Angewandte Chemie International Edition in English

Cover image for Vol. 36 Issue 4

March 3, 1997

Volume 36, Issue 4

Pages 305–417

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 4/1997)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703031

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      The cover picture shows a “wheel with a hydrocarbon tire”. This is how the authors F. H. Köhler et al. describe the molecule that they isolated from the reaction of FeCl2 with tetrahydro-4,4,8,8-tetramethyl-4,8-disila-s-indacenediyl dilithium. In this hexane-soluble compound, seven ferrocene units are linked by seven pairs of Me2Si groups to form an almost regular cycle. The compound can undergo three chemically reversible oxidations in which three, one, and again three electrons are transferred. More about this fascinating “super-ferrocene” is reported on pages 387 ff.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. The Chemistry of Spider Toxins and Spider Silk (pages 314–326)

      Priv.-Doz. Dr. Stefan Schulz

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703141

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      Found previously nowhere else in nature, compounds with highly interesting functions were discovered amongst the low molecular weight components of spiders' silks and toxins. Examples are the longchain, methyl-branched 1-methoxyalkanes, acylpolyamines consisting of polyazaalkane chains linked to aromatic acids and amino acids, and the guanosine fucopyranoside derivative 1. Isolation and identification of these compounds is difficult, because they are often available only in microgramm quantities and in complex mixtures.

    2. Novel High-Performance Ceramics—Amorphous Inorganic Networks from Molecular Precursors (pages 328–343)

      Dr. Hans-Peter Baldus and Prof. Dr. Martin Jansen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703281

      High thermal stabilities are a characteristic feature of ceramic Si/B/N/C materials, which consist of amorphous inorganic networks. For instance, SiBN3C is not only the most stable nonoxide ceramic known to date with respect to oxidation but also under inert conditions it remains amorphous up to 1900°C. These properties are attributed to the presence of boron and carbon, which seem to occur in the ideal ratio. Additional advantages of this ceramic include its ready accessibility, its low thermal coductivity, and its high mechanical durability.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. New Sequential Reactions with Single-Electron-Donating Agents (pages 345–347)

      Dr. Troels Skrydstrup

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703451

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      Complex polycyclic ring systems related to those of many natural products can be prepared from readily accessible starting materials by novel sequential reactions promoted by either SmI2 or tetrathiafulvalene. Combinations of anionic and radical steps are possible, as in, for example, the SmI2-promoted transformation of 1 into 2 with twofold cyclization, which was described by Molander and Harris. TBS = tBuSiMe2, TMS = Me3Si, HMPA = (Me3N)2PO.

    2. The Fascination of Large Rings: Cyclic Metal Complexes of Polydendate Ligands (pages 348–350)

      Priv.-Doz. Dr. Herbert Plenio

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703481

      Coupling reactions in the coordination spheres of metal ions are the most important steps in the synthesis of very large inorganic ring complexes. The majority of such compounds can be categorized as coordination complexes. In addition, there are also examples from organometallic chemistry, such as the ferrocene scoop wheel presented by F. H. Köhler et al. in this issue. Before a planned synthesis of these compounds can be achieved, principles that govern the formation of these unusually large macrocycles must be determined. Insights into these principles are given herein.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. Coordinative Stabilization of Cyclo-Tetratellurium as [Te4{Cr(CO)5}4]: The First Organometallic Derivative of a Tellurium Allotrope (pages 352–353)

      Olivier Blacque, Prof. Dr. Henri Brunner, Prof. Marek M. Kubicki, Dr. Bernhard Nuber, Bernhard Stubenhofer, Dr. Joachim Wachter and Prof. Dr. Bernd Wrackmeyer

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703521

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      Elimination of tellurium from the niobocene complex 1, which contains the novel η2-Te2H ligand, leads to the title compound 2 under the action of [Cr(CO)5(thf)]. Characteristic for the structure of 2 is the folded four-membered ring in which all adjacent Cr(CO)5 fragments are in a trans arrangement.

