bluuebunny/crossref_metadata_2025 huggingface dataset:
Unsaturated Hetero Chains, II. 1‐Oxa‐3,5,7‐triaza‐1,3,5,7‐octatetraenes – Syntheses and Structures
Authors: Buhmann Martin , Würthwein Ernst‐Ulrich , Möller Manfred H. , Rodewald U.
Published: July 2007

Three independent routes for the synthesis of the hitherto unknown substituted 1‐oxa‐3,5,7‐triazaoctatetraenes 4 have been developed. Method 1 utilizes N‐lithiated imines 1 and 1,3,5‐oxadiazinium salts 2 for the synthesis of 4b–e. Method 2 takes advantage of the new 6‐alkoxy‐1‐oxa‐3,5‐diazahexatrienes 5, which are allowed to react with imino lithium compounds to produce 4f. Method 3 is based on the combination of the lithiated 1,3‐diazabutadiene 7 with the N‐acylimidate 8 and gives access to 4g–j. Depending on the substitution pattern, the title compounds show ring‐chain tautomerism; in the case of the pentaphenyl system, only the triazine derivative 3a is observed. An X‐ray analysis of 4f reveals a non‐planar structure with (+)‐gauche‐Z‐(–)‐gauche‐Z‐(+)‐gauche conformation, resulting from amide‐like n/π interactions between C=N–π systems and the lone pair of the adjacent nitrogen atoms. Detailed spectroscopic data for all open‐chain and cyclic compounds are given. Quantum mechanical calculations (MP2/6‐31G*//6‐31G*) of model compounds 13 predict that non‐planar isomers with gauche‐configurated subunits are favored by more than 8 kcal/mol over a planar all‐trans structure as in polyenes. Most planar isomers correspond to low‐lying transition states for the rotation around the C–N bonds, but not to local minima, indicating high molecular flexibility of these oligonitrile chains.
all‐Homocalixarene: Carbocyclische Wirtverbindungen mit intra‐ und extraannularen Ligandarmen
Authors: Schmitz Jürgen , Vögtle Fritz , Nieger Martin , Gloe Karsten , Stephan Holger , Heitzsch Olaf , Buschmann Hans‐Jürgen , Hasse Wolfgang , Cammann Karl
Published: July 2007

all‐Homocalixarenes: Carbocyclic Host Compounds with Intra‐ and Extraannular Ligand Arms

Methoxy‐substituted [2n]metacyclophanes 1–10, obtained by Müller‐Röscheisen cyclization, are converted into all‐homocalixarenes 11–20 with free phenolic hydroxy functions. The well‐soluble cyclic pentamer 11 and octamer 14 with endo‐acidic host properties are investigated with regard to guest binding. They exhibit selectivity towards alkaline earth metal ions (Ba2+) in liquid/liquid extraction studies. Some of the macrocyclic oligophenols are transformed into homocalixarenes 21–25 with intra‐ or extraannular oxapropionate groups. The diester 22 and the tetraester 23 are converted into carbocycles 26 and 27 with two and four free oxapropionic acid groups. Complexation properties of the oligoesters in extraction studies and log K values in water are reported. X‐ray structural analyses were performed of the [6]‐, [8]‐ and [4]‐ homocalixarenes 9 and 21, 14 and 23; the inclusion of solvent molecules is proven.
4,5,12,13‐Tetrabromo[2.2]paracyclophane – A New Bis(aryne) Equivalent
Authors: König Burkhard , Knieriem Burkhard , Rauch Karsten , Meijere Armin De
Published: July 2007

The reaction of 2 with nBuLi at –78°C generates aryne intermediates within the aromatic rings of [2.2]paracyclophane which are trapped in Diels‐Alder reactions with dienes like furan, 1,9‐diphenylisobenzofuran, or cyclopentadiene. Reductive deoxygenation with low‐valent titanium reagents or TMSI converts the adducts of furan and isobenzofuran into anti‐[2.2]paracyclophanes 4 and 5, respectively. The reaction of two aryne intermediates with [2.2](2,5)furanophane (7) yields 8 with three [2.2]paracyclophane units arranged in a stair‐like fashion; yet, in this compound the highly shielded oxygen atoms cannot be removed anymore by reduction.
A Soluble Benzodifluoranthene Derivative by Dehydration of an Oxygen‐Bridged Precursor
Authors: Schirmer Heike , Schlüter Arnulf‐Dieter , Enkelmann Volker
Published: July 2007

Synthesis and characterization of the alkyl chain‐substituted benzodifluoranthene 6 are described. The final synthetic step involves an acid‐promoted dehydration whose conversion is determined to be quantitative. The solubilities of compounds 4e, 5, and 6 are qualitatively correlated with structural features. The molecular structure of 6 in the crystal is elucidated by an X‐ray structure analysis.
Synthese mittlerer und großer Ringe, XXXIV. Stereoselektive Synthese überbrückter und verzweigter Methyl‐desoxyfuranoside aus 3,6‐Hexanooxepin‐4,5‐dicarbonsäure‐dimethylester
Authors: Tochtermann Werner , Popp Brigitta , Mattauch Anne‐Katrin , Peters Eva‐Maria , Peters Karl , Schnering Hans Georg Von
Published: July 2007

Syntheses of Medium and Large Rings, XXXIV[1,2]. – Stereoselective Synthesis of Bridged and Branched Methyl Deoxyfuranosides from Dimethyl 3,6‐Hexanooxepine‐4,5‐dicarboxylate

The stereoselective synthesis of the bridged methyl furanosides 4–8 with four, five, and six stereogenic centers is described. The reaction sequence starts with the addition of methanol to the oxepine 1. The photochemical electrocyclic ring closure of 2 gives the cyclobutene 3. Ruthenium tetraoxide oxidation of 3 leads to the title compound 4 that is further converted to 5–8 by stereoselective reductions.
Soluble (Phthalocyaninato)ruthenium(II) Phosphane Complexes
Authors: Bulatov Alexander , Knecht Siegfried , Subramanian L. R. , Hanack Michael
Published: July 2007

Hitherto unknown ruthenium phthalocyanine complexes with phosphane ligands – PcRu(PEt2Ph)2 (1) and PcRu(PPh3)2 (2) – soluble in common organic solvents were prepared. Two methods were used for their synthesis: 1) Reaction of phthalonitrile with [Ru2Cl3(PEt2Ph)6]Cl in n‐pentanol in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) and 2) reaction of PcRu with the corresponding phosphanes. The products 1 and 2 were characterized by their IR, UV/Vis, FD‐MS, and 1H‐NMR data.
Synthese und Struktur des ersten oligomeren cyclischen Dimethylsilyl‐substituierten Carbodiimids
Authors: Kienzle Andreas , Aldinger F. , Obermeyer Axel , Simon Arndt , Riedel Ralf
Published: July 2007

Synthesis and Structure of the First Oligomeric Cyclic Dimethylsilyl‐Substituted Carbodiimide

New oligomeric cyclic silylcarbodiimides 1–3 are synthesised by the reaction of the respective dichlorosilanes with cyanamide. From the resulting reaction mixture with dichloro‐dimethylsilane the tetrameric compound of the hypothetical [(CH3)2Si=N–CN] is isolated. In this molecule sixteen atoms build a nearly planar ring structure with a special steric arrangement of the groups. This oligomeric silylcarbodiimides present a new kind of precursors for the pyrolytic synthesis of ceramics in the ternary system SiCN.
Synthese eines 2H‐Inden‐2‐on‐Dianion‐Komplexes durch Reduktion eines metallgebundenen Dicarbens
Authors: Öfele Karl , Dyckhoff Florian , Krist Herbert G.
Published: July 2007

Synthesis of a 2H‐Inden‐2‐one Complex by Reduction of a Metal‐Bound Dicarbene

Herrn Professor Dr. Dr. h. c. mult. E. O. Fischer zum 75. Geburtstag gewidmet.

