more than one direction. ITQ-54 has a framework density of 11.1 T atoms per 1000 A3, which is one of the lowest among the known zeolites. ITQ-54 was obtained together with GeO2 as an impurity. A heavy liquid separation method was developed and successfully applied to remove this impurity from the zeolite. ITQ-54 is stable up to 600 [degree]C and exhibits permanent porosity. The structure was further refined using powder X-ray diffraction (PXRD) data for both as-made and calcined samples.

  • 6.
    Krajangsri, Suppachai
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Wu, Haibo
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Liu, Jianguo
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rabten, Wangchuk
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Singh, Thishana
    Andersson, Pher G.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. University of Kwazulu-Natal, South Africa.
    Tandem Peterson olefination and chemoselective asymmetric hydrogenation of -hydroxy silanes2019In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 10, no 12, p. 3649-3653Article in journal (Refereed)
    Abstract [en]

    Here, we report the first Ir-N,P complex catalyzed tandem Peterson olefination and asymmetric hydrogenation of -hydroxy silanes. This reaction resulted in the formation of chiral alkanes in high isolated yields (up to 99%) and excellent enantioselectivity (up to 99% ee) under mild conditions. Modification of the reaction conditions provides a choice to transform either an olefin or the -hydroxy silane in a chemoselective manner. Additionally, based on this method, an expedient enantioselective synthesis of (S)-(+)--curcumene, from a simple ketone, was accomplished in two steps with 75% overall yield and 95% ee.

  • 7. Leshem, Guy
    et al.
    Richman, Michal
    Lisniansky, Elvira
    Antman-Passig, Merav
    Habashi, Maram
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Wärmländer, Sebastian K. T. S.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Rahimipour, Shai
    Photoactive chlorin e6 is a multifunctional modulator of amyloid-β aggregation and toxicity via specific interactions with its histidine residues2019In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 10, no 1, p. 208-217Article in journal (Refereed)
    Abstract [en]

    The self-assembly of A to -sheet-rich neurotoxic oligomers is a main pathological event leading to Alzheimer's disease (AD). Selective targeting of A oligomers without affecting other functional proteins is therefore an attractive approach to prevent the disease and its progression. In this study, we report that photodynamic treatment of A in the presence of catalytic amounts of chlorin e6 can selectively damage A and inhibit its aggregation and toxicity. Chlorin e6 also reversed the amyloid aggregation process in the dark by binding its soluble and low molecular weight oligomers, as shown by thioflavin T (ThT) fluorescence and photoinduced cross-linking of unmodified protein (PICUP) methods. Using HSQC NMR spectroscopy, ThT assays, amino acid analysis, SDS/PAGE, and EPR spectroscopy, we show that catalytic amounts of photoexcited chlorin e6 selectively damage the A histidine residues H6, H13, and H14, and induce A cross-linking by generating singlet oxygen. In contrast, photoexcited chlorin e6 was unable to cross-link ubiquitin and -synuclein, demonstrating its high selectivity for A. By binding to the A histidine residues, catalytic amounts of chlorin e6 can also inhibit the Cu2+-induced aggregation and toxicity in darkness, while at stoichiometric amounts it acts as a chelator to reduce the amount of free Cu2+. This study demonstrates the great potential of chlorin e6 as a multifunctional agent for treatment of AD, and shows that the three N-terminal A histidine residues are a suitable target for A-specific drugs.

  • 8. Li, Hongji
    et al.
    Subbotina, Elena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bunrit, Anon
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Dalian Institute of Chemical Physics (DICP), China .
    Wang, Feng
    Samec, Joseph S. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Functionalized spirolactones by photoinduced dearomatization of biaryl compounds2019In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 10, no 12, p. 3681-3686Article in journal (Refereed)
    Abstract [en]

    The idea of using biaryl structures to generate synthetic building blocks such as spirolactones is attractive because biaryl structures are abundant in biomass waste streams. However, the inertness of aromatic rings of biaryls makes it challenging to transform them into functionalized structures. In this work, we developed photoinduced dearomatization of nonphenolic biaryl compounds to generate spirolactones. We demonstrate that dearomatization can be performed via either aerobic photocatalysis or anaerobic photooxidation to tolerate specific synthetic conditions. In both pathways, dearomatization is induced by electrophilic attack of the carboxyl radical. The resulting spirodiene radical is captured by either oxygen or water in aerobic and anaerobic systems, respectively, to generate the spirodienone. These methods represent novel routes to synthesize spirolactones from the biaryl motif.

