bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untersuchungen am System Phosphirenimin/Iminophosphan — Insertionsreaktionen und Isomerisierung
Authors: Link Manfred , Niecke Edgar , Nieger Martin 
Published: July 2007

Investigations of the System Phosphirene Imine/Iminophosphane ‐ Insertion and Isomerization ReactionsTreatment of the iminophosphanes R1PNR2 1 [R2 = tBu, R1 = Et3C (a); R2 = Aryl, R1 = Et (b), Me (c)] with 1,4‐diphenyl‐butadiyne (2) leads to the phosphirene imines R1‐(R2N=)P̌(Ph)CCCPh 3a‐c and [R1(R2N=)P̌(Ph)CC]2 4a‐c. Further reaction with 1a, c gives the 1,2‐diphosphetes R1(R2N)PP(R1)(NR2)C(Ph)CCCPh 5a, b, which isomerize in the case of R1 = Me into the triphosphabicyclo[3.2.0]‐hepta‐1,6‐diene 7. In the reaction of the phosphirene imines R1(ArylN)P̌(R2)C(R2) 3 [R1 = Me, R2 = Ph (d); R1 = Et, R2 = COOMe (e)] with the iminophosphanes 1b, d the initially formed diphosphetes 9a, b isomerize to the 1,2‐diazaphosphole Cl(Mes*N)PN(Mes*)P(Me)C(Ph)C(Ph) 10 or the dioxadiphosphabicyclooctadiene CC(OMe)OP(N‐Mes*)(Et)CC(OMe)OP(NMes*)(Et) 12 depending on the substituents. A reaction of the phosphirene imine 3d with dimethylamino‐borane furnishes the vinylphosphane. Ph(H)CC(Ph)P(Et)N(H)Mes* (14) by ring opening. The compounds 7, 10, 12 have been characterized by X‐ray structure analyses.
Metallkomplexe funktioneller Isocyanide, XXI. N‐Isocyandialkylamin‐Derivate von Carbonyl‐ und Aren‐Metallverbindungen
Authors: Fehlhammer Wolf Peter , Metzner Robert , Kunz Rainer 
Published: July 2007

Metal Complexes of Functional Isocyanides, XXI[1]. — N‐Isocyanodialkylamine Derivatives of Metal Carbonyl and Arene CompoundsThe N‐isocyanodialkylamine complexes [M(CO)6‐n‐(CNNR2)n] (M = Cr, Mo, W; n = 1–3) (2a–7c), [Mn(CO)2(η‐C5H5)CNNR2] (8b,c), and [RuCl2(η‐TMB)CNNR2] (9a‐c) (TMB = 1,2,4,5‐tetramethylbenzene) have been prepared from appropriate metal carbonyl and arene precursors and the “free” N‐isocyanides CNNEt2 (1a), CNNiPr2 (1b), and CNNCH(Me)(CH2)3CHMe (1c), respectively. The structural assignments are made on the basis of IR, NMR (1H, 13C), and mass spectrometry as well as of an X‐ray structure analysis of [RuCl2(η‐TMB)CNNiPr2] (9b).
Strukturen und Moleküleigenschaften sterisch überfüllter Moleküle, 43. Triisopropylammonium‐chlorid: Einkristallstruktur und Berechnungen zur Protonierung des p‐Typ‐Stickstoff‐Elektronenpaares
Authors: Bock Hans , Göbel Ilka , Bensch Wolfgang , Solouki Bahman 
Published: July 2007

Structures and Molecular Properties of Sterically Overcrowded Molecules 43[1]. — Triisopropylammonium Chloride: Single‐Crystal Structure and Calculations Concerning the Protonation of the p‐Type Nitrogen Electron Pair[2]The protonation of triisopropylamine, which contains an almost planar NC3 skeleton of C3 symmetry and, therefore, a p‐type N electron pair, with HCl in methanol causes severe structural perturbation due to extreme steric overcrowdedness: the single‐crystal structure determination (orthorhombic Pbca, Z = 8) proves that the molecular symmetry is reduced to C5 by the rotation of one isopropyl group around its CN axis by almost 90° and the decrease of the angles CNC from 119° each to 115, 115 and 111°, respectively. The Cl⊖ ⃛(H)N hydrogen bond distance of 315 pm is presumably slightly increased by steric overlap of the van der Waals radii of Cl⊖ and one of the three adjacent methyl groups. The protonation of the p‐type lone pair of triisopropylamine including the pyramidalization of the nitrogen centre and the twist of one isopropyl group can be simulated by a one‐dimensional energy hypersurface calculation, if H⊕ attack outside the C3 axis is assumed.
Elektrophile Additionen an das Bicyclo[1.1.0]butan‐System von 1‐Phenyl‐ und 1‐(4‐Anisyl)tricyclo[4.1.0.02,7]heptan: Säure‐katalysierte Reaktionen mit Wasser und Methanol, Anlagerung von Essigsäure und Oxymercurierung
Authors: Christl Manfred , Gerstner Erwin , Kemmer Ralf , Llewellyn Gareth , Bentley T. William 
Published: July 2007