Tetracarbonylchromium complexes with chelating o‐phenylene‐biscarbene ligands are reduced in two steps as shown by cyclic voltammetry. The first step corresponds to a reversible one‐electron transfer, the second to an irreversible one‐electron reduction followed by a rapid rearrangement of the biscarbene ligand into an η5‐bound 2H‐inden‐2‐one system by a twofold C–C coupling with one CO ligand. By reaction of tetracarbonyl[o‐phenylenebis(methoxymethylene)]chromium (4) with sodium amalgam in acetonitrile the diamagnetic tricarbonyl(η5‐1,3‐dimethoxy‐2‐indenone)chromium dianion [6]2– is formed as the final reduction product. Its structure was determined by NMR and IR spectroscopy.
C*Ru‐Thiolkomplexe, II[1]. Adduktbildung in [Cp*RuII(π‐SR)]2 und [Cp*Ru(C6F5)(μ‐SC6F5)(μ‐S)RuCp*]. Molekülstruktur von cis‐[Cp*Ru(μ2‐StBu)(CO)]2 und [Cp*Ru(C6F5)(μ‐SC6F5)(μ‐S)RuCp*]
Authors: Hörnig Andreas , Rietmann Christian , Englert Ulli , Wagner Trixie , Kölle Ulrich
Published: July 2007

Cp*Ru Thiol Complexes, II[1]. – Adduct Formation in [Cp*RuII(μ‐SR)]2 and Cp*Ru(C6F5)(μ‐SC6F5)(μ‐S)RuCp*]. Molecular Structure of cis‐[Cp*Ru(μ2‐StBu)(CO)]2 and [Cp*Ru(C6F5)(μ‐SC6F5)(μ‐S)RuCp*]

Reaction of [Cp*Ru(μ‐OMe)]2 (1) with thiols RSH gave the sulfur analogues to 1, [Cp*Ru(μ‐SR)]2 (2), and with PhSH after carbonylation cis‐[Cp*Ru(μ‐SPh)(CO)]2 (11). C6F5SH as thiol reacts with 1 to form [Cp*Ru(C6F5)(μ‐SC6F5)(μ‐S)RuCp*] (3a) with oxidative migration of a C6F5 group from S to Ru. For elucidation of the constitutions molecular structures of 3a and cis‐[Cp*Ru(μ‐StBu)(CO)] (10) were determined by single crystal X‐ray diffraction. Adduct formation and bridge cleavage of the doubly coordinatively unsaturated dinuclear complexes 2 and singly unsaturated complex 3 with donor and acceptor ligands is investigated and the donor/acceptor character of the Ru centers in thiol complexes 2 compared to those in 1. Substitution reactions of [{Cp*Ru(μ‐OMe)}2(dppm)] (4) with PhSH and C6F5SH yield complexes [{Cp*Ru(μ‐SR)}2(dppm)] (R = Ph 5, C6F5 6).
Synthese und Röntgenstrukturanalyse einer neuartigen gemischtvalenten zwitterionischen Diphosphor‐Fluor‐Verbindung
Authors: Dunmur Richard E. , Thönnessen Holger , Müller Christian , Farkens Michael , Fischer Axel , Jones Peter G. , Schmutzler Reinhard
Published: July 2007

Synthesis and X‐Ray Crystal Structure Analysis of a Novel Mixed‐Valent Zwitterionic Diphosphorus Fluoro Compound

The cyclic zwitterionic λ6P,λ4P‐diphosphorus compound F5P–N(Me)P+ [N(Me)C(=O)]2NMe (3), which contains a biuret system, was synthesized by the reaction of (MeNPF3)2 (1) with MeNCO (2). Compound 3 was characterized by means of 1H‐, 13C‐, 19F‐ and 31P‐NMR spectroscopy, IR spectroscopy, and mass spectrometry. A single‐crystal X‐ray structure determination revealed the presence of two independent formula units, in which the –N(Me)PF5 side chains display widely differing conformations.
Gasphasenthermolyse von Pyrazolinen, 3[1]. Elektronische Struktur und Gasphasenpyrolyse von 4‐substituierten 3,5,5‐Trialkyl‐3,5‐dihydro‐4H‐1,2,3‐triazolen untersucht durch Photoelektronenspektroskopie und semiempirische Rechnungen
Authors: Kindermann Markus Karl , Kowski Klaus , Rademacher Paul , Quast Helmut
Published: July 2007

Gas‐Phase Thermolysis of Pyrazolines, 3[1]. – Electronic Structure and Gas‐Phase Pyrolysis of 4‐Substituted 3,5,5‐Trialkyl‐3,5‐dihydro‐4H‐1,2,3‐triazoles Studied by Photoelectron Spectroscopy and Semiempirical Calculations

The PE spectra of the 3,5‐dihydro‐4H‐1,2,3‐triazoles 1–3 have been recorded. The ionization potentials have been assigned to molecular orbitals on the basis of MNDO, AM1, and PM3 calculations. The most important occupied MOs are characterized as πNNN, πC=X (X = O, NCH3, CH2), nN‐3, nNN+, nNN– and nX. The gas‐phase thermolyses of 1–3 have been studied by PE‐controlled real‐time gas analysis. After extrusion of molecular nitrogen, the remaining reactive species cyclize to three‐membered rings. At higher temperatures and in flash vacuum pyrolysis, subsequent reactions lead to smaller acyclic compounds.
Synthese mittlerer und großer Ringe, XXXV[1]. Funktionalisierte Hydroazulenone durch transannulare Cyclisierungen von 10‐Oxo‐3,6‐hexanooxepin‐4,5‐dicarbonsäure‐dimethylester
Authors: Tochtermann Werner , Habeck Thorsten , Wolff Christian , Peters Eva‐Maria , Peters Karl , Schnering Hans Georg Von
Published: July 2007

Synthesis of Medium and Large Rings, XXXV[1]. – Functionalized Hydroazulenones by Transannular Cyclizations of Dimethyl 10‐Oxo‐3,6‐hexanooxepine‐4,5‐dicarboxylate

Two differently bridged hydroazulenones 2 and 3 are obtained in 69 and 61% yield, respectively, by treatment of the title compound 1 with sodium methoxide. The course of these intramolecular transannular cyclizations strongly depends on the amount of added base. 2 is hydrogenated to the ketones 9 and 10. Oxidative cleavage of the enol ether double bond of 3 and 10 leads to the octahydroazulene‐1,6‐dione 11 and to the decahydroazulene‐3,8‐dione 12, respectively.
Photochemical and Thermal Rearrangement of Acyl‐Substituted Quinone Methides, Accessible by Dimethyldioxirane Oxidation of Benzofurans and Subsequent Valence Isomerization of the Resulting Epoxides
Authors: Adam Waldemar , Sauter Markus
Published: July 2007

