Angewandte Chemie International Edition in English

Cover image for Vol. 35 Issue 4

March 1, 1996

Volume 35, Issue 4

Pages 355–459

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 4/1996)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603531

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      The cover picture shows the catalytic asymmetric aminohydroxylation (AA) of alkenes in action. Methyl cinnamate can be transformed directly into a derivative of the taxol side chain with the catalyst system K2OsO2(OH)4 and a phthalazine ligand; Chloramine T serves as the nitrenoid source. Either enantiomer can be produced at will by selection of the appropriate ligand. The asymmetric aminohydroxylation (AA) follows the development of the asymmetric epoxidation (AE) and the asymmetric dihydroxylation (AD)—three reactions whose importance for organic synthesis cannot be overstated. Li, Chang, and Sharpless report more on the new catalytic AA on p. 451 ff. (The cover picture was created by Michael E. Pique, The Scripps Research Institute, La Jolla, CA, USA.)

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. New Books
    1. Control of the Structure and Functions of Biomaterials by Light (pages 367–385)

      Professor Itamar Willner and Dr. Shai Rubin

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603671

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      Two methods of making biomaterials photoswitchable are presented here: the covalent linkage of photoiso-merizable components (A ⇌ B) to biomolecules and the interaction of the biomaterials with photoswitchable microenvironments. The diagram on the right illustrates the first principle with the formation and dissociation of, for instance, an enzyme–substrate or antibody–antigen assembly. In the isomer state A the bioactive structure of the biomaterial is retained, and formation of the complex with the substrate is activated. In the photoisomer state B the active site is distorted, and dissociation is induced. Such modified compounds form the basis of opto-bioelectronic devices.

    2. Nonstabilized Alkyl Complexes and Alkyl-Cyano-Ate Complexes of Iron(II) and Cobalt(II) as New Reagents in Organic Synthesis (pages 386–403)

      Prof. Dr. Thomas Kauffmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603861

      The willingness to undergo oxidative addition of electrophiles, the high selectivity, and several unexpected reactions are responsible for making the title compounds, which had been disregarded or unknown for a long time, widely applicable, mild alkylating reagents. For example, (E,Z)-β-fluorostyrene can be converted with Me4CoLi2 into (E,Z)-1-phenylproprene in 92% yield. The reaction of bromophenylacetylene with MeCo(CN)2Li (see below) shows other possibilities.

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  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. New Books
    1. Radical Reactions as Key Steps in Natural Product Synthesis (pages 405–407)

      Dr. Ulrich Koert

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604051

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      A prime example of applied radical chemistry is the last step of Curran's total synthesis of the antitumor agent camptothecin (below). This and other key sequences demonstrate the importance of radical reactions in natural products chemistry.

    2. Enantioselective Catalytic Hydrogenation (pages 407–409)

      Judith Albrecht and Prof. Dr. Ulrich Nagel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604071

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      Very different ligands have been employed recently for enantioselective hydrogenation. With rhodium phospholane complexes, not only the usual, but also highly substituted enamides such as 1 and acylhydrazones can be hydrogenated. With ruthenium complexes containing chiral amino alcohols, ketones can be converted into the corresponding alcohols with high enantioselectivities.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. New Books
    1. Synthesis of Highly Substituted Cyclopentane and Tetrahydrofuran Derivatives by Crossed Olefin Metathesis (pages 411–412)

      Dipl.-Chem. Matthias F. Schneider and Prof. Dr. Siegfried Blechert

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604111

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      Crossed ring-opening metatheses (ROM) close the gap between ring-opening metathesis polymerization (ROMP) and ring-closing metathesis (RCM). According to this principle, easily accessible functionalized bicycles of type 1 and symmetric olefins 2 can be converted with ruthenium catalysts into highly substituted five-membered rings of type 3.

