bluuebunny/crossref_metadata_2025_split huggingface dataset:
Umlagerungen von 6‐Bicyclo[3.2.1]octyl‐Kationen
Authors: Brandt Sigrid , Kirmse Wolfgang , Mönch Dietmar , Wroblowsky Heinz‐Jürgen 
Published: July 2007

Rearrangements of 6‐Bicyclo[3.2.l]octyl Cations6‐Bicyclo[3.2.1]octyl cations were generated by nitrous acid deaminations of the amines 12, 14 and by acetolyses of the tosylates 9, 20. the major products are bicyclo[3.2.1]octan‐exo‐6‐ol (17), bicyclo[3.2.1]octan‐exo‐2‐o. (18), and bicyclo[2.2.2]octan‐2‐ol (19). 4,6(4,5) hydride shifts account for the formation of 18 and 19. The product distributions indicate substantial kS contributions for he endo precursors while the exo precursors react almost exclusively by way of carbocations, as confirmed by the ring expansion of bicyclo[4.1.1]octane‐2‐di‐azonium ions (30. The product distributions obtained from the exo‐diazonium ion 15n and from the exo‐tosylate 20 are rather similar, but hte distributions of a deuterium label differ strongly. Dediazoniation of 15 leads to a highly unsymmetrical intermediate, whereas acetolysis of 20 involves an effectively equilibrated species. These findings cannot e interpreted in terns of open ions. Unsymmetrically bridged ions, whose conformational equilibration competes with substitution and hydride shifts, provide a consistent explanation.
Reaktionen von Homobenzvalenen mit 4 ‐Phenyl‐3H‐l,2,4‐triazol‐3,5(4H)‐dion, Tetracyanethylen, Chlorsulfonylisocyanat und Schwefeldioxid. Einige konzertierte 1,4‐Additionen an eine Vinylcyclopropan‐Einheit
Authors: Lang Reinhard , Herzog Clemens , Stangl Roland , Brunn Erich , Braun Max , Christl Manfred , Peters Eva‐Maria , Peters Karl , Schneringb Hans Georg Von 
Published: July 2007

Reactions of Homobenzvalenes with 4‐Phenyl‐3H‐1,2,4‐triazole‐3,5(4H)‐dione, Tetracyanoethylene. Chlorosulfonyl Isocyanate, and Sulfur Dioxide. Several Concerted 1,4‐Additions to a Vinylcyclopropane SubunitHomobenzvalene (le) and its derivatives 1f.g with an anellated four‐membered ring reacted with 4‐phenyl‐3H‐l,2,4‐tri‐ azole3,5(4H)‐dione (PTAD) to give the pentacyclic urazole 2e and its hexacyclic derivatives 2f, g, respectively. Tetracyano‐ ethylene (TCNE) and le in benzene afforded only the Diels‐ Alder adduct 5 of norcaradiene. In other solvents the homo Diels‐Alder adduct 3a of le was formed as the main product together with some 5 and a small fraction of the cyclohexa‐ dienylcyclopropanetetracarbonitrile 4a. 5‐Methylhomobenz‐ valene (lh) and TCNE in acetonitrile gave 3b and 4b in the ratio 10: 1. On treatment with TCNE, dihydrohomobenzvalene (6) was converted into 8, which is structurally related to 4. In contrast, tetracyc10[4.1.0.02,4.03,5]]heptane (7) and TCNE gave rise to the tetracyclic adduct 9 and a minor quantity of 5. Chlorosulfonyl isocyanate reacted with le to furnish mainly the N‐(chlorosulfony1)imino ether 10 and the N‐(chlorosulfonyl)‐lactams 11 and 12a as well as a further isomer as byproducts. On heating, 10 rearranged to 12a. The Ksulfonyl chlorides 10, 11, and 12a were transformed to the N‐unsubstituted compounds 16,15, and l7, respectively, by treatment with sodium sulfite/aqueous potassium hydroxide. In wet [D6]dimethyl‐ sulfoxide 10 was converted into a cycloheptatriene derivative (14) as well as the rearranged and hydrolyzed lactam 15, whereas 11 gave 15 exclusively. Exposure of le to sulfur dioxide yielded the 1,4 adduct 18 to the vinylcyclopropane subunit of le. Possible mechanisms of the reactions of the homobenzvalenes are discussed. In particular, the pathways to 3, 18, and at least to a fraction of 10 and 11 are considered to be concerted six‐electron processes. – The structures of 4a and 10 have been established by X‐ray analyses.
Schwermetall‐π‐Komplexe, V. Das Schichtenpolymer {([C6H6SnCl][GaCl4])2}x, y
Authors: Frank Walter 
Published: July 2007

