bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blausäure‐N‐methylid: Darstellung, spektroskopische Eigenschaften und seine Beziehung zu anderen C2H3N‐Isomeren
Authors: Maier Günther , Schmidt Christiane , Reisenauer Hans Peter , Endlein Edgar , Becker Dieter , Eckwert Jürgen , Andes Jr. B. Hess , Schaad Lawrence J. 
Published: July 2007

Hydrogen Cyanide N‐Methylide: Preparation, Spectroscopic Identification, and Its Relationship to Other C2H3N IsomersWith the intention of isolating 1H‐azirene (8) we studied several precursors which should offer an entry into the C2H3N potential energy hypersurface. It was found that in addition to the known isomers 1, 2, 3, and 6 hydrogen cyanide N‐methylide (5) — and probably aminoacetylene (4) — can be detected in an argon matrix at 10 K. No spectroscopic evidence for the formation of 1H‐azirene (8) was found. In other words, the first six members 1—6 are now all identified. The elucidation of the structure of the new C2H3N species is based on the comparison of the observed IR spectra with those calculated by ab initio methods.
Bis[(di‐tert‐butylphosphanyl)methyl]methylphosphan
Authors: Krill Jochen , Shevchenko Igor V. , Fischer Axel , Jones Peter G. , Schmutzler Reinhard 
Published: July 2007

Bis[(di‐tert‐butylphosphanyl)methyl]methylphosphane[1]The synthesis of [(di‐tert‐butylphosphanyl)methyl]dimethyl‐phosphane (3) and of the title compound 5 is described. 5 reacts with sulfur to form the trisulfide 6. Both 3 and 5 behave as bidentate ligands in forming the molybdenum complexes 8 and 10, which are characterized by single crystal X‐ray structure determinations. 10 reacts with sulfur to yield the sulfide 11, which decomposes in solution within 6 h.
Strukturell unterschiedliche Metallamide (Li, Cu, Ag, Cd) mit dem Chelatliganden [tBu–N–SiMe2–O–C6H4–O–Sime2–N–tBu]2–
Authors: Veith Michael , Woll Karl Ludwig 
Published: July 2007

Structurally Different Metal Amides (Li, Cu, Ag, Cd) with the Chelating Ligand [tBu‐N–SiMe2–O–C6H4–O–SiMe2–N–tBu]2–Herrn Professor Heinrich Nöth zum 65. Geburtstag gewidmet.
The amino hydrogen atoms in the silylamine o‐C6H4O2(Me2SiN(H)tBu)2 (1) can be replaced by monovalent (Li, Cu, Ag) or divalent (Cd) metallic elements. Whereas the lithium compound is obtained as an ether adduct, [C6H4O2(Me2SiNtBu)2]Li2 · OEt2 (2), the copper and silver compounds are solvens‐free. The latter two form similar dimers comprising four metal atoms: [C6H4O2(Me2SiNtBu)2]2Cu4 (3) and [C6H4O2 (Me2SiNtBu)2]2Ag4 (4). The cadmium compound is also a dimer with two ligands and two cadmium atoms making up the molecule, [C6H4O2(Me2SiNtBu)2]2Cd2 (5). X‐ray structure analyses reveal that in all compounds the metallic elements are highly coordinated by N and O interactions, with coordination numbers of 4 (2, 3, 4) and 5 (5). The oxygen contacts are quite long ranging from 260 to 301 pm. In the Cu und Ag compounds quadratic planar arrangements at the metals are found (bridged by nitrogen) with distances Cu–Cu 262.6(2)–270.1(2) and Ag–Ag 291.7(1)–301.8(2) pm.
Übergangsmetall‐Stannyl‐Komplexe, 9[1]. Substitutions‐Reaktionen der anionischen Hydrid‐Komplexe [(π‐MeC5H4)(CO)2MnH]– und [(π‐Aromat)(CO)2CrH]–
Authors: Mock Stefan , Schubert Ulrich 
Published: July 2007

