bluuebunny/crossref_metadata_2025 huggingface dataset:
2,6‐Dicyan‐1,5‐tetramethylensemibullvalene
Authors: Quast Helmut , Mayer Andreas , Peters Eva‐Maria , Peters Karl , von Schnering Hans Georg
Published: July 2007

[4.3.3]Propellan‐8,11‐dion (10) reagiert mit Thiophenolen in Gegenwart von Titan(IV)‐chlorid/Triethylamin zu gleichen Mengen der Bis(vinylsulfide) C2/Cs‐11 (Ausb. 87–93%), die unter Trifluoressigsäure‐Katalyse zu einem 3:2‐Gemisch äquilibriert werden. Oxidation von C2/Cs‐11 mit Natriumperborat‐tetrahydrat in Essigsäure ergibt mit 81–93% Ausbeute die Bis(vinylsulfone) C2/Cs‐12. Die 4‐Chlorsulfone C2/Cs‐12b liefern mit Kaliumcyanid auf Aluminiumoxid in siedendem 2‐Methyl‐2‐butanol ein Gemisch der α,β‐ungesättigten Dinitrile 14–17 und 19, die chromatographisch getrennt werden. Dabei werden auch die Zwischenstufen 13 und 18 isoliert. Das Hauptprodukt 14 wird mit N‐Bromsuccinimid zu einem Gemisch von exo‐20, endo‐20, exo,exo‐21, exo,endo‐21, endo,endo‐21 und 22 bromiert, das chromatographisch getrennt wird. Die Konfiguration der γ‐Bromdinitrile exo‐20 und endo,endo‐21 wird durch Röntgenstrukturbestimmung geklärt. Das γ,γ′‐Dibromdinitril endo,endo‐21 reagiert nur sehr träge mit Zink/Kupfer oder Lithiumpulver und mit Tetracarbonylnikkel zu einem neuartigen Semibullvalen‐Dimeren, für das eine der regioisomeren Strukturen 26 und 27 vorgeschlagen wird. Beide γ‐Bromdinitrile exo‐20 und endo‐20 werden von Kalium‐tert‐butylat in Ether/tert‐Butylalkohol zu dem Dicyansemibullvalen 1c dehydrobromiert (Ausb. 38%). Das aus 14 mit zwei mol N‐Bromsuccinimid erhaltene Gemisch der γ‐Bromdinitrile wird auf die gleiche Weise dehydrobromiert und liefert 10% 1c und 28% Bromdicyansemibullvalen 32 (bez. auf 14), die chromatographisch getrennt werden. Erwartungsgemäß ist das Dicyansemibullvalen 1c thermisch stabiler als 1a (bis ca. 440 K), dem die Tetramethylen‐Brücke fehlt. Die Nitril‐IR‐Banden von 1c verändern sich zwischen 293 und 437 K reversibel, was mit der extrem hohen Geschwindigkeit (1011 s−1) der entarteten Cope‐Umlagerung zusammenzuhängen scheint.
Direct aminolysis of nonactivated and thermally unstable esters at high pressure
Authors: Matsumoto Kiyoshi , Hashimoto Shiro , Uchida Takane , Okamoto Tadashi
Published: July 2007

The preparation of the amides 3 from a wide variety of nonactivated esters 1 and secondary amines 2 has been achieved at 8 kbar and around 45°C; scope and limitations are discussed. The method was also successfully applied for the aminolysis of alkyl 2‐arylsulfinylacetates 7 that are relatively sensitive to heat.
Enantioselektive Gewinnung beider optischer Antipoden von 1‐(4‐Pyridyl)ethanol
Authors: Rasor J. Peter , Rüchardt Christoph
Published: July 2007

Enantioselective Preparation of both Enantiomers of 1‐(4‐Pyridyl)ethanol

4‐Acetylpyridin is reduced enantioselectively in high chemical yield by nonfermenting bakers' yeast to form (S)‐1‐(4‐pyridyl)‐ethanol. The kinetic resolution of racemic 1‐(4‐pyridyl)ethyl acetate by pig liver esterase yields (R)‐1‐(4‐pyridyl)ethanol, the (S)‐enantiomer remains in the acetate.
Metal ion binding by amino acids. Preparation and crystal structures of lithium hydrogen L‐aspartate hydrate and potassium hydrogen L‐aspartate dihydrate
Authors: Schmidbaur Hubert , Bach Ina , Wilkinson Dallas L. , Müller Gehard
Published: July 2007

Lithium hydrogen L‐aspartate, prepared by neutralisation of lithium carbonate with aqueous L‐aspartic acid L‐AspH2, crystallizes as the monohydrate Li(L‐AspH)· H2O. Saturated solutions show pH 7.30. Potassium hydrogen L‐aspartate, synthesized similarly from L‐AspH2 and KOH, crystallizes from aqueous solutions (pH 7.52) as the dihydrate K(L‐AspH)· 2 H2O. The NMR spectra of the two complexes exhibit no major differences. – Crystalline Li(L‐AspH). H2O has a layer structure, in which each lithium atom is in a tetrahedral environment of four oxygen atoms belonging to four different amino acids. The hydrate water molecule and the nitrogen function (protonated to give an ammonium center) have no metal contact, but are components of a network of hydrogen bonds interconnecting the layers. One of the carboxylate oxygen atoms is in a bridging position between the metal atoms, which are arranged in pairs and participate in edge‐sharing six‐membered rings. In each of the layers large empty channels are formed. – Crystals of K(L‐AspH)· 2 H2O show a chain structure with the potassium atoms exhibiting coordination number 7. The metal atoms are again arranged in double strings with the β‐carboxylate oxygen atoms of the L‐AspH− counter anions in chelating and bridging positions. The α‐carboxylate and protonated amino functions show no metal contacts, but are part of the hydrogen‐bonding system interconnecting the chains of the coordination polymer. Both hydrate water molecules are K‐coordinated, one in a metal‐bridging position.
Eine einfache Synthese neuartiger alkenylsubstituierter Chromcarben‐Komplexe
Authors: Wienand Anette , Reißig Hans‐Ulrich , Fischer Helmut , Hofmann Josef
Published: July 2007

