bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermolyse von 1,2,3,4,6,7,8–Heptaazaspiro[4.4]nona–2,7–dienen, [3 + 2]‐Cycloaddukten von Aziden an 5–Alkyliden–4,5–dihydro–1H‐tetrazole
Authors: Quast Helmut , Balthasar Jürgen , Hergenröther Thomas , Regnat Dieter 
Published: July 2007

Thermolysis of 1,2,3,4,6,7,8–Heptaazaspiro[4.4]nona–2,7–dienes, [3 + 2] Cycloadducts of Azides and 5–Alkylidene–4,5–dihydro–1H‐tetrazolesOn thermolysis of the title compounds at 20–150°C, three modes of ring cleavage are observed, viz. [3 + 2] cycloreversion of the triazole (path A) or the tetrazole ring (path B) to azide 2 and the corresponding dipolarophile, or extrusion of molecular nitrogen from the triazole ring with concomitant 1,2 shift of a nitrogen atom of afford an iminotetrahydrotetrazine 31 (path C). An equilibrium between [3 + 2] cycloaddition and cycloreversion (path A) is established starting from the heptaazaspiro[4.4]nonadienes 4. Irreversible [3 + 2] cycloreversion of the tetrazole ring (path B) is observed on thermolysis of 6, yielding azide 2 and iminodihydrotriazoles 7. Path A and B compete in the thermolysis of 6e affording, besides methyl azide (2a), 5c and 7e. Because path A is reversible, the former disappears again while the latter extrudes molecular nitrogen to yield the iminoaziridines (E)‐ and (Z)‐12 which decompose to the imine 13 and methyl isocyanide (14). Competition between path A and B is also observed on thermolysis of 15 and, probably, the diphenyl compound 21 as well. The latter affords a complex mixture comprising the iminodihydrotriazole 16, the iminoaziridines 18 and 23, the [2 + 1] cycloreversion products 14 and 19 of 18, and the 2–aminoindole 26 which is formed by isomerization of 18 and/or 23. None of the [3 + 2] cycloreversion reactions, but only extrusion of molecular nitrogen and formation of 31 (path C) are observed on thermolysis of the nitrophenyl spirocycles 29. The course of the thermolyses is mainly governed by the size and the electronic character of the substituent that stems from the azide used in the formation of the title compounds.
Organische Synthesen mit Übergangsmetall–Komplexen, 61[1] Pyridine und Pyridinium–Salze aus (β‐Aminovinyl)carben–Komplexen (MCr, W) und Alkinen über 4(1H)‐Pyridinyliden–Komplexe
Authors: Aumann Rudolf , Hinterding Peter 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 61[1]. – Pyridines and Pyridinium Salts from (β‐Aminovinyl)carbene Complexes (MCr, W) and Alkynes via 4(1H)‐Pyridinylidene ComplexesPyridines and pyridinium salts were obtained in good yields by the condensation of (β‐aminovinyl)carbene complexes with alkynes. The reaction of [(Z)‐β‐(monoalkylamino)vinyl]carbene complexes [ 4‐(monoalkylamino)‐1–metalla–1,3–dienes)] LnMC(OEt)CHCRNHR1 (Z)‐6a–f (R, R1Ph, Me, iPr, nBu, CH2Ph, CH2OMe) with alkynes R2CCH 7a–c (R2  nBu, Ph, CH2OMe) involves the highly regioselective formation of 4(1H)‐pyridinylidene complexes . Protonation of 8 with HBF4 leads to pyridinium salts 13 by the regiospecific substitution of the metal moiety LnM by a proton. The reaction may conveniently be performed in a one–pot procedure. {[(Z)‐β‐(H2‐Amino)vinyl]carbene}chromium complexes, e.g. 14, react with alkynes to give pyridines, e.g. 15. The thermal decomposition of 6 yields enol ethers 11. A regiospecific formation of (E)‐11 is observed in the thermolysis of 6 in the presence of pyridine.
Organische Synthesen mit Übergangsmetall–Komplexen, 62. Erste Carbenkomplexe (MCr, W) mit Kohlenhydrat–Substituenten
Authors: Aumann Rudolf 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 62. – First Carbene Complexes (MCr, W) with Carbohydrate SubstituentsThe first examples of transition metal carbene complexes of carbohydrate derivatives are described: 1,2:5,6–Di‐O‐isopropyliden‐α‐D–glucofuranose (2a), 1,2:5,6–di‐O‐isopropylidene‐α‐D–allofuranose (2b), and 2,3:5,6–di‐O‐isopropyliden‐α‐D–mannofuranose (2c) add regiospecifically at C–3 of alkynylcarbene complexes LnMC(OEt)–CCPh 1 [LnMCr(CO)5 (a), W(CO)5 (b)] to give vinylcarbene complexes LnMC(OEt)–CHC(Ph)–O(sugar) (E/Z)‐3a–g in good to excellent yields. As a minor side reaction the alkynyl carbene complex (CO)5WC(OEt)–CCPh (1b) isomerises to give the 1,2–propadienylidene complex (CO)5WCCC(OEt)C6H5 (4b).
Synthesis of 9,10–Dihydro–9,10–propanoanthracen–12–ones Substituted at the Bridgehead
Authors: Martin H. , Hoffmann R. , Karama Usama 
Published: July 2007

