bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioselektive Protonierung von Lacton‐Enolaten
Authors: Gerlach Uwe , Haubenreich Thomas , Hünig Siegfried 
Published: July 2007

Stereoselective Protonation of Carbanions, 4[1]. — Enantioselective Protonation of Lactone Enolates[2]The prochiral lithium enolates derived from the five‐membered lactones rac‐1 and rac‐2 were protonated by 37 OH‐and 21 NH‐chiral proton sources in THF at — 78°C. The enantioselectivities, determined directly from the reaction mixture by chiral HPLC, are always higher for system 1, probably due to restricted rotation of the phenyl group in 1Li at low temperature (NMR) and range from 0–54% ee. The strongest stereodifferentiation is observed if the OH or NH acids carry an adjacent O‐ or N‐containing group (structures G–J) which allows complexation with the lithium ion. A plausible transition state involving the dimeric lithium enolate is proposed.
Die fördernde Rolle von Phosphinoester‐Liganden bei der Synthese neutraler Carben‐, Vinyliden‐ und Allenyliden‐Ruthenium(II)‐Komplexe
Authors: Werner Helmut , Stark Arthur , Grönwald Paul Steinert, Claus , Wolf Justin 
Published: July 2007

AbstractVinylidene Transition‐Metal Complexes, XXXV[1]. — The Supporting Role of Phosphino Ester Ligands for the Synthesis of Neutral Carbene, Vinylidene and Allenylidene Ruthenium(II) ComplexesThe reaction of [RuCl2(PPh3)3] (1) with the phosphino esters iPr2P(CH2)nCO2R (2–4) leads to complete (n = 1; R  CH3, C2H5) or partial (n = 2; R CH3) displacement of the PPh3 ligands and formation of the octahedral ruthenium(II) complexes [RuCl2{k2(P,O)‐iPr2PCH2CO2R}2] (5, 6) and [RuCl2(PPh3){k(P)‐iPr2PCH2CH2CO2Me}{k2(P,O)‐iPr2PCH2CH2CO2Me}] (7). Treatment of 5 with LiBr and LiI affords the dibromo‐ and diiodoruthenium derivatives 8 and 9. While compound 5 reacts with CO and SO2 by cleavage of one Ru—O bond to yield the 1:1 adducts [RuCl2(L){k(P)‐iPr2PCH2CO2Me}{k2(P,O)‐iPr2PCH2CO2Me}] (10, 11), the reaction of the dibromo derivative 8 with CO in solution gives the dicarbonyl complex [RuBr2(CO)2{k(P)‐iPr2PCH2CO2Me}2](13). If CO is passed over 8 in the solid state, the corresponding monocarbonyl compound 14 is formed. The hydridoruthenium(II) complex 16, which is obtained from equimolar amounts of [RuHCl(CO)(PiPr3)2] (15) and 2, reacts with HCCMe by insertion to give the vinyl derivative [RuCl{E—CHCHMe}(CO)(PiPr3){k2(P,O)‐iPr2CH2CO2Me}] (17). Treatment of 5 with HC̊' (R'  H, Me, tBu, Ph) and of 6, 8, 9 with HCCPh affords upon photochemical activation the octahedral vinylidene complexes [RuX2‐(CCHR){k(P)‐iPr2PCH2CO2R}{k2(P,O)‐iPr2PCH2CO2R}] (18–21 and 23–25) in good to excellent yield. At room temperature, these compounds (with the exception of 25) are highly fluxional in solution. From 31P‐NMR measurements, the free energies of activation ΔG‡ for the intramolecular rearrangement have been determined. Whereas the reaction of 5 with HCČH2CH2OH leads to the carbene complex 30 containing the cyclic oxycarbene :C(CH2)3O as ligand, the functionalized vinylidene derivatives 31 and 32 are formed on treatment of 5 with aryl‐substituted alkynols HC≡RR'OH (R  Ph, R'  Ph, o‐Tol). These react in toluene solution at 80°C by elimination of water to give the allenylidene complexes [RuCl2(CCCRR'){k(P)‐iPr2PCH2CO2Me}{k2(P,O)‐iPr2PCH2CO2Me}] (33, 34). The X‐ray structure analysis of 33 reveals a trans disposition of the chloro ligands, the phosphorus atoms as well as of one CO oxygen and the α‐C atom of the allenylidene unit. Compound 33 reacts with CO, CNtBu and pyridine to give the 1:1 adducts [RuCl2(L)(CCCPh2){k(P)‐iPr2PCH2CO2Me}2] (35–37) and with HCl by attack on the central CC bond to yield the vinylcarbene complex [RuCl2(C(Cl)CHCRR'){k((P)‐iPr2‐PCH2CO2Me}{k2(P,O)‐iPr2PCH2CO2Me}] (38). The preparation of the phosphino ketone iPr2PCH2C(O)CH3 (40) and its ruthenium complexes 41 and 42 is briefly described.
Synthesis of Transient Silenes by a Modified Peterson Reaction
Authors: Krempner Clemens , Reinke Helmut , Oehme Hartmut 
Published: July 2007