Electrophilic Additions to the Bicyclo[1.1.0]butane System of 1‐Phenyl‐ and 1‐(4‐Anisyl)tricyclo[4.1.0.02,7]heptane: Acid‐Catalyzed Reactions with Water and Methanol, Addition of Acetic Acid, and Oxymerucuration1‐(4‐Anisyl)tricyclo[4.1.0.02,7]heptane (37) was prepared from 1‐(4‐anisyl)cyclohexene, tetrabromomethane, and methyllithium in a one‐pot reaction. Starting from 37 and the analogous phenyl compound 19, the oxymercuration/demercuration sequence provided the exo‐6‐aryl‐endo‐6‐norpinanols 30a and 20a, respectively. By reaction with triphenyl‐stannane, the bromo compound 27a was converted into endo‐6‐phenyl‐exo‐6‐norpinanol 28a. Treatment of 19 with aqueous sulfuric acid led to a mixture of the alcohols 20a–25a. Mixtures of a very similar composition were obtained on hydrolysis of the 3,5‐dinitrobenzoates 20b and 28b of 20a and 28a in 80% aqueous acetone. Kinetic measurements revealed the same rate for the hydrolysis of 20b and 28b. The proof of the presence of 20a among the products of the reactions of 19, 20b, and 28b showed the intermediacy of an unrearranged cation, to which the classical structure 16 is ascribed. That acetic acid is too weak a nucleophile to intercept 16 follows from the structure of the adducts to 19. All of them (21b, 22b, 25b, 26b) have rearranged skeletons. In contrast, the stronger nucleophile methanol trapped 16 more efficiently than water to give the diastereomeric 6‐norpinyl methyl ethers 20d and 28d. The reaction of 37 with acetic acid and 10−4 M hydrochloric acid as well as the hydrolysis the 3,5‐dinitrobenzoate 30c of 30a produced mainly the diastereomeric 6‐norpinyl acetates 30b and 31b and 6‐norpinanols 30a and 31a, respectively. Whereas the protonation of 19 and 37 gives the classical cations 16 and 17, respectively, the oxymercuration of these substrates results in the generation of the nonclassical cations 44 and 46. This was concluded from the configuration of the demercuration products 20a and 30a and the absence of the diastereomers 28a and 31a.
Diastereoselective Functionalization of a Spherand‐Type Calixarene
Authors: O'Sullivan Patrick , Böhmer Volker , Vogt Walter , Paulus Erich F. , Jakobi Ralf A. 
Published: July 2007

AbstractCondensation of 5,5′‐di‐tert‐butyl‐2,2′‐dihydroxybiphenyl (1) with formaldehyde yields a cyclic trimer 2 (and tetramer 3) having three (four) methylene groups less than a calix[6]‐arene (calix[8]arene). Alkylation of the (flexible) trimer with ethyl bromoacetate gives exclusively the stereoisomer 4 with C2 symmetry, while the isomer with D3 symmetry is not observed. Two isomers 6a and 6b (C2 and C1 symmetry) are obtained by treatment with tert‐butyl bromoacetate which both are converted by transesterification with methanol into the same hexamethyl ester 5 having C2 symmetry. These results are rationalized by restricted rotation around ArAr bonds for larger O‐alkyl groups also around ArCH2Ar bonds. The structure of the hexaethyl ester 4 is also confirmed by single crystal X‐ray analysis.
Darstellung und Eigenschaften von S‐(Trifluormethyl)polysulfanmonosulfonaten CF3SxSO2M [x = 1, M = OH, NH40O, 1/2 HgO2, (CH3)3SiO, (CH3)2N, NH2; x = 2, M = NH4O]
Authors: Brosius Axel , Haas Alois , Pryka Michael 
Published: July 2007