    2. Palladium Complexes of the New Porphyrin Isomers (Z)- and (E)-Isoporphycene—PdII-Induced Cyclization of Tetrapyrrolealdehydes (pages 353–357)

      Prof. Dr. Emanuel Vogel, Martin Bröring, Christoph Erben, Ralf Demuth, Dr. Johann Lex, Maja Nendel and Prof. Dr. Kendall N. Houk

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703531

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      Template-controlled syntheses open the way to stable metal complexes of the previously unknown, energy-rich porphyrin structural isomer isoporphycene. The rapid photochemical equilibrium between (Z)- and (E)- octaethylisoporphycene Pd complexes 1 and 2 confirms the prediction that (Z)- and (E)-isoporphycene have similar energies. The small Pd–H distance in 2, a C-C-C bond angle of almost 150° in 1, and parallels in 1H NMR spectra to the all-cis- and the mono-trans-cyclononatetraenyl anion make 1 and 2 very interesting objects of study.

    3. Nickel and Copper Corroles: Well-Known Complexes in a New Light (pages 357–361)

      Dr. Stefan Will, Dr. Johann Lex, Prof. Dr. Emanuel Vogel, Dr. Hans Schmickler, Dr. Jean-Paul Gisselbrecht, Dr. Catherine Haubtmann, Maxime Bernard and Prof. Dr. Maurice Gorss

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703571

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      Until very recently the Ni and Cu corroles, already described in the sixties, were regarded as the MII complexes 1 (M = Ni, Cu). Some doubt arose about this interpretation after the existence of FeIV corroles demonstrated that corroles can stabilize metals in unusual oxidation states. Thorough physical studies have now shown that the metal atoms in the Ni and Cu corroles do in fact have the formal oxidation state +III(2).

    4. Novel Cleft-Containing Porphyrins as Models for Studying Electron Transfer Processes (pages 361–363)

      Dr. Joost N. H. Reek, Dr. Alan E. Rowan, Dr. René de Gelder, Prof. Dr. Paul T. Beurskens, Prof. Dr. Maxwell J. Crossley, Steven De Feyter, Prof. Dr. Frans de Schryver and Prof. Dr. Roeland J. M. Nolte

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703611

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      The photoinduced electron transfer between the zinc porphyrin and the quinone unit of the U-shaped host 1 (R = tBu) is accelerated by an aromatic guest molecule complexed within its cavity. This rate enhancement is due to through-space electron transfer across the interspaced guest. This process mimics the proposed behavior of some aromatic protein residues in certain photosynthetic centers.

    5. Reversible Dimerization of Diphenylpolyene Radical Cations: An Alternative to the Bipolaron Model (pages 363–367)

      Dipl.-Chem. Andreas Smie and Prof. Dr. Jürgen Heinze

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703631

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      A new interpretation of the charge storage mechanism of conducting polymers is provided by the results of cyclic voltammetric studies of diphenylpolyenes like 1. For the first time these investigations indicate the formation of σ bonds in the reversible dimerization of radical cations of these conjugated systems. Furthermore, these reactions also have general importance for the understanding of the chemistry of radical ions.

    6. A Novel [3+2] Annelation between ortho-Carboranyltrimethylsilane and Conjugated Carbonyl Compounds (pages 367–369)

      Dr. Hiroyuki Nakamura, Kouichi Aoyagi, Associate Prof. Dr. Bakthan Singaram, Dr. Jianping Cai, Prof. Dr. Hisao Nemoto and Prof. Dr. Yoshinori Yamamoto

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703671

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      Carborane-annulated cyclopentanols were produced by the reaction between 1,2-carboranes as dianionic C2 building blocks and α, β-unsaturated ketones or aldehydes as dicationic C3 units [see, for example, Eq. (a)]. This is a conceptionally unusual route to five-membered carbocycles.

    7. Molecular Cubic Hyperpolarizabilities of Systematically Varied (Triphenylphosphane)–gold-σ-Arylalkynyl Complexes (pages 370–371)

      Ian R. Whittall, Dr. Mark G. Humphrey, Dr. Marek Samoc and Prof. Barry Luther-Davies

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703701

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      The largest cubic nonlinear optical activities thus far determined for monomeric organometallic complexes in solution (schematic representation on the right) have been found for alkynyl(triphenylphosphane)gold complexes. In structure–property studies the influence of structural changes in the chromophore on the nonlinear response was systematically investigated.