AbstractTris(trimethylsilyl)silylmagnesium bromide, obtained in situ from tris(trimethylsilyl)silyllithium and magnesium bromide, reacts with acetone, pivalaldehyde, or 2,4,6‐trimethylbenzaldehyde to give the (1‐hydroxyalkyl)tris(trimethylsilyl)silanes (Me3Si)3SiC(OH)Me2 (1a), (Me3Si)3CH(OH)tBu (1b), and (Me3Si)3SiC(OH)Mes (1c), resp. After deprotonation with methyllithium in ether at ‐78°C 1a‐c eliminate trimethylsilanolate according to a modified Peterson mechanism to form transient silenes (Me3Si)2Si=CR1R2 (6a: R1 = R2 = Me; 6b: R1 = H, R2 = tBu; 6c: R1 = H, R2 = Mes). In the absence of trapping agents these silenes dimerize, 6a leading to the linear dimer 1‐isopropenyl‐2‐isopropyl‐1,1,2,2‐tetrakis(trimethylsilyl)disilane (7) and 6b giving the head‐to‐head cyclodimerization product (E)‐3,4‐di‐tert‐butyl‐1,1,2,2‐tetrakis(trimethylsilyl)‐1,2‐disilacyclobutane (8), whereas 6c in a very unusual cyclodimerization step affords (E)‐1,2,3,8a‐tetrahydro‐1‐mesityl‐5,7,8a‐trimethyl‐2,2,3,3‐tetrakis(trimethylsilyl)‐2,3‐disilanaphthalene (9). Compound 9 is the result of an unexpected [2 + 4] reaction, in which the silene formally acts as the monoene and – involving the aromatic substituent – simultaneously also as the diene. The reaction of 1a‐c with methyllithium in THF at low temperature initiates 1,3‐Si,O‐trimethylsilyl migrations leading to (trimethylsiloxy)‐[bis(trimethylsilyl)silyl]alkanes (Me3Si)2SiH–CR1R2OSiMe3 3a‐c. Reaction of 1a‐c with an excess of methyllithium, tert‐butyllithium, or phenyllithium, leads to trisilanes (Me3Si)2‐SiR3–CHR1R2 11a‐e, formed by the addition of the organolithium reagent to the Si=C bond of the transient silences 6a‐c. Deprotonation of 1b and 1c in the presence of 2,3‐dimethyl‐1,3‐butadiene gives the [2 + 4] cycloadducts 6‐tert‐butyl‐3,4‐dimethyl‐1,1‐bis(trimethylsilyl)‐1‐sila‐3‐cyclohexene (12a) and 6‐mesityl‐3,4‐dimethyl‐1,1‐bis(trimethylsilyl)‐l‐sila‐3‐cyclohexene (12b). For 8 and 9 the results of the X‐ray analyses are given.
Platin(II)‐Komplexe mit Porphyrinliganden: Synthese und Synergismen bei der photodynamischen Tumortherapie
Authors: Brunner Henri , Obermeier Herbert , Szeimies Rolf‐Markus 
Published: July 2007