AbstractA variety of 9,10–dihydro–9,10–propanoanthracen–12–ones 1–11 has been prepared from anthracenes 15–23, α,α′‐dibromo ketones 12–14 and zinc/copper couple by using dioxane as solvent and ultrasonication at 15–20°C. 2,2,4,4–Tetrabromoacetone (12) afforded cycloadducts, in which the two bromine atoms at C–11 and C–13 are introduced stereoselectively cis and adopt a syndiaxial instead of a cis‐diequatorial position (5 examples). Even the cis‐configurated methyl groups in adducts 8, 9 and cis‐11 adopt syndiaxial positions preferentially.
Mehrfachbindungen zwischen Hauptgruppenelementen und übergangsmetallen, CVIII. Stöchiometrische und katalytische Oxidation elektronenarmer Olefine mit Osmiumtetraoxid: Eine neue Oxidationsmethode für Fluorolefine
Authors: Herrmann Wolfgang A. , Eder Stefan J. 
Published: July 2007

Multiple Bonds between Atoms of Main Group Elements and Transition Metals, CVIII. — Stoichiometric and Catalytic Oxidation of Electron‐poor Olefins with Osmium Tetraoxide: A Novel Oxidation Method for FluoroolefinsIn contrast to current opinion, osmium tetraoxide reacts even with very electron‐poor olefins. For example, both partially and fully fluorinated osmate(VI) esters 2 are thus formed from fluoroolefins 1 by cycloaddition. Hydrolysis of the osmate(VI) esters leads to the corresponding 1,2‐diols 3 and, eventually, consecutive fluoroorganic products by HF elimination. A catalytic version of this route opens a new, general, and efficient entry to oxidation products in fluoroolefin chemistry. Tetrahalide ethylene derivatives of formula py2O2Os(OCX2CX2O) (X = Cl, F) split off oxalyl halide upon thermal treatment with the complexes py2O2OsX2 thus being formed in good yields.
Notizen / Notes [Li2(THF)4DAD] und [DAD — H][ZrCl5(THF)]: Neue Strukturvarianten phenylsubstituierter 1,4‐Diaza‐1,3‐dien‐Liganden
Authors: Scholz Joachim , Richter Bodo , Goddard Richard , Krüger Carl 
Published: July 2007

[Li2(THF)4DAD] and [DAD — H][ZrCl5(THF)]: New Types of Phenyl‐;Substituted 1,4‐Diaza‐1,3‐diene LigandsTwo extreme situations in 1,4‐diaza‐1,3‐diene (DAD) chemistry are described. Reaction of phenyl‐substituted DAD 1a — c with lithium in the molecular ratio of 1:2 affords in high yield the extremely air‐sensitive complexes [Li2(THF)4DAD] (2a — c). The structure of 2b has been determined by X‐ray diffraction. Each of the Li+ ions is coordinated by the two terminal N atoms of the s‐cis‐configurated DAD dianion and by two molecules of THF. Protonation of ZrCl4 · DAD (3a) by HCl in THF gives the ionic complex [ZrCl5(THF)][DAD — H] (4), which contains a protonated [DAD — H]+ cation. The structure of the sterically crowded N = C — C = N skeleton of the [DAD — H]+ cation is not influenced by the positive charge and adopts the unusual Z‐gauche‐Z conformation.
Reaktive E = C(p‐p)π‐Systeme, XXXIII. Side‐on‐Koordination des Phosphaalkins P ≡ C — N(iPr)2 im 16e‐Nickel(0)‐Komplex Ni(CO)PCy3[PCN(iPr)2]
Authors: Grobe Joseph , Van Duc Le , Hegemann Marianne , Krebs Bernt , Läge Mechtild 
Published: July 2007

