Angewandte Chemie International Edition in English

Cover image for Vol. 36 Issue 16

September 1, 1997

Volume 36, Issue 16

Pages 1665–1771

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 16/1997)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199716631

      Thumbnail image of graphical abstract

      The cover picture shows a thin section of a brain from a patient who died of Creutzfeldt–Jakob disease. The severe perforation of the cortex is clearly seen. A class of neurodegenerative diseases, the transmissible spongiform encephalopathies, was named after these spongelike alterations in the tissue. Among them are also scrapie in sheep and bovine spongiform encephalopathy (BSE, the “Mad Cow Disease”). The biochemical mechanism discussed as the cause of this kind of disorder is shown in the foreground: the conversion of α-helices of the prion protein into β-sheet domains. The β-sheet-rich pathogenic form of the prion protein aggregates in the brain of the affected organisms and triggers the pathological changes. The pathogenic form of the prion protein seems to be intrinsically infectious—it might therefore represent a novel class of pathogens that replicate in the absence of a nucleic acid. The latest results on this topic are reported by E.-L. Winnacker, M. Famulok et al. on pp. 1674 ff.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Chemistry and Molecular Biology of Transmissible Spongiform Encephalopathies (pages 1674–1694)

      Dipl.-Chem. Frank Edenhofer, Dr. Stefan Weiss, Prof. Dr. Ernst-Ludwig Winnacker and Priv.-Doz. Dr. Michael Famulok

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199716741

      Thumbnail image of graphical abstract

      Replication without the information contained in nucleic acids seems to be possible for the pathogen of the transmissible spongiform encephalopathies. According to present-day knowledge, the pathogenic prion protein differs from the cellular form merely in its spatial structure (shown schematically on the right), and not in its amino acid sequence.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Pentalene as a Complex Ligand: New Developments in the Chemistry of Nonalternant, Highly Unsaturated Hydrocarbons (pages 1695–1697)

      Prof. Dr. Holger Butenschön

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199716951

      Thumbnail image of graphical abstract

      A totally new mode of complexation is exhibited by the pentalene dianion (12−): All eight carbon atoms are coordinated to only one metal atom, and the pentalene ligand is folded along the central C[BOND]C bond. Like the complex-bound 12−, the acepentalene dianion (22−) is not planar, but has a shell-like structure, and is therefore also expected to be able to function as a ligand in transition metal complexes.

    2. Electron-Transfer Transition States: Bound or Unbound—That is the Question! (pages 1697–1700)

      Dr. Hendrik Zipse

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199716971

      A third pathway other than the known outer-sphere and inner-sphere processes needs to be considered, according to quantum mechanical studies of electron-transfer (ET) processes. This new outer-sphere reaction type, which proceeds via “bound” transition states, shows clear stereochemical preferences as well as significant intermolecular orbital overlap in the transition state. In contrast to inner-sphere ET processes, no bond formation occurs during the reaction.

    3. Amino Acid Derivatives by Multicomponent Reactions (pages 1700–1702)

      Prof. Dr. Gerald Dyker

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717001

      Thumbnail image of graphical abstract

      The ideal synthesis uses simple, inexpensive starting materials that can be converted in a single step and in excellent yield into the final product. Multicomponent reactions such as the palladium-catalyzed amidocarbonylation (a) described by Beller et al. are aimed at approaching this ideal situation.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Search for Chiral Catalysts Through Ligand Diversity: Substrate-Specific Catalysts and Ligand Screening on Solid Phase (pages 1704–1707)

      Dr. Ken D. Shimizu, Dr. Bridget M. Cole, Clinton A. Krueger, Kevin W. Kuntz, Prof. Marc L. Snapper and Prof. Amir H. Hoveyda

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717041

      Thumbnail image of graphical abstract

      An efficient strategy in the search for chiral catalysts is ligand optimization on solid support. This diversity approach provides unique opportunities for the identification of substrate-specific catalysts and leads to the discovery of ligands with unusual properties that might have otherwise escaped detection. Thus, addition of TMSCN to cyclopentene oxide with ligands 1 or 2, which are very similar, results in opposite enantioselectivities (see reaction on the right; TMS = trimethylsilyl).

    2. Isomers of the Elemental Composition CN2O (pages 1707–1709)

      Prof. Dr. Günther Maier, Dr. Hans Peter Reisenauer, Dr. Jürgen Eckwert, Dipl.-Chem. Matthias Naumann and Dipl.-Chem. Michael De Marco

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717071

      Thumbnail image of graphical abstract

      Do isomers of nitrosyl cyanide (1) exist? The answer is undoubtedly yes! Not only can matrix-isolated 1 be photochemically converted into nitrosyl isocyanide (2) by a reversible reaction, but also into isonitrosyl cyanide (3).