Synthesis and Properties of S‐(Trifluoromethyl)polysulfanemonosulfonates CF3SxSO2M [x=1, M = OH, NH4O, 1/2 HgO2, (CH3)2N, NH2; x=2, M = NH4O]*Hydrolysis of CF3SNSO with 2 equiv. of H2O provides [NH4][CF3SSO3] (1), which on treatment with chlorine gives CF3SCl and [NH4][ClSO3]. Trifluoromethyl thiosulfates are synthesized from Hg(SCF3)2 and ClSO2M [M = NH4O, (CH3)3SiO (2), (CH3)2N (3), NH2 (4)]. Insertion of SO3 into Hg(SCF3)2 provides Hg[CF3SSO2O]2 (6). Similarly, S‐(trifluoromethyl)thiosulfuric acid (5) is obtained from CF3SH and SO3. New preparations for CF3SXNSO (x=1, 2) are described. These compounds are formed either from Hg(NSO)2 or (CH3)3SiNSO and CF3SxCl in good yields. CF3SSNSO (8) reacts with water to give [NH4][CF3SSSO3] (9). A 1:1 adduct (10) is obtained from CF3SNSO and AsF5. A preliminary X‐ray structure investigation proved that AsF5 is coordinated to the oxygen atom. Some reactions of [NH4][CF3SSO3] and CF3SSO2OSi(CH3)3 are mentioned.
Funktionalisierte Tripod‐Liganden: Synthese und Koordination von Tris[(diphenylphosphanyl)methyl]methan
Authors: Janssen Bernd C. , Asam Alexander , Huttner Gottfried , Sernau Volker , Zsolnai Laszlo 
Published: July 2007

Functionalized Tripod Ligands: Synthesis and Coordination of 1,1,1‐Tris[(diphenylphosphanyl)methyl]methaneThe tripod ligand HC(CH2PPh2)3 (4) is easily available from the reaction of 1,3‐dichloro‐2‐(chloromethyl)propane (3) with lithium diphenylphosphide. The ligand 4 itself and two of its coordination compounds, [(HC(CH2PPh2)3)Co(OOCMe)]+‐[BPh4]− (5 · BPh4) and [(HC(CH2PPH2)3)Co(OOCMe)]2+ · 2[BF4]− [7 · (BF4)2] have been characterized by X‐ray analyses. Coordination of 4 leads to an opening of the CH2CHCH2 bond angles (114° in 7 · (BF4)2 and 5 · BPh4 versus 111° in 4). This change in structure is reflected by the unusual low field shift of the methine hydrogen of 7 · (BF4)2 (δ = 3.90) in comparison with the corresponding signal of the free ligand 4 (δ = 1.53).
Study of Calixarenes, V. Friedel‐Crafts Reaction of Calixarenes
Authors: Huang Zhi‐Tang , Wang Guo‐Qiang 
Published: July 2007

AbstractThe para‐acylation of calix[4]arene (2), calix[6]arene (3), and calix[8]arene (4) by Friedel‐Crafts reaction with a wide variety of acyl chlorides leads to 5–7 in moderate to good yields. Friedel‐Crafts reaction of 26,28‐dimethoxycalix[4]arene (8) gave products 9 selectively disubstituted in the para‐positions of phenol rings.
Comparison of the Nucleophilicities of Alkynes and Alkenes. Quantitative Determination of the Nucleophilicities of Alkynes toward Carbenium Ions
Authors: Mayr Herbert , Gonzalez Jose L. , Lüdtke Kerstin 
Published: July 2007

AbstractRelative reactivities of alkenes and alkynes toward diarylmethyl cations have been determined by direct rate measurements and by competition experiments in dichloromethane. At −70°C alkynes are found to be one to two orders of magnitude less reactive than analogously substituted alkenes (e.g. phenylacetylene/styrene), but the reactivity difference reduces strongly as the temperature is raised. The stereochemistry of the vinyl chlorides produced by addition of benzhydryl chlorides to alkynes is characterized.
Metal Complexes with Tetrapyrrole Ligands, LXVI. Synthesis, Characterization, and Variable‐Temperature 1H‐ and 19F‐NMR Investigations of Cerium(IV) Double‐Deckers Derived from Monofunctionalized Tetraarylporphyrins
Authors: Buchler Johann W. , Eiermann Volker , Hanssum Helmut , Heinz Georg , Rüterjans Heinz , Schwarzkopf Markus 
Published: July 2007

