Angewandte Chemie International Edition

Cover image for Vol. 42 Issue 44

November 17, 2003

Volume 42, Issue 44

Pages 5371–5525

    1. Cover Picture: Multicenter Strategy for the Development of Catalytic Enantioselective Nucleophilic Alkylation of Ketones: Me2Zn Addition to α-Ketoesters (Angew. Chem. Int. Ed. 44/2003) (page 5371)

      Ken Funabashi, Markus Jachmann, Motomu Kanai and Masakatsu Shibasaki

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200390615

      The Senjyu Kannon statue in the Koufukuji temple in Nara, Japan (see picture), has thousands of hands to manipulate thousands of things at once. A new catalyst, a 2,4-cis-hydroxyprolinol derivative, was developed for the enantioselective addition of dimethylzinc to α-ketoesters. The catalyst has three hands in a cis-stereochemical array, which activates both the ketoester substrate and the organozinc reagent simultaneously. M. Shibasaki et al. describe on page 5489 ff. the excellent enantioselectivities obtained from aromatic and heteroaromatic substrates.>

    2. Nucleic Acids Chemistry and Biology (pages 5384–5385)

      Jens Kurreck

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200320080

    3. On the Way to a New Class of Catalysts—High-Valent Transition-Metal Complexes That Catalyze Reductions (pages 5390–5392)

      Werner R. Thiel

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200301685

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      Surprise! Owing to its rhenium(V) center, which bears two terminal oxo ligands, [ReI(O)2(PPh3)2] appears at first glance to be an oxygen-transfer reagent. The complex is, however, a novel catalyst for a reduction: the hydrosilylation of aldehydes and ketones (see scheme).

    4. Novel Substrates for Palladium-Catalyzed Coupling Reactions of Arenes (pages 5394–5399)

      Alexander Zapf

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200301681

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      Alternative coupling partners: Not only haloarenes, but also aryl carbonic acids and heteroaryl thioethers (see formulas) can take part in palladium-catalyzed coupling reactions. The substrate scope has thus become broader and the catalyst systems simpler. Furthermore, the reaction of carbonic acid derivatives allows the simple synthesis of ketones.

    5. Modern Synthetic Methods for Copper-Mediated C(aryl)[BOND]O, C(aryl)[BOND]N, and C(aryl)[BOND]S Bond Formation (pages 5400–5449)

      Steven V. Ley and Andrew W. Thomas

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200300594

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      The right conditions: The development of new stoichiometric and catalytic variants of the copper-mediated arylation of heteroatoms (see figure) is of particular interest for the synthetic chemist. The authors give a thorough account of the state-of-the-art of the reaction and discuss the broad range of substrates and suitable choices of catalyst systems and reaction conditions.

    6. Structures and Solid-State Dynamics of One-Dimensional Water Chains Stabilized by Imidazole Channels (pages 5452–5455)

      Lionel E. Cheruzel, Maxim S. Pometun, Matthew R. Cecil, Mark S. Mashuta, Richard J. Wittebort and Robert M. Buchanan

      Version of Record online: 6 OCT 2003 | DOI: 10.1002/anie.200352157

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      Proton wires: One-dimensional water chains play an important role in proton permeation through transmembrane proteins. The X-ray crystal structures as well as solid-state 2H and 17O NMR and calorimetry studies of two imidazole hydrates that stabilize infinite one-dimensional water chains are reported (see picture; N blue, O red, H white). The 2H NMR spectroscopic studies suggest that water molecules in both compounds undergo different reorientational dynamics.

    7. Atropos but Achiral Tris(phosphanyl)biphenyl Ligands for Ru-Catalyzed Asymmetric Hydrogenation (pages 5455–5458)

      Kohsuke Aikawa and Koichi Mikami

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352277

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      Axial chirality is generated upon complexation of the novel triphos ligand with a metal. In the presence of the diamine dm-dabn, isomerization to the enantiopure triphos–Ru complex was observed. The dm-dabn ligand of the Ru complex exchanges with dpen at room temperature without racemization. dm-dabn=3,3′-dimethyl-2,2′-diamino-1,1′-binaphthyl, dpen=1,2-diphenylethylenediamine.