Der Chromcarben‐Komplex 1 reagiert mit den β‐donorsubstituierten Acrylnitrilderivaten 3 und 5 zu neuartigen alkenylsubstituierten Carben‐Komplexen 4 und 6. Die Struktur dieser Insertionsprodukte wurde spektroskopisch geklärt. Die von 4 durch Kristallstrukturanalyse erhaltenen Daten werden mit denen verwandter Carben‐Komplexe verglichen.
Zur Chemie des (2,4,6‐Tri‐tert‐butylphenyl)isocyanids
Authors: Pakusch Jeachim , Rüchardt Christoph
Published: July 2007

On the Chemistry of (2,4,6‐Tri‐tert‐butylphenyl)isocyanide

The thermal rearrangement of (2,4,6‐tri‐tert‐butylphenyl)isocyanide, available from 1,3,5‐tri‐tert‐butylbenzene in 45% yield by a four‐step synthesis, offers a high‐yield access to 2,4,6‐tri‐tert‐butylbenzonitrile and ‐benzoic acid. The rate of this rearrangement is only slightly retarded by the bulkyorthosubstituents, confirming the pericyclic transition state proposed earlier.
Schwefel(IV)‐Verbindungen als Liganden, IX: Molybdän‐Rhodium‐Zweikernkomplexe mit Schwefeldioxid als Brückenligand
Authors: Schenk Wolfdieter A. , Hilpert Georg H. J.
Published: July 2007

Die heteronuklearen Zweikernkomplexe [MoRhCl(CO)3(μ‐SO2)(μ‐Ph2E1CH2E3Ph2)(μ‐Ph2E2CH2E4Ph2)] (E = P, As, 1–4), [MoRhBr(CO)3(μ‐SO2)(μ‐Ph2PCH2PPh2)2] (5) und [MoRh(CN)(CO)3‐(μ‐SO2)(μ‐Ph2PCH2PPh 2)2] (6) sind die ersten Verbindungen, in denen Schwefeldioxid als Brückenligand an zwei Metallatome aus verschiedenen Gruppen des Periodensystems gebunden ist. Die Synthese geht von Mo(CO)3(NCMe)3 (7) aus, das mit den Chelatliganden Ph2PCH2PPh2 (dppm), Ph2AsCH2PPh2 (dapm) und Ph2AsCH2AsPh2 (daam) zu den einkernigen Vorstufen Mo(CO)3(η2‐Ph2E1CH2E3 Ph2) (η1‐Ph2E2CH2E4 Ph2) (9–12) umgesetzt wird. Daraus entstehen mit [Rh2Cl2(CC)4] die Zweikernkomplexe [MoRhCl(CO)4(μ‐Ph2E1CH2E3Ph 2)(μ‐Ph2E2CH2E4Ph2)] (15–18). Reversibler CO/SO2‐Austausch ergibt schließlich 1–4 und das analoge Bromid 5, der Cyanokomplexe 6 wird aus 1 und NaCN in flüssigem Ammoniak erhalten.
Darstellung und Struktur eines neungliedrigen Niob‐haltigen Heterocyclus mit oxidischen und nitridischen Struktureinheiten
Authors: Roesky Herbert W. , Liebermann Johannes , Noltemeyer Mathias , Schmidt Hans‐Georg
Published: July 2007

Synthesis and X‐ray Structure of a Nine‐Membered Heterocycle Containing Niobium and Oxidic and Nitridic Structural Elements

(Me3SiNPPh2CH2)2 (1) reacts with NbCl5 to form (H2CPPh2NNbCl4)2 (2). The reaction of 2 with THF yields the nine‐membered metallaheterocycle (3). Simultaneously, (ClCH2CH2)2 is produced. The X‐ray structure of 3 is reported.
Aminoglycoside antibiotics — Enantiomerically pure sannamine building blocks
Authors: Kühlmeyer Rainer , Seitz Bernhard , Weller Thomas , Fritz Hans , Schwesinger Reinhard , Prinzbach Horst
Published: July 2007

Starting from the prochiral dianhydrodeoxy‐epi‐inositol 9 a highly efficient synthesis for rac‐sannamines (1, salts, derivatives) and rac‐de‐O‐methylsannamine (18, salt) has been developed. Key steps are two regiospecific, practically quantitative epoxide opening reactions: intramolecularly in the diepoxyurethanes 11 and intermolecularly in the epoxyurethanes rac‐13. With (R)‐1‐phenyl‐ethylamine as potential primary amino group in the second step separation of the corresponding diastereomers (16, 16′) is achieved without significant loss of material. By this route enantiomerically pure (de‐O‐methyl)sannamines become available in which all functionalities are protected except that to be glycosidated. Attempts for an asymmetric realization of this synthesis resulted in only very small ee(de) values.
Aminoglycoside antibiotics — Enantiomerically pure sporamine building blocks
Authors: Seitz Bernhard , Kühlmeyer Rainer , Weller Thomas , Meier Walter , Ludin Christian , Schwesinger Reinhard , Knothe Lothar , Prinzbach Horst
Published: July 2007

Starting from the 1,2:4,5‐dianhydro‐epi‐deoxyinositol 2a (available ultimately from benzene) and expedient total synthesis of rac‐sporamine (rac‐3) has been developed. Key steps are two regiospecific and quantitative epoxide openings, effected intramolecularly in the diepoxyurethane 2b and intermolecularly by potassium iodide in the epoxyurethanes rac‐4, and the equally uniform substitution in the iodide rac‐5d by hexa(tetra)methylguanidinium azide. The separation of diastereomeric esters with (−)‐camphanic acid (19/19′) opens the way to the pure enantiomers 3/ent‐3. The scheme allows chemical modifications and provides sporamine equivalents in which only the OH group to be ultimately glycosidated remains unprotected.
1,5‐Cyclooctandiylborylselenide — Herstellung, Charakterisierung und Anwendung
Authors: Köster Roland , Seidel Günter , Yalpani Mohamed
Published: July 2007