Transition Metal Stannyl Complexes, 9[1]. – Substitution Reactions of the Anionic Hydrido Complexes [(π‐MeC5H4)‐(CO)2MnH]– and [(π‐Arene)(CO)2CrH]–The anionic hydrido complexes K[(π‐MeC5H4)(CO)2MnH] (2c) and K[(π‐arene)(CO)2CrH] (π‐arene = C6H6, C6H5Me, 1,2,3‐C6H3Me3, C6Me6, C6H5Ph, indan) (5a–f) are spontaneously formed on stirring THF solutions of the dianionic complexes K2 [(π‐MeC5H4)(CO)2Mn] (1) or K2[(π‐arene)(CO)2Cr] (4) at – 78°C. The dianionic complexes are obtained by potassium naphthalenide reduction of (π‐MeC5H4)(CO)2MnL or (π‐arene)(CO)2CrL (L = pyridine or THF). Reaction of 2c with Me3SnCl or Ph2SnCl2 yields the bis(stannyl) complexes Cp*(CO)2Mn(SnR3)2 (SnR3 = SnMe3, SnPh2Cl), while reactions with the „smaller”︁ stannanes Me2SnCl2 or Et2SnCl2 results in the SnR2‐bridged complexes [Cp′(CO)2Mn]2(μ‐SnR2)((Mn–Mn). The bis(stannyl) complexes (π‐arene)(CO)2Cr(SnR2Cl)2 (R = Me, Ph) are obtained from 5 and R2SnCl2. However, the reaction is strongly influenced by steric effects: with Me2SnCl2, bis(stannyl) complexes are obtained for π‐arene = C6H6, C6H5Me, 1,2,3‐C6H3Me3, or C6Me6, with Ph2SnCl2 only for π‐arene = C6H6 and C6H5Me. Reaction of the sterically demanding complexes K[(π‐C6H5Ph)(CO)2CrH] or K[(π‐indan)(CO)2CrH] with Ph2SnCl2 stops at the stage of the anionic stannyl complexes K[(π‐arene)(CO)2Cr‐SnPh2Cl].
Synthesis and Structure of a Silyl‐aminoalane Ring
Authors: Janik Jurik F. , Duesler Eileen N. , Paine Robert T. 
Published: July 2007

AbstractThe reactions of hydrazine with tris(trimethylsilyl)aluminium‐ether have been studied: Reactant ratios of 0.5:1 and 0.8:1 produce the cyclic aminoalane [(Me3Si)2AlN(H)(SiMe3)]2 (1), which is formed by N–N bond cleavage and silyl group migration from aluminium to nitrogen. Pyrolysis under NH3 of a polymeric product formed from a 1:1 reaction produces an AlN/Si3N4 composite.
Anticancer Agents, 19[1]. Synthesis of the Reduced A‐Unit (CI) of the Antitumor Antibiotic CC‐1065
Authors: Tietze Lutz F. , Grote Thomas 
Published: July 2007

AbstractThe synthesis of the reduced A‐unit 2 (CI) of CC‐1065 (1) using a metal‐mediated cyclisation is described. Reaction of N‐allyl‐N‐benzylaniline 4b and zirconocene(methyl) chloride with tert‐BuLi leads via a zirconocene‐stabilized benzyne complex 5 to the 3,4‐difunctionalized indoline derivative 7, which was converted in five steps into 2.
Die verschiedenartigen Konformationen N‐Trimethylsilyl‐substituierter p‐Phenylendiamin‐Derivate: Untersuchungen an Einkristallen sowie in der Gasphase
Authors: Bock Hans , Meuret Jochen , Näther Christian , Krynitz Ulrich 
Published: July 2007

Structures of Sterically Overcrowded and Charge‐Perturbed Molecules, 38[1]. — The Different Conformations of N‐Trimethylsilyl‐Substituted p‐Phenylenediamine Derivatives: Investigation of Single Crystals and in the Gas PhaseThe ESR‐proven generation of a Wurster's Blue radical anion by one‐electron reduction of N,N,N′,N′‐tetrakis(trimethylsilyl)‐p‐phenylenediamine is rationalized by a posterior singlecrystal structure determination of the neutral molecule, which demonstrates inter alia that the bulky [(H3C)3Si]2N substituents are twisted out of the benzene plane by 83°. In contrast, the skeleton of the sterically congested N,N′‐bis(trimethylsilyl)‐p‐phenylenediamine remains almost planar and, accordingly, allows nN/π interaction between the p‐type nitrogen electron pairs of the also flattened [(H3C)3Si]HN groups and the benzene π system. These conformational differences are reflected in the gas‐phase photoelectron spectra, in which nN/π ionisation bands are split by less than 1 eV or more than 3 eV, respectively. The evidence for analogous structures of the two organosilicon p‐phenylenediamine derivatives in solution is confirmed by geometry‐optimized AM1 calculations, which readily explain the surprising insertion of an extra electron into an already electron‐rich molecule.
Bis(pentamethylcyclopentadienyl)methanol: Synthese, Struktur und Derivatisierung
Authors: Jutzi Peter , Mix Andreas , Lindermeier Tanja , Stammler Hans‐Georg , Neumann Beate 
Published: July 2007