The photoisomerization of quinone methides 3 to benzocycloheptafuran 4 and the thermolysis of the latter to xanthenes 5 are reported. The quinone methides 3 are accessible by dimethyldioxirane oxidation and subsequent valence isomerization of the resulting benzofuran epoxides 2. On irradiation (λ > 400 nm), the quinone methides 3 rearrange by cyclization to the corresponding norcaradiene, and ring enlargement affords the benzocycloheptafurans 4. Thermolysis of the cycloheptatrienes 4 leads to the xanthenes 5, first by cycloreversion to the norcaradienes, followed by electrocyclization to the chromenes and tautomerization of the latter. The new cycloheptatrienes 4 and xanthenes 5 were fully characterized.
Zur Energiedelle des orthogonalen Trimethylenmethans. – 1‐Methylen‐2‐phenylcyclopropan‐Thermolyse
Authors: Roth Wolfgang R. , Winzer Markus , Lennartz Hans‐Werner , Boese Roland
Published: July 2007

Energy Well of the Orthogonal Trimethylenemethane. – 1‐Methylene‐2‐phenylcyclopropane Thermolysis

From the heat of hydrogenation of 5, the activation enthalpy for the racemization of the title compound, and the oxygen dependance of the trapping rate of the intermediate diradical 8 the energy profile for the degenerate methylene‐cyclopropane rearrangement can be constructed, which leads to heats of formation for the triplet and singlet state of the diradical 8 of ΔHf0 · 93.9 and 95.6 kcal mol–1, respectively.
NMR Spectroscopy of Organolithium Compounds, XV[1]. Two‐Dimensional 6Li,1H‐NMR Shift Correlation by Multiple Quantum Spectroscopy and Polarization Transfer: New Tools for Structural Research in the Field of Organolithium Compounds
Authors: Mons Hans‐Egbert , Günther Harald , Maercker Adalbert
Published: July 2007

Sizable scalar 6Li,1H spin‐spin coupling constants have been observed for the new dilithio compound (Z)‐2‐lithio‐1‐(o‐lithiophenyl)ethene (3) which allow an assignment of the two non‐equivalent 6Li resonance signals measured for the dimer of 3. Two‐dimensional 6Li,1H shift correlation experiments based on multiple quantum spectroscopy as well as on polarization transfer are introduced as new tools for structural research in the field of organolithium compounds.
Stereoselektive Synthese von 3‐substituierten Cyclobutanolen und Folgeprodukten
Authors: Dehmlow Eckehard V. , Büker Sabine
Published: July 2007

Stereoselective Synthesis of 3‐Substituted Cyclobutanols and Products Derived Therefrom

3‐Substituted cyclobutanones 2 are prepared by alkene/dichloroketene cycloadditions and subsequent dehalogenation. Reduction with LiAlH(OtBu)3 furnishes cis‐cyclobutanols 3 in 95–100% selectivity. Mitsunobu inversion turned out to be the only practical method to get trans isomers 4 in high selectivity. A stereoselective cyclobutanol→bromocyclobutane conversion could be achieved only by a modified Mitsunobu reaction. Cross coupling between zinc derivatives of bromocyclobutanes 9 and aromatic bromides is not stereoselective.
Anwendungen der Phasentransfer‐Katalyse, 61[1]. Notiz über die Steuerung von O‐/C‐Alkylierungen mit Hilfe von Phasentransfer‐Katalysatoren
Authors: Dehmlow Eckehard V. , Richter Rolf
Published: July 2007

Applications of Phase Transfer Catalysis, 61[1]. – Directing Effects on O‐ vs. C‐Alkylations by Phase Transfer Catalysts

Strong catalyst effects on the O‐ vs. C‐alkylation ratio of 1,1‐dimethylindan‐2‐one (4) by dimethyl sulfate are found. They differ in the two consecutive alkylation steps and range between <1 and ≈60. No such catalyst influence exists in the methylation of 2‐methylindane‐1,3‐dione (1).
4H,5H‐Benzo[1,2‐c;3,4‐c′]bis[1,2,5]thiadiazole‐4,5‐dione
Authors: Mataka Shuntaro , Ikezaki Youji , Shimojo Yoshiro , Tashiro Masashi , Tori‐I Akiyoshi
Published: July 2007

4H,5H‐Benzo[1,2‐c;3,4‐c′]bis[1,2,5]thiadiazole‐4,5‐dione (2) was prepared by oxidation of 4‐bromobenzobis[1,2,5]thiadiazole (3d) with nitric acid and subsequently converted into 5,6‐dihydroxybenzenetetramine dihydrochloride (10) and the dimethoxy derivative 13. Treatment of the 4‐hydroxy derivative 3a with chromium(VI) reagents led to cleavage of the benzene ring, giving dicarboxylic acid 4.
Allenkomplexe des Titanocens und Zirkonocens: Darstellung und Reaktivität
Authors: Binger Paul , Langhauser Franz , Wedemann Petra , Gabor Barbara , Mynott Richard , Krüger Carl
Published: July 2007

Allene Complexes of Titanocene and Zirconocene: Synthesis and Reactivity

Bis(trimethylphosphane)titanocene (1) and (η2‐Ethene)(trimethylphosphane)titanocene (2) react with one equivalent of allene (3a), phenylallene (3b), 1,1‐dimethylallene (3c), and 1,1‐diphenylallene (3d) readily by displacement of one trimethylphosphane from 1 and of ethene from 2 to give regiospecifically the corresponding (η2‐allene)(trimethylphosphane)‐titanocene complexes 4a–d in good yields. From (η2‐1‐butene)(trimethylphosphane)zirconocene (6) and 3d the corresponding (1,2‐η2‐3,3‐diphenylallene)zirconocene complex 7d is obtained in the same manner. The structures of these new allene complexes have been established unambiguously by 1H‐ and 13C‐NMR‐spectroscopy. A crystal structure analysis of the titanocene complex 4d confirms the spectroscopic structure determination. All the above mentioned allene‐metallocene complexes consume readily a second equivalent of the allene derivatives to produce, in most cases, regiospecifically the corresponding 1‐metalla‐2,5‐dimethylenecyclopentane derivatives 5a–d (M = Ti) and 8c, d (M = Zr); only the (allene)zirconocene complex 7a gives rise to a 1:1 mixture of the regioisomers 8a and 9. More conveniently 5a–d and 8c, d are synthesized directly from metallocene dichloride and the corresponding allenes 3.
Chlorotrioxorhenium. Neue Synthesen, Reaktionen und Derivate
Authors: Herrmann Wolfgang A. , Kühn Fritz E. , Romão Carlos C. , Kleine Matthias , Mink Janos
Published: July 2007

Multiple Bonds between Main Group Elements and Transition Metals, CXXIX[1]. — Chlorotrioxorhenium. Novel Syntheses, Reactions, and Derivatives

Chlorotrioxorhenium (1a) and homologs of formula X‐ReO3 (1b–e) are generated from Re2O7 and either ZnX2, (n ‐ C4H9)3SnX, [(n‐C4H9)4N]X, or [(C6H5)4P]X in clean reactions. Compounds 1a–f form with stable six‐coordinate adducts XReO3 ·L (2a–f, 3a, 4a, 5a: L = N,N′‐ligand) upon addition of the free ligand L, e.g. 2,2′‐bipyridine. 1a is readily alkylated by means of SnR4 or ZnR2 to form organorhenium(VII) oxides in good yields. These synthetic routes have the advantage to proceed under very mild conditions. The adducts of 2,2′‐bipyridine with halorhenium(VII) oxides show characteristic thermogravimetric (TG) behavior that reflects the volatility of the uncoordinated complexes X‐ReO3.
Synthese und Charakterisierung von Gallium‐Phosphor‐Heterocubanen
Authors: Niediek Katharina , Neumüller Bernhard
Published: July 2007

