Angewandte Chemie International Edition in English

Cover image for Vol. 36 Issue 10

May 15, 1997

Volume 36, Issue 10

Pages 1023–1129

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 10/1997)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710211

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      The cover picture shows a representation of organic–inorganic films containing well-organized layers of a polyoxometalate Keggin anion and a cationic surfactant. This new kind of supramolecular assembly has been obtained by using the Langmuir–Blodgett technique, and, considering the photochemical, electrochromic, magnetic, and catalytic properties associated with these metal-oxide clusters, it opens a wide range of new possiblities for applications. More about these organic–inorganic films is reported by E. Coronado and C. Mingotaud et al. on pages 1114ff.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. Biosynthesis of Vitamin B1 (Thiamin): An Instance of Biochemical Diversity (pages 1032–1046)

      Prof. Dr. Ian D. Spenser and Prof. Dr. Robert L. White

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710321

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      Even though more than half a century has elapsed since the isolation of Vitamin B1 (thiamin, 1), the determination of its structure, and the elucidation of its biochemical function, present day understanding of its biosynthesis is still incomplete. This review summarizes the current state of knowledge of thiamin biosynthesis, based on investigations with isotropic tracers and on genetic studies.

    2. Organometallic Homogeneous Catalysis—Quo vadis? (pages 1048–1067)

      Prof. Dr. Wolfgang A. Herrmann and Prof. Dr. Boy Cornils

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710481

      Less apodictic! That homogeneous and heterogeneous catalysis will be better integrated with one another in the future is certain when one peruses the developments of the past few years. Tailor-made homogeneous and surface-bound catalysts, multiple-component catalysts, and electroenzymatic processes are just a few of the advances that will bridge the gap between the “two-cultures”. An approach to unification can be seen in research as well as industry. Catalysis is a central theme in chemical research.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. Protein Synthesis by Chemical Ligation of Unprotected Peptides in Aqueous Solution (pages 1069–1071)

      Dr. Michael A. Walker

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710691

      Orthogonal and native chemical ligation are two terms of a novel method for synthesizing proteins. It is particularly useful where molecular biology techniques fail, for example, for the synthesis of analogs of natural proteins from unnatural building blocks. Since the innovative method proceeds without carboxyl-group activation or side-chain protection, it is very easy to use and will find application by the average organic chemist.

  3. Correspondences

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. Requirements for Quantifications of Weak Intermolecular Interactions from Equilibrium Studies with Supramolecular Complexes (pages 1072–1073)

      Prof. Dr. Hans-Jörg Schneider

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710721

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      How can meaningful values be determined for the energies of weak interactions? That this is not a trivial question is revealed by the printed correspondence, which is concerned with the correct choice of model and method for the analysis of π-π interactions between aromatic rings with the help of complexes such as 1.

    2. Requirements for Quantifications of Weak Intermolecular Interactions from Equilibrium Studies with Supramolecular Complexes (page 1073)

      Dr. Christopher A. Hunter

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710731

      Thumbnail image of graphical abstract

      How can meaningful values be determined for the energies of weak interactions? That this is not a trivial question is revealed by the printed correspondence, which is concerned with the correct choice of model and method for the analysis of π-π interactions between aromatic rings with the help of complexes such as 1.

    3. A Novel Strategy towards the Total Synthesis of Cyclopeptide Alkaloids (page 1074)

      Prof. Dr. Ulrich Schmidt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710741

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      Fourteen-membered cyclopeptides are strained (J. Zhu) or only rigid (U. Schmidt) and therefore difficult to prepare. However, in the opinion of U. Schmidt the degree of novelty of the work by Zhu et al. is less than the latter claim, while Zhu regards their success in avoiding the ring opening of 1 by an attack of a base as a remarkable feature of their synthesis.

    4. A Novel Strategy towards the Total Synthesis of Cyclopeptide Alkaloids (pages 1074–1075)

      Dr. Jieping Zhu

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710742

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      Fourteen-membered cyclopeptides are strained (J. Zhu) or only rigid (U. Schmidt) and therefore difficult to prepare. However, in the opinion of U. Schmidt the degree of novelty of the work by Zhu et al. is less than the latter claim, while Zhu regards their success in avoiding the ring opening of 1 by an attack of a base as a remarkable feature of their synthesis.

  4. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. Self-Assembly of Submicrometer Rings of Particles from Solutions of Nanoparticles (pages 1078–1080)

      Pamela C. Ohara, Prof. James R. Heath and Prof. William M. Gelbart

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710781

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      Thousands of individual metal nanocrystals with a diameter of 2.5 nm form the five particle rings shown in the transmission electron microscope image on the right. Each ring has a diameter of about 1 μm. The experimental and theoretical explanation for these rings are discussed.

