Angewandte Chemie International Edition in English

Cover image for Vol. 23 Issue 8

August 1984

Volume 23, Issue 8

Pages 539–644

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 8/1984)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198405391

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      Charge transfer reactions on porphyrin-quinone systems have been the subject of numerous studies in recent years. A compound in which the structural prerequisites are ideal for such a study is described by H. A. Staab et al. in a communication on p. 623 f.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. Cobalt-Mediated [2 + 2 + 2]-Cycloadditions: A Maturing Synthetic Strategy [New Synthetic Methods (43)] (pages 539–556)

      Prof. Dr. K. Peter C. Vollhardt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198405393

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      Dicarbonyl(η5-cyclopentadienyl) cobalt functions as a matrix for the formation of bonds between unsaturated organic species. A straightforward example is outlined below. The method has been used for the synthesis of natural products and molecules of theoretical interest.

    2. Chelation or Non-Chelation Control in Addition Reactions of Chiral α- and β- Alkoxy Carbonyl Compounds [New Synthetic Methods (44)] (pages 556–569)

      Prof. Dr. Manfred T. Reetz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198405561

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      The stereoselectivity of the diastereogenic title reactions can be controlled by using either Lewis-acidic or non-chelating reagents. Decisive are the electronic and/or steric factors in the intermediate and educt, respectively.

    3. Microbial Asymmetric Catalysis—Enantioselective Reduction of Ketones [New Synthetic Methods (45)] (pages 570–578)

      Prof. Charles J. Sih and Ching-Shih Chen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198405701

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      The enormous advantages presented by enzymes and intact cells as reducing agents are illustrated using the example of ketones. From the underlying principles described, strategies for controlling the stereochemical course of microbial reductions can be developed.

    4. Mercury(II)- and Palladium(II)-Catalyzed [3,3]-Sigmatropic Rearrangements [New Synthetic Methods (46)] (pages 579–586)

      Prof. Larry E. Overman

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198405791

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      The title reactions, leading to formation of C[BOND]O, C[BOND]N, C[BOND]S, or C[BOND]C σ bonds, have found wide application. At a catalyst concentration of 1M, the reaction rate is often increased by a factor of 1010 to 1014.

    5. Carbene Complexes in Organic Synthesis [New Synthetic Methods (47)] (pages 587–608)

      Dr. Karl Heinz Dötz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198405871

      On the borderline between organic and inorganic chemistry, transition metals are finding use in organic synthesis. The rapid advances made in this area of chemistry are delineated using the example of carbene complexes, which in less than twenty years have developed from laboratory curiosities into useful synthetic reagents. These compounds not only function as carbene-transfer agents but also undergo cycloadditions.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. Synthesis and Structure of a 1,2,4,5-Tetraborinane (pages 608–613)

      Herbert Fisch, Dr. Hans Pritzkow and Prof. Dr. Walter Siebert

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406081

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      Stabilization of the B4C2 skeleton as a classical boron-carbon compound with cyclohexane structure has been achieved for the first time by introduction of electronically active dimethylamino groups. In the crystal, 2 adopts a chair conformation. Because they are electron deficient, compounds of the type (RB)4(CR′)2, R,R′ = H, alkyl, have carbaborane structures.

    2. Isoelectronic Radical Ions from Single-Electron Transfer Reactions: Direct Observation of Persistent Solvent-Separated Radical Anion/Radical Cation Pairs (pages 613–614)

      Priv.- Doz. Dr. Wolfgang Kaim

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406131

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      Simultaneous generation of persistent radical anions and radical cations following single-electron transfer — an unusual phenomenon for organic compounds of main group metals — is facilitated by using electron-rich and sterically hindered donors 1. Compound 2, for example, functions as an acceptor.

