European Journal of Organic Chemistry

Cover image for Vol. 2013 Issue 4

February 2013

Volume 2013, Issue 4

Pages 623–788

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Microreview
    6. Short Communications
    7. Full Papers
    1. You have free access to this content
      Synthetic Progress in cMyc-Max Oncoprotein Miniaturization: Semi-Online Monitoring Gives Solid-Phase Access to Hydrophobic b(-HLH-)ZIP Peptidosteroid Tweezers (Eur. J. Org. Chem. 4/2013)

      Dieter Verzele and Annemieke Madder

      Article first published online: 23 JAN 2013 | DOI: 10.1002/ejoc.201390006

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      The cover picture shows a schematic impression of our solid-phase methodology developed for the synthesis of macromolecular peptidosteroid tweezers. An orthogonally protected bile acid scaffold (D. Verzele, A. Madder, Eur. J. Org. Chem. 2007, 1793) was used as an artificial dimerization interface, imposing a specific pre-organization to the appended peptide strands. Such conjugates represent a new design towards the miniaturization of so-called zipper-type transcription factors. Unprecedented, enigmatic and involved in various malignancies, we focus on the cMyc-Max basic helix–loop–helix zipper (b-HLH-ZIP) oncoprotein. By facilitating a semi-online monitoring approach during the automated peptide elongations, the use of a photocleavable linker completed our synthetic toolbox, and a first generation of model compounds was obtained. Details are discussed in the article by D. Verzele and A. Madder on p. 673 ff.

  2. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Microreview
    6. Short Communications
    7. Full Papers
    1. Graphical Abstract: Eur. J. Org. Chem. 4/2013 (pages 623–628)

      Article first published online: 23 JAN 2013 | DOI: 10.1002/ejoc.201390008

  3. News

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Microreview
    6. Short Communications
    7. Full Papers
  4. Microreview

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Microreview
    6. Short Communications
    7. Full Papers
    1. Asymmetric Catalysis

      Bifunctional Chiral Quaternary Ammonium Salt Catalysts: A Rapidly Emerging Class of Powerful Asymmetric Catalysts (pages 637–648)

      Johanna Novacek and Mario Waser

      Article first published online: 19 DEC 2012 | DOI: 10.1002/ejoc.201201425

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      Bifunctional ammonium salts have emerged as promising catalysts for demanding reactions that are not possible with other methods. This review will highlight some of the most impressive recent examples in this field and illustrate the potential of these catalysts to facilitate complex transformations in a highly stereoselective fashion under mild reaction conditions.

  5. Short Communications

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Microreview
    6. Short Communications
    7. Full Papers
    1. Tetrahydroindoles

      Synthesis of 4,5,6,7-Tetrahydro-1H-indole Derivatives Through Successive Sonogashira Coupling/Pd-Mediated 5-endo-dig Cyclization (pages 649–652)

      Ivan A. Andreev, Dmitry S. Belov, Alexander V. Kurkin and Marina A. Yurovskaya

      Article first published online: 17 DEC 2012 | DOI: 10.1002/ejoc.201201417

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      A one-pot sequence based on Sonogashira cross-coupling/Pd-mediated 5-endo-dig cyclization was developed and applied to the gram-scale synthesis of 2-aryl-4,5,6,7-tetrahydroindoles (21 examples).

    2. Organocatalysis

      Asymmetric Organocatalytic 1,4-Addition Reactions Starting from Enals with gem-Difluoroalkyl Side Chains (pages 653–657)

      Ali Khalaf, Danielle Grée, Hassan Abdallah, Nada Jaber, Ali Hachem and René Grée

      Article first published online: 19 DEC 2012 | DOI: 10.1002/ejoc.201201427

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      New chiral β-thio and β-amino aldehydes with CF2R chains can be obtained in high yields with high ee values by asymmetric organocatalytic processes after selection of the appropriate catalyst and optimization of the reaction conditions.

    3. Carbonyl Translocation

      A Unique Synthetic Method to Convert a D-Sugar into 2-Deoxy-L-ribitol Through Carbonyl Translocation (pages 658–661)

      Nai-Yun Hsu and Che-Chien Chang

      Article first published online: 20 DEC 2012 | DOI: 10.1002/ejoc.201201489

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      A unique and highly efficient radical process (complete within minutes) was developed to prepare of 2-deoxy-L-ribitol. Radical cyclization followed by fragmentation gave exclusively the desired product, with carbonyl translocation in an acyclic carbohydrate system. By using this synthetic approach, a D-sugar derivative could be transformed into a 2-deoxy-L-sugar in a single radical reaction.