Synthesis and Characterization of Gallium‐Phosphorus Heterocubanes

The reaction of iPrGaCl2 with tBuPLi2 in Et2O at −78°C gives the heterocubane [iPrGaP(tBu)]4 (1) by using the “dilution principle”. {(MesGa)3[GaP(H)tBu][P(tBu)]4} (2) was formed, when three equivalents of MesGaCl2 and one equivalent of GaCl3 in THF at −78°C were treated with 5 equivalents of tBuPLi2. Compounds 1 and 2 were characterized by NMR, IR, and MS techniques as well as by X‐ray structure determination. The heterocubane molecules of 1 are disordered in the crystal; every atom site of the central cubical frame work is occupied by gallium and phosphorus atoms (occupation factor 0.5). The structure of 2 contains two crystallographically unique molecules, which are not disordered because of the additional P(H)tBu groups.
Ein neuer Zugang zum ikosaedrischen closo‐NB11‐Gerüst
Authors: Schneider Lenka , Englert Ulli , Paetzold Peter
Published: July 2007

A Novel Access to the Icosahedral closo NB11 Skeleton

At 200°C, the open skeleton of NB9H12 is closed to the icosahedral skeleton of NB11H10Y (3) by the action of three equivalents of Et3N · BH3, whereby one equivalent forms a bridge Y = BH2NEt2CH2CH2 between the adjacent cluster atoms N1 and B2; the product 3 crystallizes in the space group P¯. With L · BH3 (L = NMe3, SMe2) instead of Et3N · BH3, the nido‐borane NB9H12 is transformed into the closo‐borane (LBH2)NB11H11 (4a, b) at 140°C. By allowing tBuNH2 to react with 4b, the N‐bonded ligand Me2SBH2 is removed with formation of the aza‐closo‐dodecaborate [t BuNH3] [NB11H11], thus opening a new route to closo‐NB11H12.
Zur Kenntnis der carbonylmethylenierenden Molybdän‐Aluminium‐ und Wolfram‐Aluminium‐μ‐methylen‐Komplexe
Authors: Kauffmann Thomas , Enk Manfred , Fiegenbaum Petra , Hansmersmann Ursula , Kaschube Wilfried , Papenberg Michael , Toliopoulos Euripides , Welke Siegfried
Published: July 2007

Organomolybdenum and Organotungsten Reagents, VI[1]. On the Carbonyl‐Methylenating Molybdenum‐Aluminium and Tungsten‐Aluminium μ‐Methylene Complexes

MoCl5, MoOCl3(THF)2, MoO2Cl2, (MeO)2MoCl3, (MeO)4MoCl, WOCl3(THF)2, and WOCl4 form carbonyl‐methylenating complexes and 1–2 equiv. of CH4 by reacting with 2 equiv. of Me3Al. These thermolabile complexes are prepared in solution and differ in their properties (e.g. ability to transfer mostly more than 1 CH2 unit per Mo or W atom in carbonyl‐olefinating processes; high sensitivity to water, no hydroxy ketone affinity) from the carbonyl‐olefinating 1,3‐dimetallacyclobutanes (M = Mo, W) and are believed to be mono‐ and bicyclic analogs (e.g. hypothic structures 3, 6–8) of the Tebbe reagent (1), containing Mo‐μCH2 Al or W ‐μCH2 Al groups, respectively. Analogous complexes seem to be produced by treating MoOCl3(THF)2 with 2 Me2Zn or (MeO)2MoCl3 and (MeO)4MoCl with 2 MeMgBr in each case. Unlike the dimeric and, due to a MoMo bond, diamagnetic Mo derivatives (MeO)2MoCl3 and (MeO)4MoCl (according to 1HNMR structure 9 or 10 and 11 or 12, respectively) the complexes obtained by the reactions (MeO)2MoCl3 + 2 Me3Al and (MeO)4MoCl + 2 Me3Al are paramagnetic, indicating the expected absence of a MoMo bond. The 1HNMR spectrum of the reaction mixture obtained by treating the MoVI derivative MoO2Cl2 with 2 Me3Al in THF shows various signals for μCH2 groups, whereas signals of t‐CH2 ligands are missing (t = terminal). In analogy to 1 the carbonyl‐olefinating activity of the MoAl and WAl reagents is activated by the addition of 2 equiv. of HMPA. Treatment of PhCOCH2NEt2 (19) with {MoO2Cl2 + 2 Me3Al} leads to carbonyl olefination with formation of 20 and also to α‐methylation with formation of PhCOCH(Me)‐NEt2 (21), pointing to the intermediate formation of a t‐CH2Mo ligand. {MoO2Cl2 + 2 Me3Al + 2 HMPA} has found to be the best reagent for the carbonyl olefination of aldehydes, whereas {WOCl3(THF)2 + 2 Me3Al + 2 HMPA} was optimal for ketones. In 1:1 reactions both reagents normally give better yields than the Tebbe reagent. By applying (WOCl3(THF)2 + 2 Me3Al} and {MoO2Cl2 + 2 Me3Al} on ketones 16–18 an interesting neighbour group effect of electron donor atoms in the δ position to the keto group was observed.
Relative Reactivities of Alkyl Chlorides under Friedel‐Crafts Conditions
Authors: Dau‐Schmidt Jan‐Peter , Mayr Herbert
Published: July 2007

Competition experiments have been performed to determine the relative reactivities of 23 alkyl chlorides toward allyltrimethylsilane in the presence of catalytic amounts of ZnCl2.The krel scale spans over 11 orders of magnitude from 1‐adamantyl chloride (least reactive) to bis(p‐methoxyphenyl)methyl chloride (most reactive compound). A fair correlation between the alkylating ability and the SN1 reactivity in solvolysis reactions is found, thus providing a quantitative basis for our long‐standing working hypothesis that Lewis acid‐catalyzed additions of alkyl halides to CC multiple bonds only yield 1:1 products if the reactants ionize faster than the products. Trityl chlorides do not follow this correlation and are 105 times less reactive than predicted from their SN1 reactivities.
(1α,2α, 7α,8α,12α,17α,18α,19α)‐Heptacyclo[17.3.1.18,12.05,23.06,18.07,17.016,24]‐tetracosa‐5(23),16(24)‐dien, ein hyperstabiles Alken
Authors: Boldt Peter , Köpper Holger , Trog Rolf‐Stefan , Döring Detlev , Jones Peter G.
Published: July 2007

(1α,6α,7α,8α,12α,17α,18α,19α)‐Heptacyclo[17.3.1.18,12.05,23.06,18.07,17.016,24]tetracosa‐5(23),16(24)‐diene, a Hyperstable Alkene