Bis(1,5‐cyclooctandiylboryl)selenid (C8H14B)2Se (1) wird unter H2‐Entwicklung aus Bis(9‐borabicyclo[3.3.1]nonan) (9‐BBN)2 und elementarem Selen in Mesitylen bei ca. 150°C quantitativ hergestellt. Bis(1,5‐cyclooctandiylboryl)diselenid (C8H14BSe)2 (2) gewinnt man aus 1 und Selen mit hohen Ausbeuten, 9‐(Hydroseleno)‐9‐BBN (1H) [als kristallines cis‐(1H)2] aus 1 mit Anilin neben 9‐(Phenylamino)‐9‐BBN (3). – γ‐Picolin (γPic) und 1 bilden die 2:1‐Additionsverbindung γPic2‐1, Trimethylphosphan (TMP) und 1 die 1:1‐Additionsverbindung TMP‐1. Selenid 1 reagiert bei Raumtemperatur spontan unter Substituentenaustausch mit Trialkoxyboranen B(OR)3 (R = CH3, C2H5, C4H9) oder mit ClnAl(C2H5)3−n‐Verbindungen. – Aus 1H werden mit γPic, TMP und Chinuclidin (Q) die 1:1‐Additionsverbindungen γPic‐1H, TMP‐1H und Q‐1H hergestellt. — 1, 1H und 2 eignen sich zum Se/O‐Austausch mit organischen und anderen Sauerstoff‐Verbindungen sowie zur Addition an bestimmte C  C‐Dreifachbindungen. Reines Fe2Se3 wird aus 1 und Fe2O3 quantitative hergestellt.
Reaktionen am koordinierten Trichlormethylisocyanid, III: Heterofunktionalisierte (Alkylidenamino)carbene und Carbamoylisocyanide
Authors: Fehlhammer Wolf Peter , Beck Gerhard
Published: July 2007

Die Umsetzung von Pentacarbonyl(trichlormethylisocyanid)‐chrom (2) mit den sekundären Aminen Pyrrolidin, 2,6‐Dimethylpiperidin und Diethylamin im Verhältnis 1:2 führt zu den [Amino(imino)carben]chrom‐Komplexen Cr(CO)5{C(NR2)N  CCl2} 〈 R2 = [CH2]4 (5), MeCH[CH2]3CHMe (7), Et2 (11)〉; mit weiterem Amin erfolgt Substitution eines Chloratoms der Isocyaniddichlorid‐Gruppe und Bildung der Amino(chlorformamidino)carben‐Komplexe Cr(CO)5{C(NR2)N  C(Cl)NR2} 〈 R2 = [CH2]4 (6), [CH2]2 (8), [CH2]5 (9)〉. Letztere hydrolysieren leicht zu Carbamoylisocyanid‐Komplexen Cr(CO)5CNC(O)NR2 〈 R2 = [CH2]5 (10), Et2 (12) und [CH2]4 (13)〉. [Amino(guanidino)carben]chrom‐Komplexe (16a,b) entstehen durch nucleophilen Austausch beider Chloratome in 5 gegen die Ethylendiamin‐Funktion NR[CH2]2NR (R = Me, H). Aus 2 und Ethanthiol resultieren die Verbindungen [Bis(ethylthio)carben]‐pentacarbonylchrom (14, Nebenprodukt) und Cr(CO)5{C(SEt)N  C(Cl)SEt} (15, Hauptprodukt).
Synthese und Struktur eines viergliedrigen Tellur — Stickstoff‐Rings
Authors: Münzenberg Jörg , Noltemeyer Mathias , Roesky Herbert W.
Published: July 2007

Synthesis and Stucture of a Four‐Membered Tellurium‐Nitrogen Ring

Reaction of Ph3P  NSiMe3 (1) with TeCl4 leads to (Ph3P  NTeCl3)2 (3). Single crystals of 3 were obtained by recrystallization from CH2Cl2; they contain two molecules of solvent. 3 forms a four‐membered planar Te2N2 ring with alternating TeN bonds.
Dithia‐diaza[n.2]metacyclophan‐ene
Authors: Grützmacher Hans‐Friedrich , Schmiegel Jürgen
Published: July 2007

Dithia‐diaza[n.2]metacyclophan‐ene 5a–f mit n = 6, 7, 8, 10, 12 und 16 werden nach dem „Rigid‐Group”︁‐Prinzip durch Kupplung von 1,2‐Bis[3‐(brommethyl)phenyl]‐4,4‐dimethyl‐3,5‐pyrazolidindion (2) mit entsprechenden 1,ω‐Alkandithiolen 3a–f unter Anwendung der Verdünnungsmethode und anschließende Abspaltung der Dimethylmalonyl‐Schutzgruppe hergestellt. 1H‐NMR‐Spektren beweisen für 5a (n = 6) und für 5b (n = 7) eine. cis‐Azokonfiguration mit schneller anti/anti′‐Konformationsumwandlung, für 5d–f mit längeren Verbindungsketten eine trans‐Azokonfiguration. Alle trans‐Isomere lassen sich photochemisch bei λ = 369 nm quantitativ in die cis‐Isomeren umwandeln. cis‐5b liefert unter diesen Bedingungen ein photostationäres cis/trans‐Gemisch mit ca. 60% des erheblich gespannten trans‐5b, während 5a weder thermisch noch photochemisch in das trans‐Isomere übergeführt werden kann.
Synthesis and ring transformation of a new fused as‐triazinium salt
Authors: Juhász‐Riedl Zs. , Hajós Gy. , Kollenz G. , Messmer A.
Published: July 2007

The 1,2‐Diaminopyridinium salt 1 was treated with furandione 2 to give pyrido‐as‐triazinone 3, which could be cyclized to the tricyclic furo[2,3‐e]pyrido[1,2,‐b]‐as‐triazinium salt 5. Reaction of 5 with nucleophiles resulted in different types of products. Thus, aqueous base afforded bicyclic triazinone 4, methoxide ion or secondary amine led to stable zwitterions 7a, b, whereas ammonia and hydrazines resulted in ring transformation of the furan moiety, and gave new fused tricyclic pyrroles (10, 11) and pyridazines (13, 14), respectively.
Enolether, XIX: Untersuchungen zur Autoxidation und zur Umlagerung von [n] (2,4) Phloroglucinophanen
Authors: Effenberger Franz , Spachmann Bernd , Schönwälder Karl‐Heinz
Published: July 2007