Heavy Metal π Complexes, V1. ‐ The Layer Polymer {([C6H6SnCl][GaCl4])2}x,yIn the system C6H6/SnC12/GaC13 crystalline (benzene)chlorotin(+2) tetrachlorogallate(+3) (1) is obtained. According to an X‐ray structure analysis (Pca21) the solid contains polymeric {([C6H6SnCl][GaCl4])2}x,y layers built up by ((C6H6SnC1][GaCl4])2 structural units. A unit consists of an Sn2Cl22+ four‐ membered ring, two GaCl4− tetrahedra at opposite sides of the ring plane, and two benzene molecules bound to the tin atoms in a distorted η6 state. A pseudorotational disorder of one of the benzene ligands was found. The tin‐arene bonding is much weaker in 1 compared to the chain polymer (([C6H6SnCl](AICl4])}x(2).
Organosubstituierte Kalium‐2,5‐dihydro‐1,2,5‐oxasilaboratolate aus cis‐2‐Boryl‐1‐silylalkenen mit Kaliumhydroxid
Authors: Köster Roland , Seidel Günter , Wrackmeyer Bernd , Horchler Klaus 
Published: July 2007

Organosubstituted Potassium 2,5‐Dihydro‐1,2,5‐oxasilaboratolates from cis‐2‐Boryl‐1‐silylalkenes with Potassium HydroxideThe compounds (E)‐CH3ElIV(R2)2CR3C(C2H5)B(C2H5)2 [R2,2,3 = CH3: 1a; R2 = C2H5, R2,3 = CH3: 1b; R2,2 = C6H5, R3 = CH3: 1c; R2,2 = CH3, R3 = C6H5: 1d; R2,2 = CH3, R3 = c‐C6H11: 1e] add KOH in THF at – 20°C to form the pure solid 1:1 adducts KOH‐1ElIV with ElIV = Si, Sn, and Pb. Above ≥0°C compounds KOH‐1Si liberate quantitatively R2H to give the potassium salts of the cyclic anions K‐2a to K‐2e. With Me4NCl or Me3NHCl the corresponding salts Me4N‐2 or Me3NH‐2 are obtained from K‐2. Above ≈︁80°C KOH‐1aGe and KOH‐1aSn eliminate gas (CH4, C2H6) with formation of mixtures. The compounds KOH‐1ElIV and K‐2Si are characterized by multi‐NMR spectroscopy (1H, 11B, 13C, 17O, 29Si, 119Sn, 207Pb), and the NMR data of KOH‐1aElIV are compared to the data of the compounds .
Notizen / Notes. Eine neue Bildungsweise der Phosphor – Phosphor‐Bindung. Kristallstrukturanalyse von Tetramethyldiphosphanmonosulfid
Authors: Gruber Matthias , Jones Peter G. , Schmutzler Reinhard 
Published: July 2007

A New Mode of Formation of a Phosphorus ‐ Phosphorus Bond. X‐ray Crystal Structure of Tetramethyldiphosphane MonosulfideTetraphenyldiphosphane monosulfide (7) was formed during an attempt to synthesize the diphenylphosphino‐substituted thioureas 5 and 6 by the reaction of thiourea (1) or N,N′‐bis‐(trimethylsilyl)thiourea (2) with chlorodiphenylphosphane. The attempted distillation of the dimethylphosphino‐substituted N,N′‐dimethylthiourea 9 furnished tetramethyldiphos‐phane monosulfide (10). These reactions provide a new mode of formation of phosphorus – phosphorus bonds. – According to an X‐ray analysis, 10 crystallizes in the space group P21/n. The molecule adopts a trans configuration, with the S atom antiperiplanar to the lone pair.
Die Funktion der 4′‐Aminopyrimidin‐Komponente im Katalysemechanismus von Thiaminpyrophosphat‐Enzymen aus heutiger Sicht
Authors: Schellenberger Alfred 
Published: July 2007

