bluuebunny/crossref_metadata_2025_split huggingface dataset:
1,3,5‐Triphenyl‐2,4,6‐trimesityl‐1,3,5,2,4,6‐triphosphatriborinane: A 6π‐Electron Heteroaromatic Ligand
Authors: Kaufmann Bernhard , Metzler Nils , Nöth Heinrich , Paine Robert T. 
Published: July 2007

AbstractThe preparation of tricarbonyl(η6‐1,3,5‐triphenyl‐2,4,6‐trimesityl‐1,3,5,2,4,6‐triphosphatriane)chromium (4) is reported. Its X‐ray structure reveals an orientation of the Cr(CO)3 moiety with respect to the almost planar B3P3 ring typical of an arene metal tricarbonyl complex.
Metallkomplexe funktioneller Isocyanide, XXIV. Reaktionen von N‐Isocyandialkylamin‐Metallkomplexen mit sekundären Aminen
Authors: Fehlhammer Wolf Peter , Metzner Robert , Sperber Wilfried 
Published: July 2007

Metal Complexes of Functional Isocyanides, XXIV. — Reactions of N‐Isocyanodialkylamine Complexes with Secondary AminesReactions of pentacarbonyl(N‐isocyanodialkylamine) group 6‐metal complexes [M(CO)5CNNR2] [M = Cr, W; R = Et, iPr; 2R = ‐{MeCH(CH2)3CHMe}‐] with secondary amines proceed with cleavage of the NN bond and C→N migration of the metal to give the corresponding N‐cyanamide complexes [M(CO)5NCNR′2] (1a–2g) [R′ = Me, Et, nPr, nBu; 2R′ = (CH2)4, (CH2)5, (CH2)2O(CH2)2]. However, when diiodobis(N‐isocyanodialkylamine)platinum(II) was allowed to react with an excess of the amine amine(guanidine)platinum(II) complexes [PtI2(HNR′2){HNC(NR′2)2}] (3a–c) [R′ = Et; 2R′ = (CH2)5, (CH2)2O(CH2)2] were obtained. Structural assignments are made on the basis of IR, NMR (1H, 13C), and mass spectroscopy as well as of an X‐ray structure analysis of trans‐[PtI2(HNEt2){HNC(NEt2)2}] (3a).
Synthesis of Silver(I) Complexes with the Bis(diphenylphosphanyl)‐o‐carborane Ligand. Crystal Structure of [Ag(phen){(PPh2)2C2B10H10}]ClO4 and [Ag{(SPPh2)2CH2}{(PPh2)2C2B10H10}]ClO4 · CH2Cl2
Authors: Bembenek Eberhard , Crespo Olga , Concepción Gimeno M. , Jones Peter G. , Laguna Antonio 
Published: July 2007

AbstractSilver(I) perchlorate or nitrate react readily with bis(di‐phenylphosphanyl)‐o‐carborane to give the complexes [AgX{(PPh2)2C2B10H10}] [X = ClO4 (1), NO3, (2)]. The perchlorate ligand is weakly bound to the silver atom and thus can be displaced by other ligands affording the three‐coordinated complexes [AgL{(PPh2)2C2B10H10}]ClO4 [L = PPh3 (3), PPh2Me (4), AsPh3 (5), C5H4NCOOH (6), C9H6NCOOH (7), SPPh3 (8)]. Compounds 3 and 4 can also be obtained by reaction of [Ag(OClO3)PR3] with the diphosphane. Treatment of complex 1 with bidentate ligands leads to the cationic four‐coordinated [Ag(LL){(PPh2)2C2B10H10}]ClO4 [LL = (PPh2)2C2B10H10 (9), bipy (10), phen (11), (SPPh2)2CH2 (12)] or to the neutral [Ag(S2CNR2){(PPh2)2C2B10H10}] [NR2 = NEt2 (13), NC4H8 (14)]. The crystal structures of 11 and 12 have been established by X‐ray crystallography. In both complexes the silver(I) atoms exhibit tetrahedral coordination by two phosphorus and two nitrogen or two sulfur atoms, respectively.
Electroorganic Synthesis, 58. Synthesis of Substituted Benzoquinones and their Use for Mediated Electrochemical Conversions
Authors: Riering Helmut , Schäfer Hans J. 
Published: July 2007