Bei der Autoxidation von [n](2,4)Pholoroglucinophanen3können in einigen Fällen Hydroperoxide7als erste Oxidationsprodukte isoliert werden, die unterschiedlich rasch in die stabileren monohydroxylierten Verbindungen8übergehen. Aclphloroglucinophane5reagieren mit Luftsauerstoff dagegen zu den zweifach hydroxylierten Verbindungen9. Die Geschwindigkeit der Autoxidation ist bei den Phloroglucinophanen3, 5deutlich größer als bei den 2,4‐Diethylphloroglucinen6. Im alkalischen Medium lagern sich die Hydroxyverbindungen8in die Dihydroxycyclopentenone12um, wobei für die Geschwindigkeit der Umlagerung eine Korrelation mit der Abnahme an Ringspannung gefunden wird.
Radikalreaktionen an N‐Heterocyclen, IX: Oxidationsreaktionen cyclischer Amidrazone
Authors: Schulz Manfred , Kluge Ralph , Höll Bernd Volker , Drewelies Jürgen
Published: July 2007

Die cyclischen Amidrazon‐Derivate 1 und 2 werden mittels Dibenzoylperoxid oder Brom zu den entsprechenden Dehydroverbindungen 5 bzw. 6 oxidiert. Aus 2 und auch aus 6 entsteht durch Oxidation mit Fremys Salz das Chinonimin 7. Das cyclische Amidrazon 3 liefert mit Ag2O einen isolierbaren Silberkomplex, nach dessen Zersetzung mit Salpetersäure das 5,6‐Diketo‐Derivat 9 und das 5‐Keto‐Derivat 10 isoliert werden. Das durch Nitrosierung aus 3 dargestellte Dimer Bis(1,4,5,6‐tetrahydro‐4‐nitroso‐1,3‐diphenyl‐1,2,4‐triazin) 11 reagiert bei UV‐Belichtung oder thermisch zum 1‐(p‐Nitrophenyl)‐Produkt 12 von 3. In Gegenwart von O2 führt die Photolyse von 11 zu den Hydroperoxiden 13 und 14, Verbindungen eines neuartigen Peroxid‐Typs. Mit Mineralsäure wird aus 13 die Imido‐azo‐Verbindung 17 gebildet. Durch Basenzersetzung der Hydroperoxide 13 und 14 entstehen die entsprechenden cyclischen Diketoverbindungen 15 und 16. 2,5‐Dihydro‐1,3‐diphenyl‐1,2,4‐triazin‐6(1H)‐on (4) reagiert quantitativ mit drei Äquivalenten des stabilen 2,4,6‐Tri‐tert‐butylphenoxyls (18) zu Hippursäure und Phenyldiimid (20).
Mehrfachbindungen zwischen Hauptgruppenelementen und Übergangsmetallen, LXXI: Offenkettige und ringförmige Organorhenium‐Komplexe der π‐Aromaten‐Reihe: sauerstoff‐, schwefel‐ und selenhaltige Derivate. Starker statischer trans‐Einfluß in der Kristall‐ und Molekülstruktur von Di‐μ‐sulfido‐bis‐[oxo(η5‐pentamethylcyclopentadienyl)rhenium(V)]
Authors: Herrmann Wolfgang A. , Jung Karin A. , Herdtweck Eberhardt
Published: July 2007

Durch Umsetzung des Re(V)‐Komplexes (η5‐C5Me5)ReCl4 (1b) mit Lithiumhydroxid läßt sich sehr einfach die Schlüsselverbindung (η5‐C5Me5)2Re2O4 (2) herstellen. Behandlung von 2 mit Kohlenstoffdisulfid in der Hitze gibt den neuen μ‐Sulfido‐Komplex (η5‐C5Me5)2Re2(μ‐S)2O2 (3), der einer Röntgenstrukturanalyse zufolge zueinander trans‐ständige, stark dezentral π‐koordinierte Ringliganden und brückenständige Schwefelatome aufweist (pseudotetraedrische Metallkoordination). Der Komplex (η5‐C5Me5)ReOCl2 (1a) ergibt mit Silbersalzen von anorganischen und organischen Säuren die neuen Verbindungstypen 4–8 und 9a. Die η2‐Sulfito‐ und η2‐Selenito‐Komplexe 9b bzw. 9c erhält man durch Cycloaddition von Schwefel‐ bzw. Selendioxid an Rhenium‐Sauerstoff‐Bindungen von 2.
(Ligand)Übergangsmetall‐π‐Komplexe organosubstituierter 2,5‐Dihydro‐1,2,5‐azasilaborole — Herstellung und Charakterisierung in Lösung
Authors: Köster Roland , Seidel Günter , Wrackmeyer Bernd , Schlosser Dieter
Published: July 2007

Aus den Heterocyclen 4, 5 und 7 sowie 5a, η6‐Cr(CO)3 werden durch thermische oder photochemische Umsetzung mit geeigneten Organometall‐Verbindungen folgende η4‐Komplexe erhalten: (OC)4M‐4a (M = Cr, Mo), (OC)3Fe‐4f, j, die exo/endo‐Komplexe (OC)3Fe‐4c, ‐7c, d, CpCo‐4h, j, CpCo‐5a‐η6‐Cr(CO)3, endo/exo‐CpCo‐7c, exo‐CpCo‐7d, (OC)3Ru‐4a, (acac)Rh‐4a, [ClRh‐4a]2 und (C2H4)ClIr‐4a. Die cyclodiastereotopen Heterocyclen 4c, 7c und 7d komplexieren am Ligand‐Übergangsmetall diastereoselektiv. Aus (Na‐3a) und [(C2H4)2RhCl]2 erhält man [(C2H4)Rh‐η1η4‐3a]2. Die Vinyl‐Verbindungen 4b und 5b führen zu η4‐Komplexen unter Anbindung der Metall‐Atome an die endo‐C  CB  N‐ und/oder exo‐C  CC  C‐Gruppierung. Sämtliche π‐Komplexe sind massenspektrometrisch und mittels Multikern‐NMR‐Spektroskopie (1H, 11B, 13C, 14,15N, 17O, 29Si, 59Co, 103Rh) charakterisiert. Ihre Bindungsverhältnisse werden aufgrund der NMR‐Daten diskutiert.
Oligophosphan‐Liganden, XXX: Mono‐ und Bis(distickstoff)molybdän(0)‐Komplexe des dreizähnigen Chelat‐Phosphans MeP(CH2CH2CH2PMe2)2: Synthesen, Strukturen und Reaktionen mit Kohlendioxid
Authors: Dahlenburg Lutz , Pietsch Bernd
Published: July 2007

