The synthesis of 2,6-dimethylenetricyclo[3.3.0.03,7]octane

The synthesis of the title compound is reported together with that of 2-methyl-6-methylenetricyclo[3.3.0.0^3,7]octane. During the synthesis a rearrangement of the tricyclo[3.3.0.0^3,7]octane skeleton to the tricyclo[3.2.1.0^3,6]octane system has been observed.     

An INDO-LMO and 13C NMR spectroscopic study of the C-H bonds in tetracyclo[3.2.0.02,7.04,6]heptane (quadricyclane) and tricyclo[3.1.0.02,4]hexane

Using an INDO approximation to Von Niessen's charge density localization method, the percent s character of the C atom hybrid orbitals engaged in C-H bonds is computed for a series of open-chain and cyclic saturated and unsaturated hydrocarbons. A semi-empirical linear relationship is found between these quantities and the experimental nuclear spin-spin coupling constants J_CH (standard deviation 4·98 Hz). The experimental values of J_CH were measured for quadricyclane (1) and tricyclo[3.1.0.0^2,4]hexane (2) and were shown to be in fair agreement with the theoretical predictions. An analogous relationship is also established between the percent s character of the involved C atom hybrid orbital and the C-H bond distance, the standard deviation being 0·0040Å. This relation is used in order to predict the different C-H bond lengths in the vibrational ground state of 1 and 2, for which equal CH distances were assumed in the analysis of electron diffraction experiments. The results indicate that molecular geometries can be refined with the use of semi-empirical correlations of the above mentioned type.     

Silver(I) induced rearrangement of the benzotricyclo[3.2.0.02,7]heptene ring system

The silver ion promoted isomerization of several substituted benzotricyclo- [3.2.0.0^2,7]heptenes to benzonorbornadienes has been found to readily occur.     

Palladium-catalyzed syntheses of condensed cyclopentanes. The crystal and molecular structure of 3-benzylidenpentacyclo[9.2.1.5,8.11,11.02,10.04,9]-pentadecane

New syntheses of condensed cyclopentanes are described, based on insertion into a sufficiently stable PdC bond of molecules able to provide an easy reductive elimination step. These reactions are highly stereoselective. Interesting features are revealed by the X-ray investigation of the title compound, which was obtained in good yield from β-bromostyrene and norbornene. The structural parameters are reported; the molecule adopts the conformation with the bridging carbon atoms of the two norbornanes trans with respect to the mean plane of the cyclopentylidene ring. The condensed cyclopentane system is highly symmetric. The phenyl group is twisted out of the plane of the cyclopentylidene ring by 25.3°.     

Stereoelectronic effects on cyclobutyl participation. The 10-tetracyclo[5.2.1.02,6.O3,9]decyl cation

While the solvolysis of tosylate 5c proceeds very rapidly to generate 4 or its rapidly equilibrating classical alternative, the epimeric compound 6c proved to be unreactive; bond orientation effects are implicated.     

The photosensitized rearrangement of aryl-substituted tricyclo[2.2.0.02,6]hexanes to bicyclo[3.1.0]hex-2-enes

The triplet sensitized irradiation of 3-allyl-diaryl-substituted cyclopropenes to bicyclo[3.1.0]hex-2-enes proceeds via an intramolecular [2+2]-cycloaddition followed by a subsequent rearrangement of the initially formed tricyclo[2.2.0.0^2,6]hexane skeleton.     

Zur kenntnis von [O2]+[Mn2F9]−

[O₂]⁺[Mn₂F₉]^? has been prepared for the first time by reaction of MnO₂ or MnF_x (x = 2,3,4) with a mixture of fluorine and oxygen (P_F2/O₂ ≈ 300–3500 atm., t ≈ 350–550°C) either as a dark red powder or as ruby red needles or plates. From single crystal studies the space group is C2/c - C⁶_2h (No. 15) with a = 17.55₂, b = 8.37₃, c = 9.10₁ Å, β = 102.3°, Z = B (at ?150°C). The crystal structure has been refined to R = 0.053 (1619 unique reflections). From the structure determination [O₂]+[Mn₂F₉] has ‘mänder’ like bands of double chains of [MnF₆] octahedra, which are stacked up in layers parallel to (100) with O₂⁺-cations (d_0?0 = 1.10₀ Å) located between the layers. ν_O2 is at 1838 cm^?1 and the magnetic moment μ_eff = 5.63 B.M. is as expected for a ‘spin only’ case without spin-spin interaction.     

Asymmetrical nitrogen-40;1 Geminal systems-261 N-chlorohydrazines3

The factors determining the kinetic and thermodynamic stabilities of N-chlorohydrazines are discussed. Acyclic N-chlorohydrazines exist only as trialkyldiazenium chlorides 3a,b. Chlorination of 2-acyl-1, 1-dimethylhydrazines 6a,b gave 1,4-diacyl-2,3-dimethylhexahydro-1,2,4,5-tetrazines 7a,b via hydrazyl radical intermediates, and chlorination of a 1-phenylpyrazolidin-5-one 8 gave phenylazoisovaleric esters 9a,b. Stable N-chlorohydrazines were obtained from bicyclic hydrazines; viz. the 2-chloro-1,2-diazabicyclo [2.2.2]octan-3-one 12 and 7-chloro-1,7-diazabicyclo[2.2.1]heptane 16. The restricted inversion of N(7) in 16 and its 1-methyl quaternary salt 21 were observed in the ¹³C-NMR spectra. The acyclic N-chloro-hydrazinium salt 25 was isolated.     

Dihydrodiazepine aus valenzisomeren diazatricyclo[3.2.0.0.2,4]Heptanen1)

Cycloaddition of diazoalkanes to diazabicyclo[2.2.0]hexenes and subsequent extrusion of nitrogen afford diazatricyclo[3.2.0.0^2,4]heptanes that are easily valence isomerized to novel dihydrodiazepines.     

Darstellung und schwingungsspektren von [Me3TlCN]− und [(Me3Tl)2F]−

The preparation, some properties and the vibrational spectra of NMe₄ - [Me₃TlCN] (I) and NMe₄[(Me₃Tl)₂F] (II) are reported. A C_3v point-group can be assigned to the complex anion in (I), whereas in (II) a linear TlFTl-bridged system (symmetry D_3h) is present.