AbstractHydroxy‐ (1a‐3a) and hydroxyalkyl‐substituted benzoquinones (6a‐8a, 27a), suited to be immobilized by esterification with polyacrylic acid, are prepared. Their cathodic reduction potential Ep,c (1) correlates linearly with their substituent constant. The cathodic reduction of dioxygen and the palladium(II)‐catalyzed anodic oxidation of alkenes are mediated by the benzoquinones 7b, 8b and 27b, respectively.
Carbon‐Carbon Bond Cleavage of the [2.2]Paracyclophane Radical Cation Generated by Electron Transfer Oxidation with Cerium(IV) Ammonium Nitrate
Authors: Adam Waldemar , Miranda Miguel A. , Mojarrad Fatemeh , Sheikh Hamid 
Published: July 2007

AbstractSingle electron transfer (SET) oxidation of [2.2]paracyclophane (1) with cerium ammonium nitrate (CAN) produces the corresponding radical cation (1+.), which undergoes cleavage of the carbon‐carbon bond of the ethano bridge to generate the double‐benzylic radical cation 2+. Trapping of this intermediate by oxygen and nucleophiles gives rise to aldehydes 3, while a second oxidation and subsequent nucleophilic trapping affords nitrates 4. This facile cleavage of the carbon‐carbon bond is explained by alignment of the latter with the π systems in the rigid structure of [2.2]paracyclophane, which enables charge delocalization across both benzene rings. When the reaction is carried out in methanol, aromatic substitution takes also place as a minor reaction pathway, which is responsible for the formation of the polyfunctionalized cyclophane 5d.
Dendrimere und Dendrimer‐Bausteine mit trisubstituiertem Benzol und “Hexacyclen” als Kern
Authors: Kadei Klaus , Moors Rolf , Vögtle Fritz 
Published: July 2007

Dendrimers and Dendrimer Building Blocks with Trisubstituted Benzene and “Hexacyclene” as Core UnitsThe preparation of new dendritic compounds containing 1,3,5‐substituted aromatic units or “hexacyclene” is described. Bulky dendrimers are obtained in few generations starting with polyfunctional core units like 1, 4, 5, 12, and hexacyclene (21). The dendrimers were synthesized by using both the divergent method (for 7) and the convergent method (for 13 and 22). 22 is the first dendrimer containing a crown unit as core.
Chelat‐kontrollierte diastereoselektive Addition an α,ß‐Epoxy‐Aldehyde
Authors: Ipaktschi Junes , Heydari Akbar , Kalinowski Hans‐Otto 
Published: July 2007

Chelate‐Controlled Diastereoselective Addition to α,β‐Epoxy AldehydesLiClO4‐mediated reaction of trans‐substituted α,β‐epoxy aldehydes 1 with allyltributyltin (2) or trimethylsilyl cyanide provides a general method for the synthesis of the corresponding syn‐alcohols 3 with high selectivity. In the case of cis‐substituted α,β‐epoxy aldehydes the selectivity depends on the size of the substituents.
Michael Addition of Imines to Alkynylcarbene Complexes with Subsequent Intramolecular Cyclization ‐ An Efficient Three‐Step Synthesis of 2H‐Pyrroles
Authors: Funke Frank , Duetsch Michael , Stein Frank , Noltemeyer Matthias , Meijere Armin De 
Published: July 2007

AbstractImines 7, 11–13 were added to (1‐alkynylcarbene)chromium complexes 6a–d to form {[2‐(methyleneamino)ethenyl]‐carbene}chromium complexes 8a–d, 14a–d, 15a–d, 16a–d in good to very good yields (63–98%) except for two cases (41–59%). The carbene ligands of the latter compounds cyclize to 2H‐pyrroles 9a–d, 17a–d, 18a–d, 19a–d upon heating in tetrahydrofuran solution to 50–55°C.
Ring Cleavage of Benzofurans and Tetrahydrobenzofurans by m‐Chloroperbenzoic Acid Epoxidation
Authors: Adam Waldemar , Ahrweiler Michael , Sauter Markus 
Published: July 2007