    2. Light-Directed Assembly of Nanoparticles (pages 1080–1083)

      Dr. Tobias Vossmeyer, Erica DeIonno and Prof. Dr. James R. Heath

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710801

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      How can patterned thin films of nanocrystals be self-assembled? This contribution describes a general strategy that combines biochemical and lithographic techniques to restrict the assembly of nanocrystals to parts of a surface previously exposed to UV/Vis irradiation. The scanning electron microscope image on the right shows a pattern of gold nanoparticles assembled on a silicon substrate.

    3. The[Cu2(O2CMe)4(H2O)2]/(py)2CO System as the Source of an Unusual Heptanuclear Complex and a Novel Dodecanclear “Flywheel” Cluster (pages 1083–1085)

      Vasilis Tangoulis, Dr. Catherine P. Raptopoulou, Sofia Paschalidou, Prof. Dr. Evangelos G. Bakalbassis, Prof. Dr. Spyros P. Perlepes and Dr. Aris Terzis

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710831

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      A chair-within-a-chair arrangement of the twelve copper atoms (bottom left) is characteristic of one of the complexes reported here; the other complex features two Cu tetrahedra sharing a common vertex (bottom right). Both were isolated from the reaction mixture [Cu2(O2CMe)4(H2O)2]/(py)2CO in MeCN. Magnetic susceptibility data show that the heptanuclear complex has an S = 1/2 ground state.

    4. Kinetically Stabilized [4]Paracyclophane—The 1, 4-Bis-(dicyanomethylene)-2-ene Derivative: 1H NMR Measurement and Assessment of Its Diatropicity (pages 1085–1087)

      Masahiro Okuyama and Prof. Dr. Takashi Tsuji

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710851

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      The benzene ring is nonplanar but sustains significant aromatic ring current in [4]paracyclophane 1. The strained skeleton of this molecule was kineticaly stabilized by substituents, which permitted the measurement of the 1H NMR spectrum of a [4]paracyclophane for the first time.

    5. One-Dimensional Semiconducting Chains of the Quaternary Zintl Anion in (Et4N)4[Au(Ag1-xAux)2Te9] (pages 1087–1090)

      Dr. Sandeep S. Dhingra, Dong-Kyun Seo, Glen R. Kowach, Dr. Reinhard K. Kremer, Dr. Julie L. Shreeve-Keyer, Dr. Robert C. Haushalter and Prof. Myung-Hwan Whangbo

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710871

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      Metal atoms in isolated chains are the sole components of the first quaternary Zintl anion [Au(Ag1-xAux)2Sn2Te9]-4 (x = 0.32; structure of depicted below) in the compound (Et4N4)[Au(Ag1-xAux)2Sn2Te9]. Electronic structure calculations and the diamagnetic and semiconducting properties of of this new compound show that the anion displays a Peierls distortion at room temperature.

    6. Diastereo- and Enantioselective Synthesis of 1,2,3-Substituted Cyclopropanes with Zinc Carbenoids (pages 1090–1092)

      Prof. André B. Charette and Jacinthe Lemay

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710901

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      Substituted, functionalized iodoalkylzinc reagents in combination with the chiral dioxaborolane 2 give excellent diastereo- and enantiomeric selectivities in cyclopropanations when substituted allyl alcohols 1 (R1 [DOUBLE BOND] H, Et, CH2OBn; R2 [DOUBLE BOND] H, Ph, nPr; R3 [DOUBLE BOND] H, Me) are used as starting materials and CH2Cl2 as solvent. This efficient preparation of chiral, nonracemic 1,2,3-trisubstituted cyclopropanes 3 might be useful in natural product synthesis.

    7. Generation of Alkyl(dicarbonyl)(chloro)-ruthenium Dimers in the Ruthenium-Catalyzed Addition of Alkyl Formates to Ethylene (pages 1092–1095)

      Sylvie Fabre, Prof. Philippe Kalck and Dr. Guy Lavigne

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710921

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      An ususual migration of the alkyl group away from the C[BOND]O bond of added formate leads to strictly stereospecific formation of the stable ehtyl complex 2 when the catalytic addition of ethyl formate to ethylene (catalyst = 1) is terminated by freezing. Both ethylene and the alkyl formate act as sources of the alkyl groups and can thus be used for C[BOND]C bond-forming reactions below ambient temperature. PPN+ = (Ph3P)2N+.