Reactive E = C(p‐p)π Systems, XXXIII. — Side‐on Coordination of the Phosphaalkyne P ≡ C — N(iPr)2 in the 16e Nickel(0) Complex Ni(CO)PCy3[PCN(iPr)2]The reaction of (diisopropylamino)phosphaethyne P ≡ C — N(iPr)2 with the nickel complex [Ni(CO)3PCy3] – in contrast to the analogous reactions with Ni(CO)4 or Ni(CO)3PR3 (R = Me, Ph) – leads to the novel 16e nickel(0) system [Ni{η2‐P ≡ C — N(iPr2)}(CO)PCy3] with a planar geometry of all skeleton atoms besides the methyl and cyclohexyl groups. Side‐on coordination of the P ≡ C triple bond results in an increase of the PC distance to 1.665 Ȧ typical for phosphaalkenes.
Struktur eines Silaethen‐Aminaddukts
Authors: Wiberg Nils , Joo Kwang‐;Suk , Polborn Kurt 
Published: July 2007

Structure of a Silaethene Amine AdductThe reaction of Me2SiBr‐CBr(SiMe2Ph)2 with PhLi in the presence of NEtMe2 leads to EtMe2N…︁SiMe2…︁C(SiMe2Ph)2 (3). NEtMe2 is coordinated to the central silicon. The SiN distance is comparably long (1.988 Ȧ). The bond distance between the central (distorted tetrahedra) silicon and the central (planar) carbon (1.761 Ȧ) is longer than the SiC distances in silaethenes (1.70 Ȧ) and shorter than the SiC distances in silaethanes (1.87 Ȧ). From a comparison of structures of D…︁SiMe2 \documentclass{article}\pagestyle{empty}\begin{document}$ \underline \cdots $\end{document} C(SiR3)2 it is concluded that increasing Lewis basicity of D (THF < NEtMe2 < F¯) leads to a SiC bond lengthening and to more regularity in the geometry of the distorted tetrahedral silicon.
Zur Tautomerie von 5,5‐Diphenyldihydro‐4H‐1,2,3‐triazol‐4‐on und 5‐Amino‐4,4‐diphenyl‐4H‐1,2,3‐triazolen
Authors: Quast Helmut , Hergenrüther Thomas , Banert Klaus , Peters Eva‐;Marie , Peters Karl , Schnering Hans Georg Von 
Published: July 2007

Tautomerism of 5,5‐Diphenyldihydro‐4H‐1,2,3‐triazol‐4‐one and 5‐Amino‐4,4‐diphenyl‐4H‐1,2,3‐triazolesMethylation of the 5‐amino‐4H‐1,2,3‐triazole 5 affords the N‐methyl‐ (12) and the N,N‐dimethylaminotriazole 13. X‐ray diffraction analyses show that the tautomer 5b exists in the crystal and that 5b and 13 possess similar structures and atomic distances. Both compounds exhibit restricted rotation of the amino groups in solution. The comparison of UV, carbon‐13 and nitrogen‐15 spectra of the tautomeric triazoles 2 and 5 with those of the N‐methyl compounds 3 and 13 demonstrates that the tautomers 2a and 5b are strongly favoured also in solution.
3‐Azabicyclische Ketone durch Reaktionen von 1,3‐Diethoxy‐2‐azapropenylium‐Salzen mit Enaminen cyclischer Ketone
Authors: Schleimer Richard , Hornig Knut , Würthwein Ernst‐;Ulrich , Müller Manfred H. 
Published: July 2007