    2. A Versatile New Preparation of Cyclopropylamines from Acid Dialkylamides (pages 413–414)

      Dipl.-Chem. Vladimir Chaplinski and Prof. Dr. Armin de Meijere

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604131

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      The reaction of acid N,N-dialkylamides with alkylmagnesium bromides in the presence of a stoichiometric amount of titanium tetra(2-propanolate) produces dialkylcyclopropylamines like 1 and 2 in moderate to good yields. Previously inaccessible aminocyclopropane derivatives are now readily available.

    3. A Step-Growth Approach to Metal-Capped One-Dimensional Carbon Allotropes: Syntheses of C12, C16, and C20 μ-Polyynediyl Complexes (pages 414–417)

      Dr. Tamás Bartik, Dr. Berit Bartik, Dr. Monika Brady, Dr. Roman Dembinski and Prof. Dr. J. A. Gladysz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604141

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      Novel chain extensions of [{Re*}[BOND]C[TRIPLE BOND]C[BOND]C[TRIPLE BOND]C[BOND]H] ({Re*} = (η5-C5Me5)Re(NO)(PPh3)) with alkyne or diyne building blocks lead to rhenium-capped oligomers of up to 20 sp carbon atoms (shown on the right, n = 6, 8, 10). This methodology allows, for the first time, access to such materials with a homogeneous chain length.

    4. Photochemically Induced Metathesis Reactions of Tetradehydrodianthracene: Synthesis and Structure of Bianthraquinodimethanes (pages 417–419)

      Dipl.-Chem. Stefan Kammermeier and Priv.-Doz. Dr. Rainer Herges

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604171

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      Relief of strain is the driving force for the [2 + 2] cycloaddition and subsequent [2 + 2] cycloreversion of 1 with both open-chain and cyclic alkenes. The metathesis can even be performed with benzene as the olefin component [Eq. (a)]. The product can be roughly described as a ribbon- or beltlike conjugated system.

    5. Structural Characterization of a Tris-Agostic Lanthanoid[BOND]H[BOND]Si Interaction (pages 419–422)

      Prof. Dr. William S. Rees Jr., Dr. Oliver Just, Prof. Dr. Herbert Schumann and Dr. Roman Weimann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604191

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      All the tert-butyl groups of [Er{N(tBu)[Si(CH3)2(H)]}3] (structure shown on the right) reside on the same face of the N3 plane, whereas all Si[BOND]CH3 groups are rotated toward the periphery of the molecule. This results in Er[BOND]H interatomic distances of 231.7–236.7 pm for the Si[BOND]H moieties folded in toward the metal center.

    6. Eight-Coordinate Iron(II) and Iron(III) Ions in Complexes with Distorted Dodecahedral FeN8 Environments: Synthesis and Structures of Bis(2,11-diaza[3.3](2,6)pyridinophane)iron Complexes (pages 422–424)

      Welf O. Koch, Adriana Barbieri, Dr. habil. Michael Grodzicki, Dr. Volker Schünemann, Prof. Dr. Alfred X. Trautwein and Dr. Hans-Jörg Krüger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604221

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      Eight-coordination and identical ligand environments have been unequivocally established in the pair of stable iron(II) and iron(III) complexes shown on the right. The synthesis, structures and electrochemical properties of these iron complexes are presented here, together with some Mössbauer spectroscopic data on the iron(II) complex.

    7. Transition Metal Stabilized AlI and GaI Complexes; Structure of [(CO)5Cr[BOND]Ga{(CH3)(tmeda)}] (pages 424–426)

      Dipl.-Chem. Markus M. Schulte, Dr. Eberhardt Herdtweck, Dr. Gabriele Raudaschl-Sieber and Dr. habil. Roland A. Fischer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604241

      Redox reactions in the initial products formed from K2[Cr(CO)5] and Cl2ER (E = Al, Ga; R = Cl, alkyl) lead to the formation of aluminum(I) and gallium(I) transition metal complexes of type 1 (shown below) that are surprisingly stable. Stoichiometric CrGa films were prepared from 1 (E = Ga, R = CH2CH3) by MOCVD. tmeda = N,N,N′,N′,-tetramethylethylenediamine.