Hydrogenation of the cis‐photodimer 1 of acenaphthylene yields the title compound 2, which, though still containing two double bonds, undergoes no further hydrogenation or reaction with bromine for steric reasons. The cyclobutane ring of 2 shows strong steric distortions as revealed by X‐ray analysis as well as by force‐field and semiempirical MO calculations.
Syntheses and Properties of New Quinone‐Bridged Diphenyl‐ and Tetraphenylporphyrins
Authors: Staab Heinz A. , Carell Thomas , Döhling Annelie
Published: July 2007

Syntheses and spectroscopic properties of the porphyrin‐quinone cyclophanes 1, 2 and 3 of which structural and/or conformational studies have recently reported[1] are described. Physical properties related to photoinduced electron‐transfer reactions like redox potentials, absorption and emission spectra were determined for these compounds.
Zinc Complexes of Porphyrin‐Quinone Cyclophanes: Syntheses, Structures and Electron‐Transfer‐Related Properties
Authors: Staab Heinz A. , Anders Claus Krieger, Christine , Rückemann Andreas
Published: July 2007

In order to increase the driving force for photoinduced electron‐transfer reactions of porphyrin‐quinone cyclophanes, the zinc complexes 3a‐e and 4a‐e were prepared from the corresponding cyclophanes of the 1 and 2 series. Electron‐transfer‐related properties like redox potentials and fluorescence spectra were determined for 3a‐e and 4a‐e. The X‐ray structure analysis of 4a indicates that for the very fast and solvent‐independent electron transfer in these systems a specific mechanism involving an interaction of a quinone carbonyl group with the zinc might be considered as an alternative to through‐space electron‐transfer.
Gas‐Phase Kinetics of the Pyrolysis of Some 3,3‐Dimethyl‐1‐(trimethylsilyl)‐cyclopropenes — Unexpected Product Distribution in the Cyclopropene Rearrangement
Authors: Walsh Robin , Untiedt Sven , Meijere Armin De
Published: July 2007

The gas‐phase pyrolyses of 1,3,3‐trimethyl‐2‐(trimethylsilyl)‐cyclopropene (9), 3,3‐dimethyl‐1,2‐bis(trimethylsilyl)cyclopropene

Reactant
log (A/s−1)
Ea/kj mol−1
(kcal mol−1)

9
13.41 ± 0.22
192.1 ± 2.5
(45.9 ± 0.6)

10
13.54 ± 0.19
184.4 ± 2.1
(44.1 ± 0.5)

11
12.17 ± 0.38
124.6 ± 3.1
(29.8 ± 0.7)

(10), and 3,3‐dimethyl‐1‐(methylthio)‐2‐(trimethylsilyl)cyclopropene (11) have been studied, and the pressure‐independent Arrhenius parameters listed in the table were obtained. All three rearrangements are homogeneous, first‐order and unimolecular reactions. Rather surprisingly all reactions give the corresponding isomeric allenes as the main products. Amongst possible mechanisms discussed, 10 is proposed to react via a cyclopropylidene intermediate, whilst the results for 9 and 11 throw light on the relative importance of the diradical‐ and vinylcarbene‐type intermediates produced by cyclopropene ring opening.
Übergangsmetall‐Silyl‐Komplexe, 48. Synthese neuartiger heteronuklearer Silyl‐Zweikernkomplexe (OC)3(R3Si)Fe(μ‐PR′R″)Pt(1,5‐COD)(Fe‐Pt), Phosphan‐Austauschreaktionen an (OC)3 (R3Si)Fe(μ‐PR′R″)Pt(PPh3)2(Fe ‐ Pt) und Darstellung der Dihydrido‐Komplexe [(OC)3Fe(μ‐PPh2)(μ‐H)2Pt(PR3)2][BF4](Fe ‐ Pt)
Authors: Knorr Michael , Stährfeldt Thomas , Braunstein Pierre , Reinhard Georg , Hauenstein Peter , Mayer Brigitte , Schubert Ulrich , Khan Saeed , Kaesz Herbert D.
Published: July 2007

Transition Metal Silyl Complexes, 48[1]. ‐ Synthesis of the New Heterobimetallic Dinuclear Silyl Complexes (OC)3(R3Si)‐Fe(μ‐PR′R″)Pt(1,5‐COD)(Fe‐Pt), Phosphane Exchange Reactions of (OC)3(R3Si)Fe(μ‐PR′R″)Pt(PPh3)2(Fe‐Pt), and Preparation of the Dihydrido complexes [(OC)3Fe(μ‐PPh2)(μ‐H)2Pt(PR3)2][BF4](Fe‐Pt)

The dinuclear, silyl‐substituted complexes (OC)3(R3Si)Fe(μ‐PR′r″)Pt(1,5‐COD) (1) [μ‐PR′R″ = PPh2, PCY2, PHPh; SiR3 = SiPh3, Si(OMe)3] were prepared in high yields by the oxidative addition of the hydrido complexes (OC)3(PHR′R″)Fe(H)‐SiR3 to Pt(1,5‐COD)2. Upon reaction of (OC)3(R3Si)Fe(μ‐PR′R″)Pt(PPh3)2 [μ‐PR′R″ = PPh2, PHCy; SiR3 = SiPh3, SiPh2Me, SiPhMeCl, Si(OMe)3] with two equivalents of PR (PMe3, PBu3, PEt3) or with one equivalent of chelating di‐phosphanes (vdpp, dppe, dppm) both PPh3 ligands are displaced, and (OC)3(R3Si)Fe(μ‐PR′R″)Pt(PR)2 or (OC)3(R3Si)‐Fe(μ‐PR′R″)Pt[(PPh2)2X] (X = CCH2, C2H4, CH2) are formed, respectively. When one equivalent of PMe3 is used, only the PPh3 ligand trans to the μ‐PPh2 bridge is substituted, and (OC)3(Ph3Si)Fe(μ‐PPh2)Pt(PPh3)(PMe3 is formed. The 1,5‐COD ligand in 1 is displaced by P(OR)3 to give (OC)3‐(Ph3Si)Fe(μ‐PPh2)Pt[P(OR)3]2 (R = Me, Ph). The complexes (OC)3(Ph3Si)Fe(μ‐PPh2)Pt(PMe3)2and (OC)3(Ph3Si)Fe(μ‐PPh2)Pt[(PPh2)2CCH2] were characterized by X‐ray structure analysis. The short Fe‐Si distances [233.0(2) and 235.6(3) pm] and the infrared v(CO) absorptions indicate that the Fe‐Pt bonds are quite polar. Protonation of (OC)3(Me2‐PhSi)Fe(μPPh2)Pt(PPh3)2 with CF3COOH gives the hydrido‐bridged complex [(OC)3(Me2PhSi)Fe(μ‐PPh2)(μ‐H)Pt‐(PPh3)2][O2CCF3]. Upon addition of an excess of HBF4 · Et2O to (OC)3(R3Si)Fe(μ‐PPh2)Pt(PPh3)2 (R = Ph, OMe), (OC)3‐Si)Fe(μ‐PPh2)Pt[Pt[P(OMe)3]2 or (OC)3(Ph2MeSi)Fe(μ‐PPh2)‐Pt(dppe) R3SiF is split, and the corresponding μ‐dihydrido complexes [(OC)3Fe(μ‐PPh2)(μ‐H)2Pt(PR3)2][BF4] are obtained.
Synthesis and Characterization of Phthalocyanines Containing Four 14‐Membered Tetraaza Macrocycles
Authors: Koçak Makbule , Güek Ayşegül , Gül Ahmet , Bekaroǧlu Özer
Published: July 2007