AbstractThe oxidation of the benzofurans 1a–f (tetrahydrobenzofurans 1g, h) with excess m‐CPBA is reported. The in situ generated, highly reactive benzofuran epoxides 2a–f and their quinone methides 3a–f (cis‐ene diones 3g, h) afford the labile tautomeric peroxy esters 5 and 5′ by nucleophilic addition of the peroxy acid. On elimination of m‐chlorobenzoic acid, the peroxy esters 5/5′ of the benzofuran derivatives 1a–f rearrange thermally to the keto esters 6 by CC cleavage or to the spiro epoxides 7 by CO cleavage. The latter undergo thermal isomerization to the 1,3‐benzodioxoles 8 and Diels‐Alder cycloaddition to the corresponding dimers 9. Independently, the keto esters 6 and the 1,3‐dioxoles 8 were synthesized by thermolysis of the dioxetanes 11. The tautomeric m‐CPBA adducts 5/5′ of the persistent ene diones 3g, h, derived from the tetrahydrobenzofuran derivatives 1g, h, rearrange as well to the spiro epoxides 7g, h. In contrast to the benzofuran derivatives 6a–f, the keto enol ester 6h suffers Baeyer‐Villiger rearrangement with another molecule of m‐CPBA to form the ene diester 10h.
Effect of Fluorine and Chlorine Substituents on Stabilities of Diphosphaallene, Diphosphirene, and Phosphanylphosphaalkyne Isomers (XX′ CP2 Species with X, X′ = H, F, and Cl)
Authors: Fitzpatrick Noel J. , Brougham Dermot F. , Groarke Peter J. , Nguyen Minh Tho 
Published: July 2007

AbstractAb initio MO calculations at the QCISD(T)/6–31G* */MP2/6–31G* * + ZPE level on the XX′CP2 isomers (X = H1 F and Cl) show that the energies of the isomeric species are often reordered following halogen substitution. The phosphorushalogen moiety behaves as the main stabilizing factor on the rest of the molecular structure. This is particularly true when X = F is involved. In the dihalogenated series phosphanyl‐phosphaalkyne (4) becomes the most stable species followed by diphosphaallene (3) and 1 H‐diphosphirene (6). The effect on the geometry following halogenation is larger if substitution takes place at carbon than at phosphorus. The behaviour of the P species is found to be quite different from, if not opposite to, that of their nitrogen analogues. Finally, the infrared spectra of the most stable isomers are also predicted.
Bis(trifluormethylsulfonyloxy)organosilicium‐Verbindungen als Synthesebausteine für neuartige Siliciumpolymere
Authors: Uhlig Wolfram 
Published: July 2007

Bis(trifluoromethylsulfonyloxy)organosilicon Compounds as Synthetic Materials for New Silicon PolymersThe new polycarbosilanes, polysiloxanes, and polysilylenealkynes 1c–6c were obtained by condensation of electrophilic α,ω‐bis(trifluoromethylsulfonyloxy)organosilicon compounds 1b–6b with nucleophiles such as organolithium and organomagnesium compounds. The required silyl triflate derivatives 1b–6b have been prepared by reaction of the corresponding amino‐, allyl‐, or phenylsilanes 1a–6a with trifluoromethanesulfonic acid.
3,4‐Dimethylenborolane und 3,7‐Diborabicyclo[3.3.0]oct‐1(5)‐ene
Authors: Herberich Gerhard E. , Eigendorf Uwe , Englert Ulli 
Published: July 2007

3,4‐Dimethyleneborolanes and 3,7‐Diborabicyclo[3.3.0]oct‐1(5)‐enesThe tetramethyleneethane derivative K2[C2(CH2)4] which is readily prepared from 2,3‐dimethylbutadiene by metallation with the Lochmann‐Schlosser base reacts with BC12(NR2) (RMe, Et, iPr) to give the highly reactive, liquid 1‐(dialkylamino)‐3,4‐dimethyleneborolanes (3). These dienes react with activated magnesium to give soluble magnesium adducts 5 which upon treatment with BC12(NR2) (R = Me, iPr) yield crystalline 3,7‐bis(dialkylamino)‐3,7‐diborabicyclo‐[3.3.0]oct‐1(5)‐enes (4). The crystal structure of the dimethyl‐amino compound 4a was determined by X‐Ray‐diffraction. The molecule of 4a shows crystallographic C2h symmetry with an almost perfectly planar skeleton.
Iron‐Catalyzed Coupling of Tricyclo[4.1.0.02,7]hept‐1‐ylmagnesium Bromide and Related Grignard Reagents with Propargylic and Allylic Halides
Authors: Hashmi A. Stephen K. , Szeimies Günter 
Published: July 2007