The Function of the 4′‐Aminopyrimidine Component in the Mechanism of the Catalysis of Thiamine Pyrophosphate Enzymes from Today's ViewBinding mechanism and coenzyme function of thiamine pyrophosphate (TPP) are described with the help of site‐directed substitutions at different positions of the coenzyme. In accordance to the earlier suggestions of Langenbeck (see this issue2) it is shown, that besides the thiazolium moiety (C2 atom) also the aminopyrimidine part plays an essential role in the catalytic mechanism of TPP enzymes such as pyruvate decarboxylase, pyruvate dehydrogenase, and transketolase, respectively. A two‐center mechanism of TPP is proposed explaining the function of the amino group as an internal proton relay in the catalytic mechanisms of TPP enzymes.
Kooperative Wirkung in π‐Ligand‐verbrückten Zweikernkomplexen, IX. Einfluß der Cp′XCp′‐Brücke in CpM(CO)3‐Zweikernkomplexen (M  Mo, W) auf die Reaktion mit Alkinen2
Authors: Abriel Walter , Baum Gerhard , Heck Jürgen , Kriebisch Karin‐Anke 
Published: July 2007

Co‐operative Effect in π‐Ligand‐Bridged Dinuclear Complexes, IX. ‐ Influence of Cp′ ‐ X ‐ Cp′‐Bridged Dinuclear CpM(CO)3 Complexes (M  Mo. W) on Reactions with AlkynesThe Cp′  X  Cp′‐bridged dinuclear complexes Me2Si[Cp′M(CO)3)2 (4, Cp′  C5H4, M  Mo, W) react thermally as well as photochemically with alkynes RCCR′ to form the monoalkyne compounds {Me2Si(Cp′M(CO)2]2‐μ‐(η2:2‐RCCR′)} (6, 7, 9) which possess M2C2 dimetallatetrahedrane units (X‐ray structure analysis of 7a). A molecular fluxionality is shown for R  R′ (7) by NMR spectroscopy. The activation barrier for this process depends on the steric bulkiness of the alkyne substituents R. For this kind of dynamic behaviour a new mechanism is proposed. In the reaction of 4 (M  Mo) with the electron‐rich alkyne bis(diethylamino)ethyne (R  R′  NEt2) a novel bis(carbene) complex 8 is formed, which contains a 1,2‐dimetallacyclobutadiene core in the central M2C2 unit. In some cases products are isolated and characterized, in which three (R  Ph, 10) and two (R  nPr, 11) alkyne units are co‐ordinated under C ‐ C linkage. Based on spectroscopic results a structural proposal is made for 10. By X‐ray structure analysis of 11 it is shown that besides a dimerisation of the two alkynes an isomerisation occurs with formation of a complexed vinylallene.
Cycloadditionsreaktionen von Organometallkomplexen, XI. Cobalta‐Heterocyclen durch [2 + 3]‐Cycloaddition von α‐Ketocarbenen an Co‐CO‐ und Co‐ CNR‐Bindungen
Authors: Strecker Beate , Zeier Bernd , Schulz Michael , Wolf Justin , Werner Helmut 
Published: July 2007

Cycloaddition Reactions of Organometallic Complexes, XI. ‐ Cobaltaheterocycles by [2 + 3) Cycloaddition of α‐Keto Carbenes to Co ‐ CO and Co ‐ CNR BondsThe reactions of the carbonyl(cyclopentadienyl) and (cyclopentadienyl)isocyanidecobalt complexes C5H5Co(CO)(PR3) (1‐4) and C5H5Co(CNR)(PMe3) (5, 6) with α‐diazocarbonyl compounds R1C(O)C(N2)R2 lead to the formation of the cobaltaheterocycles C5H5(PR3)magnified image(O) (7‐12) and C5H5(PMe3)magnified image(NR) (13‐16), respectively. For R  (S)‐CH(Me)Ph a mixture of diastereoisomers RCoSCoSc is obtained. The complexes 13‐16 react with HBF4 in ether to give the cations [C5H5(PMe3)‐magnified image(NHR)]+ (17‐20, with BF4 as anion), which on treatment with base regenerate the uncharged cobaltaheterocycles. The X‐ray structural analysis of 19‐RCoSc reveals the presence of a planar CoOC3 five‐membered ring which presumably is formed by a [2+3] cycloaddition of an α‐ketocarbene to the CoCNR bond.
Alkinverbrückte Dreikerncluster mit Organo‐Rhodium‐Bausteinen
Authors: Albiez Thomas , Bantel Harald , Vahrenkamp Heinrich 
Published: July 2007