    8. Stereoselective Synthesis and Isomerization of η1-2-Phosphabutadiene Complexes to η1-2,3-Dihydrophosphete Complexes (pages 1095–1097)

      Dr. Rainer Streubel, Dipl.-Chem. Markus Hobbold, Dipl.-Chem. Jörg Jeske and Prof. Dr. Peter G. Jones

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710951

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      Unexpected reactivity of in situ generated carbene complex anions in seen upon treatment with a P-chloro(methylene)phosphane. A stereoselective P[BOND]C coupling reaction provides the η1-2-phosphabutadiene complexes 1a,b. Thermal isomerization of these compounds leads to the novel η1-2,3-dihydrophosphete complexes 2a,b. a: M [DOUBLE BOND] Cr; b: M [DOUBLE BOND] W.

    9. C-Terminally Modified Peptides and Peptide Libraries—Another End to Peptide Synthesis (pages 1097–1099)

      Dr. Michael Davies and Dr. Mark Bradley

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710971

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      Conventional solid-phase synthesis and a novel inversion step allows ready access to peptides modified at the C-terminus (the principle is outlined below). These compounds have important biological roles and a wide range of applications in research.

    10. Protease-Catalyzed Peptide Synthesis from N- to C-Terminus: An Advantageous Strategy (pages 1099–1101)

      Frank Bordusa, Dr. Dirk Ullmann and Prof. Dr. Hans-Dieter Jakubke

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199710991

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      Not possible with chemical methods: Protein synthesis from the N- to C- terminus using the reverse hydrolysis potential of proteases was accompolished for the model petide 1. The stereo- and regiospecificity of the enzymes used ensured integrity of the stereogenic center and allowed ecological reaction conditions without side-chain protection.

    11. Template-Directed Ring-Closing Metathesis: Synthesis and Polymerization of Unsaturated Crown Ether Analogs (pages 1101–1103)

      Dr. Michael J. Marsella, Heather D. Maynard and Prof. Robert H. Grubbs

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711011

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      A highly efficient combination: template directing and olefin metathesis. The polyether dienes 1 react in good yields to give crown ethers 2 in the presence of LiClO4 and the Ru catalyst 3 (Cy = cyclohexyl). Ring-opening metathesis polymerization (ROMP) of the cyclic olefins 2 results in polymers that are capable of regenerating 2 by template-directed methathesis depolymerization.

    12. Proof of Chiral Dihydride Complexes Including Catalyst and Substrate during the Bis(phosphinite)rhodium(I)-Catalyzed Hydrogenation of Dimethyl Itaconate (pages 1103–1105)

      Dr. Andreas Harthun, Dr. Renat Kadyrov, Prof. Dr. Rüdiger Selke and Prof. Dr. Joachim Bargon

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711031

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      The PHIP-NMR method (PHIP = parahydrogen induced polarization) can be used to detect dihydride catalyst–substrate complexes of the general formula [Rh(P[BOND]P)(X[BOND]X)(H)2]BF4 (shown on the right, X[BOND]X = dimethyl itaconate as substrate), which are formed in situ under hydrogenation conditions with chiral bis(phosphinite)rhodium(I) catalysts. Remarkable is the absence of typical (H,P)trans coupling (2J(H,P)trans); the Rh[BOND]P bond trans to HB is therefore lenthened, and the octahedral geometry distorted.

    13. S(NtBu)math image: A Dianion Isoelectronic to SOmath image and the Related MeS(NtBu)math image (pages 1105–1107)

      Dipl.-Chem. Roland Fleischer, Alexander Rothenberger and Prof. Dr. Dietmar Stalke

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711051

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      The nitrogen analogue of the sulfate ion, tetraimidosulfate S(NR)math image is easily accessible from S(NR)3 and LiN(H)R. S(NR)3 can be prepared from S(NR)2 and LiN(H)R by oxidation of the resulting [Li2(NR)3S]2 with bormine or iodine. In an addition reaction organolithium compounds and S(NR)3 yield the related triimidosulfonate RS(NR)math image. Both anions form molecular contact ion pairs with lithium cations (structure of S(NR)math image shown on the right, the thf ligands on Li1 and Li2 have been omitted), which makes them promising ligands in coordination chemistry.

    14. A Restitutive Bergman Rearrangement: Synthesis of a CpCo-Complexed, Tetraethynylated Cyclobutadiene (pages 1107–1109)

      Dr. Markus Altmann, Dipl.-Chem. Gaby Roidl, Priv.-Doz. Dr. Volker Enkelmann and Dr. Uwe H. F. Bunz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711071

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      Conditions of flash vacuum pyrolysis (FVP) result in the conversion of bisdiyne 1 into the complexed, tetraethynylated cyclobutadiene 2, which is isolated as the sole product in high yield. Complex 2 can be protected, and both the partially as well as the fully deprotected, complexed, tetraethynylated cyclobutadienes are stable under ambient conditions. TIPS = triisopropylsilyl.