    3. 2,3-Dihydrothiazol-2-ylidene (pages 1709–1712)

      Prof. Dr. Günther Maier, Dipl.-Chem. Jörg Endres and Dr. Hans Peter Reisenauer

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717091

      Thumbnail image of graphical abstract

      Nucleophilic carbenes are not only accessible as sterically hindered derivatives. Matrix-isolation techniques allow facile trapping of the unsubstituted parent compounds. An example is the formation of the title compound 2 from thiazole carboxylic acid (1).

    4. Novel Mononuclear Vanadium Complexes Having Pentalene Ligands η8- Bonded to a Single Metal Atom—A New Type of Coordination in Organometallic Chemistry (pages 1712–1714)

      Prof. Dr. Klaus Jonas, Barbara Gabor, Dr. Richard Mynott, Dr. Klaus Angermund, Dr. Oliver Heinemann and Prof. Dr. Carl Krüger

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717121

      Thumbnail image of graphical abstract

      The pronounced folding of the η8-coordinated pentalene ligand along the bond between the two bridgehead carbon atoms is the most prominent structural feature of the vanadium complex 2. This compound and further 18e complexes of this type are readily prepared by the reaction of vanadocene monohalides 2 or their derivatives with dilithium pentalenediide. Although these mononuclear complexes are air-sensitive, they are thermally so stable that they can be sublimed in high vacuum at 80–100°C without decomposition.

    5. Mononuclear Pentalene and Methylpentalene Complexes of Titanium, Zirconium, and Hafnium (pages 1714–1718)

      Prof. Dr. Klaus Jonas, Dipl.-Chem. Peter Kolb, Dipl.-Chem. Guido Kollbach, Barbara Gabor, Dr. Richard Mynott, Dr. Klaus Angermund, Dr. Oliver Heinemann and Prof. Dr. Carl Krüger

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717141

      Thumbnail image of graphical abstract

      Not only mononuclear complexes having a single pentalene or methylpentalene ligand but also homoleptic complexes with two η8-C8H6 or η8-C8H5CH3 ligands can be formed by titanium, zirconium, and hafnium. The syntheses, which start from the corresponding metallocene dihalides, are particularly simple. The homoleptic pentalene complex 1 reacts with [ZrCl4(thf)2] to form the dichloro complex 2, the first mononuclear “half-sandwich” complex having a pentalene ligand.

    6. Direct Proof for O[DOUBLE BOND]Mnv (salen) Complexes (pages 1718–1719)

      Dipl.-Naturwissenschaftler Derek Feichtinger and Dr. Dietmar A. Plattner

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717181

      Thumbnail image of graphical abstract

      Electrospray mass spectroscopy has finally provided proof for the formation of oxomanganese(v) complexes such as 1 under the conditions of the Kochi-Jacobson-Katsuki epoxidation. Collision of 1 with olefins or sulfides in the gas phase regenerates the initial (salen)MNIII complexes by transfer of the oxygen atom.

    7. On the Viability of Oxametallacyclic Intermediates in the (salen)Mn-Catalyzed Asymmetric Epoxidation (pages 1720–1723)

      Nathaniel S. Finney, Paul J. Pospisil, Sukbok Chang, Michael Palucki, Reed G. Konsler, Karl B. Hansen and Prof. Eric N. Jacobsen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717201

      Thumbnail image of graphical abstract

      A mechanism that is simpler than the recently advanced is followed for the (salen)Mn-catalyzed asymmetric epoxidation of olefins. Oxametallacycles such as B or B′ are not viable intermediates; radical species such as A, which are directly formed by attack of the olefin on the oxomanganese catalyst are more likely candidates; salen [DOUBLE BOND] N,N′-bis(salicylidene)ethylenediamine dianion.

    8. Is There a Radical Intermediate in the (salen)Mn-Catalyzed Epoxidation of Alkenes? (pages 1723–1725)

      Christian Linde, Moritz Arnold, Prof. Dr. Björn Åkermark and Prof. Dr. Per-Ola Norrby

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717231

      Thumbnail image of graphical abstract

      For the direct epoxidation of alkenes radical intermediates play no role. Instead investigations with the radicals traps 1a–c indicate that manganaoxetane intermediates are present. Radicals can form from the latter, particularly in the case of sterically crowded oxetanes, by homolytic of the Mn[BOND]C bond.

