bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organische Synthesen mit Übergangsmetallkomplexen, 42 Allene als Liganden in zweikernigen Eisencarbonyl‐Komplexen; Carbonylierungen von Allenen sowie deren Kupplung mit Alkinen und Allenen; dynamische “Keten‐Scheibenwischer”‐Komplexe
Authors: Aumann Rudolf , Melchers Hans‐Dieter , Weidenhaupt Hermann‐Josef 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 42. ‐ Allenes in Dinuclear Iron Carbonyl Complexes; their Carbonylation and Coupling with Alkynes and Allenes; Fluxional “Ketene Windshield‐Wiper” ComplexesOn photochemically induced metallation with pentacarbonyl iron allenes H2C = C = CHR 1 (R = H, C6H5) give dinuclear acyl iron complexes 2, in which the central carbon of the C = C = C unit is attached to a carbonyl group. 2 on warming yield π‐ally1,σ complexes 3 by loss of carbon monoxide. The reaction 2 ⇌ 3 + CO is reversibel. 3 add alkynes R1 ‐ C = C ‐ R24 (R1 = C6H5r, CH2OCH3; R2 = Hr C6H5) with insertion of the C = C triple bond into the M ‐ C σ‐bond to give dinuclear ketene complexes 5. The latter are fluxional, as was shown by NMR measurements. The ketene unit is moving back and forth like a windshield wiper. Thermolysis of 5 under normal pressure affords ferracyclopentadiene iron complexes 6 (by 1,3‐hydrogen shifts) and 4‐methylene‐2‐cyclopenten‐1‐one 7 (by cyclocarbonylation). Thermolysis of 5 under CO pressure gives 7 as the sole products. Complexes 3 also add allenes 1 with insertion into the M–C σ‐bond and formation of a C–C bond between the central carbon atoms of both allene units to give dinuclear bis(allyl) complexes 8 and 8′.
Elektrophile β‐Bromierung und nucleophile α‐Methoxylierung α,β‐ungesättigter Carbonylverbindungen
Authors: Fischer Hans , Klippe Michael , Lerche Holger , Severin Theodor , Wanninger Gabriele 
Published: July 2007

Electrophilic β‐Bromination and Nucleophilic α‐Methoxylation of α,β‐Unsaturated Carbonyl CompoundsOximes 29a, b, semicarbazones 11a–d, dimethylhydrazones 4, and [3‐methyl‐2(3H)‐benzothiazolylidene]hydrazones 23a–c of unsaturated aldehydes and ketones are brominated at the β‐carbon by an addition‐elimination sequence (→ 21a,b, 13a–d, 7, and 27c, respectively). When unsaturated ketone hydrazones are treated with bromine and methanol the α‐methoxy‐β‐bromo derivatives 35a–c are obtained, which after hydrolysis and hydrobromic acid elimination give α‐methoxy substitution products 36a–c of the starting compounds.
Synthese von 5,5‐disubstituierten 2,5‐Dihydro‐4H‐isoindol‐4‐onen
Authors: Spreitzer Helmut , Mustafa Stefan 
Published: July 2007

Syntheses of 5.5‐Disubstituted 2.5‐Dihydro‐4H‐isoindol‐4‐onesTosylmethyl isocyanide attacks 6,6‐disubstituted cyclohexadienones selectively in position 3 to furnish 4H‐isoindol‐4‐one derivatives 4. This is caused by charge distribution, characteristic of cyclohexadienones, and by sterical reasons.
γ‐Oxoisocyanid‐Komplexe von Eisen(II), Ruthenium(II), Palladium(II) und Platin(II) aus Cyano‐Komplexen und α,β‐ungesättigten Carbonylverbindungen in Gegenwart von Et2O–HBF4. Kristallstrukturanalyse von cis‐(phen)2Fe[CNC(CH3)2CH2C(O)CH=C(CH3)2]2+2(BF‐4)2
Authors: Weigand Wolfgang , Nagel Ulrich , Beck Wolfgang 
Published: July 2007