Alkyne‐Bridged Trinuclear Clusters with Organo‐Rhodium MoietiesSeveral approaches are utilized to incorporate rhodium‐containing building blocks in alkyne‐bridged trinuclear clusters. The metal exchange procedure allows to introduce a Rh(CO)3 unit into cluster 1 with formation of RuMoRhCp(CO)8(μ‐MeCCMe (6). Starting from dinuclear alkyne‐bridged complexes, RhCp units are attached, as in Co2RhCp(CO)6(μ‐HCCR) (10, 11) and CoMoRhCpCp*(CO)5(μ‐HCCR) (12). Side reactions yield tetranuclear clusters with Co2Rh2 and Co3Rh frameworks.
Conformational effects in 2‐deoxyglucopyranos‐1‐yl radicals
Authors: Korth Hans‐Gert , Sustmann Reiner , Giese Bernd , Rückert Brigitte , Gröninger Kai Stefan 
Published: July 2007

Abstract2‐Unsubstituted and 2‐substituted (fluoro, tosylamino, n‐propyl) 3,4,6‐tri‐O‐acetyl‐2‐deoxypyranosyl radicals are obtained by reaction of the corresponding pyranosyl bromides or phenylselenides with photolytically generated trimethyltin radicals in benzene solution. Analysis of the ESR hyperfine splittings reveals that the 2‐deoxy‐2‐fluoroglucopyranosyl radical exists in a boat‐like conformation at room temperature, whereas the others retain the 4C1 chair conformation of the starting material. The observed conformational effects are explained by a “quasi‐homo‐anomeric” frontier orbital interaction of the nx lone pair of the ring oxygen atom with the σ* MO of the β‐C‐O bond, in which the singly occupied p orbital at C‐1 acts as a mediator for this 1,3‐anomeric interaction.
Preparation and characterisation of 9,10‐dihydroanthracene and tert‐butyl‐9,10‐dihydroanthracene complexes with one or two tricarbonylchromium units; crystal structure of tricarbonyl (η1,2,3,4,4a,9a‐9,10‐dihydroanthracene)chromium
Authors: Whitton Alan J. , Kumberger Otto , Müller Gerhard , Schmidbaur Hubert 
Published: July 2007

AbstractThe complexes [9,10‐dihydroanthracene][tricarbonylchromium]n [9,10‐DHA][Cr(CO)3]n [n = 1 (1), 2 (2)] and the related mono‐ and bis(tricarbonylchromium) complexes of 2,6‐ and 2,7‐di‐tert‐butyl‐9,10‐dihydroanthrancene [2,6‐DB‐9,10‐DHA][Cr(CO)3]n [n = 1 (3), 2 (4)] and [2,7‐DB‐9,10‐DHA][Cr(CO)3]n [n = 1 (5), 2 (6)] have been prepared by heating the 9,10‐DHA species in the presence of hexacarbonylchromium [Cr(CO)6]. Evidence for the existence of the complex [2,6,9‐tri‐tert‐butyl‐9,10‐DHA][Cr(CO)3] (7) is also presented. The complexes have been characterised spectroscopically, and for complex 1 an X‐ray crystallographic structure determination has been carried out. This complex adopts the unexpected structure in which the non‐coordinated arene ring is bent towards the Cr(CO)3 moiety. The syntheses and spectroscopic characterisations of 2,6‐ and 2,7‐di‐tert‐butylanthracene (2,6‐ and 2,7‐DBA), 2,6‐ and 2,7‐di‐tert‐butyl‐9,10‐dihydroanthracene (2,6‐and 2,7‐DB‐9,10‐DHA), 2,6,9‐, 2,7,9‐, and 2,7,10‐tri‐tert‐butyl‐9,10‐dihydroanthracene (2,6,9‐, 2,7,9‐ and 2,7,10‐TB‐9,10‐DHA), and 2,6,9,10‐ and 2,7,9,10‐tetra‐tert‐butyl‐9,10‐dihydroanthracene(2,6,9,10‐ and 2,7,9,10‐TeB‐9,10‐DHA) are also given.
Cycloadditionen von 1,3,4‐Oxadiazin‐6‐onen (4,5‐Diaza‐α‐pyronen), 9. 6‐Oxo‐5‐phenyl‐1,3,4‐oxadiazin‐2‐carbonsäure‐methylester — Synthese und Reaktionen mit Norbornen, Norbornadien, Cyclopropenen, Cyclobuten und Benzvalen
Authors: Christl Manfred , Lanzendörfer Ulrike , Grötsch Maria M. , Ditterich Elke , Hegmann Joachim 
Published: July 2007