    9. Three-Dimensional Framework with Channeling Cavities for Small Molecules: {[M2(4, 4′-bpy)3(NO3)4]·xH2O}n (M [DOUBLE BOND] Co, Ni, Zn) (pages 1725–1727)

      Dr. Mitsuru Kondo, Tomomichi Yoshitomi, Dr. Hiroyuki Matsuzaka, Prof. Dr. Susumu Kitagawa and Kenji Seki

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717251

      Thumbnail image of graphical abstract

      Reversible adsorption of gases distinguishes the coordination polymers {[M2(4,4′-bpy)3(NO3)4](H2O)x}n (M = Co., x = 4; M = Ni, x = 4; M = Zn, x = 2), which are formed from M(NO3)2 and 4,4′-bipyridine in acetone/ethanol. The channeling cavities in the crystal frameworks (shown schematically on the right) have dimensions of about 3 × 6 Å along the a axis and about 3 × 3 Å along the b axis, and reversibly adsorb CH4, N2, and O2 in the pressure range of 1–36 atm without deformation of the crystal framework.

    10. A Bis(carceplex) from a Cyclic Tetramer of Cavitands (pages 1727–1729)

      Naveen Chopra and Dr. John C. Sherman

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717271

      Thumbnail image of graphical abstract

      Yields of 74% were obtained for the preparation of 2 from the tetrameric cavitand 1 in the presence of pyrazine. This first bis(carceplex) may provide a unique opportunity for studying guest-guest communication by virtue of the close proximity of the two covalently attached capsules, which, according to MM2 calculations, are rotated by 90° with respect to each other.

    11. Gas-Phase Enantiodifferentiation of Chiral Molecules: Chiral Recognition of 1-Phenyl-1-propanol/2-Butanol Clusters by Resonance Enhanced Multiphoton Ionization Spectroscopy (pages 1729–1731)

      Dr. Macro Pierini, Dr. Anna Troiani, Prof. Maurizio Speranza, Dr. Susanna Piccirillo, Dr. Cesare Bosman, Dr. Daniela Toja and Prof. Anna Giardini-Guidoni

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717291

      A combination of high-resolution spectroscopy and time-of-flight mass spectrometry was used for the first time to study the fundamental properties of supersonically expanded van der Waals complexes between (R)-(+)-1-phneyl-1-propanol (PR) and the enantiomers of 2-butanol (BR or BS) at the microscopic level. Chiral discrimination is based on the different fragmentation patterns of PRBR and PRBS or on the different bathochromic shift of their electronic band origin relative to that of pure PR.

    12. Multipolymer-Supported Substrate and Ligand Approach to the Sharpless Asymmetric Dihydroxylation (pages 1731–1733)

      Dr. Hyunsoo Han and Prof. Kim D. Janda

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717311

      Thumbnail image of graphical abstract

      The correct combination of soluble and insoluble polymers allows a multipolymers reaction in which the substrate trans-cinnamate and the chiral ligand are bound to different polymer supports. The reactions (shown schematically on the right) proceed with 98% conversion and 98% ee.

    13. Stabilization of Iron Centers in High Oxidation State in the Mononuclear Complex [Fev(I)(′N2S2′)] (pages 1734–1736)

      Prof. Dr. Dieter Sellmann, Dipl.-Chem. Susanne Emig and Dr. Frank W. Heinemann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717341

      Thumbnail image of graphical abstract

      The first stable molecular Fev complex, [Fev(I)(′N2S2′)], forms in the metal-centered oxidation of the readily accessible FeIV complex [FeIV(pnPr3)(′N2S2′)] with elemental iodine according to Equation (a). The high-valent character of the iron center is proved by structural, spectroscopic, and electrochemical data.

    14. Intra-Cavity Inclusion of [CpFeII(arene)]+ Guests by Cyclotriveratrylene (pages 1736–1738)

      K. Travis Holman, Prof. Jerry L. Atwood and Dr. Jonathan W. Steed

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717361

      Thumbnail image of graphical abstract

      Polar one- and two-dimensional stuctural motifs feature in the crystal structures of the inclusion complexes 1 between [CpFeII(arene)]+ and the cryptophane cyclotriveratrylene. These structure result from π-stacking interactions between the electron-rich host and the electron-deficient guest.