Pseudohalogeno Metal Compounds, LXXIII. ‐ γ‐Oxoisocyanide Complexes of Iron(II), Ruthenium(II), Palladium(II), and Platinum(I1) from Cyano Complexes and α,β‐Unsaturated Carbonyl Compounds in the Presence of Et2O ‐ HBF+ Crystal Structure of cis‐(phen)2Fe[CNC(CH3)2CH2C(O)CH=C(CH3)2]2+2(BF‐4)2Reactions of trans‐(R3P)2M(CN)2 (M = Pd, Pt), cis‐[(phen)2‐Fe(CN)2], Cp(dppe)Fe(CN), and Cp(Ph3P)2Ru(CN) with several α,β‐unsaturated ketones in the presence of Et2O–HBF4 yield complexes containing the γ‐oxoisocyanide ligand: trans [R3P)2M(CN–CR1R2–C(O)R4)2]2+(BF4‐)2 (5–8), trans ‐[(R3P)2Pt(CN)(CN‐CR1R2–CHR3–C(O)R4)]+ BF4‐ (9), cis [(phen2)]Fe(CN–CR1R2–CHR3–C(O)R4)2]2+(BF4‐)2 (10), and [CpL2M(CN–CR1R2‐CHR3–C(O)R4)]*BF4‐ (11, 12) (M = Fe, Ru; L = PPh3, 1/2 dppe). The compounds were characterized by their spectroscopic data, 10g by X‐ray crystallography. The carbonyl function of the coordinated ligands could be reduced by NaBH4/CeCl3·6H2O in some cases to give complexes of γ‐hydroxyisocyanide and oxazine‐2‐ylidene ligands.
Reaktionen von (Pentamethylcyclopentadienyl)bis(trifluormethylisocyanid)cobalt mit Nucleophilen
Authors: Lentz Dieter , Marschall Robert 
Published: July 2007

Reactions of (Pentamethylcyclopentadienyl)bis(trifluoromethyl isocyanide)cobalt with NucleophilesThe title complex 1, reacts with amines in water‐saturated diethyl ether to form the five‐membered cobaltaheterocycles 3/. In addition these complexes 3a–c contain an N(trifluoromethyl)formimidoyl ligand. The structure of 3a has been established by an X‐ray crystal structure analysis.
Synthese und Strukturen von Bis(trietanolamin)lanthanoid‐Komplexen
Authors: Ekkehardt Hahn F. , Mohr Jörg 
Published: July 2007

Synthesis and Structures of Bis(triethanolamine)lanthanide ComplexesThree novel lanthanide triethanolamine chelates {Ln[N(CH2‐CH2OH)3]2}(CF3SO3)3 (Ln = Pr, 1; Yb, 2; Lu, 3) were synthesized from Ln(CF3SO3)3 and triethanolamine in THF. The structures of 1 and 2 were determined by single‐crystal X‐ray diffraction studies. The isostructural compounds crystallize with three molecules of THF and possess nonacoordinate lanthanide ions with a monocapped tetragonal antiprismatic coordination geometry.
[2+2]‐Cycloaddition vo Iminoboranen mit einem Neopentylidentantal‐Komplex
Authors: Braunschweig Holger , Paetzold Peter , Boese Roland 
Published: July 2007

[2 + 2] Cycloaddition of Iminoboranes to a Neopentylidenetantalum ComplexThe neopentylidene complex(η‐Cp)cl2Ta=CHtBu (1) and the iminoboranes R′B≡NR (2a–d, R′/R = Et/tBu, Bu/tBu, iBu/ iBu, Ph/tBu) undergo a [2 + 2] cycloaddition yielding the corresponding 1‐aza‐2‐bora‐4‐tantalacyclobutanes 3a–d. The crystal and molecular structure of 3c is reported.
Synthese angularer Tetraquinane durch Photo‐Thermo‐Metathese diastereomerenreiner Benzochinon–Tetrahydropentalen‐Addukte
Authors: Griesbeck Axel G. 
Published: July 2007