Die Reduktion von mer‐MoCl3[MeP(CH2CH2CH2PMe2)2] · 0.75 THF mit fein verteiltem Natrium in Gegenwart eines Äquivalents PMe3 in THF unter N2 ergibt den Bis(distickstoff)‐Komplex Mo(N2)2[MeP(CH2CH2CH2PMe2)2](PMe3) (1) als Gemisch von cis‐ und trans‐Isomeren. Die Umsetzung von 1 mit PMe3 liefert das Mono(distickstoff)‐Derivat Mo(N2)[MeP(CH2CH2CH2PMe2)2](PMe3)2 (2), das auch aus mer‐MoCl3 [MeP(CH2CH2CH2PMe2)2] · 0.75 THF, Na, N2 und überschüssigem PMe3 entsteht. 1 und 2 reagieren mit CO2 zu Mo(CO3)(CO)[MeP(CH2CH2CH2PMe2)2](PMe3), (3), das im Vakuum, nicht aber in Lösung, PMe3 unter Bildung von Mo(CO3)(CO)[MeP(CH2CH2CH2PMe2)2] (4) verliert. Für das mer,cis‐Isomer von 2 liegt eine Röntgenstrukturanalyse vor.
Die PP‐Doppelbindung und die phosphoraromatischen Verbindungen P und P6. Ab‐initio‐Berechnungen von Strukturen und Stabilitäten
Authors: Janoschek Rudolf
Published: July 2007

Phosphor zeigt in den Eigenschaften seiner Doppelbindung eine engere Verwandtschaft mit Kohlenstoff als das dazu homologe Silicium. Das phosphoraromatische P6 unterscheidet sich von Benzol weniger in den π‐Elektroneneffekten als im σ‐Gerüst, während sich P in jeder Hinsicht als der phosphoraromatische Prototyp erweist.
A chelate‐controlled route to disubstituted and tetrasubstituted γ‐lactones stereoselectivity in lewis acid promoted additions to chiral methyl β‐formylcarboxylates
Authors: Kunz Thomas , Janowitz Agnes , Reißig Hans‐Ulrich
Published: July 2007

On reaction with allyltrimethylsilane/TiCl4, chiral methyl β‐for‐mylcarboxylates 1a–1h provide disubstituted and tetrasubstituted γ‐lactones 3a–3h with moderate to excellent diastereoselectivities. Other Lewis acids are less selective. The formation of seven‐membered ring chelates 1 · TiCl4 has been proven unambiguously by NMR spectroscopy in several cases. Trichloromethyltitanium displays a selectivity pattern similar to the reagen combination allylsilane/TiCl4. Aldehydes 1a–1d, 1g, and 1h give primarily trans‐γ‐lactones, whereas under appropriate conditions 1f affords an excess of cis‐γ‐lactone 3f. These results are discussed with regard to the Felkin‐Anh model and to chelate formation. Model studies with simpler chiral aldehydes 5 and 7 as well as with acetals 9a/b and 11a/b are presented and discussed. They emphasize the importance of chelate control in additions to β‐formyl esters 1.
2‐Acetyl‐4,5,6‐trichlor‐1,3‐tropolon durch Ringerweiterung von Tetrachlor‐o‐benzochinon mit Aceton
Authors: Kogler Herbert , Fehlhaber Hans‐Wolfram , Leube Karl , Dürckheimer Walter
Published: July 2007

2‐Acetyl‐4,5,6‐trichloro‐1,3‐tropolone form Ring Enlargement of Tetrachloro‐o‐benzoquinone with Acetone

Reaction of tetrachloro‐o‐benzoquinone with acetone leads to 2‐acetyl‐4,5,6‐trichloro‐1,3‐tropolone (2). The correct structure of this product was now determined using C,C‐correlating NMR spectra. Methanolysis of the tropolone 2 opens an interesting pathway to the substituted phthalide 4.
Hetero diels‐alder reactions of allenes on silica gel surface and under liquid‐phase conditions
Authors: Conrads Martin , Mattay Jochen , Runsink Jan
Published: July 2007

Some examples of cycloadditions of 1‐ethoxy‐1,2‐propadiene with 1‐oxa‐1,3‐dienes, catalyzed by acid‐free silica gel, are reported.
Reactivity of titanium(II) Arene derivatives with substituted alkynes. Cyclooligomerization reactions and crystal and molecular structure of [η4‐C4(C6H5)4]Ti[(μ‐Br)2(AlBr2)]2
Authors: Calderazzo Fausto , Marchetti Fabio , Pampaloni Guido , Hiller Wolfgang , Antropiusová Helena , Mach Karel
Published: July 2007