Bis(pentamethylcyclopentadienyl)methanol: Synthesis, Structure, and DerivatizationBis(pentamethylcyclopentadienyl) ketone (1) reacts at low temperatures with LiAlH4 to form in good yields (pentamethylcyclopentadienyl)methanol (2) and its corresponding intramolecular Diels‐Alder product 3 in a ca. 2:1 ratio. The alcohol 2 is separated from the tetracyclic compound 3 by crystallisation at −70°C from hexane/pyridine as pyridine adduct. The pyridine‐free alcohol 2 is available by repeated dissolving of the adduct in hexane and removal of the volatile components in vacuo. The alcohol tends to intramolecular [4 + 2] cycloaddition even at room temperature with formation of 3. A derivatization of 2 is possible by deprotonation with alkyllithium compounds, which leads to the alcoholate 4, and subsequent treatment with phosgen and tosyl chloride, thus affording the chloroformate 6 and the tosylate 7, respectively, in good yields. The thermolabile tosylate 7 decomposes to pentamethylbenzene or, under basic conditions, to the pentacyclic compound 7.
A Molecular‐Dynamics Simulation of the Complex Formation between Methyl (R)/(S)‐2‐Chloropropionate and Heptakis(3‐O‐acetyl‐2,6‐di‐O‐pentyl)‐β‐cyclodextrin
Authors: Köhler Jutta E. H. , Hohla Manfred , Richters Martina , König Wilfried A. 
Published: July 2007

AbstractThe energies of complexation of methyl (R)/(S)‐2‐chloropropionate [(R)/(S)‐2] with heptakis(3‐O‐acetyl‐2,6‐di‐O‐pentyl)‐β‐cyclodextrin (1) and the structures of the corresponding complexes were determined by molecular‐dynamcis (MD) simulations at 300 and 333 K. The geometry of the complexes, the conformations of complexed and uncomplexed 1 and (R)/(S)‐2 and the closest H–H distances between host and guest in the complexes were determined from the trajectories. The results correspond to the experimental findings from enantioselective gas chromatography.
Charge‐Transfer‐Komplexe von Metalldithiolenen, XIII. cis‐trans‐Photoisomerisierbare Viologene als redoxaktive Akzeptoren —Synthese und elektrische Leitfähigkeit
Authors: Schmauch Georg , Knoch Falk , Kisch Horst 
Published: July 2007

Charge‐Transfer Complexes of Metal Dithiolenes, XIII[1]. ‐ cis‐trans‐Photoisomerisable Viologens as Redoxactive Acceptors — Synthesis and Electrical ConductivityIon Pair Charge‐Transfer (IPCT) complexes of the type [A2+[ML2]2−} (1a‐f to 4a‐f) are synthesized from dianionic metal dithiolenes [M = Ni, Zn, L = cis‐1,2‐dicyano‐1,2‐ethene‐dithiolate (mnt2−), 2‐thioxo‐1,3‐dithiol‐4,5‐dithiolate (dmit2‐)] and dicationic viologens [A2+ = 4,4′‐(1,2‐ethenediyl)bis(1‐alkylpyridinium)]. The acceptors can exist as cis/trans isomers and may have coordinating properties in the case of 1‐cyanoalkyl groups. The IPCT bands are in the range of 500 to 1200 nm and their energy follows the Hush‐Marcus relation. For the nickel complexes the reorganization energy amounts to 73, for the zinc compounds to 115 kJ/mol. As shown by X‐ray analysis of {A2+[Ni(mnt)2]2−} (2d), A2+ = trans‐4,4′‐(1,2‐ethenediyl)‐bis[1‐(3‐cyanopropyl)pyridinium], the structure consists of stacks of alternating donors and acceptors with a typical plane‐to‐plane distance of 350 pm. There is no interaction between the cyano group of the acceptor and the nickel atom of the donor. The electrical conductivities of the nickel compounds are in the range of 5 · 10−6 to 3 · 10−11 Ω−1 cm−1, and the corresponding activation energies vary from 0.24 to 0.61 eV. For the dmit complexes these values agree well with the free activation enthalpy of the electron transfer reaction A2+ + [ML2]2− → A+ + [ML2]− calculated from the Hush‐Marcus model. This suggests that charge carrier generation occurs by electron transfer. When a trans acceptor is replaced by its cis isomer in [A2+[NiL2]2−}, conductivity changes from 5 · 10−7 to 5 · 10−6 Ω−1 cm−1 and the activation energy from 0.43 to 0.24 eV, when L ‐ dmit2− but stays at about 1 · 10−8 Ω−1 cm−1 for L = mnt2−.
From Azole—Borane Adducts to Azaboles — Molecular Structure of an Imidazabole
Authors: Padilla‐Martinez Itzia I. , Rosalez‐Hoz Maria De Jesus , Contreras Rosalinda , Kerschl Susanna , Wrackmeyer Bernd 
Published: July 2007