Synthesis of Angularly Annulated Tetraquinanes by Photo‐Thermo Metathesis of Diastereomerically Pure Adducts Between Benzoquinone and TetrahydropentalenesA retrosynthesis is presented for an angularly fused tetraquinane, the central step of which is the photo‐thermo metathesis of a tetrahydropentalene ‐ benzoquinone adduct. A sequence of Michael addition/condensation reaction gives the 3‐methyl‐ l‐phenyl‐1,2‐dihydropentalene (2) in 70% yield from benzalacetone and cyclopentadiene. Reaction with lithium aluminum hydride lead to a 1.0: 1.0:0.8 mixture of the 1,2,3,4‐tetra‐hydropentalenes 4a and 4b and the 1,2,3,5tetrahydropentalene 5. This reaction is highly diastereoselective (d.s. > 96%) and provides the cis compounds exclusively. Diels‐Alder cycloadditon of 4a, b and 5 to benzoquinone also proceeds highly stereoselectively. The adducts 7a, b and 8 may be separated by fractional crystallization. Their relative configuration can be determined by means of 2D‐COSY and NOE experiments. The endo arrangement is demonstrated by the photoreactivity of the cycloadducts. Gas‐phase thermolysis (700°C/0.05 Torr) of the cage molecules 9a and 9b (from irradiation in benzene) gives the angularly annulated tetraquinanes 10a and 10b in 95 and 88% yield, respectively.
Herstellung, Struktur und Eigenschaften neuartiger kettensubstituierter und chiraler Trimethincyanin‐Farbstoffe mit Indolin‐Endgruppen1)
Authors: Reichardt Christian , Engel Horst‐Detlef , Allmann Rudolf , Kucharczyk Damian , Krestel Magda 
Published: July 2007