Cycloadditions of 1,3,4‐Oxadiazin‐6‐ones (4,5‐Diaza‐a‐pyrones), 9. — Methyl 6‐0xo‐5‐phenyl‐1,3,4‐oxadiazin‐2‐carboxylate — Synthesis and Reactions with Norbornene, Norbornadiene. Cyclopropenes, Cyclobutene. and BenzvaleneMethyl 6‐oxo‐5‐phenyl‐1,3,4‐oxadiazin‐2‐carboxylate (7) was prepared by treatment of hydrazone 6 with dicyclohexylcarbodiimide. The reactions of 7 with norbornene and norbornadiene afforded the Diels‐Alder adducts 8 and 9, respectively, which decomposed in solution at 20°C to give mainly the γ‐oxoketenes 10 and 12 and small amounts of the β‐lactones 11 and 13, respectively. The stable γ‐oxoketenes 10, 12, and the bis(γ‐oxoketene) 14 were obtained directly from solutions of 7 and the respective olefin. Cyclopropene, 1‐methylcyclopropene, and cyclobutene were converted by 7 mainly into the oxepin derivatives 15, 17, 18 and the oxocin derivative 19, respectively. Benzvalene and 7 provided the tetracyclo[3.3.0.02,8.04,6]octanone 21. In these reactions, small quantities of β‐lactones were formed, too, which together with the β‐lactones 11 and 13 give evidence for the dihydropyryliumolates 24 as intermediates in the thermal denitrogenation of the Diels‐Alder adducts of 7, e.g. 8 and 9.
Concave reagents, 6. Can the structure of concave reagents determine selectivities?
Authors: Lüning Ulrich , Schillinger Fritz 
Published: July 2007

AbstractThe concave position of the proton in protonated concave pyridines 8·H+ or 9·H+ leads to increased selectivities in protonation reactions of nitronate anions 2a–d. Thus, the reprotonation of the nitronate anion 2a by the protonated concave pyridine 8·H+ selectively yields the nitro compound 1a whereas the nitronate anions 2b–d are transformed to the Net products 4b–d.
Titanocen‐ und Zirconocen(diazadien)‐Komplexe: Darstellung, Charakterisierung und Struktur
Authors: Scholz Joachim , Dlikan Mansour , Ströhl Dieter , Dietrich Andreas , Schumann Herbert , Thiele Karl‐Heinz 
Published: July 2007

Titanocene‐ and Zirconocene(diazadiene) Complexes: Preparation, Characterization, and StructureBy treating Cp2MCl2 (M = Ti, Zr) with magnesium in the presence of the diazadienes R1N = CR2CR2  NR1 (R1  R2  Ph:1a; R1  Ph, R2  Me: 1b) metallocene complexes of formula Cp2) (M  Ti: 2a, b; M  Zr: 3a, b) have been obtained in good yields. 2a–3b exhibit dynamic NMR spectra indicating a rapid intramolecular migration of the bent metallocene unit Cp2M from one “face” of the reduced diazadiene to the other. From the 1H‐NMR Cp‐coalescence ΔG‡ values for the activation barrier of this automerization process have been obtained. Complex 3a was characterized by X‐ray diffraction. The five‐membered metallacyclic ZrNCCN ring system adopts an “envelope”‐conformation.
Über Reaktionen des 2,4,6‐Tris(trifluormethyl)phenols mit Verbindungen von Hauptgruppen‐ und Nebengruppen‐Elementen (Li, Na, Mg, Ca, Ba, Ge, Sn und Ti, W, Mn, Cd)
Authors: Roesky Herbert W. , Scholz Mario , Noltemeyer Mathias 
Published: July 2007

Reactions of 2,4,6‐Tris(trifluoromethyl)phenols with Compounds of Main Group (Li, Na, Mg, Ca. Ba, Ge. Sn) and Transition (Ti, W, Mn, Cd) ElementsThe 2,4,6‐tris(trifluoromethyl)phenoxides of composition RfONa · 1.5 THF (2), [Rf = 2,4,6‐(CF3)3C6H2], RfOLi · 0.75 Et2O (3), (RfO)2Mg · 3 THF (4), (RfO)2Ca · 3 THF (5), (RfO)2Ba · THF (6), (RfO)2 (7), (RfO)2Me2NWWNMe2(ORf)2 (8), (RfO)2Ge · THF (9), (RfO)2Sn · THF (10), (η5‐C5Me5)TiCl2ORf (11), (RfO)2Mn · 3 THF (12), and (RfO)2 · 2 THF (13) are prepared. The singlecrystal X‐ray structures of 4, 8, and 12 are described.
Molybdänkomplexe mit hochalkylierten Cyclopentadienyl‐Liganden
Authors: Sitzmann Helmut 
Published: July 2007