Platinum(II) Complexes with Porphyrin Ligands: Synthesis and Synergisms in the Photodynamic Tumor TherapyTwelve porphyrin ligands (2–5, 8, 13–16, 19, 27, 28) and their platinum(II) complexes (29–40) were synthesized and characterized. Nine of the porphyrins are derived from hemin, and three are based on tetraphenylporphyrin. The ligands were transformed into diammine‐dicarboxylatoplatinum(II) complexes and diamine‐dichloroplatinum(II) complexes. The antitumor activity in the photodynamic therapy of the ligands and their complexes was tested in vitro towards the MDA‐MB‐231 mammary carcinoma cell line. The results obtained showed an additive effect of the photodynamic activity of the porphyrin skeleton when irradiated with visible red light and the cytotoxic activity of the platinum moiety in the complexes.
Derivate des Imidazols, XIII. Carben‐Komplexe des Siliciums und Zinns
Authors: Kuhn Norbert , Kratz Thomas , Bläser Dieter , Boese Roland 
Published: July 2007

Imidazole Derivatives, XIII. – Carbene Complexes of Silicon and TinHerrn Professor Peter Paetzold zum 60. Geburtstag gewidmet.
Stable adducts of the composition L · SiCl4 (2), L · SiR2Cl2 (3,4), and L · SnR2Cl2 (6) are formed by the reaction of the imidazol‐2‐ylidenes L (1) with the corresponding silicon and tin halides. For L = SiCl4 (2b; L = 1,3‐diethyl‐4,5‐dimethylimidazol‐2‐ylidene) and L · SnPh2Cl2 (6c; L = 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) the monomeric nature of the compounds containing pentacoordinated silicon and tin is established by X‐ray structure analyses. The reaction of 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene (1c) with SnCl2 leads to the formation of the monomeric stannylene complex L · SnCl2 (7c; L = 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) whose molecular geometry indicates a week carbon‐to‐tin donor bond [SnC(1) 2.290(5) Å].
Metallorganische CO2‐Speichersysteme aus Nickel(0)‐1‐azadieneinheiten und ihre Reaktivität bei der Carboxylierung von Acetophenon
Authors: Walther Dirk , Geßer Susann , Ritter Uwe , Schmidt A. , Hamza Khairi , Imhof Wolfgang , Görls Helmar , Sieler Joachim 
Published: July 2007

Organometallic CO2 Reservoires from Nickel(0)‐1‐Azadiene‐Type Ligands and Their Reactivity in the Carboxylation of Acetophenone1‐Azadiene‐type ligands yield with nickel(0) binuclear organometallic compounds of the type [Ni(1‐azadiene)n,]2 (n = 1, 2). The structures of the complexes 1 (n = 2, ligand A) and 3 (n = 1, ligand C) have been characterized by X‐ray crystallography. 1 is unreactive towards CO2, 3 and similar compounds are able to react with CO2 to give metallacyclic carbamato complexes of Ni(II). In these compounds CO2 is activated and can carboxylate acetophenone to yield benzoylic acid upon protolysis. These reactions mimic biologic conversion reactions of CO2 into organic material by organometallics. – The addition of two moles of the (bpy)Ni(0)‐fragment [from (bpy)Ni(COD)] to 3 gives the tetranuclear complex 6. The X‐ray analysis of the monomeric model compound (bi‐py)Ni(A) (11) shows that only the olefin part is coordinated. 6 and 11 can also react with CO2. Cu(I) complexes with 1‐azadiene‐type ligands are not reactive towards CO2.
Charge‐Transfer‐Komplexe von Metalldithiolenen, XVIII. Ionenpaare von Dithiolencobaltaten mit Bipyridinium‐Akzeptoren
Authors: Schmauch Georg , Knoch Falk , Kisch Horst 
Published: July 2007