    3. π-Back Bonding and Stability of the Oxidation States in Tetracarbonyldicyclopentadienyl-(μ-pyrazine)dimanganese(I) Complexes (pages 614–615)

      Renate Gross and Priv.-Doz. Dr. Wolfgang Kaim

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406141

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      The extraordinary π-back bonding capacity of the MnCp(CO)2 moiety as well as the stability of the reduced form are revealed by studies of the complex 1. The oxidized state corresponding to the Creutz-Taube ion 2 is not stable because of electrocatalytic substitution by the solvent (Cp[DOUBLE BOND]C5H5, C5H4Me, C5Me5).

    4. p-Phenylenediboranes: Mirror Images of p-Phenylenediamines? (pages 615–616)

      Priv.-Doz. Dr. Wolfgang Kaim and Andreas Schulz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406151

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      The same redox behavior–except for a reversal in sign — is displayed by the long-known p-phenylenediamine 1 (R = alkyl, aryl) and the novel B,B,B′,B′-tetramesityl-p-phenylenediborane 2. Electrochemical and ESR/ENDOR studies reveal that the acceptor strength of the dimesitylboryl substituent is only surpassed by the nitro group.

    5. Sequential Lithiation and Silylation of Stannocene (pages 616–617)

      Prof. Dr. Alan H. Cowley, Prof. Dr. Peter Jutzi, Franz X. Kohl, Jonathan G. Lasch, Dr. Nicholas C. Norman and Ewald Schlüter

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406161

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      Silylated cyclopentadienyl groups are about to gain a place for themselves as ligands in coordination chemistry. Until now, silylcyclopentadienyl groups were first lithiated and then converted by metal chlorides into complexes. Now, silyl groups have been introduced for the first time into a pre-formed metallocene 1. Lithiation and silylation yield the unusually distorted hexasilylstannocene derivative 2.

    6. High-Pressure Syntheses: The Henry Reaction (pages 617–618)

      Prof. Dr. Kiyoshi Matsumoto

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406171

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      High yields of nitro alcohols in the reaction of nitroalkanes with ketones (Henry reaction) could, until now, only be obtained in a limited number of special cases. However, use of high pressure and n-Bu4NF as catalyst considerably extends the range of application of the Henry reaction.

    7. Molecular Structure of a 1,3-Diphosphaallene: (2,4,6-tBu3C6H2)P[DOUBLE BOND]C[DOUBLE BOND]P(2,4,6-tBu3C6H2), a Phosphorus Analogue of Carbon Disulfide (pages 618–619)

      Priv.-Doz. Dr. Hans Heinz Karsch, Dipl.-Chem. Hans-Ulrich Reisacher and Dr. Gerhard Müller

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406181

      The first structure determination of a phosphacumulene by X-ray diffraction indicates that the 1,3-diphosphaallene 1, synthesized independently, is a genuine allene analogue. Isolated molecules are present in the crystal and the bulky substituents are arranged othogonally. The P[DOUBLE BOND]C bonds of the almost linear P[DOUBLE BOND]C[DOUBLE BOND]P moiety are markedly shorter (1.63 Å) than “normal” PC double bonds (1.68–1.72 Å); the C[DOUBLE BOND]S bonds in CS2 are also shorter than the C[DOUBLE BOND]S bonds in thioketones

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    8. Phosphaallenes (pages 619–620)

      Prof. Dr. Rolf Appel, Peter Fölling, Bernhard Josten, Dr. Mustafa Siray, Volker Winkhaus and Falk Knoch

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406191

      Novel, independent syntheses of phosphacumulenes are reported for the 1-phosphaallene 1 and the 1,3-diphosphaallene 2. 1 is prepared via a Wittig reaction from R [BOND]P[DOUBLE BOND]C[DOUBLE BOND]O and Ph3P[DOUBLE BOND]CPh2. 2 is obtained from the same educt with R[BOND]P(X)SiMe3; as desired, the reactions can be performed using either a two-step (X[DOUBLE BOND]H) or one-step (X[DOUBLE BOND]Li) procedure.