AbstractElimination of H2 from the imidazole—borane adduct 1 leads to a mixture of the imidazaboles 2 and 2′. The symmetrical isomer 2 (two H2BNC fragments) is isolated in pure state and characterized by an X‐ray structure analysis (monoclinic, space group P21). 2‐(Trimethylstannyl)thiazole (3a) and 1‐methyl‐5‐(trimethylstannyl)‐1,2,4‐triazole (3b) react with triethylborane to form adducts 4 from which, in the presence of an excess of Et3B, tetraalkyltin is elimated to give the thiazabole 5a and the triazabole 5b, respectively. Multinuclear 1H‐, 11B‐, 13C‐, 14N‐, and 119Sn‐NMR spectroscopy serve for following the reactions (compounds 3 to 5) and to characterize all final products.
Stereoelektronische Effekte und chirale Erkennung, I. Diastereoselektive Etherbildungen aus Alkylarylcarbinolen
Authors: Noe Christian R. , Knollmüller Max , Dungler Karin , Miculka Christian 
Published: July 2007

Stereoelectronic Effects and Chiral Recognition, I. — Diastereoselective Formation of Ethers from AlkylarylcarbinolsAcid‐catalysed etherification of various alkylarylcarbinols 1 leads to a mixture of diastereomeric products 2 and 3. As found in the closely related formation of diastereomeric acetals, the ratio 2/3 is shown to be time‐dependent. Preferred formation of the meso‐diastereomer 3 under kinetic condition and preferred formation of the racemic diastereomer 2 under thermodynamic conditions is observed. A reaction path based on π‐π interactions and stereoelectronic effects is presented to explain experimental results.
Synthesis and Characterization of Soluble Oligo(9,10‐anthrylene)s
Authors: Müller Uwe , Adam Martin , Müllen Klaus 
Published: July 2007

AbstractA homologous series of oligo(9,10‐anthrylene)s up to the heptamer have been synthesized by reductive coupling of quinones with lithioanthrylenes, followed by reductive aromatization of the intermediate hydroxy species. The method used allows the introduction of different alkyl substituents, which ensure sufficient solubility of the newly synthesized anthrylene systems in common organic solvents. The solid‐state conformations of trimers4and5have been established by X‐ray structure analysis; UV/Vis‐spectroscopic investigations in solution reveal the anthracene moieties in 9,10‐anthrylenes to exist as electronically independent electrophores. The trianthrylenes can be subjected to electrophilic substitution which regioselectively provides e.g. 10‐bromo‐ and 10,10″‐dibromo derivatives. These bromides can easily be converted into the corresponding cyano compounds. Under the influence of potassium hydroxide in quinoline the trimer5partially cyclizes to helianthrene compounds.
Synthese und Koordinationschemie hemilabiler P,N‐Hybridliganden mit terminalen 2‐Pyridyl‐Donorgruppierungen
Authors: Heßler Antonella , Fischer Jörg , Kucken Stefan , Stelzer Othmar 
Published: July 2007