Charge‐Transfer Complexes of Metal Dithiolenes, XVIII. – Ion Pairs of Dithiolene Cobaltates with Bipyridinium AcceptorsIon pair charge‐transfer (IPCT) complexes of the type {A2+[Co(mnt)2]2−}, mnt2− = cis‐1,2‐dicyano‐1,2‐ethenedithiolate, A2+ = a bipyridinium derivative, posses IPCT bands in the range from 590 to 950 nm. An X‐ray structure analysis of {BQ2+[Co(mnt)2]2−}, BQ2+ = 6,7,8,9‐tetrahydrodipyrido[1,2‐a:2,1‐c][1,4]diazocinium, reveals that the strongly twisted acceptor and planar donor do not form mixed stacks, as usually observed in less twisted systems. Electrical conductivities of pressed powder pellets are in the range of 10−15 to 10−7 Ω−1 cm−1 and do not exhibit a simple correlation with the driving force of electron transfer between the ion pair components. The cis‐trans isomerization of an ethene‐bridged methyl viologen acceptor leaves the conductivity almost unchanged.
Pyridine as an C‐Orthometalated and σ‐N‐Complexed Heteroarene Ligand on the Surface of a Co3 Cluster
Authors: Schneider JöRg J. 
Published: July 2007

AbstractReaction of [(η5‐Cp*)(acac‐O,O′)Co] (1) with potassium metal in pyridine results in reductive ligand transfer of the acac ligand to potassium and formation of a mixture of two organocobalt complexes which can be separated from each other by chromatography. Besides a mononuclear complex containing no pyridine unit the trinuclear cobalt cluster [{(η5‐Cp*)‐Co}3‐μ‐pyridine] (3) is formed in a cyclometalation reaction in 57% yield. The pyridine ligand in 3 is located on one edge of the Co3 core according to the spectroscopic data and a preliminary X‐ray crystal structure analysis.
Synthesis, Structures and Properties of CF3S‐Substituted Tellurium Compounds
Authors: Boese Roland , Dworak Jürgen , Haas Alois , Pryka Michael 
Published: July 2007

AbstractNew preparations for the following compounds are described: Te(SCF3)2, Te(NSO)2, and Cl2Te(NSO)2. The catalytic or thermal SO2 elimination from Cl2Te(NSO)2 affords a coordinated or non‐coordinated thiachalcogenadiazole. Conversions of these compounds are reported. Evidence for the proposed mechanism for the reaction between Te(NSO)2 and SbCl5 is provided. Cl4Te2N2(SCF3)2, prepared from TeCl4 and CF3SN(SiMe3)2, reacts with LiN(SiMe3)2 to form [(Me3Si)2N]4Te2N2(SCF3)2. An X‐ray structural analysis of Cl4Te2N2(SCF3)2 is presented.
On the Regioselectivity and Stereoselectivity of the Carbene Transfer from Fischer Carbene Complexes to Trisubstituted Electron‐Deficient 1,3‐Dienes
Authors: Buchert Matthias , Hoffmann Matthias , Reißig Hans‐Ulrich 
Published: July 2007

AbstractThermal reactions of Fischer carbene complex 1 with trisubstituted electron‐deficient 1,3‐dienes 7, 8, 23, 25, 32, and 35 provided highly substituted vinylcyclopropanes in good yields. The carbene transfer proceeds highly regioselectively favouring cyclopropanation of the double bond not bearing the ester function. In addition, the diastereoselectivity is generally fairly high in preference of cyclopropanes with the methoxy group cis‐positioned with respect to the olefin moiety. The reaction of methylcarbene complex 2 with diene ester 8 displays inversed regioselectivity. These observations are discussed together with solvent effects, and a mechanistic rationale is presented.
Formation and Structure of a New Dinuclear Rhodium Complex [(iPr3P)RhCl]2[P3C3tBu3]
Authors: Binger Paul , Haas Josef , Betz Peter , Krüger Carl 
Published: July 2007

AbstractThe new dinuclear rhodium complex 4 was synthesized by reaction of [(iPr3P)2RhCl]2 (1) or [(iPr3P)2(CH2=CH2)RhCl] (2) with 2‐tert‐butyl‐1‐phosphaacetylene (3) in 58% yield. An X‐ray analysis reveals that in 4 a 1,3,6‐triphosphahexadiene‐1,6‐diyl chain is bound to each of the two rhodium atoms in an η1,η3 manner.
DBU ‐ nicht einfach nur eine starke Base: Eine Eintopfreaktion für ein polycyclisches Ringgerüst mit Diphosphet ‐ Grundstruktur unter Einbeziehung von doppelt deprotoniertem DBU
Authors: Karsch Hans H. , Rupprich Thomas , Heckel Maximilian 
Published: July 2007