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    9. The ab initio Calculation of the Structure of 1,3-Dilithioacetone (pages 620–621)

      Dr. Alexander J. Kos, Dr. Timothy Clark and Prof. Dr. Paul von Ragué Schleyer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406201

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      The structure of the simplest dilithium salt of an α,α′-diketo dianion, the title compound 1,3-dilithioacetone, is still unknown. However, according to ab initio calculations, the chiral structure 1 with Y-conjugation is preferred to the four other structures investigated.

    10. Structure of a “Y-Conjugated” Dilithium Salt of an α,α′-Keto Dianion: 1,3-Dilithiodibenzyl Ketone-(Me2NCH2CH2NMe2)2 (pages 621–622)

      Prof. Dr. Hans Dietrich, Dr. Waruno Mahdi, Dipl.-Chem. Dieter Wilhelm, Dr. Timothy Clark and Prof. Dr. Paul von Ragué Schleyer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406211

      The first X-ray structure analysis of a monomeric dilithium salt with an α,α′-keto dianion was successfully carried out on the TMEDA complex 1. With approximate C2 symmetry, 1 is chiral. Comparison of the experimentally determined structure with that calculated semiempirically (MNDO) reveals good overall agreement. According to ab initio calculations, 2 has an analogous structure.

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    11. 1,4,7,10-Tetraphenyldibenzo[a,e]cyclooctene-5,6,11,12-tetrone from 3,6-Diphenylphthalic Anhydride (pages 622–623)

      Priv.-Doz. Dr. Theodor Troll, Dr. Georg W. Ollmann and Helga Leffler

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406221

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      Tetraketone 4 can be prepared electrochemically by reduction of 1 in the presence of ClMe3Si. Apart from 2, the polycycle 3 is also formed (R [DOUBLE BOND] SiMe3), and is converted into 4 by desilylation and hydrolysis.—Phthalic anhydride reacts differently.

    12. Synthesis of a Porphyrin Sandwiched between Two Parallel p-Benzoquinone Units (pages 623–625)

      Dipl.-Chem. Jürgen Weiser and Prof. Dr. Heinz A. Staab

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406231

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      p-Benzoquinone-porphyrin-p-benzoquinone is the layer sequence in the sandwich compound shown on the cover. This compound is formed in 0.1% yield from 1, R[DOUBLE BOND]CHO and pyrrole in refluxing propionic acid. The four bridges in the sandwich compound are short and contain no heteroatoms. It may serve as a model for the study of biochemically important electron-transfer reactions.

    13. Diastereoselective Formation of Substituted (η3-Allyl)(η4-diene)ZrCp Complexes by Intramolecular Ligand Interaction (pages 625–626)

      Priv.-Doz. Dr. Gerhard Erker, Klaus Berg, Dr. Reinhard Benn and Gerhard Schroth

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406251

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      For the designed synthesis of transition-metal catalysts for organic reactions a detailed knowledge of the strong intramolecular interactions between the ligands in simple metal complexes is indispensable. In appropriately substituted allyl(diene)ZrCp complexes, such interactions lead to the formation of one isomer of the complex system with very high diastereoselectivity. Thus, the 55 :45 mixture of anti-2 and syn-2 rearranges thermally into >95% anti-1.

    14. Complexation of PhAs[DOUBLE BOND]CH2 and Synthesis of a Novel RhAs3-Metallaheterocycle (pages 626–627)

      Prof. Dr. Helmut Werner, Wilfried Paul and Ralf Zolk

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406261

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      Generation of the first methylenearsane in the coordination sphere of rhodium has been achieved by reaction of C5Me5Rh(CO)(I)(CH2I) with LiAsHPh. In solution, the complex 1, E [DOUBLE BOND] As, obtained surprisingly affords the cyclic product 2, in which the RhAs3-ring is puckered.

    15. Chemical Bonds without Bonding Electron Density — Does the Difference Electron-Density Analysis Suffice for a Description of the Chemical Bond? (pages 627–628)

      Priv.-Doz. Dr. Dieter Cremer and Dr. Elfi Kraka

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406271

      Formation of a covalent bond is not necessarily associated with an increase in electron density in the bonding region. This can be established by analysis of the single electron density distributions ρ(r) with the aid of the assigned Laplace field ▽2ρ(r). For “bonds without bonding electron density ρ(r)”, it is decisive that the density ρ(r) actually present in the region between the atoms results in a decrease in the local energy density and, hence, produces a stabilizing effect.