    4. Tricarbonyl Compounds

      Regio- and Diastereoselective Crotylboration of vic-Tricarbonyl Compounds (pages 662–665)

      Jan Roßbach, Julia Baumeister, Klaus Harms and Ulrich Koert

      Article first published online: 21 DEC 2012 | DOI: 10.1002/ejoc.201201517

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      (E)-Crotylboration of α,β-diketoamides resulted in high yields (91–99 %) of β-crotylated products obtained as a single diastereomer (anti). Lewis acid promoted crotylboration of α,β-diketo esters yielded the α-crotylated species with the anti product as main diastereomer.

    5. Oxidative Coupling

      Brønsted Acid Catalyzed C–H Functionalization of N-Protected Tetrahydroisoquinolines via Intermediate Peroxides (pages 666–671)

      Bertrand Schweitzer-Chaput and Martin Klussmann

      Article first published online: 13 DEC 2012 | DOI: 10.1002/ejoc.201201527

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      An organocatalytic oxidative synthesis of N-protected tetrahydroisoquinolines was achieved by C–H functionalization via Intermediate PeroxideS (CHIPS). The peroxides were synthesized under metal-free thermal conditions and were converted into the final products by reaction with a variety of nucleophiles by using Brønsted acid catalysis.

  6. Full Papers

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Microreview
    6. Short Communications
    7. Full Papers
    1. Solid-Phase Peptidosteroid Tweezers

      Synthetic Progress in cMyc-Max Oncoprotein Miniaturization: Semi-Online Monitoring Gives Solid-Phase Access to Hydrophobic b(-HLH-)ZIP Peptidosteroid Tweezers (pages 673–687)

      Dieter Verzele and Annemieke Madder

      Article first published online: 6 DEC 2012 | DOI: 10.1002/ejoc.201201235

      Thumbnail image of graphical abstract

      Decoration of a bile acid scaffold with two recognition peptides in a 2 × 2 solid-phase design brought us one step closer towards an unprecedented model of the oncogenic cMyc-Max transcription factor. Feasible by monitoring the stepwise synthesis of our b(-HLH-)ZIP peptidosteroids through a photocleavable linker strategy, a versatile methodology amenable to library generation is presented.

    2. Tetrazole Synthesis

      Synthesis of Aminotetrazolyl Esters from Cyanogen Azide with Amino Esters (pages 688–692)

      Young-Hyuk Joo, Soo Gyeong Cho, Eun Mee Goh, Damon A. Parrish and Jean'ne M. Shreeve

      Article first published online: 7 DEC 2012 | DOI: 10.1002/ejoc.201201153

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      5-Aminotetrazolyl esters were prepared by a reaction between cyanogen azide and an amino ester to give 1-substituted aminotetrazoles in good yields. Compounds were fully characterized, and the structures of 37 were supported by single-crystal X-ray structure analysis. Heats of formation for all compounds were calculated by the Gaussian 03 program and differential scanning calorimetry.

    3. Heteroannulation of Alkynes

      Diversely Substituted Imidazo[1,2-a]pyrazine-8-oxo-3-carbaldehydes: An Iodine-Mediated Cyclization/Oxidation Approach (pages 693–700)

      Nigam M. Mishra, Dipak D. Vachhani, Sachin G. Modha and Erik V. Van der Eycken

      Article first published online: 11 DEC 2012 | DOI: 10.1002/ejoc.201201150

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      An iodine-mediated heteroannulation approach for the construction of (dihydro)imidazo[1,2-a]pyrazinone motifs have been developed. For terminal alkynes, a hydrolysis/oxidation sequence or an amination gives direct access to imidazo[1,2-a]pyrazin-3-carbaldehydes or aminomethyl-imidazo-[1,2-a]pyrazinones in a one-pot process.