    8. First Examples of a Claisen Rearrangement Stereocontrolled by a Sulfinyl Group: Synthesis of Novel α-Sulfinyl Dithioesters (pages 371–374)

      Dr. Carole Alayrac, Christophe Fromont, Dr. Patrick Metzner and Dr. Nguyen Trong Anh

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703711

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      Diastereomeric excesses up to 98% are a characteristic of the Claisen rearrangement of ketene dithioacetals 1, which contain a chiral sulfinyl group, to afford γ-unsaturated α-sulfinyl dithioesters 2. This reaction is the first example of a [3,3] rearrangement whose stereochemical course is controlled by a sulfinyl group. Owing to the mild thermal conditions (room temperature) undesired elimination of sulfenic acid was not observed.

    9. Unusually Stable Organomercury Hydrides and Radicals (pages 374–376)

      Prof. Eiichi Nakamura, Yong Yu, Seiji Mori and Dr. Shigeru Yamago

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703741

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      A remarkably long half-life of 74 h has been observed for the HgH-substituted p-nitrophenylacrylate 1 (R1 = Et, R2 = p-NO2C6H4) at 75°C in C6D6. This unusual stability stems from the electron-withdrawing effects of the acrylic ester moiety, as revealed by quantum mechanical calculations. The corresponding organomercury radical 2 is also stable enough to be trapped intermolecularly ([RIGHTWARDS ARROW]3; X = Cl, Br).

    10. New Ligands for the Titanium (IV)-Induced Asymmetric Reduction of Ketones with Catecholborane (pages 376–377)

      Fredrik Almqvist, Lillemor Torstensson, Anette Gudmundsson and Prof. Torbjörn Frejd

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703761

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      High to moderate enantiomeric excesses were achieved for the reduction of ketones with catecholborane in the presence of a titanium-based catalyst bearing the new optically active diols 1 a or 1 b as ligands. Of particular interest is the relatively high enantiomeric excess obtained in the reductions of linear nonaromatic methyl ketones.

    11. Unexpected Intramolecular Reactions of Intermediate Phosphacarbonyl Ylide Tungsten Complexes (pages 378–381)

      Dr. Rainer Streubel, Dipl.-Chem. Annette Ostrowski, Dipl.-Chem. Hendrik Wilkens, Dipl.-Chem. Frank Ruthe, Dipl.-Chem. Jörg Jeske and Prof. Dr. Peter G. Jones

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703781

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      Thermolysis of a 2H-azaphosphirene tungsten complex in the presence of benzophenone generates the phosphacarbonyl ylide complex 1 as an intermediate, as confirmed by the formation of the complexes 2 and 3. The use of acetophenone and (E)-N-methyl(benzylidene)amine as trapping reagents leads to an acyclic rearrangement product and an azaphosphiridine tungsten complex, respectively.

    12. Direct Study of a Nondegenerate Cyclopropene-to-Cryclopropene Isomerization (pages 381–383)

      Prof. Dr. Henning Hopf, Wilhelm Graf von der Schulenburg and Prof. Robin Walsh

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703811

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      Cyclopropenes interconvert upon heating! This remarkable process takes place via vinylidene intermediates, namely unsaturated carbenes that are also involved in the ring opening of these highly strained hydrocarbons (see below).

    13. Preparation of Non-Oxidic Silicon Ceramics by an Anhydrous Sol–Gel Process (pages 384–386)

      Dipl.-Ing. Andreas O. Gabriel and Prof. Dr. Ralf Riedel

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703841

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      A crack-free, transparent monolithic gel composed of 3 and 4 is obtained from silane 1 and carbodiimide 2. This is the first example of the application of the sol–gel process, which has frequently been used for the synthesis of oxidic glasses and ceramics, to nonoxidic systems for the preparation of oxygen-free Si-C-N ceramics.

    14. Asymmetric Mannich Synthesis of β-Amino Acids with Two New Stereogenic Centers at the α and β Positions (pages 386–387)

      Prof. Dr. Horst Kunz, Dr. Andreas Burgard and Dr. Dirk Schanzenbach

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703861

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      α-Branched β-amino acids 1 with erythro configuration can be made selectively and with high asymmetric induction by the reaction of O-pivaloyl-protected N-galactosylaldimines 2 with prochiral bis(silyl) ketene acetals 3. The corresponding reaction with the prochiral lithium ester enolate 4 exclusively leads to the threo-configured β-amino acid derivatives 5.