  • 9.
    Liang, Jie
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Peking University, China.
    Xia, Wei
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Peking University, China.
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Dou, Maofeng
    Zou, Ruqiang
    Liao, Fuhui
    Wang, Yingxia
    Lin, Jianhua
    A multi-dimensional quasi-zeolite with 12 x 10 x 7-ring channels demonstrates high thermal stability and good gas adsorption selectivity2016In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 7, no 5, p. 3025-3030Article in journal (Refereed)
    Abstract [en]

    A novel quasi-zeolite PKU-15, with a rare 3-dimensional structure containing interconnected large (12-ring), medium (10-ring) and small (7-ring) multi-pore channels, was hydrothermally synthesised and characterised. A unique tri-bridging O2- anion is found to be encapsulated in the cage-like (Ge,Si)(12)O-31 building unit and energetically stabilises the PKU-15 framework. The removal of this oxygen atom would convert PKU-15 into a hypothetical zeolite PKU-15H. Thus, PKU-15 can be considered as a unique 'quasi-zeolite', which bridges porous germanates and zeolites. Owing to the absence of terminal Ge-OH groups in its structure, PKU-15 shows a remarkably high thermal stability of up to 600 degrees C. PKU-15 is also the first microporous germanate that exhibits permanent porosity, with a BET area of 428 m(2) g(-1) and a good adsorption affinity toward CO2.

  • 10. Liang, Zuozhong
    et al.
    Huang, Zhehao
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yuan, Haitao
    Yang, Zhiyuan
    Zhang, Chaochao
    Xu, Yang
    Zhang, Wei
    Zheng, Haoquan
    Cao, Rui
    Quasi-single-crystalline CoO hexagrams with abundant defects for highly efficient electrocatalytic water oxidation2018In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 9, no 34, p. 6961-6968Article in journal (Refereed)
    Abstract [en]

    Defects and structural long-range ordering have been recognized as two crucial characters for advanced electrocatalysts. However, these two features have rarely been achieved together. Herein, we report the preparation of single-crystalline CoO hexagrams and demonstrate their exceptional electrocatalytic properties for water oxidation. The quasi-single-crystalline CoO hexagrams, prepared at the critical phase transition point of -Co(OH)(2)/Co(OH)F hexagrams, possess both abundant oxygen vacancies as defects and structural long-range ordering. The matching between the b-axis of Co(OH)F crystals and the a-axis of -Co(OH)(2) crystals is critical for the formation of the CoO hexagram single crystals. The quasi-single-crystalline CoO hexagrams with abundant defects are highly efficient for water oxidation by delivering a 10 mA cm(-2) current density at a low overpotential of 269 mV in a 1 M KOH aqueous solution.

  • 11.
    Liao, Rong-Zhen
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Huazhong University of Science & Technology, People's Republic of China.
    Siegbahn, Per E. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanism and selectivity of the dinuclear iron benzoyl-coenzyme A epoxidase BoxB2015In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 6, no 5, p. 2754-2764Article in journal (Refereed)
    Abstract [en]

    Benzoyl-CoA epoxidase is a dinuclear iron enzyme that catalyzes the epoxidation reaction of the aromatic ring of benzoyl-CoA with chemo-, regio- and stereo-selectivity. It has been suggested that this enzyme may also catalyze the deoxygenation reaction of epoxide, suggesting a unique bifunctionality among the diiron enzymes. We report a density functional theory study of this enzyme aimed at elucidating its mechanism and the various selectivities. The epoxidation is suggested to start with the binding of the O-2 molecule to the diferrous center to generate a diferric peroxide complex, followed by concerted O-O bond cleavage and epoxide formation. Two different pathways have been located, leading to (2S,3R)-epoxy and (2R,3S)-epoxy products, with barriers of 17.6 and 20.4 kcal mol(-1), respectively. The barrier difference is 2.8 kcal mol(-1), corresponding to a diastereomeric excess of about 99 : 1. Further isomerization from epoxide to phenol is found to have quite a high barrier, which cannot compete with the product release step. After product release into solution, fast epoxide-oxepin isomerization and racemization can take place easily, leading to a racemic mixture of (2S,3R) and (2R,3S) products. The deoxygenation of epoxide to regenerate benzoyl-CoA by a diferrous form of the enzyme proceeds via a stepwise mechanism. The C2-O bond cleavage happens first, coupled with one electron transfer from one iron center to the substrate, to form a radical intermediate, which is followed by the second C3-O bond cleavage. The first step is rate-limiting with a barrier of only 10.8 kcal mol(-1). Further experimental studies are encouraged to verify our results.

  • 12.
    Lübcke, Marvin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bezhan, Dina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Trifluoromethylthiolation-arylation of diazocarbonyl compounds by modified Hooz multicomponent coupling2019In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 10, no 23, p. 5990-5995Article in journal (Refereed)
    Abstract [en]

    A new Zn-mediated trifluoromethylthiolation-based bifunctionalization reaction is developed. In this process, simultaneous C-SCF3 and C-C bond formation takes place in a multicomponent reaction, in which an aryl and a SCF3 group arise from different reagents. Our studies show that the reaction mechanism is similar to the Hooz multicomponent coupling. The process involves in situ generation of BAr3, which reacts with a diazocarbonyl compound, and the reaction is terminated by an electrophilic SCF3 transfer. The reaction can also be extended to fluorination based bifunctionalization which proceeds with somewhat lower yield than the analogous trifluoromethylthiolation reaction.