By treating Ti(η6‐toluene)[(μ‐X)2(AlX2)]2 (X = Cl: 1a, X = Br 1b) with C2R2 (R = Me, Ph) tetraorganylcyclobutadiene complexes of formula Ti(η4‐C4R4)[(μ‐X)2(AlX2)]2 (R = Ph, X = Cl: 2a, X = Br: 2b; R = Me, X = Br: 3b) have been obtained in good yields. Compound 2b has been studied by X‐ray diffraction methods. The titanium atom possesses an approximate square pyramidal coordination, the apical position being occupied by the symmetrically bonded tetraphenylcyclobutadiene ring, the four bridging bromides to the two AlBr2 groups forming the base of the pyramid, 0.99 Å away from the titanium atom. The tetrabromoaluminato moiety of 2b can be substituted by carbocyclic anionic ligands, such as Cp and COT, and the corresponding complexes 4 and Ti(η4‐C4Ph4)(COT) were obtained. The spectroscopic study of the Ti(η6‐benzene)[(μ‐X)2(AlX2)]2/diphenylacetylene (DPA) system (X = Cl: 5a, X = Br: 5b) has revealed the existence of three products, corresponding to the 1:1, 1:2, and 1:3 molar ratios. The possible role of the known AlX3 · C4R4 complexes in this reaction is discussed. The cyclotrimerization reactions of substituted acetylenes in the presence of η6‐arenetitanium(II) complexes as precursors have been studied. In toluene or methylcyclohexane Ti(η6‐toluene)[(μ‐Br)2(AlBr2)]2 was found to catalyze the formation of alkyl‐substituted aromatic hydrocarbons from 2‐butyne, phenylacetylene, and 1‐hexyne at about 80°C over 15 h with turnovers (moles of converted alkyne per mole of titanium) of about 520, 900, and 990, respectively. The cyclooligomerization of DPA in the presence of Ti(η6‐benzene)[(μ‐X)2(AlX2)]2 (X = Cl, Br) was studied in detail. The activity of the chloro derivative 5a is higher than that of the bromide catalytic precursor 5b. In addition to hexaphenylbenzene and octaphenylcyclooctatetraene, other oligomerization by‐products (triphenylethylene, 1,1,2,2‐tetraphenylethane, 1,2,3‐triphenylnaphthalene, and 1,2,3‐triphenylazulene) were observed, whose formation was drastically reduced in the presence of alkyl aluminium halides.
Dichlorobis(η5‐cyclopentadienyl)rhenium(VII)‐tris(hexafluoroantimonat): Synthese des ersten Rhenocen(VII)‐dichlorid‐Kations
Authors: Gowik Petra , Klapötke Thomas , Tornieporth‐Oetting Inis
Published: July 2007

Dichlorobis(η5‐cyclopentadienyl)rhenium(VII) Tris(hexafluoroantimonate): Synthesis of the First Rhenocene(VII) Dichloride Cation

Rhenocene trichloride ([Cp2ReCl2]⊕ Cl⊖, 1) reacts with one equivalent of AgSbF6 and three equivalents of SbF5 to provide [Cp2ReCl2]3⊕[SbF6]⊖3 (2) in high yield. 2 contains the first rhenocene(VII) dichloride cation and is the first member of a 16‐electron group‐7 species of the type [Cp2MCl2]n⊕ [EF6] (M = Ti, Zr, Hf: n = 0; M = V, Nb: n = 1; M = Mo, W: n = 2; M = Re: n = 3; E = As, Sb).
Heterocyclen als Liganden, VI: Die verbrückende Koordination eines 1,1′‐Diazaferrocens in einem zweikernigen Silberkomplex — eine ungewöhnliche Struktur
Authors: Kuhn Norbert , Horn Eva‐Maria , Boese Roland , Bläser Dieter
Published: July 2007

Heterocycles as Ligands, VI1. ‐ The Bridging Coordination of a 1,1′‐Diazaferrocene in a Dinuclear Silver Complex ‐ an Uncommon Structure

[Ag2(μ‐pyrFe)2](BF4)2 · 2 MeOH (4, pyr* = C4Me4N) is obtained by reaction of pyrFe · 2 Hpyr* (3) with AgBF4 in MeOH. The X‐ray structure of 4 shows the bridging coordination mode of the diazaferrocene ligands with a nearly linear geometry at the silver atoms.
Synthese und Eigenschaften von iPr2InCl, iPrInCl2 und (iPr2InNHtBu)2
Authors: Neumüller Bernhard
Published: July 2007

Synthesis and Properties of iPr2InCl, iPrInCl2, and (iPr2InHRtBu)2

The reactions of triisopropylindium (1) with half an equivalent or two equivalents of indium (III) chloride leads to iPr2InCl (2) and iPrInCl2 (3), respectively. (iPr2InNHtBu)2 (4) can be synthesized from 2 and LiNHtBu. According to NMR, IR, and RE studies, 2–4 from dimers in solution and solid state. The X‐ray analysis of 4 is reported.
Anwendungen der 13C‐NMR‐Spektroskopie, XXVIII: Die Aktivierungsparameter der Cope‐Umlagerung von 3,7‐Diethoxy‐1,5‐dimethyl‐2,4,6,8‐tetraazabarbaralan
Authors: Moskau Detlef , Leber Winfried , Günther Harald , Gompper Rudolf , Spes Peter
Published: July 2007

Die entartete Cope‐Umlagerung von 3,7‐Diethoxy‐1,5‐dimethyl‐2,4,6,8‐tetraazabarbaralan wurde mittels dynamischer 13C‐NMR‐Spektroskopie im Temperaturbereich von 192 bis 242 K untersucht. Aus der NMR‐Linienformanalyse ergaben sich folgende Aktivierungsparameter nach Arrhenius und Eyring: Ea = 10.4 kcal mol−1, lg A = 13.8; ΔH≠ = 9.94 kcal mol−1, ΔS≠ = 3.4 cal K−1 mol−1 und ΔG298≠ = 8.93 kcal mol−1. Aus dem Vergleich mit Freien Aktivierungsenthalpien verwandter Systeme kann gefolgert werden, daß Tetraaza‐Substitution in 2,4,6,8‐Stellung die Barriere der Cope‐Umlagerung von Barbaralan geringfügig erniedrigt.
Substitutionen und Additionen an (R)‐2‐tert‐Butyl‐Δ4‐1,3‐oxazolin‐3‐carbonsäure‐methylester
Authors: Stucky Gerhard , Seebach Dieter
Published: July 2007