    15. Seven Doubly Bridged Ferrocene Units in a Cycle (pages 387–389)

      Dipl.-Chem. Birgit Grossmann, Prof. Dr. Jürgen Heinze, Dr. Eberhardt Herdtweck, Prof. Dr. Frank H. Köhler, Prof. Dr. Heinrich Nöth, Dipl.-Chem. Holger Schwenk, Dipl.-Chem. Michael Spiegler, Dipl.-Chem. Wolfgang Wachter and Dr. Bernd Weber

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703871

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      What looks like a scoop wheel on the right are seven ferrocene units, which are linked by four Me2Si groups to the two nearest neighbors. The cycle, which is formed in a polygemination reaction (that is, the reaction of a transition metal halide with a biscyclopentadienyl dianion to give a polymer), has the rare C7h symmetry (idealized). The compound is stable up to 360°C and can be oxidized in three steps up to a heptacation.

    16. New Active-Site Analogues of Chloraperoxidase—Syntheses and Catalytic Reactions (pages 390–392)

      Hans-Achim Wagenknecht and Prof. Dr. Wolf-Dietrich Woggon

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703901

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      The iron(III) porphyrin 1 catalyzes the chlorination of activated C[BOND]H bonds. It is therefore a model compound for the as yet unidentified intermediate of the catalytic cycle of the heme–thiolate protein chloroperoxidase (CPO). Neither “free HOCl” nor Cl are involved in the CPO-catalyzed chlorination, but rather an iron-bound HOCl is the source of Cl+.

    17. A Short-Lived Radical Dication as a Key Intermediate in the Rearrangement of a Persistent Cation: The Oxidative Cyclization of 2,2-Dimesityl-1-(4-N,N-dimethylaminophenyl)ethenol (pages 392–395)

      Prof. Dr. Michael Schmittel and Dipl.-Chem. Anja Langels

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703921

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      Almost completely unknown—the chemistry of radical dications. A reactive intermediate of this type (1•2+) plays a key role in the oxidative rearrangement of the persistent cation 1+.

    18. First Biosynthetic Studies on Trail Pheromones in Ants (pages 395–397)

      Prof. Dr. Hans Jürgen Bestmann, Dr. Elke Übler and Prof. Dr. Bert Hölldobler

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703951

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      On the trail of ants! For the first time the biosynthesis of trail pheromones in ants of one subfamily could be traced. The odorous substances are formed by the lipid metabolism pathway by incorporation of acetate or propionate or both, as shown by feeding experiments with deuterated compounds (see below).

    19. Synthesis and Characterization of Photolabile Compounds Releasing Noracetylcholine in the Microsecond Time Range (pages 398–400)

      Dr. Ling Peng, Prof. Dr. Jakob Wirz and Prof. Dr. Maurice Goeldner

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199703981

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      The rapid and efficient photochemical release of noracetylcholine 2, and analogue of the neurotransmitter acetylcholine, from its precursor 1 makes this probe well-suited for a dynamic study of the mechanism of hydrolysis of acetylcholine by acetylcholinesterase. The nitrobenzyl derivative 1, the most promising candidate for time-resolved crystallographic studies of this rapid enzyme, displays the required photo-fragmentation kinetics in the microsecond time-range and inhibitory properties oacetylcholinesterase.

    20. The Trimesitylsilylium Cation (pages 400–401)

      Prof. Joseph B. Lambert and Dr. Yan Zhao

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704001

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      Clever choice of a leaving group produced the first free silylium ion, Mes3Si+ [Eq. (a)]. The low-field resonance at δ = 225.5 is charactistic for the tricoordinated triarylsilylium ion. Constancy of this value in several aromatic solvents indicates that the silicon center is well protected by the ortho methyl groups. Mes = 2,4,6-trimethylphenyl, TPFPB = tetrakis(pentafluorophenyl)borate.