AbstractSeveral uncatalyzed and transition metal‐catalyzed cross coupling reactions of the Grignard compounds 1c or 2c with propargylic or allylic halides were investigated. Fe(acac)3 was the most effective catalyst for the preparation of allyl‐and propargylbicyclo[1.1.0]butanes 7 and 5. In the latter case, the formation of the isomeric allenylbicyclo[1.1.0]butanes 6 was also observed. Stereoelectronic factors of substituents like a trimethylsilyl group as a directing group could be utilized for the formation of either 5 or 6. A number of bicyclo[1.0.0]butanes 15–21 with two substituents in the bridgehead positions were accessible by that route as well. In the case of the bis‐allenyl compound 24c, an ene‐type reaction leading to the first known derivative of a [4.1.1]propella‐2,4‐diene 25 was observed. Base‐catalyzed isomerizations of the propargylbicyclo[1.1.0]butanes 5 opened a new route to alkynylbicyclo[1.1.0]butanes 30–32.
Structure of Octamethylene‐Bridged Derivatives of 1,3‐Cyclohexadiene and Bicyclo[3.1.0]hexene
Authors: Irngartinger Hermann , Oeser Thomas , Jahn Reiner 
Published: July 2007

AbstractSynthesis and photochemical generation of the octamethylene‐bridged 1,3‐cyclohexadiene and bicyclo[3.1.0]hexene derivatives 1 and 2, which are to be classified as anti‐Bredt olefins, are reported. out Orientation of the octamethylene bridge at the sp3‐hybridized bridgehead atom of 1 generates strain effects while in orientation of the bridge in 2 does not give rise to deformations of the bicyclo[3.1.0]hex‐2‐ene subunit. X‐ray analyses indicate a twisted double bond (12.2 and 15.0°) at the bridgehead atom of 1 and a deformation of the six‐membered ring from an ideal boat conformation. In contrast, the five‐membered ring of compound 2 is planar. The folding angle between the five‐ and the three‐membered ring is 111.8(2)°. The olefinic carbon atoms of 1 are slightly pyramidalized.
Syntheses of Zindoxifene and Analogues by Titanium‐Induced Oxo‐Amide Coupling
Authors: fürstner Alois , Jumbam Denis N. , Seidel Günter 
Published: July 2007

AbstractHighly reactive titanium on graphite is used to reductively cyclize electron‐rich acylamino carbonyl compounds 7, 8, 12, 14, and 16 to the corresponding indole derivatives 9, 10, 13, 15, and 17. Compound 9b is a known precursor of the mammary tumor‐inhibiting compound zindoxifene (2). The other products are new analogues of this anticancer drug, exhibiting the substitution pattern previously recognized to be essential for high pharmacological activity.
Darstellung, Struktur und konformatives Verhalten gespannter Adamantanophane
Authors: Lemmerz Ralf , Nieger Martin , Vögtle Fritz 
Published: July 2007

Preparation, Structure, and Conformational Behaviour of Strained AdamantanophanesExchange of aromatic units (e.g. benzene) for aliphatic/alicyclic building blocks (e.g. adamantane) in cyclophanes leads to new molecules of the “araliphane” type. In the framework of this concept the araliphanes 3(a), 5–7a, 10(a), and 11 are synthesized. Their stereochemical behaviour differs significantly from that of their aromatic counterparts as shown by NMR studies and X‐ray crystallographic analyses. Extremely upfield‐shifted signals of the intraanular adamantane hydrogen atoms are found as well as a planar chiral adamantanophane. A Diels‐Alder addition of 8 to the benzene ring of 6 yields 9. Complete replacement of benzene units by adamantane leads to the fully aliphatic/alicyclic “aliphanes”. The crystal structure of 15 is described.
Chelat‐stabilisierte 1,3‐Bis(acyloxy)‐1,3‐diethyldiboroxane aus Triethylboroxin und Carbonsäureanhydriden
Authors: Köster Roland , Sporzyński Andrzej , Schüßler Wilhelm , Bläser Dieter , Boese Roland 
Published: July 2007