Metal phthalocyanines (M = Cu, Ni, Co, SnCl2) 3–6 containing four 14‐membered tetraaza macrocycles have been prepared. Detosylation of the aza functions has provided donor sites for binding four Ni2+ ions giving a pentanuclear complex which is extremely soluble in polar solvents. The mass spectrum of the [hexadecakis(N‐p‐tosyl)‐tetrakis‐macrocycle‐phthalocyaninato]copper(II)3 is described
Thermal and Photochemical Rearrangement of 3‐Substituted 2‐Methylbenzofuran Epoxides and Their Valence‐Isomeric Quinone Methides
Authors: Adam Waldemar , Käb Günther , Sauter Markus
Published: July 2007

The dimethyldioxirane oxidation of the 3‐substituted 2‐methylbenzofurans 1 [1a: 3(E)‐styryl, 1b: 3‐acetoxy, 1c: 3‐(tert‐butyldimethylsilyloxy)] is reported. Only quinone methide 3a, none of the benzofuran epoxides 2a–c, could be detected by 1H‐ and 13C‐NMR spectroscopy at low temperature (−30°C), which on photoisomerization led to chromene 7a. The benzofuran‐3‐ones 5b, c and the α‐diketone 6c are presumably formed by thermal isomerization of the transient benzofuran epoxides 2b, c and quinone methide 3c.
Transanulare Wechselwirkungen in difunktionellen mittleren Ringen, 4. Spektroskopische und theoretische Untersuchungen an bicyclischen Boraalkenen
Authors: Rademacher Paul , Wiesmann Reinhard F.
Published: July 2007

Transanular Interactions in Difunctional Medium Rings, 4[1]. — Spectroscopic and Theoretical Investigations on Bicyclic Boraalkenes

The 3‐borabicyclo[3.3.1]nonene and ‐nonane derivatives 3 and 5 with an endo‐ or exocyclic CC double bond, respectively, have been synthesized as well as the corresponding monofunctional compounds bicyclo[3.3.1]non‐2‐ene (1), 3‐methylenebicyclo[3.3.1]nonane (2), and the 3‐borabicyclo[3.3.1]nonanes 4. The compounds were investigated by PE, 13C‐ and 11B‐NMR spectroscopy. In addition, molecular mechanics and semi‐empirical quantum‐chemical calculations have been performed. Although the transanular distances in both groups of compounds vary little, the difunctional compounds with an exocyclic double bond (5) show distinct transanular interactions whereas in the compounds with an endocyclic double bond (3) such effects are virtually absent. While the theoretical methods proved to be insufficient for the investigation of transanular interactions, PE and 11B‐NMR spectroscopy were well suited for this study.
On the Reaction of 1‐Aza‐2‐azoniaallene Salts with Acetylenes
Authors: Wang Quanrui , Al‐Talib Mahmoud , Jochims Johannes C.
Published: July 2007

1‐Aza‐2‐azoniaallene cations 3, prepared in situ from geminal chloro(alkylazo) compounds 2, react with acetylenes 4 to give either 1H‐pyrazolium salts 6 or 4H‐pyrazolium salts 7 or mixtures of both. 4H‐Pyrazolium salts with a hydrogen atom attached to C(4) rearrange to the protonated 1H‐pyrazoles 8, from which the free bases 9 are obtained upon treatment with aqueous NaOH. According to AM1 calculations the cycloaddition of acetylenes to 1‐aza‐2‐azoniaallene cations is a concerted process, which can be classified as a “1,3‐dipolar cycloaddition with reverse electron demand”. The cycloaddition forming the intermediates 5 is followed by an [1,2] alkyl shift to furnish the final products 6–8. The direction of the [1,2] shift has been found to be governed by subtle steric effects.
Synthesis and Structural Characterization of the Bent Nitrosyl Organometallic Complex [NBu4][Pt(C6Cl5)2Cl2(NO)]
Authors: Forniés Juan , Menjón Babil , Sanz‐Carrillo Rosa María , Tomás Milagros
Published: July 2007

The title complex has been prepared in 36% yield by reaction of [NBu4]2[trans‐Pt(C6Cl5)2Cl2] with NOClO4 (1:1) in CH2Cl2. The anion exhibits an almost tetragonal‐pyramidal geometry (X‐ray analysis), the platinum atom being virtually located in the basal plane and the NO ligand occupying the apical position. The PtNO unit is bent [119.5(8)°].
Alkyleisen‐ und Alkylcobalt‐Reagenzien, IX. Umlagerung aliphatischer terminaler Epoxide zu Methylketonen durch Eisenalkyl‐Reagenzien statt durch Co2(CO)8 oder Edelmetallkatalysatoren
Authors: Kauffmann Thomas , Neiteler Christel , Neiteler Gabriele
Published: July 2007

Alkyliron and Alkylcobalt Reagents, IX[1]. — Rearrangement of Aliphatic Terminal Epoxides to Methyl Ketones by Iron Alkyl Reagents instead of Co2(CO)8 or Noble Metal Catalysts

The highly selective rearrangement of aliphatic terminal epoxides to methyl ketones, hitherto possible only with Co2(CO)8 or noble metal catalysts, occurs smoothly with Me4‐FeLi2, Me3FeLi, or the catalytic systems [RLi + 2.5 mol% FeCl3] (R = Me, Bu). This was demonstrated by the rearrangement of 1‐decene oxide (1) to 2‐decanone (2) (yield 80–81%; Table 1) and 6‐bromo‐1‐hexene oxide (5) to 6‐bromo‐2‐hexanone (6) (yield 78%, Me4FeLi2 applied only). The competition reaction of Me4FeLi2 with 1 and 2‐octanone (8) (mole ratio 0.5:1:1) led to 87% 2‐methyl‐2‐octanol (9) and not to the rearrangement 1 → 2. This indicates that Me4FeLi2 ‐ in contrast to the opposite behavior of organo cuprates ‐ reacts faster with ketones than with the aliphatic terminal epoxides. By treatment of 1 with methyl derivatives of MnII, CoII, and NiII or with Bu4FeLi2 (Table 2) other products (3, 4) besides 2 were formed. The rearrangement of 1 with Me4FeLi2 is assumed to start with an oxidative addition and yields 2 as its Li or Fe enolate (trapped with acetanhydride to give 64% of 20) after reductive elimination of CH4. The catalytic rearrangement of 1 with [MeLi + 0.25 mol% FeCl3] very probably occurs in an analogous manner with an super‐ate complex Me4FeLi2(MeLi)n as the active species and the Li enolate of 2 as end product (Scheme 4). The aromatic terminal epoxides styrene oxide and α‐methylstyrene oxide give various products in the reaction with Me4FeLi2 or Me3FeLi, including the deoxygenation products styrene and α‐methylstyrene. These products are exclusively formed on treatment of the epoxides with Me4MnLi2. (Prepared, hitherto in the literature not described compounds: 7 and 10–15.)
Organische Synthesen mit Übergangsmetallkomplexen, 71. Methylcarben‐Komplexe von Chrom und Wolfram mit Cycloheptatrienyl‐, Cyclohexadienyl[Fe(CO)3]‐ und Cycloheptadienyl[Fe(CO)3]‐Resten als α‐Substituenten
Authors: Aumann Rudolf , Läge Mechtild , Krebs Bernt
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 71[1]. — Methylcarbene Complexes of Chromium and Tungsten with Cycloheptatrienyl‐, Cyclohexadienyl[Fe(CO)3]‐ and Cycloheptadienyl[Fe(CO)3] Substituents