Synthesis, Structure, and Properties of Novel Chain‐Substituted and Chiral Trimethine Cyanine Dyes with Indoline End GroupsSynthesis and spectroscopic properties of the trimethine cyanine dyes 3, 8a, b, and 13a, b as well as 14a‐c with new substitution patterns are described. Constitutions and configurations of 3, 8a, b and 14c have been determined by X‐ray analyses (Figures 1, 2, and 6). Dye 3 exists in the previously unknown di‐cis (E, E, Z, Z) configuration along the methine chain. Attempts to prepare 3 in a base‐catalysed reaction unexpectedly led to the rearranged trimethine cyanine dyes 8a, b with a centre of chirality in one of the indoline end groups. Using this Wagner‐Meerwein rearrangement after resolution, the chiral heterocyclic quaternary salts (S)‐12a‐ c have been prepared, from which the optically active trimethine cyanine dyes (S,S)‐14a‐c have been obtained for the first time. The UV/VIS spectra of 3, 8a and 13a (Figure 7) as well as the CD spectra of 12a and 14a (Figures 3 and 4) are compared and discussed.
Pyrrole durch metallinduzierte [3 + 2]‐Cycloaddition von 2‐Azaallenyl‐( = Iminocarben‐)Komplexen unter Übertragung einer CNC‐Einheit auf ein Alkin; ein Chromacyclopropen durch Cyclocarbonylierung eines 1‐Aminoalkins
Authors: Aumann Rudolf , Heinen Heinrich , Krüger Carl , Betz Peter 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 40. ‐ Pyrroles by Metal‐Induced [3 + 21 Cycloadditions of 2‐Aza‐allenyl (= Iminocarbene) Complexes with Transfer of a CNC Unit to Alkynes; a Chromacyclopropene Complex by Cyclocarbonylation of a 1‐AminoalkyneThe 2‐azaallenyl (= iminocarbene) complex LnM⊖ ‐ CR = N⊕ = CXR1 1a [LnM = Cr(C0)5 = OEt, R1 = Ph] adds to the polarized alkyne Et2N ‐ C≡C‐CH3 (3) to give a 2H‐pyrrole complex 4 in a metal‐induced [3+2] cycloaddition. On warming 4 yields the 2H‐Pyrrole 5. Since the regiochemistry of the addition of the CNC unit is opposite to that of a nitile ylide, we consider 1 as an Umpolung equivalent (RC⊕ = N ‐ C⊖XR1) of a nitrile ylide (RC⊕ = N ‐ C⊖XR1). The 2H‐pyrrole 5 is kinetically unstable and isomerizes smoothly to the 1H‐pyrrole 7 under the influence of base by an intramolecular redox reaction. A novel (cyclopentadienyl)chromacyclopropene complex 8 resulting from a cyclocarbonylation of the iminoalkyne 3 is obtained as a minor side product. The structural data of 4 and 8 have been determined by X‐ray analyses.
Kondensation von Methylcarben‐Komplexen mit Säureamiden: β‐Alkoxyalkenyl‐ und β‐Aminoalkenylcarben‐Komplexe von Chrom und Wolfram ‐ Konkurrenz von Kondensation und Insertion
Authors: Aumann Rudolf , Hinterding Peter 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 441. ‐ Condensation of Methyl Carbene Complexes with Acid Amides: β‐Alkoxyalkenyl‐ and β‐Aminoalkenyl Carbene Complexes of Chromium and Tungsten ‐ Competition of Condensation and InsertionThe condensation of the methyl(ethoxycarbene) complexes LnM = C(OEt)CH3 (4) [LnM = Cr(CO)5, W(CO)5] with acid amides RCONR1R2 (5) under the influence of POCl3/Et3N leads stereoselectively to (E)‐β‐aminoalkenyl(ethoxycarbene) complexes LnM=C(OEt)CH=C(R)NR1R2 [(E)‐6] (R = H, aryl, alkyl). A condensation of 4 can also be achieved via amidium salts 11, which are easily available from 5. In this case, (E)‐6 and (E)‐β‐alkoxyalkenyl(ethoxycarbene) complexes LnM=C(OEt)CH = C(R)OEt[(E)‐13] were obtained. Via the cyclic amidium salts 15 and 20 four‐to seven‐membered lactams (E)‐17 and (E)‐21a‐d are accessible. The reaction of 4 with acid amides RCH2CONR1R2 (2) and POCl3/Et3N yields mainly insertion products LnM=C(NR1R2)C(R)=C(OEt)CH3 [(E)/(Z)‐22] and only small amounts of condensation products LnM=C(OEt)CH=C(CH2R)NR1R2 [(E)‐23].
Wasserstoffübertragungen, 15 Zum Ablauf der Dehydrierung von Dihydroarenen durch Chinone
Authors: Radtke Rainer , Hintze Horst , Rösler Klaus , Heesing Albert 
Published: July 2007

Hydrogen Transfer Reactions, 15lI. ‐ On the Transition State in the Dehydrogenation of Dihydroarenes by QuinonesIn the hydride abstraction from 1,2‐dihydronaphthalene by o‐chloroanile the regioselectivity correlates with the stability of the carbenium ions as shown by both kinetic tests and reactions of isotopomeric hydrogen donators. ‐ The temperature dependence of primary isotope effects does not correspond with any of the categories for the transition state as proposed by Kwart2). This was examined for 1,4‐cyclohexadiene and 9,10‐dihydroanthracene by a Bell correction and the parameters of activation (AH/AD und [ΔEA]D/H). A VAT mechanism3) is proposed to explain both these results and the large primary isotope effects.
Lineare Oligophosphaalkane, XXIV Synthese und strukturelle Charakterisierung von Cu8‐Mehrkernkomplexen mit Elektronenmangel‐Phosphidobrücken
Authors: Heßler Gisbert , Knüppel Peter C. , Stelzer Othmar , Sheldrick William S. 
Published: July 2007