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    8. Synthesis of a Stable Hexagonally Packed Mesoporous Niobium Oxide Molecular Sieve Through a Novel Ligand-Assisted Templating Mechanism (pages 426–430)

      David M. Antonelli and Prof. Jackie Y. Ying

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604261

      Since the porous structure is completely retained upon surfactant removal, Nb-TMS1, a hexagonally packed mesoporous transition metal oxide, is an interesting molecular sieve. The synthesis of this material was accomplished by a novel route in which the inorganic precursor 1 and the surfactant 2 were attached by a covalent Nb[BOND]N bond; this bond is probably retained throughout the course of the synthesis.

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    9. Chiral Borane–Amine Adducts in Asymmetric Synthesis: Alkylation of Alanine Derivatives (pages 430–432)

      Vincent Ferey, Dr. Loïc Toupet, Dr. Thierry Le Gall and Dr. Charles Mioskowski

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604301

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      Enantiomeric excesses of up to 82% are obtained for the α,α-disubstituted products 4 arising from alkylation reactions of borane–amine adducts 2 and 3, which have a chiral nitrogen atom. The structure of diastereomer 2, which can be obtained selectively in the boration of 1, has been established by single-crystal X-ray analysis.

    10. Heterobimetallic Hydroxy Complexes: [Re3(CO)92-OH)33-OH)] as a Novel Tripodal Ligand (pages 432–434)

      Prof. Dr. Wolfgang A. Herrmann, Dr. André Egli, Dr. Eberhardt Herdtweck, Dr. Roger Alberto and Prof. Dr. Franz Baumgärtner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604321

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      A structure containing two cubes linked through a common metal atom (1) is formed on reaction of the novel tripodal ligand [{Re(CO)3}3(OH)4] with MII salts (M = Mn, Cu). Crystals of 1 contain extended layers whose structures are determined by the type of coordination sphere of MII. • = Re(CO)3; Counterion: NEtmath image.

    11. Synthesis and Structure of a Bridging Germylidyne Complex: A Stable Germyl Cation (pages 435–437)

      Lisa K. Figge, Patrick J. Carroll and Prof. Donald H. Berry

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604351

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      A three-coordinate, cationic germanium center is the unusual feature of this dimeric tungsten complex 1 generated by the thermolysis of [Cp2W(SiMe3)(GeMe2OTf)]. Delocalization of the charge onto only one of the tungsten centers is suggested by structural and orbital overlap considerations.

    12. The First Recombinant Hydroxynitrile Lyase and its Application in the Synthesis of (S)-Cyanohydrins (pages 437–439)

      Dr. Siegfried Förster, Dipl.-Chem. Jürgen Roos, Prof. Franz Effenberger, Dr. Harald Wajant and Dipl.-Ing.(FH) Achim Sprauer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604371

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      The cassava species Manihot esculenta provided the first recombinant hydroxynitrile lyase (MeHNL) that became accessible by overexpression in E. coli. This MeHNL catalyzes the enantioselective addition of HCN (depicted below) not only to aliphatic, aromatic, and heteroaromatic aldehydes, but also to ketones to give (S)-cyanohydrins in high optical yields. R [DOUBLE BOND] alkyl, aryl, heteroaryl; R1 [DOUBLE BOND] H, CH3.

    13. Hexa-tert-butyltribenzodecacyclenyl: A Six-Stage Amphoteric Redox System (pages 439–441)

      Takashi Kubo, Prof. Dr. Kagetoshi Yamamoto, Prof. Dr. Kazuhiro Nakasuji, Prof. Dr. Takeji Takui and Prof. Dr. Ichiro Murata

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604391

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      All seven redox states between the tricationic and the trianionic states of the decacyclenyl 1˙ are discernible by cyclic voltammetry. The electronic nature of the highly delocalized aromatic π-electron system of the neutral radical 1˙ and the charged species 13+ and 13− has been investigated by ESR and NMR spectroscopy, respectively.