Methylcarbene complexes LnMC(OEt)CH3 1 [LnM = (CO)5Cr, (CO)5W] react with tropylium tetrafluoroborate (2a) or coordinated olefins of [C6H7Fe(CO)3]BF4 (2c), [C7H9Fe‐(CO)3]BF4 (2d), and [C7H7Fe2(CO)6]BF4 (2d) in the presence of Et3N to give complexes LnMC(OEt)CH2R 3a‐e and LnMC(OEt)CHR2 7a‐d by substitution of one or two α‐hydrogen atoms. The trimetallic WFe2 carbene complexes 7c, d derived from 1b with 2c, d form three stereoisomers each, which are fully characterized spectroscopically, (R*,R*,S*)‐7c additionally also by an X‐ray structure analysis, Ligand elimination from 3 and 7 may involve a‐and/or β‐hydrogen transfer reactions: Thus enol ethers (Z/E)‐6 are eliminated from α‐monosubstituted methylcarbene complexes 3a, c, d in yields of 62–90% by a pyridine‐induced transfer of an α‐hydrogen to the carbene carbon atom; with increasing steric demand of R the elimination of the (Z) isomer (Z)‐6 from 3 is favoured over the formation of the (E) isomer (E)‐6. The enol ether 10 becomes a minor side product in the pyridine‐induced ligand elimination from α‐disubstituted complexes 7a, b. In these cases the spirocyclopropane 8 is formed as the main product (60–82%) besides the 4,5‐homotropylidene 9 by a conformationally directed β‐hydrogen transfer reaction.
Deformierte chirale [n]Metacyclophane
Authors: Müller Bernd , Pischel Ivo , Nieger Martin , Vögtle Fritz
Published: July 2007

Deformed Chiral [n]Metacyclophanes

The new dithiametacyclophane3cand the thiaazametacyclophanes6a, bare chiral, but do not contain chirality centres. They are obtained by cyclization of 1,3‐propanedithiol (2), or of the thiaza precursors5a, b, with the bis(bromomethyl) compounds1, 4a, b.The dynamic behaviour of the aliphatic chains in3c, and6a, b(flipping/rotation) have been studied by dynamic NMR. X‐ray analyses of3cand6adocument the out‐of‐plane deformation of the boat‐shaped benzene ring. The circular dichroism of enantiomer‐enriched3cis reported.
Kleine Ringe, 83. C3F2‐Isomere: Erzeugung durch gepulste Blitzpyrolyse und matrixspektroskopische Identifizierung
Authors: Maier Günther , Preiss Thomas , Reisenauer Hans Peter
Published: July 2007

Small Rings, 83[1]. — C3F2 Isomers: Generation by Pulsed Flash Pyrolysis and Matrix‐Spectroscopic Identification

Matrix‐isolated difluorovinylidenecarbene (4) has been generated by pulsed flash pyrolysis from 1‐chloro‐3,3‐difluoro‐cyclopropene (8a) and 3,3‐difluoro‐1,2‐diiodocyclopropene (8b). By subsequent photolysis 4 isomerizes to difluoropropargylene (5) and difluorocyclopropenylidene (6). The identification of the three new carbenes is based on the comparison of their experimental and calculated (MP2/6‐31G*) infrared spectra.
Dilithium‐N,N′‐bis(trimethylsilyl)hydrazid und ein Hydrolyseprodukt side‐on und end‐on an N2−2‐ und O2−2‐gebundene Li‐Kationen
Authors: Drost Christian , Jäger Carsten , Freitag Stefanie , Klingebiel Uwe , Noltemeyer Mathias , Sheldrick George M.
Published: July 2007

Dilithium N,N′‐Bis(trimethylsilyl)hydrazide and a Hydrolysis Product: Side‐On‐ and End‐On‐Coordinated Li Cations to N2−2 and O2−2

N,N′‐Bis(trimethylsilyl)hydrazine is converted into the dilithium derivative [(Me3Si)2N2Li2] · 2 thf (1) by nBuLi. Compound 1 forms a tetramer which lies on a crystallographic inversion centre. The Li+ ions are found to be end‐on to the NN units and also coordinated by thf, but three Li+ ions are also positioned symmetrically above the NN bonds. The hydrolysis of 1 in air leads to the formation of [(Me3SiOLi)4 · Li2O2 · LiN(SiMe3)2] · 2 thf (2) which contains four oxide and one peroxide ions. The O2−2 unit is side‐on‐coordinated by three Li+.
Chirale Lactole, XI. Eine Methode zur Bestimmung der Absolutkonfiguration chiraler Alkanole
Authors: Noe Christian R. , Knollmüller Max , Miculka Christian , Dungler Karin , Wagner Ernst , Ettmayer Peter
Published: July 2007

Chiral Lactols, XI. ‐ A Method for the Determination of the Absolute Configuration of Chiral Alkanols

Chiral secondary alcohols which are protected with the enantiomerically pure lactol 1 or 2 show significant differences in 13C‐chemical shifts around the glycosidic linkage. An easy method for determination of the absolute configuration of secondary alcohols based on this fact is described.
J‐Aggregate von 4‐Iod‐bis(dimethylamino)heptamethinium‐triiodid Synthese, Struktur und optische Eigenschaften
Authors: Dähne Lars , Grahn Walter , Tanaka Chizuko , Kawamoto Atsushi , Tanaka Jiro
Published: July 2007

J‐Aggregates of 4‐Iodo‐bis(dimethylamino)heptamethine Triiodide. — Synthesis, Structure, and Optical Properties

Iodination of heptamethincyanine 2a gives the title compound 3. Its cations display all‐trans configuration in solution and in the crystalline state. In contrast to cations of 2a, those of 3 form one‐dimensional J aggregates, as proved by X‐ray analysis and optical reflection spectroscopy.
On the Reaction of 1‐Aza‐2‐azoniaallene Salts with Isocyanates
Authors: Wang Quanrui , Mohr Susanne , Jochims Johannes C.
Published: July 2007

1‐Aza‐2‐azoniaallene salts 3, prepared in situ from geminal chloroalkylazo compounds 2 with Lewis acids, react with isocyanates 4 to give 4,5‐dihydro‐5‐oxo‐3H‐1,2,4‐triazolium salts 6 and 4,5‐dihydro‐5‐oxo‐1H‐1,2,4‐triazolium salts 7, respectively. The intramolecular cyclization of 3u opens a new route to cinnolinium salts 11. Allenes 3 react with isobutene to give pyrazolium salts 8. According to AM1 calculations the cycloadditions of 3 to isocyanates proceed in two steps via acylium salts 5 as intermediates. Mechanistically, the rearrangements 6 → 7 resemble Wagner‐Meerwein rearrangements rather than pericyclic [1,5]‐sigmatropic shifts.
Thermal Rearrangements, XXII. The Propargyl‐Cope Rearrangement of meso‐ and d,l‐3,4‐Dimethyl‐1,5‐hexadiyne‐3,4‐diol
Authors: Hopf Henning , Hamann Uwe , Zimmermann Gerhard , Remmler Matthias
Published: July 2007