Synthesis and Coordination Chemistry of Hemilabile P,N‐Hybride Ligands with Terminal 2‐Pyridyl Donor Groups*P,N‐hybride ligands 1–7 containing terminal 2‐pyridyl donor groups have been obtained by base‐catalyzed addition of diphenylvinylphosphane or 2‐vinylpyridine to primary or secondary phosphanes [2‐Py‐(CH2)2‐PR′H (R′ = H, Ph), HMeP‐(CH2)3‐PMeH] or by alkylation of organolithium phosphides, R2P‐(CH2)3‐PMeLi or 2‐Py‐(CH2)2‐PR′Li (R = Ph, iPr; R′ = H, Ph), with 2‐(2‐chloroethyl)pyridine or di‐tert‐butylphosphetanium bromide. Upon reaction with NiBr2 3 H2O or K2MCl4 (M = Pd, Pt) the phosphanes (L) of type 2‐Py‐(CH2)2‐P(R′)‐(CH2)m‐PR2 (1, 3, 6) form square planar Ni(II), Pd(II), and Pt(II) complexes of composition MX2(L) (10–14). With NiBr2 and K2MX4 the tripod type phosphane 2 forms square pyramidal complexes [MX(2)]X (M = Ni, Pd; X = Cl, Br; 15, 16). An X‐ray structural analysis of [NiBr(2)]+Br− (15) reveals a distorted square pyramidal coordination geometry at Ni(II), the 2‐Py donor being in apical position with a long NiN bond [2.270(15) Å]. The tetradentate ligand 7 forms Ni(II), Pd(II), and Pt(II) complexes MX2(7) which for M = Pd, Pt show dynamic behaviour by exchange of the terminal Py donor groups. With [RhCl(COD)]2 the tridentate ligands L (1 and 3) yield complexes of composition RhCl(L) (20, 21). The structure of 20 has been determinated by X‐ray diffraction. The ligand 3, acting in a tridentate manner, is coordinated to Rh(I) in a distorted square‐planar arrangement with a normal RhN distance [2.145(3) Å].
Photolyse von Naphth[2,3‐d]‐1,2,3‐oxadiazol — Ein Beitrag zum Oxiren‐Problem
Authors: Blocher Achim , Zeller Klaus‐Peter 
Published: July 2007

Photolysis of Naphth[2,3‐d]‐1,2,3‐oxadiazole — A Contribution to the Oxirene ProblemThe photolysis of [9a‐13C]naphth[2,3‐d]‐1,2,3‐oxadiazole ([9a‐13C]14) in methanol, water, and cyclohexane is studied. In the protic solvents, the Wolff rearrangement products 2‐(methoxycarbonyl)indene ([13CO]16) and 2‐indenecarboxylic acid ([13CO]23) exclusively labelled at the carbonyl carbon are obtained. Furthermore, the photolysis of [9a‐13C]14 in methanol yields [2‐13C]‐2‐naphthol (19) as hydrogen abstraction product. The photolytic decomposition of 14 in cyclohexane affords 2‐(2‐naphthoxycarbonyl)indene (25) and 1‐cyclohexyl‐2‐(2‐naphthoxycarbonyl)indene (26). The formation of 25 is explained by nucleophilic addition of 2‐naphthol (19) to the intermediate ketene 21. 2‐Naphthol (19) is generated in situ by hydrogen abstraction from cyclohexane. The cyclohexyl radicals, thereby obtained, convert 25 to 26. Similar photolysis of [9a‐13C]14 affords [13CO13CO]25 and [13CO13CO]26 labelled at the carbonyl carbon and C‐2 of the naphthalene ring. Thus, independent of the nature of the solvent (methanol, water, cyclohexane), no labelling distribution is found in the photolysis products of [9a‐13C]14. This excludes the participation of naphth‐[2,3‐b]oxirene (17) as reactive intermediate.
Synthesen und Reaktionen acyclischer fluororganischer Thiocarbenium‐Ionen
Authors: Boese Roland , Haas Alois , Krüger Carl , Möller Guido , Waterfeld Alfred 
Published: July 2007