    8. Helical Chirality Control of Palladium Complexes That Bear a Tetrakis(phosphanyl)terphenyl Ligand: Application as Asymmetric Lewis Acid Catalysts (pages 5458–5461)

      Kohsuke Aikawa and Koichi Mikami

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352300

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      Both axial and helical chirality are generated by complexation of the novel tetrakis(phosphanyl)terphenyl (tetraphos) ligand to a metal center (see picture). The tropos nature of the ligand was confirmed, and enantiopure Pd complexes controlled by diamines were applied as asymmetric Lewis acid catalysts in carbonyl–ene reactions.

    9. Benign by Molecular Design: Active Polymeric Super-Acid Catalysts and Highly Conductive Polymeric Lithium Electrolytes (pages 5462–5464)

      Zhen-Yu Yang, Lin Wang, N. Drysdale, Marc Doyle, Qun Sun and Susan K. Choi

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200351725

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      Architectures of copolymers of ethylene with α-olefinic fluorosulfonates are well controlled by tailoring palladium- or nickel-α-diimine catalysts and polymerization conditions (see scheme). These polymeric acids are shown to be “green” homogenous and heterogeneous super-acid catalysts for industrially important reactions. Their lithium salts exhibit excellent ionic conductivities as well as mechanical properties, and are attractive candidates for use in lithium batteries. (MAO=methylalumoxane)

    10. Biomimetic Total Synthesis of Litseaverticillols A, C, D, F, and G: Singlet-Oxygen-Initiated Cascades (pages 5465–5468)

      Georgios Vassilikogiannakis and Manolis Stratakis

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352180

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      Natural weapons against HIV, litseaverticillols A (2) and C, have been synthesized from sesquirosefuran (1) by a rapid and efficient biomimetic total synthesis involving a chemo- and stereoselective singlet-oxygen-initiated tandem sequence (see scheme). Litseaverticillols D, F, and G were readily synthesized from litseaverticillol A through a regioselective 1O2 ene reaction.

    11. Polymerization by Insertion of Molecular Oxygen into Crystals of 7,7,8,8-Tetrakis(ethoxycarbonyl)quinodimethane (pages 5468–5472)

      Shinji Nomura, Takahito Itoh, Masaki Ohtake, Takahiro Uno, Masataka Kubo, Atsushi Kajiwara, Kazuki Sada and Mikiji Miyata

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352355

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      Slipping through the lattice: Molecular oxygen reacts with crystals of quinodimethane 1 to give highly crystalline alternating copolymers by means of a radical mechanism. An X-ray crystallographic study indicates that the unique arrangement of 1 in the crystal is crucial to the copolymerization.

    12. Highly Enantioselective Hydrogen-Transfer Reductive Amination: Catalytic Asymmetric Synthesis of Primary Amines (pages 5472–5474)

      Renat Kadyrov and Thomas H. Riermeier

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352503

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      Ammonium formate is the hydrogen source in the catalytic asymmetric reductive amination of ketones presented here (Leuckart–Wallach-type reaction). The reaction proceeds smoothly in methanol in the presence of Ir, Rh, and Ru catalysts. Primary amines were obtained as products in good yields with high enantioselectivities after hydrolytic workup when [((R)-tol-binap)RuCl2] was used as the catalyst (see scheme). R1, R2=alkyl, aryl.

    13. Addition of Diazoalkanes to Enynes Promoted by a Ruthenium Catalyst: Simple Synthesis of Alkenyl Bicyclo[3.1.0]hexane Derivatives (pages 5474–5477)

      Florian Monnier, Dante Castillo, Sylvie Dérien, Loïc Toupet and Pierre H. Dixneuf

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352477

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      [Cp*RuCl(cod)] (Cp*=C5Me5, cod=cyclooctadiene) promotes the reaction of 1,6-enynes with an excess of diazoalkane in dioxane in one step to afford selectively 1-alkenyl bicyclo[3.1.0]hexane derivatives (see scheme, X=O, NTs; Y=CO2Et; R1=H, Me; R2=H; Ts=p-toluenesulfonyl). This novel reaction involves the stereoselective formation of three C[BOND]C bonds and a cyclopropanation step.