3‐Azabicyclic Ketones from 1,3‐Dialkoxy‐2‐azapropenylium Salts and Enamines of Cyclic Ketones1,3‐Diethoxy‐2‐azapropenylium salts 1 are powerful biselectrophiles and react diastereoselectively with enamines of five‐membered ring ketones 2 to yield novel 3‐azabicyclo[3.2.1]oct‐2‐en‐8‐one 5 after hydrolysis of the intermediate iminium salts 3, 4. Some of the iminium salts 3 can be hydrolyzed further to provide the diketo imines 6. With enamines of six‐membered ring ketones 7 the 3‐azabicyclo[3.3.1]non‐2‐en‐9‐ones 10, 11 are obtained after hydrolytic workup. Mixtures of diastereomers 10/11 are found in the case of 7a, b, whereas with 7g — j the endo‐phenyl derivatives 10 are formed exclusively. With the unsymmetrical enamine 7b only one regioisomer is observed. The decalone enamine 12 reacts with 1a to yield the tricyclic iminium salt 13. — The configuration of the bicyclic products has been determined by using NMR spectroscopic techniques (COSY, polarisation transfer by long range couplings); an X‐;Ray analysis of compound 10a is used as basis for the NMR assignments. General rules for the determination of the stereochemistry of these azabicyclic systems by 1H‐NMR shift arguments are derived.
Highly Unsaturated Oligomeric Hydrocarbons: α‐(Phenylethynyl)‐ω‐phenylpoly[1,2‐phenylene(2,1‐ethynediyl)]
Authors: Grubbs Robert H. , Kratz Detlef 
Published: July 2007

AbstractA new set of conjugated oligomers C6H5C…︁C–(1,2‐C6H4C…︁C)n – C6H5 (10; n = 3–7) comprised of acetylene and phenyl units linked together at the 1,2 positions of the aromatic ring is introduced. The facile synthesis of these compounds is achieved through the Pd‐mediated coupling reaction of diiodo‐ and dibromobenzene with the appropriate ethynyl component. Spectroscopic data of the new compounds are discussed in light of electronic conjugation of the extended π system. Thermolysis of oligomers 10 indicates that rearrangement of the triple bonds occurs to form higher conjugated oligo(acenes). The topology of two members (10; n = 2, 3) is confirmed by X‐ray analysis and reveals a propensity for intramolecular π‐stacking of the phenyl rings leading to a helical arrangement.
Trimethylsilylcyanid als Umpolungsreagens, XXI. Regioselektivität der Reaktionen von substituierten α‐Siloxy‐α‐cyanallyl‐Anionen mit α,β‐ungesättigten Ketonen
Authors: Hünig Siegfried , Schäfer Matthias , Schweeberg Walter 
Published: July 2007

Trimethylsilyl Cyanide — A Reagent for Umpolung, XXI. — Regioselectivity of the Reaction between Substituted α‐Siloxy‐α‐cyanoallylic Anions and α,β‐Unsaturated KetonesAmbident allylic anions A and ambident α,β‐unsaturated ketones B combine to the four isomeric products D — G (Scheme 1). Systematic variation of substituents in A, obtained by deprotonation of 1a — c with LDA, and in B (→ 2a — d) as well as variation of the reaction medium and temperature reveals the following results: In diethyl ether (DE) at –78°C the kinetic products 3 (1,2/α) prevail, except with 2d. On warming rearrangement occurs to the thermodynamic products 4 (1,4/α) and/or 6 (1,4/γ) depending strongly on the substituents in both 1 and 2 (Tables 1 – 3). Adducts 6 (1,4/γ) are supposed to be formed by anionic oxy‐Cope rearrangement, since the isolated products 4 rearrange thermally to 6 in rates which reflect the yields of 6 isolated (Table 7). Substitution of DE by THF (and addition of HMPT) strongly favours adducts 4 and 6 (Table 4). With 1a + 2c a series of Lewis acids was also tested (Table 5). With MgBr2 the so far missing 1,2/γ product 5ac becomes the major one. In contrast, ClTi(NEt2)3 preserves the kinetic 1,2/α product 3ac totally even at 0°C. This behaviour is found also with other combinations of 1 + 2 (Table 6). By proper choice of the conditions the reaction between a given pair of 1 and 2 can be steered to produce one of the four possible adducts predominantly.
Sterically Congested Molecules, 6. Lone Electron Pair Donor Quality of the Imino Function: Increased Front Strain and Electronic Substituent Effects on Sterically Accelerated Nitrogen Inversion in Iminocyclopentanes
Authors: Knorr Rudolf , Hoang Thi Phung , Mehlstäubl Johann , Hintermeyer‐;Hilpert Monika , Lüdemann Hans‐;Dietrich , Lang Elmar , Sextl Gerhard , Rattay Wilfried , Bührer Petra 
Published: July 2007