    15. Solvent-Anchored Supported Liquid Phase Catalysis: Polyoxometalate-Catalyzed Oxidations (pages 1738–1740)

      Prof. Dr. Ronny Neumann and Michal Cohen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717381

      Thumbnail image of graphical abstract

      A new immobilization technique for homogeneous catalysts is represented by the title process. Polyethers that are covalently attached to silica surfaces (shown schematically on the right) act as solvent and/or ligands for the catalysts, in this case polyoxometalates (POM). Such systems allow, for example, the quantitative oxidation of cyclooctene to cyclooctene oxide. The catalyst can be recycled without loss of activity.

    16. Palladium-Catalyzed Regioselective Mono- and Diarylation Reactions of 2-Phenylphenols and Naphthols with Aryl Halides (pages 1740–1742)

      Tetsuya Satoh, Yuichiro Kawamura, Prof. Dr. Masahiro Miura and Prof. Dr. Masakatsu Nomura

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717401

      Thumbnail image of graphical abstract

      Not only monoarylation but also diarylation of 2-phenylphenols with aryl iodides proceeds effectively and regioselectively when a palladium catalyst and an appropriate base are employed. The products are 1,2-diphenyl- and 1,2,3-triphenylbenzene derivatives, respectively (see below). Also discussed is the arylation of 1- and 2-naphthols. X = H, OMe; Y = H, Me; Z = H, OMe, NO2.

    17. Catalytic Three-Component Synthesis of Conjugated Dienes from Alkynes via Pd0, PdII, and PdIV Intermediates Containing 1,2-Diimine (pages 1743–1745)

      Dr. Ruud van Belzen, Dr. Helmut Hoffmann and Prof. Dr. Cornelis J. Elsevier

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717431

      Thumbnail image of graphical abstract

      Direct, efficient, selective, and catalytic all describe the synthesis of conjugated dienes from two molecules of alkyne, an organic halide, and tetramethyltin with 1 mol% of a (1,2-diimine)palladium complex in complex in DMF (see the catalytic cycle involving Pd0, PdII, and PdIV species on the right). Palladium–phosphane complexes do not catalyze this reaction. Furthermore, 1,4-dihalo-1,3-dienes were synthesized stoichiometrically from alkynes and molecular halogen.

    18. Conformation Design of a Fully Flexible βII- Hairpin Analogue (pages 1745–1747)

      Dipl.-Chem. Ulrich Schopfer, Dipl.-Chem. Martin Stahl, Trixi Brandl and Prof. Dr. Reinhard W. Hoffmann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717451

      Thumbnail image of graphical abstract

      Almost congruent with the natural prototype 1, βII-hairpin mimetic 2 was obtained through rational conformation design. The hydrocarbon backbone of 2 provides optimal preorganization of the hydrogen bond, which is decisive for inducing a β-sheet conformation.

    19. NADH-Induced Changes of the Nickel Coordination within the Active Site of the Soluble Hydrogenase from Alcaligenes eutrophus: XAFS Investigations on Three States Distinguishable by EPR Spectroscopy (pages 1747–1750)

      Dipl.-Chem. Arnd Müller, Prof. Dr. Gerald Henkel, Dr. Andreas Erkens, Dr. Klaus Schneider, Prof. Dr. Achim Müller, Dr. Hans-Friedrich Nolting and Dr. Vicente Armando Solé

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717471

      Thumbnail image of graphical abstract

      A heterobinuclear Ni-Fe-S center similar to that in the hydrogenase from Desulfovibrio gigas is also present in the considerably more complex soluble hydrogenase from the bacterium Alcaligenes eutrophus, as shown by high-resolution X-ray absorption spectroscopy. Reductive activation of this enzyme with NADH leads to a substantial change in the coordination of the nickel, which is probably due to specific substrate properties. A model for the active site after NADH reduction is shown on the right.

    20. A Facile Cycloisomerization for the Formation of Medium and Large Rings via Allenes (pages 1750–1753)

      Prof. Dr. Barry M. Trost, Dr. Pierre-Yves Michellys and Dr. Vincent J. Gerusz

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717501

      Thumbnail image of graphical abstract

      The use of allenes as proelectrophiles in Pd-catalyzed reaction provides a facile entry to macrocarbocycles, macrolactones, and macrolactams. Remarkably, medium-sized rings, notoriously the most difficult to generate, are produced in excellent yields, even in preference to the more easily formed ring sizes when both are feasible (see example below).