Linear Oligophosphaalkanes, XXIV. – Syntheses and Structural Characterisation of Cu8 Complexes with Electron‐Deficient Phosphido BridgesReaction of silylphosphanes (Me3Si)RP–CH2–PR(SiMe3) (R = iPr, tBu, 2,4,6,‐Me3C6H2) with four equivalents of copper(1) halides CuX (X = Cl, Br) or a mixture of two equivalents of CuCl and Cul in the presence of pyridine as an auxiliary ligand affords octanuclear copper(1) complexes of composition Cu8X4(RP–CH2–PR)2(Py)n(CH3CN)m (n = 5, m = 0; n = 4, m = 1; X = Cl, Br, I). Multinuclear compounds of this type may also be obtained by deprotonation of the disecondary phosphanes HRP–CH2–PRH (R = iPr, Ph, 2,4,6‐Me3C6H2) with strong organic bases (DBU) in the presence of CuCl and pyridine. The X‐ray structural analysis of Cu8Cl4(iPr–P–CH2–PiPr)2(Py)5 (3a) (space group P21/c) reveals a Cu4(P–C–P)2 skeleton to which four CuCl(Py)n units (n = 1, 2) are coordinated by Cu–Cl and Cu–P bridges. The phosphorus atoms of the electron‐deficient μ3–PRR′ bridges formed thereby show a distorted trigonal bipyramidal coordination with almost planar PCu3 units. Due to the multiple bridging of the Cu(I) ions in 3a the Cu ⃛Cu distances in the Cu8 complex are relatively short (247.1–276.5 pm).
Silylalkin‐ und Silylvinyliden‐verbrückte Heterometallcluster
Authors: Bantel Harald , Powell Anne K. , Vahrenkamp Heinrich 
Published: July 2007

Silylalkyne‐ and Silylvinylidene‐Bridged Mixed Metal ClustersAttempts to incorporate silylalkynes into FeCo2 or RuCo2 clusters by means of cluster buildup or capping reactions are reported. From RuCo2(CO)11 and Me3SiC≡CMe were obtained RuCo2(CO)9(μ3‐Me3SiC≡CMe) (5) and its more stable isomer RuCo2(CO)9(μ3‐C=C(Me)SiMe3) (6). Of the latter the isonitrile derivative 8 was characterized by structure determination. The silylalkyne‐bridged cluster 5 is very prone to desilylation forming RuCo2(CO)9(μ3‐HC≡CMe) (11). The silylvinylidenebridged cluster 6 undergoes cluster expansion with CpRh(CO)2 to form RuCo2RhCp(CO)8(μ4‐Me3siC≡CMe) (12), which again bears the silylalkyne ligand.
Alkinverbrückte Vierkerncluster durch Expansion von Dreikernclustern
Authors: Bantel Harald , Powell Anne K. , Vahrenkamp Heinrich 
Published: July 2007

Alkyne‐Bridged Tetranuclear Clusters by Expansion of Trinuclear ClustersUnder photochemical activation Fe2(CO)9 is a suitable reagent for the expansion of alkyne‐bridged trinuclear clusters 1–7 (Fe3, FeCo2, FeNi2, RuCo2, FeCoNi, RuCoNi, RuCoMo) to the corresponding tetranuclear clusters 9–15 containing Fe(CO)3 building blocks. The analogous incorporation of RhCp building blocks was possible by heating RhCp(CO)2 together with the alkyne‐bridged Fe3, FeCo2, RuCo2, RuCoMo, and RuCoW clusters 1, 2a, 4, 7, and 8. The resulting clusters 16–20 with octahedral M4C2 frameworks showed framework isomerism in two cases [RuFeCo2 (11a, b) and RuCoMoRh (19a, b)]. Crystal structure determinations were performed for the Fe4 and Fe3Rh clusters 9, 16 as well as for both isomers 19a, b of the RuCoMoRh cluster.
Nitrogen Base – Dialkyl‐1,2,4,3,5‐triselenadiborolanes
Authors: Yalpani Mohamed , Köster Roland , Boese Roland 
Published: July 2007