AbstractThe synthesis of a cerium(IV) bisporphyrinate 1b starting from (p‐hydroxyphenyl)tris(p‐tolyl)porphyrin 2b is described. Derived from 2b by substitution of the phenolic OH group, the monofunctionalized tetraarylporphyrins 2c‐f and their cerium(IV) sandwich complexes 1c‐f were synthesized. The complexes are characterized by UV/Vis, IR, and 1H‐NMR spectroscopy. 19F‐NMR spectra of 1f show the presence of a vicinal and a transversal isomer due to the rigid squareantiprismatic coordination geometry of cerium(IV) bisporphyrinates. Variable‐temperature 1H‐ and 19F‐NMR spectra were recorded to investigate the rotational rigidity of the double‐decker system. The spectra show that the vicinal and transversal isomers are stable up to 140°C, i.e. rotation of the two porphyrin macrocycles with respect to each other does not occur.
Metallkomplexe mit biologisch wichtigen Liganden, LXX. Synthese, Stereochemie und Reaktionen von Ruthenium(II) und Osmium(II)‐Komplexen mit α‐Aminocarboxylat‐Liganden
Authors: Severin Kay , Sünkel Karlheinz , Beck Wolfgang 
Published: July 2007

Metal Complexes of Biologically Important Ligands, LXX[1].‐ Synthesis, Stereochemistry and Reactions of Ruthenium(II) and Osmium(II) Complexes with α‐Amino CarboxylatesHerrn Professor Helmut Werner zum 60. Geburtstag gewidmet.
The reactions of MHCl(CO)(PPh3)3 with salts of α‐amino acids give the hydrido‐N,O‐chelate complexes MH(CO)(NH2CHR‐COO)(PPh3)2 (1a–g;) M = Ru, Os). Complexes 1a–c can alternatively be prepared by oxidative addition of the appropriate α‐amino acid to Ru(CO)3(PPh3)2. The crystal structure of 1b has been determined by an X‐ray structural analysis. The leucinato compound 1c is an effective catalyst for the decomposition of formic acid. In contrast, reactions of RuHCl‐(CO)(PPh3)3 with α‐amino acids afford the chloro‐N,O‐che‐late complexes RuCl(CO)(NH2CHRCOO)(PPh3)2 2a–h. The decomposition reactions of 2c, 2g and2h have been investigated.
Koordinationschemie mit den komplexen Chelatliganden [{Fe2Cp2(CO)3}2{CN[CH2]nNC}] (n = 2, 3). Heteropentanukleare „Superkomplexe”︁ mit μ5Diisocyanid‐Brücken
Authors: Schrölkamp Stephan , Sperber Wilfried , Lentz Dieter , Fehlhammer Wolf Peter 
Published: July 2007

Coordination Chemistry with the Complex Chelating Ligands [{Fe2Cp2(CO)3)2{CN[CH2]n NC}] (n = 2, 3). Heteropentanuclear “Supercomplexes” with μ5‐Diisocyanide BridgesHerrn Professor Dr. O. J. Scherer zum 60. Geburtstag gewidmet.
The tetranuclear complexes [(Fe2Cp2(CO)2(μ‐CO)}2(μ4‐CN[CH2]nNC}] [n = 2 (2), 3 (3)] act as bidentate chelating ligands towards the Lewis‐acidic metal halides MnCl2, MnBr2, FeCl2, CoCl2, NiCl2, NiBr2, CuCl2, CuBr2, ZnCl2, ZnI2, CdCl2, CdI2, HgCl2, the chloro complexes [MCl2‐(NCPh)2] (M = Pd, Pt), Zn(OAc)2 · H2O, and [Mo(CO)4(η‐NBD)] (NBD = 2,5‐norbornadiene) to give a total of 22 pentanuclear “supercomplexes” ,6–21, which have been characterized by elemental analyses and IR and NMR (1H, 13C) spectra. Reaction of 2 with [Ni(COD)2] in CH2Cl2 gave only rise to the dichloronickel(II) species 9a. Very remarkably, the pentairon complex [(Fe2Cp2(CO)2(μ‐CO)2(μ5‐CN(CH2)2‐NC)}]FeCl2 (7) also formed spontaneously (!) when 2 was refluxed in chloroform for several hours. The X‐ray structure analysis of [{Fe2Cp2(CO)2(μ‐CO))2{μ5‐CN(CH2)2NC}]CdI2 (14b) confirms the twofold μ3‐(C,C,N) bridging mode of a diisocyanide ligand in a cis/cis‐anti‐configurated [Fe2]2Cd pentanuclear system of crystallographic C2 symmetry.
Metallkomplexe funktioneller Isocyanide, XXIII. N‐Isocyandialkylamin‐Komplexe des Bors, Rhodiums, Palladiums, Platins und Kupfers
Authors: Fehlhammer Wolf Peter , Metzner Robert , Sperber Wilfried 
Published: July 2007