The thermal behavior of meso‐ and d,1‐3,4‐dimethyl‐1,5‐hexadiyne‐3,4‐diol (meso‐ and d,1–4) has been studied at 400°C in the gas phase. In a tandem reaction the diols isomerize via the bisallenes 5 first to cis‐ and trans‐3,4‐diacetylcyclobutene (cis‐ and trans‐8) which have been detected as intermediates by 13C‐NMR spectroscopy as well as catalytic hydrogenation to 1,2‐diacetylcyclobutane (9). Subsequently, 8 stabilizes itself by ring opening to (E,Z)‐ and (E,E)‐3,5‐octa‐dien‐2,7‐dione (E,Z) and [(E,Z)‐6]. As a side reaction retroene cleavage of 4 to 2‐butynone (10) and methyl vinyl ketone (12) is observed. By pyrolysis of the pure diastereomers 4 it is shown that the retro‐ene process is more pronounced in the d,l than in the meso series.
Transition Metal Chemistry of Main Group Hydrazides, VI. New Directed Synthetic Strategies to Functionalized Heterocyclic Phosphorus(III) Hydrazides. First Examples of Crystal and Molecular Structures of [RPN(Me)N(H)]2 (R = Et, Ph, and tBu)
Authors: Sreenivasa Reddy V. , Katti Kattesh V. , Barnes Charles L.
Published: July 2007

The reactions of methylhydrazine with RPC12 (R = Et, tBu, and Ph) produced the cyclic phosphorus (III) hydrazides (1,2,4,5,3,6‐tetrazadiphosphorinanes) [RPN(Me)N(H)2 (R = Et, 1; (Ph, 2; tBu, 3) in good yields. The 1H‐and 31P‐NMR spectroscopic analysis indicated that 1 exists in chair and boat conformations. However, it crystallizes in the chair conformation exclusively. The X‐ray crystallographic investigation of all the three cyclo‐phosphorus hydrazides 1–3 confirms the existence of these compounds in the chair conformations in the solid state. The reaction of Mo(CO)4‐(NHC5H10)2 with 1 and 2 gives the dinuclear Mo(0) complexes [{Mo(CO)4(NHC5H10)}2(μ‐[RPN(Me)N(H)]2}] (R = Et, 5; Ph, 6). Based on 1H‐ and 31P‐NMR spectroscopic data, a bridging dinuclear dimetallic formulation is proposed for 5 and 6. The IR spectra indicate that the carbonyls are disposed in cis‐geometry around the Mo(0) center.
Komplexe mit makrocyclischen Liganden, II. Synthese, Struktur und elektrochemische Eigenschaften eines makrocyclischen Cu2IIMnII‐Komplexes vom Schiff‐Basen‐Typ
Authors: Brychcy Klaus , Jens Klaus‐J. , Tilset Mats , Behrens Ulrich
Published: July 2007

Complexes with Macrocyclic Ligands, II. — Synthesis, Structure and Electrochemical Properties of a Macrocyclic CuMnII Complex of Schiff Base Type

A novel trinuclear Cu2Mn complex 4 of a macrocyclic Schiff base ligand obtained by condensation of 5‐tert‐butyl‐2‐hydroxy‐1,3‐benzenedicarbaldehyde with 1,2‐phenylenediamine was synthesized. The molecular structure of 4 was determined by X‐ray diffraction revealing a sandwich‐type structure as depicted by Figure 2. Electrochemical investigations (DCV measurements) showed two one‐electron reduction steps for the copper ions at E1/2 = ‐1.383 and ‐1.652 V (vs. Cp2Fe/Cp2Fe+).
Chemie polyfunktioneller Molekule, 112. Ringerweiterungsreaktionen an einem neuartigen spirocyclischen Cobaltaphosphazen mit Sauerstoff, Schwefel und Selen
Authors: Ellermann Jochen , Sutter Jörg , Knoch Falk A. , Moll Matthias
Published: July 2007

Chemistry of Polyfunctional Molecules, 112. — Ring Enlargement Reactions of a Spirocyclic Cobaltaphosphazene with Oxygen, Sulfur, and Selenium

Herrn Prof. Dr. Ekkehard Lindner zum 60. Geburtstag gewidmet.

The spirocyclic cobaltaphosphazene 1 which contains cobaltconnected three‐, five‐, and six‐membered rings undergoes ring enlargement reactions by treatment with O2, S8, and Se8. The resulting paramagnetic spirocyclic cobalta‐phosphazenoids 2a–c (E = O, S, Se) consist of eight‐membered chelate rings connected at the spiro‐cobalt(II) centre forming a tetrahedral CoE4 core. The compounds 2a–c have been characterized by X‐ray analyses, 1H, 13C(1H), 31P(1H) NMR, IR, Raman, UV/Vis/NIR, EI/FD mass spectroscopy, and magnetic measurements.
Studien zur CH‐Aktivierung, X. Synthese von Alkyl(carbonyl)hydrido‐ und Allylhydrido‐Osmiumkomplexen durch Metall‐initiierte Fragmentierung von primären Alkoholen und Olefinen
Authors: Wecker Ulrich , Werner Helmut , Peters Karl , Schnering Hans‐Georg Von
Published: July 2007

Studies on CH Activation, X. — Synthesis of Alkyl(carbonyl)hydrido‐ and Allylhydridoosmium Complexes by Metal‐initiated Fragmentation of Primary Alcohols and Olefins

Herrn Professor Dr. E. Lindner zum 60. Geburtstag gewidmet.

The reaction of [(Mes)OsCl2]n (1) with RCH2OH/NaOH in the presence of propene leads to complete fragmentation of the primary alcohol and formation of the alkyl(carbonyl)hydrido complexes [(Mes)OsH(R)(CO)] (2–7). The corresponding chloro derivatives [(Mes)OsC1(R)(CO)] (8–13) are obtained either by H/C1 exchange from 2–7 and CC14 or on treatment of [(Mes)OsR2(CO)] (16–21) with HC1 at ‐78°C. The carbonylosmium(II) compound [(Mes)Os(CO)C12] (15) reacts with iC4H9MgI to give a mixture of [(Mes)Os(iC4H9)2(CO)] (21), [(Mes)OsI(iC4H9)(CO)] (22), and [(Mes)Os(CO)I2] (23), whereas the reaction of 15 with C6H11CH2MgBr yields [(Mes)Os(CH2C6H11)2(CO)] (24), the olefin complex [(Mes)Os(CH2C6H10)(CO)] (25), and [(Mes)OsH(Br)(CO)] (26). The alkylhydridoosmium(II) compound [(Mes)OsH(CH2C6H11)(CO)] (28) is obtained from the chloro derivative 27 and Mg/Hg/C2H5OH. Treatment of 1 with iC3H7OH/NaOH and propene or isobutene affords the η3‐allylhydrido complexes [(Mes)OsH(η3‐2‐RC3H4)] (31, 32) in about 85% yield, while the reaction of 1 with iC3H7OH/NaOH and tert‐butylethene gives [(Mes)Os(CH2CHtC4H9)2] (35). The X‐ray structural analysis of [(Mes)OsH(η3‐2‐CH3C3H4)] (34), which like the corresponding η3‐allylchloro compound 33 is formed from the η3‐allylhydrido complex 31 or 32 and CC14, reveals a half sandwich‐type structure with an exo arrangement of the methallyl ligand.