Stickstoffbase – Dialkyl‐1,2,4,3,5‐triselenadiborolane3,5‐Dialkyl‐1,2,4,3,5‐triselenadiborolane RBSe3BR (1) [R = C2H5 (1a) und R = C3H7 (1b)] bilden bei Raumtemperatur mit überschüssigen N‐Basen [Pyridin (P), 3,5‐Dimethylpyridin (m2P), 3‐Chlorpyridin (cP) und Chinuclidin (Q)] stabile 2:1‐Additionsverbindungen [P2‐1a,b, (m2P)2‐1a, cP‐1a, Q2‐1a, b]. In Lösung existieren Gemische von (syn/anti)Q2‐1a (1H‐, 11B‐NMR). (syn)Q2‐1a steht bei –80°C mit Q‐1a und Q im Gleichgewicht. Festes Q2‐1a liegt als (anti) Q2‐1a vor (Kristallstrukturanalyse). In Lösung bilden 1 bei Raumtemperatur mit äquimolaren Mengen an N‐Basen die 1:1‐Addukte [(N‐Base)‐1], in denen nur ein Bor‐Atom vierfach koordiniert ist. 1: 1‐Addukte mit fluktuierender N‐Base zwischen den beiden Bor‐Atomen werden bei Temperatursteigerung beobachtet (120°C: 11B‐NMR). Hexamethylentetramin (Ur) bildet stabile, feste 1: 1‐ und 2: 1‐Addukte (Ur‐1a, Ur2‐1a).
Starke P – P‐Wechselwirkungen in Tetraphosphacubanen, PE‐spektroskopische Untersuchungen
Authors: Gleiter Rolf , Pfeifer Karl‐Heinz , Baudler Marianne , Scholz Guido , Wettling Thomas , Regitz Manfred 
Published: July 2007

Strong P – P Interactions in Tetraphosphacubanes. A PE‐Spectroscopic InvestigationThe comparison between the first peaks of the PE spectra of (tBuCP)4 (2a) yields about the same ionization energy for the first peak (4t2), but a large difference (ca, 0.8 eV) for the second peak (1t1). This difference is due to a strong interaction of the n orbitals at P with the P‐C σ bonds in 1. This n/σ interaction is much smaller in the case of 2. The energy difference between 24T2 and 23A1, corresponding to the lone‐pair combinations of the n orbitals at the P atoms, amounts to ≥ 3.4 eV for 1a and is estimated at ≥ 1.6 eV for 2a. The net charges for the P atoms in 1 are calculated to be positive, those for the C atoms negative. In the case of 2 negative values result for P and positive values for the net charges at Si.
Ringkontraktionsreaktionen von Octamethylcyclotetrasilazanen zu silylsubstituierten Cyclotrisilazanen
Authors: Dipel Kerstin , Klingebiel Uwe , Pauer Frank , Sheldrick George M. , Stalke Dietmar 
Published: July 2007

Ring Contractions of Octamethylcyclotetrasilazanes to Silyl‐Substituted CyclotrisilazanesReaction of the mono‐ and dilithium derivatives of bis(fluorsilyl)‐substituted cyclotetrasilazanes with fluorosilanes and fluoroboranes leads to ring contraction with formation of cyclotrisilazanes (1 – 8). The isomerisation is proved by the crystal structure determination of 1 and by NMR spectroscopy.
Synthese, Struktur und dynamisches Verhalten von 1,3,5‐Triaza‐2,4‐diphospha‐1,4‐pentadienen
Authors: Niecke Edgar , Detsch Ralph , Nieger Martin 
Published: July 2007