Molybdenum Complexes with Highly Alkylated Cyclopentadienyl LigandsReaction of hexacarbonylmolybdenum with 1,2,3,4‐tetraisopropylcyclopentadiene gives [(η5‐C5iPr4H)Mo(CO)3H] (1), which on treatment with 2,5‐norbornadiene is dehydrogenated to [{(η5‐C5iPr4H)Mo(CO)2}2](Mo  Mo) (2). The mixed‐substituted dimolybdenum complex [(η5‐C5Me5)(CO)2Mo  Mo(CO)2(η5‐C5iPr4H)] (6) is accessible, e.g., from [(η5‐C5Me5)Mo(CO)3Cl] and [(η5‐C5iPr4H)Mo(CO)3]Na (3). Complex 3 yields [(η5‐C5iPr4H)Mo(CO)3Cl] (4) with CuCl2 and [(η5‐C5iPr4H)Mo(CO)3‐SiHMe2] (5) with Me2HSiCl. Low‐temperature 1H‐NMR spectra of [(η5‐C5iPr5)Mo(CO)3CH3] (7), synthesized from [(η5‐C5iPr5)Mo(CO)3]Na and MeI, show the signals of two isomers with different orientation of the isopropyl groups about the five‐membered ring. ΔG‡ of isopropyl rotation has been calculated to be 55.6 ± 4 kJ/mol. [(η5‐C5H2tBu3‐1,2,4)Mo(CO)3]Na reacts with MeI to form [(η5‐C5H2tBu3 ‐1,2,4)Mo(CO)3CH3] (8).
Metall‐π‐Komplexe von Benzolderivaten, 36. Zur Kenntnis der Struktur von μ(η6:η6‐Biphenyl)bis[(η6‐benzol)metall]‐Komplexen in starrer Lösung und im Kristall
Authors: Elschenbroich Christoph , Heck Jürgen , Massa Werner , Birkhahn Matthias 
Published: July 2007

Metal π‐Complexes of Benzene Derivatives, 36. — The Structure of μ(η6:η6‐Biphenyl)bis[(η6‐benzene)metal] Complexes in Rigid Solution and in the Crystalline StateFor μ(η6:η6‐C6H5C6H5)[η6‐C6H6)Cr]2 (2) an antiperiplanar conformation has been established by means of X‐ray diffraction. Two (C6H6)Cr units coordinate to planar bridging biphenyl. This configuration differs from that of the diradical dication 2d⊕ d⊕ in rigid solution. According to the zero‐field splitting parameter D in the EPR spectrum, 2d⊕ d⊕ adopts a synclinal conformation, the half‐sandwich fragments coordinating to twisted biphenyl (dihedral angle α ≈︁ 60°).
Bis[tris(trimethylsilyl)methyl]diselenid: Ein ungewöhnliches Dichalkogenid mit sterisch erzwungener trans‐C2h‐Konformation
Authors: Wagner Irle , Du Mont Wolf‐Walther , Pohl Siegfried , Saak Wolfgang 
Published: July 2007

Bis[tris(trimethylsilyl)methyl] Diselenide: An Unusual Diselenide with Sterically Enforced trans‐C2h ConformationDeselenation of bis[tris(trimethylsilyl)methyl] triselenide (1) with copper occurs with formation of bis[tris(trimethylsilyl)‐methyl] diselenide (2) and minor amounts of 3,3,5,5‐tetrakis(trimethylsilyl)‐1,2,4‐triselenolane (3). The structures of 2 and 3 have been studied by multinuclear NMR spectroscopy and by X‐ray crystallography. The CSeSeC moiety of 2 adopts an unusual antiperiplanar conformation. Cleavage of the Se  Se bond by iodine providing iodo[tris(trimethylsilyl)‐methyl]selane (5) is complete with 2, but reversible with 1.
Direkte Michael‐artige Addition von Si‐Gruppen an β‐Aryl‐α,β‐ungesättigte Carbonylverbindungen mit R3SiCl/Bu2Cu(CN)Li2
Authors: Amberg Willi , Seebach Dieter 
Published: July 2007