AbstractThe p‐substituents of 2,6‐dimethyl‐N‐(2,2,5,5‐tetramethylcyclopentylidene)anilines are modified without interfering reactions at the CN double bond. The resultant series (5 – 8, 10 – 19) shows a strong (ca. —4.7 kcal/mol) steric acceleration of (E/Z) diastereotopomerization by front strain along the CN double bond but also the usual electronic substituent dependence, characterized by a Hammett s̀p– correlation (Q = +2.7). Conversely, the substituent constant for lithium at the p‐position of 7 may be estimated. The volume of activation is 1.5(8) cm3 mol–1 for 5. The π donor quality of the imino group corresponds to ca. 55 (±8)% of Pπ character as evaluated by spectral (13C NMR of 5 and 13, IR of 13) and reactivity data (of 13).
Alkylierungsreaktionen an 4,5‐Bis(trifluormethyl)‐1,3‐dithiol‐2‐thion — Erste Röntgenstrukturanalyse eines 2‐Alkylthio‐1,3‐dithiolium‐Salzes
Authors: Frasch Markus , Mono Susanne , Pritzkow Hans , Sundermeyer Wolfgang 
Published: July 2007

Alkylation Reactions of 4,5‐Bis(trifluoromethyl)‐1,3‐dithiole‐2‐thione — A First X‐ray Structure Determination of a 2‐Alkylthio‐1,3‐dithiolium SaltThe 2‐alkylthio‐1,3‐dithiolium salts 2a — e have been prepared by reaction of 4,5‐bis(trifluoromethyl)‐1,3‐dithiole‐2‐thione (1) with strong alkylating agents like alkyl perfluorobutanesulfonates or Meerwein salts. The first X‐ray structure determination shows a localized double bond in the ring system combined with a trithiocarbenium ion in 2e.
Organosubstituierte 1,2‐Diborylalkene — Herstellung und Photoisomerisierung
Authors: Köster Roland , Seidel Günter , Wrackmeyer Bernd 
Published: July 2007

Substituted 1,2‐Diborylalkenes — Preparation and PhotoisomerizationThe organo(halo)substituted cis‐1,2‐diborylalkenes cis1‐R2BC(R)C(Et)BEt2 (Z)‐1 to (Z)‐14 are prepared [route I from Na[R3BCCR] and ClBR2; route II from cis1‐R3SnC(R)C(Et)BEt2 and RnBHal3+n′ n0–2; (Z)‐11 (route III): cis1‐ClB(Ph)CHC(Et)BEt2 and Me3SiOMe]. Their 11B‐and 13C‐NMR data show the degree of pz(B)/(CC) π overlap and are compared with the corresponding data of the monoboryl alkenes [(Z)‐15, 16, (Z)‐17, (Z)‐23, (Z)‐24, (Z)‐26], the cis‐2‐boryl‐1‐silylalkenes [(E)‐18, (E)‐19, (E)‐27, (E)‐28], and the cis‐2‐boryl‐1‐stannylalkenes [(E)‐20 to (E)‐22]. — Compounds (Z)‐3, (Z)‐4, (Z)‐9, (E)‐18, and (E)‐19 with one or two nearly coplanar pz(B) and pz(CC) groups (pl1‐R2B) are isomerized by UV irradiation to their equilibria with the corresponding trans isomers (E)‐3, (E)‐4, (E)‐9, (Z)‐18, and (Z)‐19, resp., with one or two nearly orthogonal pz(B) and pz(CC) groups (or1‐R2B). Irradiation of (Z)‐9 gives the isomer pair (Z/E)1‐iso‐9 by a Ph/Et exchange between the two boron atoms.
Kristallstruktur, Festkörperpolymerisation und Ionenleitung in Alkalisalzen ungesättigter Carbonsäuren, 3. Untersuchungen an Lithiumcrotonat, Dilithiumfumarat‐tetrahydrat und Dilithiummaleat‐monohydrat
Authors: Beck Horst P. , Trübenbach Peter 
Published: July 2007