    14. Quasi Solvent-Free Enantioselective Carbonyl-Ene Reaction with Extremely Low Catalyst Loading (pages 5478–5480)

      Yu Yuan, Xue Zhang and Kuiling Ding

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352535

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      Simply mixing the neat substrates and a small amount of the chiral catalyst (0.1–0.01 mol %) under nearly solvent-free conditions makes the enantioselective carbonyl-ene reaction of glyoxylate ester with a variety of olefins proceed smoothly to afford the corresponding α-hydroxy esters in high yields with excellent enantioselectivities [Eq. (1)].

    15. (−)-FR182877 Is a Potent and Selective Inhibitor of Carboxylesterase-1 (pages 5480–5484)

      Gregory C. Adam, Christopher D. Vanderwal, Erik J. Sorensen and Benjamin F. Cravatt

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352576

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      Activity-based profiling and reporter-group-tagged compounds were used to identify carboxylesterase-1 (CE-1) as a specific target of the natural product (−)-FR182877 (see scheme). Now that a target is known, specific modification of the lactone natural product may lead to even more effective inhibitors of CE-1.

    16. Cobalt-Based Complexes for the Copolymerization of Propylene Oxide and CO2: Active and Selective Catalysts for Polycarbonate Synthesis (pages 5484–5487)

      Zengquan Qin, Christophe M. Thomas, Stephen Lee and Geoffrey W. Coates

      Version of Record online: 23 OCT 2003 | DOI: 10.1002/anie.200352605

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      CO2is an ideal feedstock for chemical synthesis; unfortunately its thermodynamic stability is a barrier to widespread use. Active cobalt catalysts for the copolymerization of propylene oxide and CO2 are reported (see scheme; L=N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine), which have excellent regioselectivity for polycarbonate synthesis without concomitant production of cyclic carbonate by-products.

    17. Iron-Catalyzed Asymmetric Sulfide Oxidation with Aqueous Hydrogen Peroxide (pages 5487–5489)

      Julien Legros and Carsten Bolm

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352635

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      An iron in the fire: Iron-based catalysts promote the asymmetric oxidation of alkyl aryl sulfides to the corresponding sulfoxides with up to 90 % ee (see scheme). Simple hydrogen peroxide (30 % in water) serves as the terminal oxidant.

    18. Multicenter Strategy for the Development of Catalytic Enantioselective Nucleophilic Alkylation of Ketones: Me2Zn Addition to α-Ketoesters (pages 5489–5492)

      Ken Funabashi, Markus Jachmann, Motomu Kanai and Masakatsu Shibasaki

      Version of Record online: 1 AUG 2003 | DOI: 10.1002/anie.200351650

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      An array of heteroatoms is essential for the activity and enantioselectivity of the catalyst 2 in the addition of Me2Zn to α-ketoesters 1 (e.g. see equation). α-Hydroxyesters 3 were obtained with up to 96 % ee in the presence of a catalytic amount of additive iPrOH, which serves to generate the catalytically active monomeric species (based on the observation of nonlinear effects).

    19. Excited-State Deprotonation and H/D Exchange of an Iridium Hydride Complex (pages 5492–5495)

      Tomoyoshi Suenobu, Dirk M. Guldi, Seiji Ogo and Shunichi Fukuzumi

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352061

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      Visible-light irradiation of the hexafluorophosphate salt of [Cp*IrIII(bpy)H]+ (1, Cp*=η5-C5Me5, bpy=2,2′-bipyridine) results in excited-state deprotonation to form the conjugate base [Cp*IrI(bpy)]. The H/D exchange reaction of 1 also occurs during photoirradiation of 1 in [D4]methanol in the steady state (see picture).

    20. Self-Supporting Elastic Film without Covalent Linkages as a Hierarchically Integrated β-Sheet Assembly (pages 5496–5499)

      Norihiro Yamada, Tsukasa Komatsu, Hirotsugu Yoshinaga, Kayo Yoshizawa, Susumu Edo and Masashi Kunitake

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352185

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      Hierarchic self-assembly: The formation of a self-supporting elastic film without the use of macromolecular materials is described. The film is prepared by using a peptide-containing amphiphile that has three or four consecutive leucinate residues. The amphiphile initially forms β-sheet structures, which stack in a fastenerlike fashion between the side chains of leucine within the different β-sheets (see picture).