Chelate‐Stabilized 1,3‐Bis(acyloxy)‐1,3‐diethyldiboroxanes from Triethylboroxin and Carboxylic Acid AnhydridesTriethylboroxin (A) reacts with carboxylic acid anhydrides (RCO)2O [R = Me: 1a; Et: 1b; tBu: 1d; Ph: 1e] with various rates to give high yields of the 3,7‐dialkyl‐1,5‐diethyl‐4,8,9‐trioxa‐2,6‐dioxonia‐1,5‐diboratabicyclo[3.3.1]nona‐2,6‐dienes OB(Et)OC(R)OB(Et)OC(R)O (2) [R = Me: 2a (X‐ray crystal structure analysis); Et: 2b; tBu: 2d; Ph: 2e], presumably via the unstable compounds OB(Et)OB(Et)OC(R)OB(Et)OC(R)O (3a,b, d, e). Compound 1c (R = CF3) reacts with A to form a mixture of 1,3‐diethyl‐1,3‐bis(trifluoroacetoxy)diboroxane OC(CF3)OB(Et)OB(Et)O(CF3)CO (2c′) and 2c (R = CF3) at room temperature. Whereas two compounds of the type 2 do not comproportionate, 1a–e spontaneously form the mixed substituted carboxylic acid anhydrides 1ab etc. on mixing at room temperature (GC, 13C NMR). ‐ From the 17O‐enriched A* and 1a–e the 17O‐enriched compounds 2a*‐e* with BO*B and YYBO*OCR groups are obtained. A* exchanges O atoms up to 200°C with succinic anhydride (1f) forming 1f* or with phthalic acid anhydride (1g) forming 1g* and 3g*. ‐ The mixed carboxylic acid anhydrides 1xy are cleaved, and the mixtures of 1 are separated with A to yield the uniform 3,7‐dialkyl‐substituted compounds 2.
Zinkkomplexe von Aminosäuren und Peptiden, 4. Zinkkomplexe von Peptiden mit C‐terminalem Cystein
Authors: Meißner Axel , Gockel Peter , Vahrenkamp Heinrich 
Published: July 2007

Zinc Complexes of Amino Acids and Peptides, 4. ‐ Zinc Complexes of Peptides with C‐terminal CysteineThe cysteine derivatives N‐Ac‐Cys, N‐Ac‐Gly‐Cys, N‐Ac‐Ala‐Cys, and N‐Ac‐Gly‐Gly‐Cys with unprotected SH and CO2H functions (LH2) were prepared by the mixed anhydride method. Their reactions with basic zinc carbonate resulted in the formation of complexes Zn(LH)2 which were converted by KOH to complexes K2[ZnL2]. Potentiometric titrations revealed ZnL and [ZnL2]2− as the major solution species. By pD‐dependent NMR measurements (1H, 13C) in D2O carboxylate coordination in acidic solution and carboxylate and thiolate coordination in neutral and basic solution was identified.
Cycloadditionen Organometallfragment‐substituierter Alkene, I. [3 + 2]‐Cycloaddition von η1‐Allyl‐Eisenkomplexen mit Nitriloxiden: Ferriomethyl‐substituierte Isoxazoline
Authors: Malisch Wolfgang , Züller Jürgen , Schwarz Marietta , Jäger Volker , Arif Atta M. 
Published: July 2007

Cycloadditions of Organometal Fragment‐Substituted Alkenes, I. ‐ [3 + 2] Cycloaddition of η1‐Allyl Iron Complexes with Nitrile Oxides: Ferriomethyl‐Substituted IsoxazolinesThe isoxazolines C5H5(OC)(L)Fe‐CH2‐CH‐CH2‐C(R) = N‐O (3a–f) [R = Ph, 2,4,6‐Me3C6H2; L = CO, P(OCH2)3CCH3, PPh3], substituted with a ferriomethyl group in 5‐position, are obtained by 1,3‐dipolar cycloaddition of the η1‐allyliron complexes C5H5(OC)(L)Fe‐CH2‐CH=CH2 [L = CO (1a), P(OCH2)3CCH3 (1b), PPh3 (1c)] with the nitrile oxides RCNO [R = Ph (2a), Mst (2b)]. The chiral complexes 1b, c produce the diastereomeric isoxazolines 3b, c, e, f with diastereomer ratios of 59:41 to 93:7. The structure of 3d is established by crystal structure analysis.
Synthese mittlerer und großer Ringe, XXXVI. Synthese eines überbrückten, in‐konfigurierten Bicyclo[2.1.0]pentan‐Derivates
Authors: Tochtermann Werner , Sdunnus Norbert , Wolff Christian , Reggelin Michael 
Published: July 2007