Crystal Structure, Solid‐State Polymerization, and Ionic Conductivity of Alkali Salts of Unsaturated Carboxylic Acids, 3[1]. — Investigations on Lithium Crotonate, Dilithium Fumarate‐Tetrahydrate, and Dilithium Maleate MonohydrateThe structures of lithium crotonate (1), dilithium fumarate tetrahydrate (2), and dilithium maleate monohydrate (3) have been determined by single‐crystal X‐ray diffraction and are discussed in detail in view of the possibility to realize a topochemical polymerization. Compounds 1 and 3 can be polymerized thermally, however this results in a complete breakdown of the crystal structure. Impedance measurements show a weak ionic conductivity in the case of 2. The other compounds and the products of thermal polymerization are isolators with a mean Dkr′ of about 4.0.
Synthesis and Structure of (Hydridosilyl)hydrazines
Authors: Mitzel Norbert W. , Bissinger Peter , Schmidbaur Hubert 
Published: July 2007

AbstractA series of (hydridosilyl)hydrazines 1 – 12 has been prepared from the corresponding chloro‐or bromosilanes and hydrazines in the presence of triethylamine as an auxiliary base. Methylsilyl (MeH2Si‐), dimethylsilyl (Me2HSi‐), and phenylsilyl (PhH2Si‐) groups have been introduced as substituents. NMR spectra (1H, 13C, 15N, 29Si) have been measured and used to determine the rotation barrier about the N — N bond in (PhH2Si)(Me2HSi)N — N(SiHMe2) (9), which has been found to be 75 kJmol–1. The crystal structure of (PhH2Si)2N — N(SiH2Ph2 (7) features each of the two NNSi2 groups as nearly planar, but with a dihedral angle close to orthogonal. Such a structure is also implied for 9 on the basis of the NMR spectra.
Reaktivität von Phosphor‐Ylid‐Derivaten auf Ru31‐Clustern: Umwandlungen durch Alkin‐Insertion
Authors: Heineke Daniel , Vahrenkamp Heinrich 
Published: July 2007

Reactivity of Derivatives of Phosphorus Ylides on Ru3 Clusters: Interconversions due to Alkyne InsertionThe Ru3 clusters with triply bridging organic ligands derived from phosphorus ylides undergo interconversions by insertion of alkynes. The phosphoniomethylidyne‐bridged cluster H2Ru3(CO)9(μ31‐C — PPh3) (1) inserts alkynes either into one Ru — H bond (HCCSiMe3, EtCCEt) forming μ21‐vinyl‐Ru3 complexes or into the Ru3‐μ31‐C unit (HCCSiMe3, PhCCPh) converting it into a μ31‐allyl ligand, e.g. in Ru3(CO)8(PPh3)(μ31‐Ph3P — CCHCSiMe3) (6). HCCPh induces fragmentation of 1. The phosphonio enolate‐bridged clusters HRu3(CO)9‐(μ31‐Ph3P — CH — CO) (2a) and HRu3(CO)8(PPh3)(μ31‐Ph3P — CH — CO) (2b) insert alkynes (HCCPh, PhCCPh, HCCSiMe3, EtCCEt) into the Ru — H bond to form μ21‐vinyl‐bridged derivatives, e.g. Ru3(CO)8(μ31‐Ph3P — CH — CO)(μ21‐RCCHR′) (9). In addition, the alkyne reactions of 2a induce cluster opening with concomitant CO and alkyne incorporation into the organic ligand and formation of an oxaruthenol‐derived trinuclear complex 11, as proved by an X‐ray structure determination of the PhCCPh product 11b. For the cluster H2Ru3(CO)7(PPh3)(μ31‐C6H4Ph2P — C(O)Me) (3) containing an ortho1‐metalated phosphonio ketone ligand, only alkyne insertion into one or two Ru — H units is observed.
Metal Complexes in Inorganic Matrices, 10. Preparation of Phosphanyl‐Spacer‐Substituted Metal Alkoxides (RO)3E‐X‐PPh2 (ETi, Zr; XSpacer)
Authors: Buhler Hermann , Schubert Ulrich 
Published: July 2007