Synthesis, Molecular Structure, and Dynamic Behaviour of 1,3,5‐Triaza‐2,4‐diphospha‐1,4‐pentadienesChloro(arylimino)phosphane (1) reacts with the 1,3‐diaza‐2‐phosphaallylic system 3 to form 1,3,5‐triaza‐2,4‐diphospha‐1,4‐pentadienes Ar‐N=P‐N(R)‐P=N‐Ar (Ar = 2,4,6‐tBu3‐C6H2; R = tBu, 2,4,6‐iPrc3C6H2) (4a‐c). the molecular structure of 4a (“Exo‐endo‐S conformation”) as well as the dynamic behaviour of the compounds in solution are discussed. the observed temperature dependance of the NMR spectra of 4c was interpreted as a sigmatropic 1,3‐rearrangement followed by a P‐N rotation.
Stereochemische Aspekte bei metallacyclischen Neunring‐Zirconoxycarbenkomplexen aus (Butadien)zirconocen, Hexacarbonylwolfram und Ketonen oder Aldehyden
Authors: Erker Gerhard , Sosua Friedrich , Noe Ralf 
Published: July 2007

Stereochemical Aspects with Metallacyclic Nine‐Membered Zirconoxycarbene Complexes from Coupling (Butadiene)‐zirconocene, Hexacarbonyltungsten, and Ketones or AldehydesReaction of (butadiene)zirconocene complexes with M(CO)6 (M =Cr, W) and subsequently with ketones or aldehydes O=CR1R2 (R1, R2 = H, alkyl, alkenyl, or aryl) produces the metallacyclic nine‐membered zirconoxycarbene complexes (7a‐r. The complexes trans‐7 contain chiral metallacyclic ring systems. Starting from many ketones two diastereomeric compounds trans‐7 and trans‐7′ are obtained. From the dynamic 1H‐NMR spectra an activation barrier of ΔG(317K)=16.5 ± 0.4 kcal/mol has been estimated fro the trans‐7k [(2R*)(4,5,6‐pS*)] → trans‐7k′ [(2R*)(4,5,6‐pR*)] rearrangement. For the tert‐alkyl‐substituted nine‐membered metalacycles trans‐7f‐h only the respective (2R*)(4,5,6‐pS*) isomers have been found Starting from aldehydes with less sterically demanding alkyl groups mixtures of the trans‐7 [(2R*)(4,5,6‐pS*)] compounds and their cis‐7 isomers are obtained. Using the more bulky bis(tert‐butylcyclopentadienyl)zirconium moiety for coupling butadiene and W(CO)6 with simple aldehydes leads to a large excess of the trans‐isomers (e. g. R1 = H, R2 = i‐C3H7: trans‐7q: Cis7q = 90: 10).
Chirale Homoenolat‐Äquivalente, III Asymmetrische synthese 3‐substituierter 3‐Phenylketone über metallierte SMP‐ Allylamine
Authors: Abbrecht Hobertas , Sommer Horst 
Published: July 2007

Chiral Homoenolate Equivalents, 111. – Asymmetric Synthesis of 3‐Substituted 3‐Phenylketones via Metallated SMP‐ AllylaminesThe diastereomeric excess obtained in alkylation reactions of the chiral homoenolate equivalents 7 with prolinol ether as chiral auxiliary leading to the formation of 3‐phenylketones 9 clearly depends on the temperature, the counter ion and the size of the alkyl iodide. But most important is the influence of the solvent used. By its variation even the course of induction may be controlled. Normally, the selectivity amounts to about 8 : 1 only. The best results (about 9 : 1) are obtained with lithium as counter ion and tert‐butyl methyl ether as solvent.
1,3,2‐Dithiazol‐2‐yl‐Radikale aus N‐substituierten 1,3,2‐Dithiazolen
Authors: Wolmershäuser Gotthelf , Kraft Gregor 
Published: July 2007