Enantiomerenreine Δ4‐1,3‐Oxazoline (1–5) mit einer tert‐Butyl‐Gruppe in 2‐Stellung werden über einen elektrochemischen Schlüsselschritt im 100‐g‐Maßstab aus Serin oder Threonin hergestellt; sie enthalten gegenüber Elektrophilen (1–3) oder Nucleophilen (4, 5) hochreaktive Doppelbindungen, so daß Formylierungen, Acylierungen (→21, 22) oder konjugierte Additionen (→11, 13) an C‐5 durchgeführt werden können. Eine Art ortho‐Metallierung (neben der Carbamoyl‐Gruppe) an C‐4 erlaubt es, auch in dieser Position Substituenten einzuführen (→4, 10). Schließlich reagiert das Dienolat aus 5 mit Aldehyden in der exocyclischen Position (→18). In so hergestellten Oxazolinen kann die tri‐ oder tetrasubstituierte Doppelbindung stereoselektiv hydriert werden (→14, 19, 24, 26). In den meisten Fällen dirigiert die tert‐Butyl‐Gruppe in 2‐Stellung des Heterocyclus den Angriff von Reaktionspartnern auf die andere Seite des Fünfringes. Eine retrosynthetische Analyse zeigt auf, welche Bindungen der ursprünglich eingesetzten Aminosäuren Serin und Threonin durch die hier beschriebenen Reaktionen letztlich betroffen sind.
Ein makrobicyclischer Großhohlraum zur selektiven Komplexierung von Alkalimetall‐Ionen
Authors: Peter‐Katalinić Jasna , Ebmeyer Frank , Seel Christian , Vögtle Fritz
Published: July 2007

A Large Macrobicyclic cavity for the Selective Complexation of Alkali Metal Ions

The preparation of the new ligand 3 was carried out starting with the podand 8 and the triamine 11. Ligand 3 forms complexes with alkali metal ions in solution (chloroform) as well as under the conditions of FAB mass spectrometry, whereby Cs⊕ selectivity is observed.
Nitroxide (Aminyloxide), XLII: Die Isolierung des ersten OC‐verknüpften Dimeren eines Vinylnitroxids
Authors: Aurich Hans Günter , Keßler Wilfried
Published: July 2007

Nitroxides (Aminyl Oxides), XLII. — The Isolation of the First OC‐Bonded Dimer of a Vinyl Nitroxide

Vinyl nitroxide 2, formed by oxidation of nitrone 1, with lead dioxide, affords the OC dimer 3. Oxidation of 1 proceeds rather slowly. A high oxidation potential is found for 1. However, if vinyl nitroxide 2 is generated from the vinylhydroxylamine 4, the aldehyde 7 is formed by a complex reaction sequence.
Nucleophile Addition von Carbonylmetallaten an kationische Alkin‐Komplexe [CpL2M(η2‐RC≡CR)]+ (M = Ru, Fe): μ‐η1:η1‐Alkin‐verbrückte Komplexe
Authors: Breimair Josef , Steimann Manfred , Wagner Barbara , Beck Wolfgang
Published: July 2007

Hydrocarbon‐Bridged Complexes, XIIII). ‐ Nucleophilic Attack of Carbonylmetallates on Cationic Alkyne Complexes [CpL2M(η2‐RC I CR)]+(M = Fe, Ru): μ‐η1 : η1‐Alkyne‐Bridged Complexes

The σ,σ‐alkyne‐bridged complexes Cp(Me3P)2Ru[μ‐η1:η1‐(MeO2C)C = C(CO2Me)]MLn (1) [MLn = Ru(CO)2Cp, Mn(CO)5, Re(CO)5] are formed by addition of [Ru(Cp)(CO)2]‐, [Mn‐(CO)5]‐, and [Re(CO)5]‐ to the alkyne ligand of [Cp‐(Me3P)2Ru(MeO2CC≡CCO2Me)]+ and by addition of [Re‐(CO)5]‐ to [Cp(OC)(Ph3P)Fe(MeC≡CMe)]+. The crystal structure of 1a was determined by X‐ray diffraction and allows the comparison of bimetallic complexes with M–C≡C–M, M–C(R)=C(R)–M, and M – CH2CH2–M bridges. Addition of [Re(CO)5]‐ to [Cp(OC)(L)Fe(RC≡CR)]+ (L = CO:R = Me; L = P(OPh)3, PPh3; R = Et) yields the complexes Cp(OC)‐(L)Fe‐Re(CO)5 (3) with metal–metal bond.
π‐Complexes of p‐Block Elements: Planar Dihydroanthracene in a Menshutkin Complex. Crystal Structure of Br3Sb · C6H4(CH2)2C6H4 · SbBr3
Authors: Schmidbaur Hubert , Nowak Reinhold , Steigelmann Oliver , Müller Gerhard
Published: July 2007

Crystals of a 1:2 complex of 9,10‐dihydroanthracene and antimony tribromide are obtained from toluene solutions of the components. In the crystal the complex forms corrugated sheets of an inorganic (SbBr3)n coordination polymer, which are cross‐linked by antimony coordination to the benzene rings of the dihydroanthracene molecules are also arranged in folded layers. The dihydroanthracene molecules reside on centers of inversion and their carbon skeleton is planar within the limits of the experiment. With contacts from opposite sides of the molecular plane, the dihydroanthracene is η6,(η6)'‐coordinated to the Sb(III) centers at distances of 3.25 Å. In a very irregular geometry the coordination sphere of the crystallographically equivalent antimony atoms contains bromine neighbours at different distances. – Antimony trichloride and dihydroanthracene form a complex of ambiguous stoichiometry, while bismuth trichloride again gives a 2;1 complex, the structure of which has not yet been determined.
7‐(Trifluormethyl)‐1λ4,3λ4,5λ4,‐trithia‐2,4,6,8,9‐pentaazabicyclo[3.3.1]nona‐1(9),2,3,5,7‐pentaen als Komplexligand
Authors: Maggiulli Roberto , Mews Rüdiger , Stohrer Wolf‐Dieter , Noltemeyer Mathias
Published: July 2007

7‐(Trifluormethyl)‐1λ4,3λ4,5λ4,‐trithia‐2,4,6,8,9‐pentaazabicyclo[3.3.1]nona‐1(9),2,3,5,7‐pentaene as Ligand in Coordination Chemistry