Metal Complexes of Functional Isocyanides, XXIII[1]. ‐ N‐Isocyanodialkylamine Complexes of Boron, Rhodium, Palladium, Platinum, and CopperThe N‐isocyanodialkylamines CNNEt2, CNNiPr2, and CNNCH(Me)(CH2)3CHMe (1a–c) react with triphenylboron, various transition metal halides, and mono‐ and dinuclear chloro complexes by addition, substitution, bridge cleavage and reduction to give the complexes Ph3BCNNR2 (2b, c), [MX2(CNNR2)2] (M = Pd, Pt; X = Cl, Br, I) (3–7), [M(Cl)‐(CNNR2)(PPh3)2]BF4 (8, 9), cis‐ and trans‐[PtCl2(CNNR2)‐(PR′3)] (R′ = Et, Ph) (10–12), [Rh(CNNR2)4]Cll (15b, c) and [Cu(CNNR2)4]ClO4 (16b, c). The complexes [PdX2(CNNR2)(PPh3)] (X = Cl, Br) (13c, 14c) have been obtained by substitution of an N‐isocyanide ligand in 3c and 4c, respectively, with PPh3. The structural assignments are made on the basis of IR, NMR (1H, 13C, 31P, 15N) and mass spectrometry as well as of an X‐ray structure analysis of [PdI2(CNNiPr2)2] (5b).
Synthese von (—)‐(Acetoxymethyl)(hydroxymethyl)methyl(phenyl)german [(—)‐MePhGe(CH2OAc)(CH2OH)] durch eine Esterase‐katalysierte Umesterung: Die erste enzymatische Synthese eines optisch aktiven Germans
Authors: Tacke Reinhold , Wagner Stephan A. , Sperlich Jörg 
Published: July 2007

Synthesis of (—)‐(Acetoxymethyl)(hydroxymethyl)methyl(phenyl)germane [(—)‐MePhGe(CH2OAc)(CH2OH)] by an Esterase‐Catalyzed Transesterification: the First Enzymatic Synthesis of an Optically Active GermaneThe prochiral germane MePhGe(CH2OH)2 (1) was synthesized by a six‐step synthesis starting from GeCl4 (3) [3 → Cl2Ge(CH2Cl)2 (4) → Ph2Ge(CH2Cl)2 (5) → (CF3S(O)2O)PhGe(CH2Cl)2 (6) → MePhGe(CH2Cl)2 (7) → MePhGe(CH2OAc)2 (8) → 1]. Reaction of 1 with Ac2O/NEt3 (molar ratio 1: Ac2O = 1:1) gave the racemic germane rac‐MePhGe(CH2OAc)(CH2OH) (rac‐2). Stereoselective transesterification of 1 with vinyl acetate (acetate source and solvent), catalyzed by immobilized porcine liver esterase (PLE; E.C.‐3.1.1.1), yielded the optically active germane (—)‐MePhGe(CH2OAc)(CH2OH) [(—)‐2] (yield 57%, enantiomeric purity 50% ee).
Reaktive EC(p‐p)π‐Systeme, XXXVII. Pentafluorethanselenol: Synthese, Spektren und Gasphasen‐Struktur
Authors: Blau Hanne , Grobe Joseph , Van Duc Le , Mack Hans‐Georg , Oberhammer Heinz 
Published: July 2007