  • 13.
    Qiu, Youai
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yang, Bin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zhu, Can
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Highly selective olefin-assisted palladium-catalyzed oxidative carbocyclization via remote olefin insertion2017In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 8, no 1, p. 616-620Article in journal (Refereed)
    Abstract [en]

    A highly selective olefin-assisted palladium-catalyzed oxidative carbocyclization via remote olefin insertion to afford cyclohexenes has been developed. It was shown that the assisting olefin moiety was indispensable for the formation of the cyclohexene product. Furthermore, preliminary studies on chiral anion-induced asymmetrical carbocyclization-borylation of enallenes have been carried out.

  • 14. Siegbahn, Anna
    et al.
    Manner, Sophie
    Persson, Andrea
    Tykesson, Emil
    Holmqvist, Karin
    Ochocinska, Agata
    Rönnols, Jerk
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sundin, Anders
    Mani, Katrin
    Westergren-Thorsson, Gunilla
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ellervik, Ulf
    Rules for priming and inhibition of glycosaminoglycan biosynthesis; probing the beta 4GalT7 active site2014In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 5, no 9, p. 3501-3508Article in journal (Refereed)
    Abstract [en]

    beta-1,4-Gatactosyltransferase 7 (beta 4GalT7) is an essential enzyme in the biosynthesis of glycosaminoglycan (GAG) chains of proteoglycans (PGs). Mammalian cells produce PGs, which are involved in biological processes such as cell growth and differentiation. The PGs consist of a core protein, with one or several GAG chains attached. Both the structure of the PGs and the GAG chains, and the expression of the enzymes involved in their biosynthesis and degradation, vary between normal cells and tumor cells. The biosynthesis of GAG chains is initiated by xylosylation of a serine residue of the core protein, followed by galactosylation by beta 4GalT7. The biosynthesis can also be initiated by exogenously added beta-D-xylopyranosides with hydrophobic aglycons, which thus can act as acceptor substrates for beta 4GalT7. To determine the structural requirements for beta 4GalT7 activity, we have cloned and expressed the enzyme and designed a focused library of 2-naphthyl beta-D-xylopyranosides with modifications of the xylose moiety. Based on enzymatic studies, that is galactosylation and its inhibition, conformational analysis and molecular modeling using the crystal structure, we propose that the binding pocket of beta 4GalT7 is very narrow, with a precise set of important hydrogen bonds. Xylose appears to be the optimal acceptor substrate for galactosylation by beta 4GalT7. However, we show that modifications of the xylose moiety of the beta-D-xylopyranosides can render inhibitors of galactosylation. Such compounds will be valuable tools for the exploration of GAG and PG biosynthesis and a starting point for development of anti-tumor agents.

  • 15. Zhang, Su-Yun
    et al.
    Kochovski, Zdravko
    Lee, Hui-Chun
    Lu, Yan
    Zhang, Hemin
    Zhang, Jie
    Sun, Jian-Ke
    Yuan, Jiayin
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Ionic organic cage-encapsulating phase-transferable metal clusters2019In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 10, no 5, p. 1450-1456Article in journal (Refereed)
    Abstract [en]

    Exploration of metal clusters (MCs) adaptive to both aqueous and oil phases without disturbing their size is promising for a broad scope of applications. The state-of-the-art approach via ligandbinding may perturb MCs' size due to varied metal-ligand binding strength when shuttling between solvents of different polarity. Herein, we applied physical confinement of a series of small noble MCs (<1 nm) inside ionic organic cages (I-Cages), which by means of anion exchange enables reversible transfer of MCs between aqueous and hydrophobic solutions without varying their ultrasmall size. Moreover, the MCs@I-Cage hybrid serves as a recyclable, reaction-switchable catalyst featuring high activity in liquid-phase NH3BH3 (AB) hydrolysis reaction with a turnover frequency (TOF) of 115 min(-1).

  • 16.
    Zhao, Jian
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Jonker, Sybrand J. T.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Meyer, Denise N.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Schulz, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tran, C. Duc
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Copper-catalyzed synthesis of allenylboronic acids. Access to sterically encumbered homopropargylic alcohols and amines by propargylboration2018In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 9, no 13, p. 3305-3312Article in journal (Refereed)
    Abstract [en]

    Tri- and tetrasubstituted allenylboronic acids were prepared via a new versatile copper-catalyzed methodology. The densely functionalized allenylboronic acids readily undergo propargylboration reactions with ketones and imines without any additives. Catalytic asymmetric propargylborylation of ketones is demonstrated with high stereoselectivity allowing for the synthesis of highly enantioenriched tertiary homopropargyl alcohols. The reaction is suitable for kinetic resolution of racemic allenylboronic acids affording alkynes with adjacent quaternary stereocenters.

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