    21. Encapsulation Induces Helical Folding of Alkanes (pages 5499–5502)

      Alessandro Scarso, Laurent Trembleau and Julius Rebek Jr.

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352235

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      Doing the twist: Incorporation of long hydrocarbons during the self-assembly of a cylindrical capsule containing an elongated cavity lined with eight benzene rings and additional π surfaces induces helical conformations of the chains so that they are fully encapsulated within the cavity (see picture).

    22. Synthesis, Structural Characterization, and Reaction of the First Terminal Hydroxide-Containing Alumoxane with an [{Al(OH)}2(μ-O)] Core (pages 5502–5506)

      Guangcai Bai, Herbert W. Roesky, Jiyang Li, Mathias Noltemeyer and Hans-Georg Schmidt

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352163

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      Towards new polymerization-catalyst activators: A new synthetic approach is described for the hitherto unknown [{LAl(OH)}2(μ-O)]⋅0.5 (C7H8)⋅C6H14 species (1; L=HC[(CMe)(2,6-iPr2C6H3N)]2). Further reaction of the Brönsted acidic OH groups of 1 with Me2AlH results in the formation of trimeric alumoxane containing a three coordinate Al center [(LAl)2(MeAl)(μ-O)3]⋅2 C7H8, the core of which is depicted. These compounds may have use as activators for olefin-polymerization catalysts.

    23. A Threefold AlH2-Coordinated Carbon Atom as Part of the First Carbaalanate (pages 5507–5509)

      Andreas Stasch, Herbert W. Roesky, Paul von Ragué Schleyer and Jörg Magull

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352502

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      The first carbaalanate consists of a carbaalane dianion [(AlH)8(CCH2tBu)6]2− that is coordinated through hydride bridges to two lithium ions on opposite sides of the cluster (see picture). Additionally, the lithium ions are each further coordinated to a neutral [tBuCH2C(AlH2⋅NMe3)3] unit. In this arrangement, the lithium ion prevents condensation of the [tBuCH2C(AlH2⋅NMe3)3] units.

    24. Highly Sensitive Recognition of Substrates of Adrenergic Receptors at the Air/Water Interface (pages 5509–5513)

      Oliver Molt and Thomas Schrader

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352186

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      Almost like the real thing: Amphiphilic properties ensure that an artificial adrenaline receptor can be embedded in lipid monolayers just like the natural example. Here it forms large domains by self-assembly, which were investigated by Langmuir–Blodgett techniques. Embedded, the macrocyclic receptor is much more sensitive and selective than in solution. Monolayers containing receptor molecules can distinguish between adrenergic receptor substrates with similar structures.

    25. Green-Emitting CePO4:Tb/LaPO4 Core–Shell Nanoparticles with 70 % Photoluminescence Quantum Yield (pages 5513–5516)

      Karsten Kömpe, Holger Borchert, Jörg Storz, Arun Lobo, Sorin Adam, Thomas Möller and Markus Haase

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200351943

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      Quantum leap: Very high quantum yields, thought to be impossible for nanocrystalline phosphor materials, were achieved with CePO4:Tb/LaPO4 core–shell nanoparticles (see picture). Because the LaPO4 shell reduces energy losses at the particle surface, transparent colloidal solutions of these 8-nm particles are highly photoluminescent.

    26. Addition of a Hydrogen Atom to Acetonitrile by Hydrated Electrons in Nanodroplets (pages 5516–5518)

      O. Petru Balaj, Iulia Balteanu, Brigitte S. Fox-Beyer, Martin K. Beyer and Vladimir E. Bondybey

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200351953

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      Nanodroplets that contain hydrated electrons provide information complementary to standard radiolysis techniques. Although the reaction of hydrated electrons with acetonitrile was observed in solution 25 years ago, its product has only now been identified in a gas-phase experiment as the hydrogen adduct. The picture shows a solvent-stabilized radical anion, which is suggested as a reactive intermediate.

    27. Preview: Angew. Chem. Int. Ed. 44/2003 (page 5525)

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200390617