    16. Stoichiometric and Catalytic Metathesis of Carbodiimides and Pentacarbonylcarbenetungsten Complexes (pages 629–630)

      Dr. Karin Weiss and Petra Kindl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406291

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      The ability of heteroallenes to undergo metathesis reactions could be demonstrated using the carbodiimides 2. The stoichiometric reaction 1 + 2 [RIGHTWARDS ARROW] 3 + 4 is the first example of a metathesis of heteroallenes with carbene complexes such as 1. The isocyanidetungsten complexes 3 thus obtained function as catalysts for the (equally novel) metathesis of symmetrical to “mixed” carbodiimides RN[DOUBLE BOND]C[DOUBLE BOND]NR′.

    17. An Iridium(III) Complex Containing a PF4-Group Bound to the Metal (pages 630–631)

      Prof. Dr. E. A. V. Ebsworth, Dr. John H. Holloway, Nicholas J. Pilkington and Dr. David W. H. Rankin

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406301

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      Oxidative fluorination of a PF2- to a PF4 -ligand with XeF2 permits preparation of the title compound 1, in which a metal atom is bonded to a pentacoordinated P atom

    18. Temperature Dependence of the UV Spectrum of 1,5-Dimethyl-2,6-semibullvalenedicarbonitrile; Evidence for an Equilibrium with a Delocalized, Homoaromatic Isomer (pages 631–632)

      Prof. Dr. Helmut Quast and Dr. Josef Christ

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406311

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      Formation of the bishomoaromatic species 2, a system with delocalized electrons, from the isomeric semibullvalene 1 can be deduced from the temperature-dependent reversible changes in the UV spectrum. 2 is defined molecule and not the transition state in the Cope rearrangement of 1.

    19. Novel Inorganic Ring Systems and Fixation of the Smath image Ion:[(S6)Cu(S8)Cu(S6)]4⊖ and [Cu3(S4)3]3⊖ (pages 632–633)

      Prof. Dr. Achim Müller, Friedrich-Wilhelm Baumann, Dr. Hartmut Bögge, Michael Römer, Erich Krickemeyer and Klaus Schmitz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406321

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      Novel Cu[BOND]S Anions with ring structures demonstrate, once again, the unusually versatile coordination behavior of polysulfide ions. [Cu3(S4)3]3⊖1, with a central (CuS)3 six-membered ring, and [(S6)Cu(S8Cu(S6)]4⊖2, with an S8 chain, were obtained by reaction of Cu(OAc)2 with S8 and H2S, respectively.

    20. Thiolate Chemistry of the Iron Group Elements: Synthesis and Structure of the Complexes [Co2{o-(SCH2)2C6H4}3]2⊖ and [Ni3{o-(SCH2)2C6H4}4]2⊖ (pages 634–635)

      Dr. Wolfgang Tremel, Prof. Dr. Bernt Krebs and Dr. Gerald Henkel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406341

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      The novel complex anions 1 and 2 with the ligand “S2-o-xyl” (o-xylene-α,α′-dithiolate) were prepared from CoCl2 and NiCl2, respectively, and S2-o-xyl2⊖. The Co2-complex 1 is an example of the rare syn-exo arrangement of the thiolate S atoms in the central Co2S2 ring. In the Ni3-complex 2, each of the Ni atoms is planar-coordinated by four sulfur atoms; the Ni3-skeleton is bent.