Direct Michael‐Type Addition of Si‐Groups to α,β‐Unsaturated p‐Aryl‐Substituted Enones with R3SiCl/Bu2Cu(CN)Li2(E)‐5‐Benzylidene‐2‐tert‐butyl‐6‐methyl‐1,3‐dioxan‐4‐one (1) undergoes conjugative silylation (Me3Si, Et3Si, tBuMe2Si, Me2PhSi, products 2 ‐ 5) with the reagent specified in the title. The reaction is highly diastereoselective, with formal anti addition of R3Si and H from the Re‐ and Si‐face, respectively, of the exocyclic double bond [proof by NMR analysis and chemical correlation (cf. 6 and 7). A screening of various enone systems showed that this unprecedented Michael addition of Si groups with chlorosilane as a reagent, and under non‐reducing conditions occurs only if the x,p‐unsaturated carbonyl system bears an aryl group in the P‐position to give β‐aryl β‐silyl ketones (products 8‐ 15).
Photochemische Reaktionen von Übergangsmetall‐Organyl‐Komplexen mit Olefinen, 3. [4 + 5]‐Cycloaddition konjugierter Diene an Tricarbonyl(η5‐2,4‐dimethyl‐2,4‐pentadienyl)mangan
Authors: Kreiter Cornelius G. , Lehr Klaus , Leyendecker Michael , Sheldrick William S. , Exner Reiner 
Published: July 2007

Photochemical Reactions of Transition Metal Organyl Complexes with Olefines, 31). – [4 + 5] Cycloaddition of Conjugated Dienes to Tricarbonyl(η5‐2,4‐dimethyl‐2,4‐pentadienyl)manganeseTricarbonyl(η5‐2,4‐dimethyl‐2,4‐pentadienyl)manganese [1] reacts photochemically with the acyclic conjugated dienes 1,3‐butadiene [A], 2‐methyl‐1,3‐butadiene [B], (E)‐1,3‐pentadiene (C), (E,E)‐2,4‐hexadiene (D), 2,4‐dimethyl‐1,3‐pentadiene (E), 2,4‐hexadien‐1‐ol (F), and methyl 2,4‐hexadienoate (G) in a formal [4 + 5] cycloaddition to give tricarbonylmanganese complexes with η3:2‐2,6‐cyclononadien‐1‐yl ligands (2A‐2G). In addition, the reaction of 1 with A yields thermolabile [η3:2:2‐1‐(3‐butene‐1,2‐diyl)‐1,3‐dimethyl‐2,6‐cyclononadiene]dicarbonylmanganese (3A) and E,E and E,Z isomers of [η3‐1‐(2‐butene‐1,1‐diyl)‐1,3‐dimethyl‐2,6‐cyclononadiene]tetracarbonylmanganese (4A, 4A] as byproducts. Similarly, 1 reacts with B to form tetracarbonyl[η3‐1‐(3‐methyl‐2‐butene‐1,1‐diyl)‐1,3,6‐trimethyl1‐2,6‐cyclononadiene]manganese (4B) in a side reaction. The crystal and molecular structures of tricarbonyl(η3:2‐1,3,5,5,7‐pentamethyl‐2,6‐cyclononadien‐1‐yl]manganese (2E) and of 3A are determined by X‐ray structure analyses. In each of the formally octahedral complexes unusual long manganese–carbon bonds are found for one coordinated CC double bond of the hydrocarbon ligands.
Notizen / Notes. Investigation on the Product from Monobutyltin(IV) Compounds and Benzoyl(thiobenzoyl)methane: a 1,3,2λ5,4λ5‐Dithiadistannetane
Authors: Seth Neena , Gupta Vishnu D. , Linti Gerald , Nöth Heinrich 
Published: July 2007

AbstractButyltin triisopropoxide reacts with benzoyl(thiobenzoyl)methane (LH) to yield BuSn(S)L and an organic sulfide 2 instead of the expected BuSnL3. The use of other butyltin(IV) starting materials invariably leads to the same products. From an X‐ray structure determination the tin sulfido complex is found to be a centrosymmetric dimer, [BuSn(S)L]2 (1) with a planar four‐membered Sn2S2 ring containing pentacoordinated tin atoms.