DBU ‐ Not Simply a Strong Base: A One‐Pot Synthesis of a Polycyclic Framework Consisting of a Diphosphete Central Unit and Two Units of Doubly Deprotonated DBUTwo condensed five‐, six‐ and seven‐membered rings are fused in a spirocyclic fashion with a central four‐membered diphosphete ring in 4, which unexpectedly is formed in a simple two‐component‐one‐pot reaction from Cl2P‐CH(SiMe3)2 and DBU. The latter is doubly deprotonated and acts as a bridge via C‐6 and N‐8 to a P‐P unit. The polyheterocycle 4 crystallizes in two modifications, whose molecular structures are almost identical.
Organophosphorus Compounds, 103. Thermal Transformation of Kinetically Stabilized Phosphaalkynes with Phosphinidene Precursors. Synthesis of Phosphorus‐Carbon Cage Compounds by Cocyclooligomerization Processes
Authors: Julino Markus , Slany Michael , Bergsträßer Uwe , Merçier Françlois , Mathey Françlois , Regitz Manfred 
Published: July 2007

AbstractPhosphaalkynes 2 undergo cocyclooligomerization reactions with the phosphinidene 14 or the phosphinidene‐W(CO)5 complex 18 to furnish the phosphorus‐carbon cage compounds 16 or 23. The phosphinidene 14 is generated by the thermal reaction of 2a‐c with the phosphole 11, a process in which the initially formed 7‐phosphanorbornadienes 12a‐c decompose to the λ3‐phosphinines 13a‐c and the desired reactive intermediate. When three further equivalents of the phosphaalkynes 2a‐c are employed, the tetraphosphahomoquadricyclanes 16a‐c can be isolated in 53‐65% yields. The second approach is based on the thermal fragmentation of 17 to generate the phosphinidene‐W(CO)5 complex 18 which, in turn, reacts with four equivalents of the phosphaalkynes 2a or b to produce the pentaphosphadeltacyclanes 23a or b. The constitutions of these novel phosphorus‐carbon cage compounds were confirmed by X‐ray crystal structure analyses of 16a and 23a.
Ylidyl 1,2,4‐Thiadiphosphetane and 1,2,4‐Selenadiphosphetane Sulfides and Selenides
Authors: Jochem Georg , Schmidpeter Alfred , Kulzer Florian , Dick Stefan 
Published: July 2007

AbstractPhosphoniumylidyl thioxophosphanes and selenoxophosphanes, the only known monomeric chalcogenoxophosphanes, react in a 2:1 ratio with triphenylphosphonium ylides. With loss of PPh3 the 1,2,4‐thia(or selena)diphosphetane monosulfides (or selenides) are formed. Their prominent structural feature are the very different PS bond lengths in the ring. They can be oxidized to the corresponding disulfides or sulfide selenides. The latter rearrange to the isomer in which the selenium atom has become a ring member.
Metal Complexes of Functional Isocyanides, XXV. Amino(hydrazino)carbene Complexes
Authors: Fehlhammer Wolf Peter , Metzner Robert , Luger Peter , Dauter Zbigniew 
Published: July 2007

AbstractThe N‐isocyanodialkylamine metal complexes [M(CO)5CN‐NR2] (M = Cr, W), trans‐[MI2(CNNR2)2] (M = Pd, Pt), trans‐[Pt(Cl)(CNNR2)(PPh3)2]BF4, and cis‐[PtCl2(CNNR2)(PPh3)] [R = Et, iPr; 2 R = ‐{CHMe(CH2)3CHMe}‐] react with primary amines to give the amino(hydrazino)carbene metal complexes [M(CO)5(C(NHR′)NHNR2}] (R′ = Me, nPr, Cy) (1–9), trans‐[PtI2{C(NHMe)NHNR2}2] (10–12) and transmagnified image, and the amine adducts cis‐[PtCl2{C(NHMe)NHNC(H)(Me) (CH2)3CHMe}(PPh3)] magnified image H2NMe (14), and trans‐[PdI2{C (NHMe)NHNC(H)(Me)(CH2)3CHMe}2] magnified image 2 H2NMe (15). With secondary amines the amino(hydrazino)carbene metal complexes transmagnified image (18) and trans‐[PtCl{C(NEt2)NHNEt2} (PPh3)2]BF4 (19) Were isolated. The complexes trans‐[PtI2{C(NHCy)NHNiPr2}CNNiPr 2] (20) and trans‐[PdI2 (NH2Cy){C(NHCy)NHNiPr2}] (21) were obtained by reaction of trans‐[MI2(CNNiPr2)2] (M = Pd, Pt) with cyclohexylamine. The structures were assigned on the basis of IR, NMR‐ (1H, 13C, 31P), and mass spectroscopy as well as an X‐ray structural analysis of 21.
Metallkomplexe mit biologisch wichtigen Lisganden, LXXX. (η3:η3‐C10H16)Ru(IV)‐Komplexe mit α‐Aminocarboxylaten, α‐Aminosäureestern und Peptidestern als Liganden
Authors: Severin Kay , Mihan Shahram , Beck Wolfgang 
Published: July 2007