    21. The Reaction of [2,3-bis(diphenylphosphino)-N-methylmaleimide]nickel(II) Chloride with PhE(SiMe3)2 (E = P, As) (pages 635–637)

      Prof. Dr. Dieter Fenske and Dipl.-Chem. Kurt Merzweiler

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406351

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      A facile approach to complexes with PhE[DOUBLE BOND]EPh (E = P, As) as ligand is opened up by the reaction of 1 with PhE(SiMe3)2. Complexes 2 and 3 are formed by exchange of chlorine and Me3Si-migration, respectively. In the reaction of 2 with CH3COCl, the diphosphene ligand is displaced by Cl; moreover, the Me3Si groups are substituted by CH3CO groups. Recrystallization of this compound leads exclusively to the meso-derivative 4.

    22. Transallenation of 1,3-Bis(dialkylamino)-1,3-diethoxyallenes with Disubstituted Malonyl Chlorides (pages 637–638)

      Prof. Dr. Rolf W. Saalfrank, Dipl.-Chem. Walter Rost, Dipl.-Chem. Franz Schütz and Dipl.-Chem. Ulrike Röss

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406371

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      A general synthetic route to 1,1-allenedicarboxamides 3 is transallenation. For this purpose 1,3-bis (dialkylamino) allenes (synthetic equivalents of malonamide dianions 1) are allowed to react with disubstituted malonyl chlorides (synthetic equivalents of 1,1-vinylidene dications 2); R1[DOUBLE BOND]NR2.

    23. CP/MAS-13C-NMR Spectra of Sclerotized Insect Cuticle and of Chitin (pages 638–639)

      Priv.-Doz. Dr. Martin G. Peter, Lothar Grün and Dr. Hans Förster

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406381

      A nondestructive method for investigating the exoskeleton of insects has facilitated structural information to be gained about the insoluble, fully sclerotized cuticle and about the highly polymeric chitin. It was known that the exoskeleton consists of chitin, proteins, and polyarenes. In contrast to previous suppositions, however, the transformation products of sclerotizating agents with 3,4-dihydroxyphenyl groups are predominantly present in the reduced state.

    24. Acid-Induced Carbyne-Acyl Rearrangement — an Unexpected CC Coupling Reaction (page 640)

      Priv.-Doz. Dr. Fritz R. Kreissl, Dipl.-Chem. Werner J. Sieber, Dr. Mathias Wolfgruber and Jürgen Riede

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406401

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      The novel title reaction is of general importance for catalytic processes such as CO reduction and the Fischer-Tropsch synthesis. Carbyne complexes like 1 even react with HCl in ether to yield acyl complexes such as 2.

    25. Cyclopropenylidene (page 641)

      Dr. Hans Peter Reisenauer, Prof. Dr. Günther Maier, Dr. Achim Riemann and Prof. Dr. Reinhard W. Hoffmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406411

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      The Simplest cyclic conjugated carbene is the title compound 2a [LEFT RIGHT ARROW] 2b, generated by pyrolysis of the polycycle 1. Compound 2 is stable in an argon matrix at 10 K and has a singlet ground state. The “atomatic ylide structure” 2b makes a major contribution to the mesomerism.

    26. Direct Photochemical Cleavage of the Cyclobutane Ring in Bicyclo[4.2.0]octane on 185nm Irradiation in Solution (pages 641–642)

      Prof. Dr. Waldemar Adam and Dipl.-Chem. Thomas Oppenländer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406412

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      The cleavage of cyclobutanes by short-wavelength UV radiation was studied using the example of the title compound 1, which contains no chromophoric substituents. 185 nm Irradiation of 1 in n-pentane leads preferentially to decompostion into 1,7-octadiene. Presumably, Rydberg excited states having radical cation character, such as 2, are involved.

    27. Formation of Phenanthrenequinone from Benzil: A Novel Reaction of Graphite-Potassium Intercalates (pages 642–643)

      Dov Tamarkin, Daphna Benny and Prof. Dr. Mordecai Rabinovitz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198406421

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      A dehydrogenative cyclization with C8K facilitates preparation of 1 and 2 from benzil and p,p′-dimethylbenzil, respectively. The constant rate of H2-formation during the reaction suggests a surface-controlled process.

  3. Book Reviews

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