    14. An Intramolecular Base-Catalyzed Proton Transfer in 1,3-Bis(4-fluorophenyl)triazene (pages 441–442)

      Dipl.-Chem. Dr. Ferdinand Männle and Prof. Dr. Hans-Heinrich Limbach

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604411

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      Through formation of a contact pair, bases are capable of transferring mobile protons from one molecular site to another. NMR experiments on a solution of diaryl-triazene 1 in ethyl methyl ether in the presence of trimethylamine (2) [Eq. (a)] verify that the contact pair does not dissociate in the process.

    15. Regioselective Palladium-Catalyzed Hydrostannylation of Unsymmetrical Oxabicyclic Alkenes (pages 442–445)

      Prof. Mark Lautens and Dr. Wolfgang Klute

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604421

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      Tertiary alcohols like 2 can prepared from 1 in two steps by palladium-catalyzed hydrostannylation followed by an organolithium-induced ring opening. Compounds regioisomeric to those obtained with [Ni(cod)2]/DIBAL-H are thus now available.

    16. Pairing Properties of Alanyl Peptide Nucleic Acids Containing an Amino Acid Backbone with Alternating Configuration (pages 445–448)

      Dr. Ulf Diederichsen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604451

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      Linear pairing complexes are presumably formed by peptide nucleic acids containing a backbone of alanyl amino acids with alternating configuration. The pairing of two strands is based on recognition of the nucleobases; however, unlike for DNA, stable self-pairing of a hexmer from adenine-substituted alanyl building blocks is possible for the PNA (1) described herein.

    17. A New Ligand Class for the Asymmetric Dihydroxylation of Olefins (pages 448–451)

      Dr. Heinrich Becker and Prof. K. Barry Sharpless

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604481

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      Remarkably high ee values in the asymmetric dihydroxylation reaction (AD) can be achieved with the pseudo-enantiomeric ligand pair (DHQD)2AQN and (DHQ)2AQN. These new ligands are superior for AD reactions of most olefins with aliphatic substituents and show exceptionally high enantioselectivity with olefins having heteroatoms in the allylic position [Eq. (a)]. DHQD = dihydroquinidinyl.

    18. Catalytic Asymmetric Aminohydroxylation (AA) of Olefins (pages 451–454)

      Dr. Guigen Li, Han-Ting Chang and Prof. K. Barry Sharpless

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604511

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      The stereospecific cis addition of “TsN” and H2O yields α-hydroxy-N-tosylamines (see below). This osmium-catalyzed process, which depends on Chloramine-T as the nitrenoid source, is rendered asymmetric in the presence of cinchona alkaloid ligands. The selectivities for reactions of the six olefins studied range from 33% ee (cis-stilbene) to 81% ee (trans-methylcinnamate). The active agent is presumably the compound Os(O)3NTs shown in square brackets. (DHQ)2-PHAL = bis(dihydro-quininyl)phthalazine (see preceding communication).

    19. Allylic Amination and 1,2-Diamination with a Modified Diimidoselenium Reagent (pages 454–456)

      Dr. Milan Bruncko, Tinh-Alfredo V. Khuong and Prof. K. Barry Sharpless

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604541

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      Replacing the tosyl with a nosyl (Ns) group—that is the key to an improved method for both allylic amination of olefins and 1,2-diamination of 1,3-dienes. The protecting group recently introduced by Fukuyama et al., the 0-nitrobenzenesulfonyl (nosyl) group, can be employed with diimidoselenium reagents. The resulting nosyl-amides can be converted into primary and secondary amines in good to excellent yields. An example of this approach is sketched below in reaction (a) (R [DOUBLE BOND] Me, CH2CHCH2, CH2Ph).

  4. Book Reviews

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

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. New Books
    1. New Books (page 459)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199604591

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