    4. C–C Coupling Reactions

      The Glaser–Hay Reaction: Optimization and Scope Based on 13C NMR Kinetics Experiments (pages 701–711)

      Mie H. Vilhelmsen, Jonas Jensen, Christian G. Tortzen and Mogens B. Nielsen

      Article first published online: 6 DEC 2012 | DOI: 10.1002/ejoc.201201159

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      Based on 13C NMR and UV/Vis kinetics studies, the rate of the oxidative Glaser–Hay homocoupling reaction of terminal alkynes was found to be apparently zero-order in the terminal alkyne. As the reaction proceeds, a change to slower zero-order kinetics is observed, which can be avoided in the presence of molecular sieves (MS). The stirring rate has the most significant impact on the reaction rate.

    5. Chiral Ionic Liquids

      Synthesis and Antimicrobial Activity of Imidazolium and Triazolium Chiral Ionic Liquids (pages 712–720)

      Paweł Borowiecki, Małgorzata Milner-Krawczyk, Dominika Brzezińska, Monika Wielechowska and Jan Plenkiewicz

      Article first published online: 10 DEC 2012 | DOI: 10.1002/ejoc.201201245

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      A series of imidazolium and triazolium chiral ionic liquids (CILs) was synthesized and biologically tested. The CILs were obtained from optically active intermediates, 1-(β-hydroxybutyl) azoles, the synthesis of which is based on a lipase-mediated kinetic enantiomeric resolution.

    6. Total Synthesis

      Total Synthesis of Eupomatilones 1, 2, and 5 by Enantioselective [2,3]-Wittig Rearrangement (pages 721–727)

      Yoshimi Hirokawa, Maria Kitamura, Makoto Mizubayashi, Rie Nakatsuka, Yuya Kobori, Chiharu Kato, Yuki Kurata and Naoyoshi Maezaki

      Article first published online: 10 DEC 2012 | DOI: 10.1002/ejoc.201201247

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      An asymmetric total synthesis of eupomatilones 1, 2, and 5 was carried out. The asymmetric [2,3]-Wittig rearrangement of biarylmethyl ethers was used for the construction of the chiral centers, using a bis(oxazoline) chiral ligand. Optimization of the reaction conditions enabled the synthesis of eupomatilones 1, 2, and 5 with high enantioselectivities (88–91 % ee).

      Corrected by:

      Correction: Total Synthesis of Eupomatilones 1, 2, and 5 by Enantioselective [2,3]-Wittig Rearrangement

      Vol. 2013, Issue 13, 2724, Article first published online: 28 MAR 2013

    7. Vitamin D Analogs

      Synthesis of 2-Ethyl-19-nor Analogs of 1α,25-Dihydroxyvitamin D3 (pages 728–735)

      Duchan R. Laplace, Michel Van Overschelde, Pierre J. De Clercq, Annemieke Verstuyf and Johan M. Winne

      Article first published online: 10 DEC 2012 | DOI: 10.1002/ejoc.201201261

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      Two new phosphanone building blocks, useful for the stereocontrolled synthesis of 2-ethyl-substituted 19-nor analogs of 1α,25-dihydroxyvitamin D3, were prepared from quinic acid. This route offers an attractive practical solution for the introduction of these synthetically challenging but highly interesting A-ring modifications.

    8. Domino Reactions

      A Straightforward Route to Homoallyl-Homocrotylamines Promoted by a Titanium Complex (pages 736–741)

      Stéphanie Toulot, Quentin Bonnin, Virginie Comte, Louis Adriaenssens, Philippe Richard and Pierre Le Gendre

      Article first published online: 14 DEC 2012 | DOI: 10.1002/ejoc.201201262

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      The titanium-promoted reductive coupling of 1,3-dienes with bis(benzotriazolyl) compounds as substrates led selectively to homoallyl-homocrotylamines through a triple cascade reaction (allyltitanation – cationic 2-aza-Cope rearrangement – allyltitanation).

    9. Metal-Free Synthesis of Secondary Arylamines: An Aliphatic-to-Aromatic Transformation (pages 742–747)

      M. Teresa Barros, Suvendu S. Dey and Christopher D. Maycock

      Article first published online: 10 DEC 2012 | DOI: 10.1002/ejoc.201201263

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      A series of arylamines have been synthesized from 2-halocyclohex-2-enones by in situ enamine formation followed by aromatization under environmentally friendly conditions using pTsOH. This metal-free, practical, relatively inexpensive protocol is of value in organic synthesis for industrial and academic applications.