Syntheses and Reactions of Fluoroorganic Acyclic Thiocarbenium IonsHerrn Prof. Dr. W. Sawodny zum 60. Geburtstag gewidmet.
Arsenic pentafluoride oxidizes (F3CS)4C (1) but not (F3CS)2C = C(SCF3)2 (2) to yield the stable salt (F3CS)3C+AsF‐6 (3). It reacts with halide ions to form (F3CS)3CX (3a–c, X = F, Cl, Br). Iodide is oxidized to iodine with formation of (F3CS)3CC(SCF3)3 (4) which reacts with nitrogen dioxide to give (F3CS)3CNO2 (3e). ‐ (F3CS)3C+AsF‐6 (3) removes from (F)‐SCF3 (5a) a ring‐bound fluorine atom to afford (F3CS)3CF and magnified image‐SCF3]+AsF−6 (5). When (F3CS)3CCl (3b) is treated with AsF5, 3 and [(F3CS)2‐CCl]+AsF−6 (6) are formed in a 2:1 molar ratio. The latter reacts with F− or Cl− to give (F3CS)2CClX (6a,b; X = F, Cl). AsF5 is capable of abstracting a fluoride ion from (F3CS)3 ‐ n Cln,CF only if n = 0 or 1. For n = 2 no similar reaction takes place, but with AlCl3 in BCl3 halogen exchange to F3CSCCl3 (7b) is observed. ‐ Alkylation of (F3CS)2CS (8) with H3CF/AsF5 yields [(F3CS)2CSCH3]+AsF−6 (9), which adds a fluoride ion to give (F3CS)2(H3CS)CF (9a). The molecular structures of (F3CS)2C = C(SCF3)2 (2) and (F3CS)3CC(SCF3)3 (4) have been determined by X‐ray diffraction methods.
Diastereoselective Radical Bromination of 5,6‐Dihydro‐4H‐1,2‐oxazines and Subsequent Substitution Reactions with Nitrogen Nucleophiles
Authors: Paulini Klaus , Reißig Hans‐Ulrich 
Published: July 2007

Abstract5,6‐Dihydro‐4H‐1,2‐oxazines 1a‐b, 2, and 3 are easily brominated at C‐4 with N‐bromosuccinimide/dibenzoyl peroxide in tetrachloromethane. The bromo substituent is incorporated with surprisingly high diastereoselectivity trans to the substituent at C‐6. 4‐Bromo‐5,6‐dihydro‐4H‐1,2‐oxazines are useful reagents for substitution reactions with N‐nucleophiles such as primary amines and azide ions. Inversion of configuration at C‐4 provides derivatives of 4‐amino‐1,2‐oxazines with uniform relative configuration. As a minor byproduct the dibromo adduct 7 is obtained by bromination of 3. The dehydrohalogenation of this compound allows the synthesis of the 4‐bromo‐6H‐1,2‐oxazine 12. The presented reaction sequence thus constitutes an “umpolung” reaction that allows the introduction of nucleophiles into a position of the oxazine ring that so far was accessible only for electrophiles. The diastereoselectivity of the bromination reaction is discussed.
Substituenteneffekte auf die CC‐Bindungsstärke, 14. Kinetische und thermodynamische Stabilität von 2,3‐Bis(dialkylamino)‐1,4‐diketonen — Stabilisierungsenergie capto‐dativ substituierter a‐Dialkylamino‐a‐Carbonylalkyl‐Radikale
Authors: Welle Frank , Verevkin Sergej P. , Keller Manfred , Beckhaus Hans‐Dieter , Rüchardt Christoph 
Published: July 2007