    15. Synthesis of Enopeptin B from Streptomyces sp RK-1051 (pages 1110–1112)

      Prof. Dr. Ulrich Schmidt, Dr. Karin Neumann, Dr. Andreas Schumacher and Dr. Stefan Weinbrenner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711101

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      A cyclopeptolide, a polyene, and an aminoreductone—species with completely different biogenetic origins—are the components of the antibiotically active natural product enopeptin B (1, see schematic representation below), which is particularly active against Staphylococcus aureus. The first total synthesis of this compound, which belongs to a new class of substances, was achieved by the clever use of the arsenal of methods available to modern peptide chemistry. The three basic units were coupled by two different routes.

    16. Trimethylene-Bridged Tri- and Tetratin Compounds as Building Blocks for Unusual Double and Triple Ladders (pages 1112–1114)

      Dipl.-Chem. Michael Mehring, Dr. Markus Schürmann, Prof. Dr. Hans Reuter, Prof. Dr. Dainis Dakternieks and Prof. Dr. Klaus Jurkschat

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711121

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      Pillar-shaped organostannoxanes with the first triple-ladder structure of type A are obtained in almost quantitative yield by reaction of the tritin compound [RCl2Sn(CH2)3]2SnCl2 with (tBu2SnO)3. In contrast, treating [RCl2Sn(CH2)3]2SnCl2SiMe with (tBu2SnO)3 affords an organostannoxane with a folded double-ladder structure. R [DOUBLE BOND] CH2SiMe3.

    17. Application of the Langmuir–Blodgett Technique to Polyoxometalates: Towards New Magnetic Films (pages 1114–1116)

      Miguel Clemente-León, Dr. Christophe Mingotaud, Dr. Bóatrice Agricole, Dr. Carlos J. Gómez-Garcia, Prof. Dr. Eugenio Coronado and Dr. Pierre Delhaès

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711141

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      A new method for the synthesis of inroganic—organic composites with promising properties is the incorporation of polyoxometalates into well-ordered organic films by the Langmuir–Blodgett (LB) method. The structure of such an LB film is depicted schematically on the right.

    18. A New Route to Tetracarba-nido-octaboranes(8); Molecular Structure of a 6,9-Diferra-5,7,8,10-tetracarba-nido-decaborane(10) Derivative (pages 1117–1119)

      Prof. Dr. Bernd Wrackmeyer, Dipl.-Chem. Hans-Jörg Schanz and Dr. Wolfgang Milius

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711171

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      The first polyborane with six heteroatoms (3) is formed when the new tetracarba-nido-octaborane(8). (2), readily available by the reaction of 1 with Et2BH, reacts with [Fe3(CO)12].

    19. Liquid-Crystalline Crown Ether: Forming Columnar Mesophases by Molecular Recognition (pages 1119–1121)

      Jörg Andreas Schröter, Prof. Dr. Carsten Tschierske, Prof. Dr. Michael Wittenberg and Prof. Dr. Joachim Heinz Wendorff

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711191

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      Rodlike 4,4″-didecyloxy-p-terphenyl derivatives with a laterally attached [18]crown-6 moiety form columnar, liquid-crystalline phases in the presence of aqueous potassium salt solutions. The building block is shown on the right.

    20. K3Sbmath imageO9Se3 · 3 H2O: The First Crystalline Nanoporous Material with a Photo-Semiconducting Host Structure (pages 1121–1124)

      Dr. Ulrich Simon, Prof. Dr. Ferdi Schüth, Dipl.-Chem. Stephan Schunk, Dr. Xiqu Wang and Prof. Dr. Friedrich Liebau

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711211

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      The natural mineral cetineite was prototype for the synthesis of the compound 1. Its nanoporous, template-free host structure is an idela object for numerous investigations. Electronic excitation and transport processes, for example, can be studied on this nanostructured semiconducting material. A part of the crystal structure is shown on the right.

      • equation image
    21. Highly Efficient Synthesis of Cephalotaxine by Two Palladium-Catalyzed Cyclizations (pages 1124–1125)

      Prof. Dr. Lutz F. Tietze and Dipl.-Chem. Hartmut Schirok

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199711241

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      Interesting for cancer therapy: The unique pentacyclic alkaloid cephalotaxine is the parent compound of the strongly cytotoxic harringtonines, which are isolable from the study-east Asian yewtree. Now the cephalotaxine precursor 2 has been synthesized highly efficiently and selectively in two steps from the readily accessible amine 1 through an intramolecular Pd-catalyzed allylic amination to form the spirocycle (85% yield) and subsequent Heck reaction to construct the seven-membered ring (80% yield).

  5. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews

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