Reactive EC(p‐p)π Systems, XXXVII[1]. ‐ Pentafluoroethaneselenol: Synthesis, Spectra, and Gas‐Phase StructureHerrn Professor Wolfgang Sawodny zum 60. Geburtstag gewidmet.
Pentafluoroethaneselenol HSeC2F5 (1) and its deuterated analogue DSeC2F5 (2) are obtained in moderate yields by cleavage of the diselane (SeC2F5)2 with Me3SnH and Me3SnD, respectively. Complete characterization of the labile compounds was accomplished by spectroscopic investigations (IR, Raman, MS; 1H, 13C, 19F, 77Se NMR). The molecular structure was determined by electron diffraction in the gas phase together with ab initio calculations.
Synthese und Struktur von (R3P)Ni(1,6‐Heptadiin)‐Komplexen
Authors: Proft Bernd , Pörschke Klaus‐Richard , Lutz Frank , Krüger Carl 
Published: July 2007

Synthesis and Structure of (R3P)Ni(1,6‐Heptadiin) ComplexesDisplacement of the alkene ligand in Ligand‐Ni(0)(1,6‐diene) complexes by 1,6‐heptadiyne, the parent 1,6‐diyne, affords the complexes (Me3P)Ni(η2,η2‐C7H8) (1) and (Ph3P)Ni(η2,η2‐C7H8) (2). According to an X‐ray structure analysis of the PMe3 derivative 1 the nickel atom is ideally trigonal‐planar coordinated by the phosphane and both CC bonds. The increased stability of the complexes as compared to Ligand‐Ni(HCCH)2 complexes is referred to the strong chelating effect which is special to the 1,6‐functionalization. The compounds can be considered to be model complexes for the key intermediates of numerous transition metal‐mediated coupling reactions of (substituted and unsubstituted) 1,6‐diynes.
Reaction of (α,β‐Epoxyalkyl)silanes with α‐Sulfonyl Anions and α‐Sulfonyl Anions in the Presence of a Lewis Acid. A Method for the Synthesis of (Z)‐sec‐Allylic Alcohols and β,γ‐Unsaturated Alkyl Phenyl Sulfones
Authors: Masnyk Marek , Wicha Jerzy 
Published: July 2007

AbstractThe reaction of 2‐alkyl‐3‐(trimethylsilyl)oxiranes (la or 1b) with anions generated from alkyl phenyl sulfones (2a‐f) followed by hydrolysis affords sec‐allyl alcohols 3–7. An analogous reaction in the presence of BF3 · Et2O affords adducts 8–11. Treatment of 8–11 with NaOH under phase‐transfer conditions affords stereospecifically the corresponding allylic alcohols 4a–5c. Reaction of oxirane 1a with anions derived from sterically hindered sulfones 2e or 2f in the presence of BF3 · Et2O was investigated. Reaction of compounds 8, 9 with phosphorus tribromide in pyridine affords β,γ‐unsaturated sulfones 19.
Synthese, Kristallstruktur und Reaktionen neuartiger metallacyclischer Dioxo‐ und Aminooxocarben‐Komplexe des Eisens
Authors: Förtsch Walter , Hampel Frank , Schobert Rainer 
Published: July 2007