Substituent Effects on the Strength of CC Bonds, 14[1]. — Kinetic and Thermodynamic Stability of 2,3‐Bis(dialkylamino)‐1,4‐diketones — Energy of Stabilization of α‐Dialkylamino α‐Carbonylalkyl Radicals with Capto‐dative SubstituentsProf. Dr. H.‐G. Viehe zum 65. Geburtstag gewidmet.
The equilibrium constants and rate constants for the dissociation of the 2,3‐bis(dialkylamino)‐1,4‐diketone diastereomers meso‐ and DL‐7a and 7b were measured over a temperature range of 40°C. From the enthalpies of dissociation ΔHDiss and enthalpies of activation ΔH≠ and the strain enthalpies of 7 the bond dissociation enthalpies BDE(CC) of 7 were determined. By comparison with the dissociation enthalpies of Ct‐Ct alkanes[21] the change of these BDEs(CC) by the cap‐to‐dative substitution was determined to be 85.4 kJ mol−1 (20.4 kcal mol−1). The heats of formation ΔH (g) of a series of amino ketones 8 were determined from their heats of combustion and their heats of evaporation. From the ΔH(g) values in combination with MM2 calculations of their strain enthalpies strain‐free increments CHn[N, CO, C2 ‐ n] with n With n = 0, 1, 2 were derived and geminal interaction enthalpies in the ground states were obtained thereof. The radical stabilization enthalpy RSE of 6 was deduced from the ΔBDE(CC) values and the ground state effect to be 73.6 kJ mol−1 (17.6 kcal mol−1). From these data and the radical stabilization enthalpies RSE of α‐aminoalkyl radicals (4.2 kJ mol−1) and α‐carbonyl radicals (28.9 kJ mol−1) a synergetic radical stabilization enthalpy of 40.5 kJ mol−1 (9.7 kcal mol−1) is deduced. This number combines “extra” resonance stabilization and general inductive or anomeric geminal substituent interaction in the radicals. The crystal structure of meso‐7a has been determined by X‐ray diffraction methods.
Organische Synthesen mit Übergangsmetallkomplexen, 70. [2‐(Galactopyranosylamino)ethenyl]carben‐ und 3‐(Galactopyranosylamino)‐1,2‐propadienyliden‐Komplexe durch 3‐Addition von 2,3,4,6‐Tetra‐O‐pivaloyl‐β‐D‐galactopyranosylamin an Alkinylcarben‐Komplexe (M = Cr, W). — Atropisomere Galactopyranosyl‐Pyrrole durch Reaktion von [2‐(Galactopyranosylamino)ethenyl]carben‐Komplexen mit Isocyaniden
Authors: Aumann Rudolf 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 70[1]. — [2‐(Galactopyranosylamino)ethenyl]carbene and 3‐(Galactopyranosylamino)‐1,2‐propadienylidene Complexes on 3‐Addition of 2,3,4,6‐Tetra‐O‐pivaloyl‐β‐D‐galactopyranosylamine to Alkynylcarbene Complexes (M = Cr, W). — Atropisomeric Galactopyranosyl Pyrroles by Reaction of [2‐(Galactopyranosyl‐amino)ethenyl]carbene Complexes with IsocyanidesEnantiomeric pure (2‐aminoethenyl)carbene complexes LnMC(OEt)CHC(Ph)NHR* (Z)‐3 and 3‐amino‐1,2‐propadienylidene complexes LnMCCC(Ph)NHR* 4 [R* = 2,3,4,6‐tetra‐O‐pivaloyl‐β‐D‐galactopyranosyl] are obtained by the addition of galactopyranosylamine R*‐NH2 2 to the corresponding alkynylcarbene complexes LnMC(OEt)CCPh 1 [LnM = (CO)5Cr, (CO)5W]. Treatment of (Z)‐3 with two equivalents of tert‐butyl isocyanide (5) affords isocyanide complexes 6 and ketene imines 7. The latter cyclize spontaneously to give galactopyranosylpyrroles 8 which form stable atropisomers 8A and 8B.
Photoreaktionen mit Fulleren‐C60 [3 + 2]‐Photocycloaddition von 2,3‐Diphenyl‐2H‐azirin
Authors: Averdung Johannes , Albrecht Evelyn , Lauterwein Jürgen , Luftmann Heinrich , Mattay Jochen , Mohn Holger , Müller Wolfgang H. , Meer Hans‐Ulrich Ter 
Published: July 2007

Photoreactions with C60‐Fullerene. [3 + 2] Photocycloaddition of 2,3‐Diphenyl‐2H‐azirineUpon irradiation 2,3‐Diphenyl‐2H‐azirine (2) is added to C60 1 with formation of mono and oligo adducts. 1,9‐(3,4‐Dihydro‐2,5‐diphenyl‐2H‐pyrrolo)fulleren‐60 (3) has been isolated and identified by standard spectroscopic methods. Mechanistic studies revealed two reaction paths leading to 3, i.e. the classic 1,3‐dipolar cycloaddition via the nitrile ylide 4 (direct irradiation) or a route via 2‐azaallenyl radical cations 5 (sensitization by photoinduced electron transfer).