Synthesis of Medium and Large Rings, XXXVI. — Synthesis of a Bridged Bicyclo[2.1.0]pentane Derivative with inside ConfigurationDihydrocyclobutafurans 4 (H instead of Br) are reactive intermediates in the photochemical rearrangement of 3,6‐hexanooxepine‐4,5‐dicarboxylic esters. The synthesis of the bromo derivative 4 was achieved by irradiation of the epoxyoxepine 1 followed by a regio‐ and stereoselective NBS bromination of 2 and deoxygenation of 3 with tungsten hexachloride/n‐butyllithium. Treatment of the allylic bromide 4 with sodium methoxide gave surprisingly the title compound 5. The structure of 5 was established by thorough NMR analysis.
Ein neuer Zugang zu 1,2‐ und 1,3‐Diborol
Authors: Gabbert Gernot , Pritzkow Hans , Kaschke Michael , Siebert Walter 
Published: July 2007

A New Approach to 1,2‐ and 1,3‐DiboroleHerrn Prof. Dr. Joachim Knappe zum 65. Geburtstag gewidmet.
Diaminoborylation of 1,3‐dilithiopropenes leads to the (Z)‐1,3‐bis(diaminoboryl)propenes 4a, b, which are transformed by an amine/chlorine exchange to the (Z)‐1,3‐bis(aminochloroboryl)propenes 5a, b. These react with sodium to yield the 2,5‐dihydro‐1H‐1,2‐diboroles 2c, d, whereas the reaction with potassium leads to the 2,3‐dihydro‐1H‐1,3‐diboroles 6a, b by rearrangement of the C3B2 skeleton. The constitutions of the heterocycles 2c, d and 6a, b are established by X‐ray structure analyses. Reaction of the 1,2‐diboroles 2c, d with (C5H5)Co(C2H4)2 leads to the red (1‐borabutadiene)cobalt complexes 3c, d. In 3c a sigmatropic rearrangement is studied by NMR spectroscopy.
Festkörper‐13C‐NMR‐Spektroskopie, 1. Titantetrachlorid‐Komplexe von Diketonen: Ihre Bedeutung für Hydrid‐Reduktionen und ihre Festkörper‐NMR‐Spektren
Authors: Maier Güunther , Seipp Ulrich , Kalinowski Hans‐Otto , Henrich Markus 
Published: July 2007

Solid‐state 13C‐NMR Spectroscopy, 1. — Titanium Tetrachloride Complexes of Diketones: Their Importance for Hydride Reductions and Their Solid‐State NMR SpectraHerrn Prof. Christoph Rüchardt zum 65. Geburtstag gewidmet.
The influence of titanium tetrachloride on the diastereoselectivity of hydride reductions of 1,2‐, 1,3‐, 1,4‐ and 1,5‐diketones has been studied. The effect is especially pronounced in the case of 1,3‐diketones, where the addition of titanium tetrachloride reverses the stereoselectivity. The assumption of a chelate of type 32 or 33 can be confirmed by several observations: β‐hydroxy ketone 7 and β‐benzyloxy ketone 9 show the same dependence on the stereochemical course as diketone 5a. This compound forms complex 34, whose conformation is known by X‐ray structure determination. From the solid‐state 13C‐NMR spectra of the TiCl4 adducts it can be deduced that 7 forms chelate 42, which is close to the assumed intermediate 32. In the case of phenyl‐substituted substrates solid‐state 13C‐NMR spectroscopy can also be used to differentiate between real chelates (coordination of TiCl4 at the oxygen atoms of the carbonyl groups) and π complexes.
Neue 1,6‐Methano[10]annulen‐Derivate mit “parallelen Dreifachbindungen”
Authors: Neidlein Richard , Kux Ulrich 
Published: July 2007

New 1,6‐Methano[10]annulene Derivatives with “Parallel Triplebonds”Herrn Professor Gerhard Fritz zum 75. Geburtstag gewidmet.