Metal Complexes Containing Biologically Important Ligands, LXXXLXXIX. Mitteilung: Lit.

.
— (η3:η3‐C10H16)Ru(IV) Complexes with α‐Amino Carboxylates, α‐Amino Acid Esters, and Peptide Esters as Ligands
Reactions of the chloro‐bridged bis(allyl) complex [(η3:η3‐C10H16)Ru(Cl)(μ‐Cl)]2 with α‐amino carboxylates and α‐amino acid esters afford the complexes (η3:η3‐C10H16)(Cl)Rmagnified imageuNH2CHRCO2 (2) and (η3:η3‐C10H16)(Cl)2‐RuNH2CHRCO2R′ (3). Abstraction of chloride from 3 by Ag+ gives the N,O‐chelates [(η3:η3‐C10H16)(Cl)Rmagnified imageuNH2CHRCO2R′]+BF4 (4). Cysteine methyl ester forms the N,S‐chelate complex (η3:η3‐C10H16)(Cl)Rmagnified imageuNH2CH(CO2CH3)CH2S (5), and with histidine methyl ester a dinuclear complex 6 with N,N‐histidine bridge is obtained. Compound 3d with L‐PheOEt as ligand was characterized by X‐ray diffraction.
Metallkomplexe mit biologisch wichtigen Lisganden, LXXXI. Synthese und Kristallstruktur von Rh(I)‐Komplexen mit α‐Aminocarboxylat‐Liganden
Authors: Severin Kay , Mihan Shahram , Beck Wolfgang 
Published: July 2007

Metal Complexes Containing Biologically Important Ligands, LXXXPart LXXX: Ref.

.
— Synthesis and Crystal Structure of Rhodium(I) Chelates with α‐Amino Carboxylates

Part LXXX: Ref.
The α‐amino carboxylate complexes magnified image were prepared from Rh(Cl)(CO)(PPh3)2 and H2NC(H)(R)CO2 in the presence of AgBF4 and characterized by X‐ray diffraction. In the crystal the complexes form chains by hydrogen bridges between amino and carboxylate groups of adjacent molecules.
Thioselonocarboxylic Ester, Selenetane, and Dihydrodiselenine Complexes Prepared from Pentacarbonyl(selenobenzaldehyde)tungsten with π‐Donor‐Substituted Alkynes
Authors: Fischer Helmut , Treier Kornelia , Troll Carsten 
Published: July 2007