    21. Crystal Structure Determination of Metaperiodic Acid, HIO4, with Combined X-Ray and Neutron Diffraction (pages 1753–1754)

      Dr. Thorsten Kraft and Prof. Dr. Martin Jansen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717531

      Thumbnail image of graphical abstract

      Neither HIO4 molecules nor trans-edge-sharing IO6 octahedra make up metaperiodic acid. Instead, chains of cis-edge-sharing IO6 octahedra form the I[BOND]O skeleton, as shown in the picture of the structure below.

    22. Gemath image: A Deltahedral Zintl Ion Now Made in the Solid-State (pages 1754–1756)

      Virginie Queneau and Prof. Slavi C. Sevov

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717541

      Thumbnail image of graphical abstract

      Direct fusion of the appropriate elements readily produces the A4Ge9 compounds (A = Rb, Cs), which contain discrete Gemath image clusters with the shape of monocapped square antiprisms (structure shown on the right). The clusters are the first deltahedral Zintl ions that can be made from solution as well as by a solid-state reaction.

    23. [2+2] Cycloaddition Products of Tetradehydrodianthracene: Experimental and Theoretical Proof of Extraordinary Long C[BOND]C Single Bonds (pages 1757–1760)

      Dipl.-Chem. Stefan Kammermeier, Prof. Dr. Rainer Herges and Prof. Dr. Peter G. Jones

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717571

      Thumbnail image of graphical abstract

      An extremely long C[BOND]C single bond of 1.713 Å is found in the [2+2] cycloadduct of ortho-didehydrobenzene and tetradehydrodianthracene. The force constant of this central bond is reduced to only 30% of that of the C[BOND]C bond in ethane. The corresponding C[BOND]C stretching vibration (687 cm−1) in the Raman spectrum is red-shifted 300 cm−1 relative to the bands of “normal” hydrocarbons.

    24. Self-Assembly of Convex and Concave Molecular Tectons to Form a Linear Molecular Array in the Solid State (pages 1760–1762)

      Frédérique Hajek, Prof. Dr. Mir Wais Hosseini, Dr. André De Cian and Prof. Jean Fischer

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717601

      Thumbnail image of graphical abstract

      A biconcave molecular module (koiland) was fashioned by the double fusion of two p-allylcalix[4]arenes through two silicon atoms. Koilands and linear molecular connectors self-assemble to form an α-network (koilate) in the solid state (see the schematic representation below).

    25. Evidence for Directed Metalation: A Structural Intermediate in the Formation of a Novel C-bound Adenine Complex of Ruthenium (pages 1762–1764)

      Clayton Price, Dr. Mark R. J. Elsegood, Prof. William Clegg, Dr. Nicholas H. Rees and Dr. Andrew Houlton

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717621

      Thumbnail image of graphical abstract

      The nucleobase–ligand conjugate from ethylenediamine and 9-ethyladenine can function as a bidentate or tridentate ligand to RuII. Both modes of coordination involve the ethylenediamine group, while the latter additionally relies on carbonmetal bond formation through C8 of the nucleobase (structure depicted on the right).

    26. Synthesis of Enantiomerically and Diastereomerically Pure Cyclopentanols by asymmetric Cyclocarbolithiation of 5-Alkenyl Carbamates (pages 1764–1766)

      Dipl.-Chem. Michael J. Woltering, Dr. Roland Fröhlich and Prof. Dr. Dieter Hoppe

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717641

      Thumbnail image of graphical abstract

      Three vicinal stereocenters are formed in the (−)-sparteine-induced cyclobolithiation of 6-phenyl-5-hexenyl carbamates. The anionic cyclization products can be trapped with various electrophiles (El) to provide enantiomerically pure cyclopentanol derivatives [Eq. (a); Cby = 2,2,4,4-tetramethyl-1,3-oxazolidin-3-carboxylate].

    27. Activation of Ti[BOND]F Bonds in [{(C5Me5)TiOF}4] and [{(C5Me4Et)TiOF}4] with AlMe3 (pages 1766–1767)

      Peihua Yu, Prof. Dr. Herbert W. Roesky, Dr. Alojz Demsar, Thomas Albers, Hans-Georg Schmidt and Dr. Mathias Noltemeyer

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199717661

      Thumbnail image of graphical abstract

      Hitherto only discussed, now isolated and characterized: The adducts of titanium fluoride oxide with trimethylaluminum contain activated Ti[BOND]F bonds (an example is depicted on the right). They are formed as intermediates in the methylation of compounds with sterically crowded titanium centers. Cp* = C5Me5.

  4. Book Reviews

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

SEARCH

SEARCH BY CITATION