Synthesis, Crystal Structure, and Reactions of Novel Metallacyclic Dioxo‐ and Aminooxocarbene Complexes of IronThe novel cationic iron carbene complexes 9 and 11 are readily prepared from the corresponding ferra lactones 7 and lactams 10, respectively. With nucleophiles the complexes 9 react chemoselectively either at the methyl group of the methoxy residue or at the terminal allylic C atom. In contrast to similar tungsten complexes 6, compounds 9 show “carbene activity” only when olefin and carbene ligands are separated by two atoms. Novel tricarboryl(2H‐pyran)iron complexes 18 are obtained by a regioselective intramolecular carbene transfer in 9 once switched to the active form 17 by deprotonation using silyl enol ether 16 as a base.
Organische Synthesen mit Übergangsmetallkomplexen, 69. [2‐(Acylamino)ethenyl]ketenimine aus [2‐(Acylamino)ethenyl]carben‐Komplexen sowie deren Ringschluß‐Metathese zu Pyrrolen oder deren Elektrocyclisierung zu 1,4‐Diaminonaphthalinen
Authors: Aumann Rudolf , Jasper Beate , Goddard Richard , Krüger Carl 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 69[1]. — 2‐(Acylamino)ethenyl Ketene Imines from [2‐(Acylamino)ethenyl]carbene Complexes and their Ring‐Closing Metathesis to Pyrroles or Electrocyclization to 1,4‐DiaminonaphthalenesHerrn Prof. Helmut Werner zum 60. Geburtstag gewidmet.
[2‐(Acylamino)ethenyl]carbene complexes LnM = C(OEt) CHCPh[N(COR)Ph] 5 [LnM = (CO)5Cr, (CO)5W; R = C6H5, pMeOC6H4, pNO2C6H4, OtBu] are obtained by N‐acylation of [2‐(amino)ethenyl]carbene complexes LnMC (OEt)‐CHCPh(NHPh) (Z)‐3 in 72–90% chemical yields with high stereoselectivity. The reaction of (Z) ‐ or (E)‐5 with two equivalents of isocyanides RNC 6 (R = cC6H11, tBu) at 20°C gives the isocyanide complexes LnM(RNC) 9 and the [2‐(acylamino)ethenyl]ketene imines RNCC(OEt)CH = CPh[N(COR)Ph] 8 (>95% yields) with configurational retention at the CC(N) bond. Thermolysis of (Z)‐8 (20–80°C) provides an efficient route to pyrroles 11 (90–95%) by a ring‐closing metathesis with elimination of isocyanates 10, while the thermolysis of (E)‐8, e.g. (E)‐8g, at 20°C leads to the formation of 1,4‐diaminonaphthalenes, e.g. 12g (>95% yield), by an electrocyclic ring closure.
Molekulare Pinzetten aus Cyclophan‐Bausteinen
Authors: Güther Ralf , Nieger Martin , Rissanen Kari , Vögtle Fritz 
Published: July 2007

Molecular Tweezers from Cyclophane Building BlocksMolecular tweezer compounds 1–6 with convergent carboxyl groups are prepared from suitable functionalized [2.2]‐and dithia[3.3]metacyclophane building blocks by using several multistep strategies. The CC coupling of two cyclophanes according to the Hagihara method leads to alkynespacered double cyclophanes. These new preorganized, acyclic host compounds of the cyclophane‐type react as molecular tweezers and can selectively “grasp” guest molecules and bind them strongly. X‐ray analyses underline the syn conformations of the dithia[3.3]‐ and the anti conformation of the [2.2]metacyclophanes.
A Convenient One‐Pot Preparation of Bis(nitroaryl) Tellurides Using a Tellurium‐Copper Couple as the Telluration Reagent
Authors: Suzuki Hitomi , Nakamura Tohru 
Published: July 2007

AbstractThe Te‐Cu couple generated in situ by the reaction of disodium telluride with copper(I) iodide in dry N‐methyl‐2‐pyrrolidone has been found to be a convenient telluration reagent for some activated iodoarenes 1. Using this reagent system, we have prepared by a one‐pot synthesis in satisfactory yields several bis(nitroaryl) tellurides 4, which are otherwise laborious to obtain.
Seven‐Membered Heterodimetallic Ring Systems from (Conjugated Diene) Group 4 Metallocene Complexes and Organoaluminium Reagents
Authors: Erker Gerhard , Noe Ralf , Wingbermühle Doris 
Published: July 2007

AbstractThe (s‐trans/s‐cis‐η4‐butadiene)zirconocene reagent adds dimethylaluminium chloride to yield the heterodimetallacyclic main group/transition‐metal system 2b, containing a seven‐membered metallacyclic framework that exhibits a “π‐agostic” s̀‐allyl zirconium interaction. Similar compounds (2c–f, 5a, 6) are obtained upon reaction of (butadiene)zirconocene with Et2All and (butadiene)hafnocene with Me2AlCl or Et2AlI. Addition of Me2AlCl or Et2AlI to (isoprene)zirconocene proceeds regioselectively to yield the corresponding heterodimetallacycles bearing the methyl substituent at C‐3 (i.e. near to the attached aluminium center). The iodide‐bridged heterodimetallacycles exhibit dynamic NMR spectra that indicate a rapid enantiomerization process on the NMR time scale (ΔG±ent ≈ 11–12 kcal mol−1). It is assumed that this automerization reaction proceeds by rate‐limiting aluminium‐halogen bond cleavage leading to an acyclic mixed metal heterodimetallic intermediate. This process is markedly inhibited by the presence of excess diethylaluminium iodide.