AbstractPentacarbonyltungsten‐coordinated selenobenzaldehyde, [(CO)5W{Se=C(Ph)H}] (1), reacts with tBu‐CC‐SMe (2) by insertion of the CC into the Se=C bond to form in a highly regio‐ and stereoselective manner the α,β‐unsaturated thioselonocarboxylic ester complex (Z)(C=C)‐[(CO)5W{1‐Se=C(SMe)C(tBu)=C(Ph)H}] (3). The thioselonocarboxylic ester ligand is cleaved intact from the metal by treatment of 3 with [NEt4]Br. Three complexes are formed in the reaction of 1 with Me‐CC‐SMe (5): the thioselonocarboxylic ester complex [(CO)5W{1‐Se=C(SMe)C(Me)=C(Ph)H}] (6) as a mixture of the (E) and (Z)(C=C) isomers, a selenetane complex (7) and a dihydrodiselenine complex (8). The product distribution depends on the ratio 1:5 and on the solvent. The reaction of 1 with the bis(organylthio)alkynes RS‐CC‐SR (9) [R = Me (a), iPr (b), 2,6‐C6H3Me2 (c)] yields mixtures of the (E) and (Z)(C=C) isomers of the α,β‐unsaturated α‐organylthio thioselonocarboxylic ester complexes [(CO)5W{1‐Se=C(SR)C(SR)=C(Ph)H)] (10a‐c). In contrast, the reaction of 1 with tert‐butoxyethyne, H‐CC‐OtBu (11), affords a bis(pentacarbonyltungsten) 5,6‐dihydro‐1,2‐diselenine complex (12). Compound 12 is probably formed by consecutive reaction of 1 with 11 to give the selonocarboxylic ester complex [(CO)5W{1‐Se=C(OtBu)C(H)=C(Ph)H}] which then further reacts as a heterodiene by highly regioselective [4 + 2] cycloaddition with the Se=C bond of a second molecule of 1 to give 12. In the reaction of 1 with 5 and 9a the isomer with a trans arrangement of C(=Se)SMe and Ph is the kinetically controlled reaction product [(E)‐6 and (Z)‐10a, respectively]. The formation of (E)‐6 and (Z)‐10a is followed by isomerization until an (E)/(Z) equilibrium is reached. Complexes 3 and 7 were characterized by X‐ray structural analyses.
Tin for Organic Synthesis, 13. A New and Regioselective Method for the Synthesis of Aromatic, Heteroaromatic, and Olefinic Sulfonamides by Electrophilic Destannylation
Authors: Lube Andreas , Neumann† Wilhelm P. , Niestroj Michael 
Published: July 2007

AbstractA mild and effective method for the preparation of aromatic and olefinic sulfonamides is described. The reaction of trialkylaryl‐ (4a–f), heteroaryl‐ (4g), and vinylic stannanes (4h) with sulfuryl chloride and secondary amines provides the corresponding sulfonamides in an ipso‐specific manner.
Synthesis and Characterization of Copper(II) Complexes of a 14‐Membered cis‐N2S2 Dibenzo Macrocycle and of Its Bis‐acetato and Bis(methylpyridyl) Derivatives
Authors: Bentfeld Roland , Ehlers Norbert , Mattes Rainer 
Published: July 2007

AbstractThe synthesis and characterization of seven copper coordination compounds with the 14‐membered macrocyclic cis‐N2S2 dibenzo ligand 6,7,13,14,15,16,17,18‐octahydrodibenzo[e,m]‐[1,4,8,11]dithiadiazacyclotetradecine (L1) and its N,N'‐bisacetato and ‐bis(methylpyridyl) functionalized derivatives H2L2 and L3 are described. The structures of five compounds were determined by single‐crystal X‐ray diffraction. The tetrahedrally distorted square‐planar coordination geometry of [CuL1](ClO4)2 (1) changes upon reduction of copper to a severely distorted tetrahedral geometry in [CuL1]Br · MeCN (2). The Cu–N bond lengths increase from 1.988(3) to 2.029(5) Å; the Cu–S bond lengths decrease from 2.293(1) to 2.255(2) Å. Copper(II) is hexacoordinated in [CuHL2]HSO4 · 2.5 H2O (5) and [CuHL2]ClO4 · H2O (6). Both compounds exhibit very similar overall structures in the cationic part. The macrocyclic ring of the ligand is folded along an N ⃜S axis, the octahedral geometry is strongly Jahn‐Teller distorted, with O and S donor atoms in the apical positions. Compound 5 contains one very short [2.271(3) Å] and one long [2.701(3) Å] Cu–S (thioether) bond. In [CuL3](ClO4)2 · 2 H2O (7) one thioether group of the ligand L3 remains uncoordinated. The coordination polyhedron is rather irregular: Cu–S 2.506(3) and Cu–N 1.960(7)–2.107(8) Å. The compounds were further characterized by electronic and EPR spectroscopy and by cyclic voltammetry. Some relationships to the structural and spectroscopic properties of “blue” copper proteins were found.