    21. Tracking Down Chlorophyll Breakdown in Plants: Elucidation of the Constitution of a “Fluorescent” Chlorophyll Catabolite (pages 401–404)

      Walter Mühlecker, Priv.-Doz. Dr. Karl-Hans Ongania, Prof. Dr. Bernhard Kräutler, Prof. Dr. Philippe Matile and Dr. Stefan Hörtensteiner

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704011

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      The biological enigma of the breakdown of chlorophyll in plants only recently began to be understood. The structure elucidation of a “fluorescent” catabolite (depicted on the right) from senescent rape cotyledons provides further insight into this process. For this purpose, the catabolite was prepared from pheophorbide a with an enzyme extract from senescent choloroplasts.

    22. Synthesis and Structure of the First Si-Al-NH Cage Compound from a Stable Triaminosilane and Trimethylaluminium (pages 404–406)

      Dipl.-Chem. Carsten Rennekamp, Dipl.-Chem. Alexander Gouzyr, Dipl.-Chem. Andreas Klemp, Prof. Dr. Herbert W. Roesky, Christiane Brönneke, Dipl.-Chem. Jörg Kärcher and Dr. Regine Herbst-Irmer

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704041

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      Access to iminoaluminosilicate chemistry has been achieved by the reaction of a soluble triaminosilane with Me3Al. The resulting Si-Al-NH compound—the first of its kind—has a prismatic Si-Al-NH cage as the central structural unit (depicted on the right) and thus has a structure analogous to those of known siloxane cage compounds.

    23. Novel Syntheses of Three C30H12 Bowl-Shaped Polycyclic Aromatic Hydrocarbons (pages 406–408)

      Dr. Stefan Hagen, Matthew S. Bratcher, Prof. Dr. Mark S. Erickson, Prof. Dr. Gerhard Zimmermann and Prof. Dr. Lawrence T. Scott

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704061

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      The missing links between the normal, planar polycyclic aromatic hydrocarbons and buckyballs are the bowl-shaped C30H12 buckybowls 1, 2, and 3. All three were prepared by flash vacuum pyrolysis of suitable aromatic precursors. The best yields are obtained when radical centers are generated at defined positions by the homolysis of C[BOND]Br and C[BOND]C bonds to initiate the critical cyclizations.

    24. Unusual Reaction Pathways in the Photolysis of Diazido(phosphane)nickel(II) Complexes: Nitrenes As Intermediates in the Formation of Nickel(0) Complexes (pages 408–410)

      Prof. Dr. Horst Henning, Dr. Katrin Hofbauer, Dipl.-Chem. Kartin Handke and Dr. Rainer Stich

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704081

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      Insertions into C[BOND]H or C[DOUBLE BOND]C bonds and addition reactions with CO or CS2 confirm the formation of nitrenenickel(II) complexes as intermediates in the photolysis of diazido(phosphane)nickel(II) complexes. Without reactive substrates the nitrene intermediates decay to coordinatively unsaturated phosphane–nickel(0) complexes, which may initiate the photocatalytic cyclization of alkynes to the corresponding benzene derivatives.

      = bis(phosphane) ligand or (PEt3)2.

    25. Asymmetric Epoxidation of Chalcones with Chirally Modified Lithium and Magnesium tert-Butyl Peroxides (pages 410–412)

      Dr. Catherine L. Elston, Prof. Dr. Richard F. W. Jackson, Dr. Simon J. F. MacDonald and Dr. P. John Murray

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704101

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      A new, efficient use for that most venerable chiral ligand, diethyl tartrate: Chalcone derivatives 1 can be converted, as shown below, into the corresponding epoxy ketones (−)-2 with good to excellent enantiomeric excess by using tert-butyl hydroperoxide in the presence of catalytic amounts of dibutylmagnesium (10 mol%) and (+)-diethyl tartrate (11 mol%).

  4. Corrigenda

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. You have free access to this content
      Corrigendum (page 412)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704121

  5. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. Book Review: Modelling Molecular Structures. By A. Hinchliffe (page 414)

      Dietmar Schomburg

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704141

    2. Book Review: Combinatorial Peptide and Nonpeptide Libraries. A Handbook. Edited by G. Jung (pages 416–417)

      Joannes T. M. Linders, Harry C. J. Ottenheijm, Cutherinu J. van Staveren and N. V. Organon

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199704163