AbstractThe reaction of HPPh2 with (PrO)3E(O2CCHCH2) (ETi, Zr), formed in situ by the reaction of E(OPr)4 with acrylic acid, gives the phosphanylpropionate derivatives (PrO)31‐E(O2CCH2CH2PPh2). The phosphanylacetate derivative (PrO)3Zr(O2CCH2PPh2) was obtained by treatment of (PrO)31‐Zr(O2CCH2Cl) with LiPPh2. (BuO)3Ti(π1‐C5H4[CH2]2PPh2) was prepared by the reaction of Li(C5H4[CH2]2PPh2) with (BuO)31‐TiCl.
Organische Synthesen mit Übergangsmetall‐Komplexen, 63. (β1‐Aminovinyl)carben‐Komplexe und (Alkinyl)aminocarben‐Komplexe von Chrom und Wolfram. — Stereochemie und Isomerisierung
Authors: Aumann Rudolf , Hinterding Peter 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 63[1]. — (β1‐Aminovinyl)carbene complexes and (Alkinyl)aminocarbene Complexes of Chromium and Tungsten. — Stereochemistry and Isomerization(Alkinyl)alkoxycarbene complexes LnMC(OEt)–CCR 3 [LnMCr(CO)5, W(CO)5; RPh, nBu, SiMe3] react with primary amines H2NR1 4 (R1Me, iPr, allyl, CH2Ph, CHMePh) to give (β1‐aminovinyl)carbene complexes LnMC(OEt)–CHCR‐NHR1 (Z)‐5 (by a Michael‐type 3‐addition) together with (alkinyl)aminocarbene complexes anti‐6 (by a 1‐aminolysis). The product ratio (Z)‐5/anti‐6 is strongly influenced by the reaction temperature: at 20°C (Z)‐5 is obtained as the main product, while at –78°C mainly anti‐6 is formed. Both reactions are stereospecifical; they yield 5 in the (Z), and 6 in the anti configuration only. An anti/syn isomerization is achieved by acidic treatment of anti‐6i. The (alkinyl)aminocarbene complex 6a adds EtOH/EtO– albeit much slower than the (alkinyl)alkoxycarbene complex 3a. A NH21‐Enamino carbene complexes (CO)5CrC(OEt)–CHC(NH2)Ph [(Z)‐8a] is obtained on addition of ammonia to 3a at 90°C.
The Stereochemistry of the Trinaphthyl‐Terrylene Conversion
Authors: Anton Ute , Adam Martin , Wagner Manfred , Qi‐Lin Zhou , Müllen Klaus 
Published: July 2007

AbstractAlkylated terrylenes can be synthesized by a twofold cyclization of an appropriately substituted trinaphthyl[1, 11]. In this paper, we consider a special case. The alkyl substitution in the starting material 1 strongly affects the interplanar angle between the naphthalene moieties. After cyclization, the substituents are positioned in the sterically crowded bay region of the title structure 2. The influence of the steric strain on the reactivity of 1 and on the stability of the resulting hydrocarbon 2 is investigated. Special emphasis is placed on the crystal structures of 1 and 2.
[3 + 2] Cycloadditions with Azirines under the Conditions of Photoinduced Electron Transfer: A New Method for the Synthesis of Imidazoles and Heterophanes
Authors: Müller Felix , Mattay Jochen 
Published: July 2007

AbstractWith the opening of azirine rings under the conditions of photoinduced electron transfer a new synthon for the synthesis of heterocycles is available. The formed 2‐azaallenyl radical cation readily reacts with imines to form N1‐substituted imidazoles in reasonable yields. The synthesis of pyrrolophanes and imidazolophanes from bicyclic azirines is possible as well. With oligocyclic azirines complex heteroaromatic systems and even a porphyrin system can be built up.