Many possibilities exist for the title compound CF3CN5S3 (3) (L) to coordinate to transition metal centers. From the reaction of 3 with [Ni(SO2)2](AsF6)2 and AgAsF6 in liquid SO2 [Ni‐(SO2)2L2(FAsF5)2) (11) and [AgL]AsF6 (13) or [AgL2]AsF6 (14), respectively, were isolated. As shown by X‐ray structure determination of 11 and 14, L coordinates as expected from MNDO calculations.
Cyclische Natrium‐ und Kalium‐(fluorsilyl)phosphide – Synthesen und Kristallstrukturen
Authors: Andrianarison Mbolatiana , Stalke Dietmar , Klingebiel Uwe
Published: July 2007

Cyclic Sodium and Potassium (Fluorosily1)phosphides ‐ Syntheses and Crystal Structures

(Di‐tert‐butylfluorosilyl)(mesityl)phosphine (1) reacts with sodium or potassium to give the alkali compounds [(CMe3)2SiFM(THF)2PC6H2Me3]2 (2: M = Na; 3: M = K). The crystal structures of the eight‐membered rings 2 and 3 have been determined.
Complexes with Sterically Demanding Ligands, XI Synthesis and Properties of Trimethyl[ 1,2,4‐tris(trimethylsilyl)cyclopentadienyl] titanium
Authors: Okuda Jun
Published: July 2007

A new polyalkyl complex of titanium, trimethyl[l,2,4‐tris(trimethylsilyl)cyclopentadienyl]titanium, [η5‐1,2,4‐(SiMe3)3C5H2]‐TiMe3, has been synthesized and found to be thermally stable up to 110°C.
Reaction of 5‐Amino‐4,5‐dihydro‐4‐methylene‐1,2,3‐triazoles with 2,4‐Diaryl‐5(4H)‐oxazolon‐4‐yl Radicals
Authors: Arlandini Emaanule , Clerici Francesca , Erba Emanuela , Rossi Luisa Maria
Published: July 2007

When bioxazolones 2 are treated at high temperature with 5‐amino‐4,5‐dihydrotriazoles, 3, the corresponding triazolylmethyl‐5(4H)‐oxazolones 4 and 5 are produced by dissociation of 2 into oxazolonyl radicals and reaction of these with 3, followed by transfer a hydrogen or morpholinyl radical. Products 4 and 5 ar also formed starting form 3 and 5(4H)‐oxazolones 1, which are oxidized during the reaction to the corresponding bioxazolone 2, In this case, besides products 4 and 5, the corresponding triazolymethyl‐5(4H)‐oxazolones 6 are also formed, presumably by nucleophilic attack of the anion of 1 on substrate 3.
An Uncomplexed 1,2,3‐Triborolane Derivative
Authors: Meller Anton , Bromm Dietmar , Maringgele Walter , Heine Andreas , Stalke Dietmar , Sheldrick George M.
Published: July 2007

(3α,4β,4aβ,7aβ,8β,8aα)‐1,2,3‐Tris(diisopropylamino)‐1,2,3,3a,44a,5,7a,8,8a‐decahydro‐4,8‐methanoindeno[5,6‐d]‐1,2,3‐triborol (1) is formed from dicyclopentadiene and dichloro(diisopropylamino)borane upon treatment with sodium/potassium alloy in hexane. 1,2,3‐Tris(diiso propylamino)triborane(5) (2) was also obtained. 1 is characterized by elemental analyses, spectroscopic data, and by an X‐ray structure analysis, 2 by its MS and NMR data.
Konformationsanalyse am Beispiel des N‐Benzylpyridinium‐bromids: Vergleich von kristallstrukturanalytischen Daten mit den Ergebnissen von semiempirischen Berechnungen (MINDO/3, MNDO, AM1 und PM3)
Authors: Anders Ernst , Tropsch JüRgen G. , Irmer Erhard , Sheldrick George M.
Published: July 2007

Conformational Analysis of N‐Benzylpyridinium Bromide: A Comparison of Crystal Structure Data with Results of Semiempirical Calculations (MINDO/3, MNDO, AM 1, and PM3)

The conformation of the title compound 1b is investigated by X‐ray analysis and semiempirical MO methods (MINDO/3, MNDO, AM1, PM3). For the calculation of bond lengths and bond angles, AM1 and MINDO/3 are superior. Without complete calculation of the hypersurfaces of the variable D1, D2 and the relative energy (e. g. Figure 2), AM1 and MNDO can lead to false interpretations. Cuts through these surfaces (Figure 1) are calculated within moderate CPU time, Normally, these cuts are sufficient to characterize the conformational situation. The electronic influence of the phenyl group on the N1–C7 bond length of N‐alkylpyridinium salts and on the dissociation energy ΔHz (eg. 2) is estimated. The comparison of the data of 1a and 1b reveals that this group causes an elongation of this bond by 2 pm and a decrease of the dissociation energy by 200 kJ/mol.
Stereochemistry of Dewar Benzenes – Molecular Structures Influenced by Electronic and Steric Effects
Authors: Irngartinger Hermann , Deuter Jürgen , Wingert Horst , Regitz Manfred
Published: July 2007

The molecular structures of the four Dewar benzene derivatives 4–7 were determined by means of X‐ray diffraction. The central C1–C4 bonds are extremely long. The carboxylate groups on the bridgehead carbon atoms of 4, 5, and 7 are in optimal orientation for an electronic interaction with the central bonds having high p‐character. Therefore the central bonds in 4, 5, und 7 (1.602–1.612 Å) are even more elongated than in 6 (1.563 Å). Repulsion between tert‐butyl groups causes bond lengthening and structural deformations. The sp2‐hybridized carbon atoms are pyramidalized. From structural comparison of Dewar benzene derivatives a strong correlation between the length of the central bond and the folding angle of the four‐membered rings can be derived. A new rule has been established for the thermal stability of Dewar benzene derivatives.
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” Complexes

On 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 Compounds

Oximes 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‐ones

Tosylmethyl 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)2

Reactions 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 Nucleophiles

The 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 Complexes

Three 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 Complex

The 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 Tetrahydropentalenes

A 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 Groups

Synthesis 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‐Aminoalkyne

The 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 Insertion

The 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].