    10. Chiral Diol Ligands

      Synthesis of Ar-BINMOL Ligands by [1,2]-Wittig Rearrangement to Probe Their Catalytic Activity in 1,2-Addition Reactions of Aldehydes with Grignard Reagents (pages 748–755)

      Long-Sheng Zheng, Ke-Zhi Jiang, Yuan Deng, Xing-Feng Bai, Guang Gao, Feng-Lei Gu and Li-Wen Xu

      Article first published online: 5 DEC 2012 | DOI: 10.1002/ejoc.201201301

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      Ar-BINMOL ligands: A new diastereoselective synthesis of optically pure Ar-BINMOL-derived diols and their analogues has been established through cascade chirality transfer of a [1,2]-Wittig rearrangement. The axial and sp3 central chirality of Ar-BINMOLs are the pivotal enantioselectivity-controlling structure elements in the 1,2-addition of aldehydes with Grignard reagents.

    11. Studies Toward Amphidinolides

      BF2OBn·OEt2: A Lewis Acid, Its Use in a Regio- and Stereoselective Opening of Trisubstituted Epoxides, and Its Application towards Amphidinolide C and F (pages 756–760)

      Nicholas A. Morra and Brian L. Pagenkopf

      Article first published online: 10 DEC 2012 | DOI: 10.1002/ejoc.201201331

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      The new Lewis acid BF2OBn·OEt2 was generated by an anionic redistribution between BF3·OEt2 and benzyloxytrimethylsilane and used in a regio- and stereoselective epoxide ring-opening reaction. The utility of this reaction was demonstrated by the conversion of commercially available 2,3-dihydrofuran into the C-1–C-9 fragment of amphidinolide C and F in five steps and 49 % overall yield.

    12. Double Stereodifferentiation

      Doing it Twice: Asymmetric Deprotonation/Alkylation of Weiss Diketone Derivatives as Key Steps in the Functionalization of Bicyclo[3.3.0]octanes (pages 761–771)

      Vanessa Lutz, Natja Park, Christian Rothe, Claudia Krüger, Angelika Baro and Sabine Laschat

      Article first published online: 10 DEC 2012 | DOI: 10.1002/ejoc.201201409

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      Pseudo-C2-symmetrical bicyclo[3.3.0]octanones 2 have been prepared from enantiopure α-substituted derivatives 1 of the Weiss diketone. The symmetrical bicyclo[3.3.0]octanones 2 were then converted into the hydropentalene core of macrocyclic polyketide tetramic acid lactams such as cylindramide.

    13. Heterocyclic Chemistry

      Conjugate Addition of Indoles and Pyrroles to Dihydronitronaphthalenes in Water: Synthesis of 3,4-Fused Tetrahydro-β-carbolines (pages 772–780)

      Rajesh Malhotra, Rajib Ghosh, Tushar K. Dey, Sagar Chakrabarti, Amit Ghosh, Swarup Dutta, Sonika Asijaa, Subho Roy, Shantanu Dutta, Sourav Basu and Saumen Hajra

      Article first published online: 14 DEC 2012 | DOI: 10.1002/ejoc.201201288

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      A catalyst-free conjugate addition of indoles and pyrroles to 1,2-dihydro-3-nitronaphthalenes in water provides 1-heteroaryl-2-nitrotetralins with moderate to good diastereoselectivity and yields. The utility of the method was demonstrated by Suzuki coupling of the bromo functionality of the adducts and the synthesis of 3,4-fused tetrahydro-β-carbolines, a new class of compounds.

    14. Cross-Coupling

      Pd-Catalyzed Tandem Chemoselective Synthesis of 2-Arylbenzofurans using Threefold Arylating Triarylbismuth Reagents (pages 781–788)

      Maddali L. N. Rao, Deepak N. Jadhav and Priyabrata Dasgupta

      Article first published online: 10 DEC 2012 | DOI: 10.1002/ejoc.201201314

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      A tandem chemoselective synthesis of 2-arylbenzofurans was accomplished from o-hydroxy-gem-(dibromovinyl)benzenes and BiAr3 reagents under palladium-catalyzed conditions. This unique and synthetically valuable strategy proceeds through three consecutive coupling reactions involving triarylbismuth reagents and provides 2-arylbenzofuran products in high yields.

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