Teil der Dissertation von U.K.(Lit.[9c]).
The peri‐ethinyl‐substituted 1,6‐methano[10]annulenes 2–5 were synthesized starting from 1c or 1d. Hydrolysis of 4 yielded 6; compounds 7 and 8 were isolated as undesired side‐products of these syntheses. The interactions between the “parallel triplebonds” were investigated.
Herstellung von 1,5‐Cyclooctadiin und 1,3,5,7‐Cyclooctatetraen aus 1,5‐Cyclooctadien
Authors: Detert Heiner , Rose Bernd , Mayer Winfried , Meier Herbert 
Published: July 2007

Preparation of 1,5‐Cyclooctadiyne and 1,3,5,7‐Cyclooctatetraene from 1,5‐CyclooctadieneBromination of 1,5‐cyclooctadiene (1) and stepwise dehydro‐bromination first with KOtBu and then with KOtBu/18‐crown‐6 yields 1,5‐cyclooctadiyne (5). A prolonged interaction of the base causes a complete transformation to cyclooc‐tatetraene (6). Diyne 5 and even more the intermediate enyne 4 are highly reactive dienophiles. The cycloadducts 10–14 formed with 1,3‐cyclohexadiene, carbon disulfide, and tetraphenylcyclopentadienone were isolated and characterized. Treatment of 5 with titanium tetrachloride induces a vigorous polymerization.
Chelating Coordination of Di‐ and Triallylamines: Syntheses and NMR Studies of Trimethylphosphane Nickel and Cobalt Complexes
Authors: Klein Hans‐Friedrich , Helwig Michael , Braun Siegmar 
Published: July 2007

Abstract16‐Electron complexes of zerovalent nickel with diallylamines, Ni[(C3H5)2NR]L [1, 2: L = P(CH3)3, R = CH3, C6H5; 3: L = P(C6H5)3, R = CH3] and [NiP(CH3)3]2CH2[N(C3H5)2]2 (4), were synthesized by reduction of NiCl2L2 with magnesium in tetrahydrofuran. NiCl(η3‐C3H5)[P(CH3)3]2 (5), a low‐yield byproduct, was also obtained in high yield from NiL4 and C3H5Cl. With triallylamine as starting material complexes Ni[(C3H5)3N]L [6: L = P(CH3)3; 7: L = P(C6H5)3] were generated exhibiting η6‐ and η4‐olefin coordination, respectively. 17‐electron cobalt(O) compounds Co[(C3H5)2NR](PMe3)2 (8, 9: R = CH3, C6H5) were obtained by reaction of Co(cyclo‐C5H8)(PMe3)3 with the corresponding diallylamine, while CoR(PMe3)4 (R = CH3, C6H5) reacted with N,N‐diallylaniline to give diagmagnetic Co[(η3‐C3H4)(η2‐C3H5)NC6H5](PMe3)2, (10). The coordination mode of allylic functions was deduced from IR, ESR and especially 1H‐ and 13C‐NMR spectra including 2D‐NMR experiments.
(Organoboryl)sulfate — Herstellung und Charakterisierung[1]
Authors: Köster Roland , Schüßler Wilhelm , Bläser Dieter , Boese Roland 
Published: July 2007

AbstractOrganoboryl Sulfates — Preparation and Characterisation[1]Triethylborane (3) reacts with sulfuric acid to form the sulfate Et2BOS(O2)OBEt2 (1a), which can also be prepared from (Et2B)2O (4a) and SO3. Sulfate 1a reacts with (C8H14B)2O (4b) to give the solid sulfate C8H14BOS(O2)OBC8H14 (1b) and 4a. Compound 1b is also obtained by treating 4b with SO3. The reaction of 4a with sulfuric acid leads to the crystalline cyclic sulfate EtBOB(Et)OS(O2)O (2a) (X‐ray structure analysis). 2a is also available from triethylboroxin (5) on reaction with SO3. The diboroxanes 4a and 4b and H2SO4 form insoluble 1:1 addition complexes 4a·H2SO4 and 4b·H2SO4, which react on heating at about 60°C to yield the cyclic sulfates 2a and C8H15BOB(C8H15)OS(O2)O (2b), respectively.