1,3,2‐Dithiazol‐2‐yl Radicals from N‐Substituted 1,3,2‐DithiazolesThermolysis of N‐substituted 1,3,2‐dithiazoles 1,2 as well as their reactions with bases affords the corresponding 1,3,2‐dithiazol‐2‐yl radical 3, 4. Radical 3 has been characterized by X‐ray structure analysis.
Beiträge zur Chemie des Bors, 203. Reaktionen einiger Nichtmetallelemente mit 9‐Fluorenyliden(2,2,6,6‐tetramethylpiperidino)boran
Authors: Mayer Erwin P. , Nöth Heinrich 
Published: July 2007

Contributions to the Chemistry of Boron, 2031 Reactions of Some Non‐Metallic Elements with 9‐Fluorenylidene(2,2,6,6‐tetramethylpiperidino)borane9‐Fluorenylidene(2,2,6,6‐tetramethylpiperidino)borane (1) is hydrogenated catalytically at its boron‐carbon double bond producing 9‐fluorenyl(2,2,6,6‐tetramethylpiperidino)borane (2). Similarly, chlorine, bromine, and iodine add to this double bond, but only the bromine adduct 6a has been fully characterized. 1 is oxygen‐sensitive. The oxidation product found is the 1,2‐oxaboretane derivative 7, which is prepared independently by a [2 + 2] cycloaddition reaction from 1 and 9‐fluorenone. Sulfur reacts with 1 to yield a trithiaborolane derivative, while P4 does not attach 1.
Darstellung, Struktur und Stereoisomerie von 1,3‐Di‐tert‐butyl‐1,3,2,4‐diazadistibetidinen
Authors: Ross Bernd , Belz Johannes , Nieger Martin 
Published: July 2007

Synthesis, Structure, and Stereoisomerism of 1,3‐Di‐tert‐butyl‐l,3,2,4‐diazadistibetidinesStarting from 1,3‐di‐tert‐butyl‐2,4‐dichloro‐1,3,2,4‐diazadistibetidine a series of 1,3,2,4‐diazadistibetidines [R–SbN–ttBu]2 with R = OMe (2), OPh (3), OtBu (4), N(Tms)2 (5), P(Tms)2 (6), Me (7), and tBu (8) has been synthesized. The NMR spectra prove most of the reaction products to be mixtures of geometrical isomers. The structure of trans‐tetra‐tert‐butyldiaza‐distibetidine 8a was confirmed by X‐ray structure determination.
Oxidative Addition von Halogenpentamethylcyclopentadienen an Metallcarbonyle: ein einfaches Verfahren zur Synthese von (η5‐Pentamethylcyclopentadienyl)metallhalogeniden
Authors: Jutzi Peter , Mix Andreas 
Published: July 2007

Oxidative Addition of Halogenopentamethylcyclopentadienes to Metal Carbonyls: A Simple Method for the Synthesis of (η5‐Pentamethylcyclopentadienyl)metal HalidesThe alkyl halides 5‐chloro‐1,2,3,4,5‐pentamethyl‐1,3‐cyclopentadiene (1), 5‐bromo‐1,2,3,4,5‐pentamethyl‐1,3‐cyclopentadiene (2) and 5‐iodo‐1,2,3,4,5‐pentamethyl‐1,3‐cyclopentadiene (3) add oxidatively to the metal centres of carbonyl complexes of group‐8 elements. Thus, 1 and 2 react with Fe(CO)5 to give compounds of the type (C5Me5)Fe(CO)2X (X = Cl, Br) (4, 5). Irradiation of Ru3(CO)12 together with 1 and 2 yields the compounds (C5Me5)Ru(CO)2X (X = Cl, Br) (6, 7). Reaction of 1, 2, and 3 with Co2(CO)8 and Ni(CO)4 leads to halide‐bridged dinuclear complexes of the type [(C5Me5)MX]2 (M = Co, Ni; X = Cl, Br, I) (8–12).