[1.1.1.1.1]paracyclophane and [1.1.1.1.1.1]paracyclophane

The first syntheses of [1.1.1.1.1]paracyclophane ($\text{1}$) and [1.1.1.1.1.1]paracyclophane ($\text{2}$) are described, featuring a trifluoroacetic acid promoted Friedel-Crafts cycloalkylation as the final step.     

Cyclophane,XIV : darstellung polymethylierter [2.2]paracyclophane

Starting from 4, 5, 12, 13-tetrakis(methoxycarbonyl)[2.2]paracyclophane ($\text{1}$), the penta-($\text{4}$), hexa-($\text{6a}$–$\text{c}$), hepta-($\text{7}$), and octamethyl-($\text{8}$) derivatives have been prepared by a repetitive formylation-reduction sequence.     

Novel iron complexes of [2.2]paracyclophane

The synthesis of [2.2]paracyclophane-iron complexes $\text{4}$ (R=H or Me) is described.     

Reaktionen des [6]paracyclophan-8,9-dicarbonsäurediethylesters: brom-addition und prisman-bildung

The title compound $\text{1}$ adds bromine at 0°C and gives the dibromide $\text{2}$ in 33 % yield; irradiation of $\text{1}$ yields the prismane $\text{3}$ in 56 % yield.     

Reduction of bicyclo[3.2.0] hept-2-en-6-one and 7,7-dimethylbicyclo[3.2.0]hept-2-en-6-one using dehydrogenase enzymes and the fungus mortierella ramanniana

Bicyclo[3.2.0]hept-2-en-6-one (1) was reduced with an alcohol dehydrogenase from $\text{Thermoanaerobium brockii}$ and a whole cell system ($\text{M. ramanniana}$) with excellent substrate enantioselectivity: 7,7-dimethylbicyclo[3.2.0]hept-2-en-6-one (2) was similarly reduced using the 3α,20β-hydroxysteroid dehydrogenase from Streptomyces $\text{hydrogenans}$ while $\text{M. ramanniana}$ furnished both 6S-alcohols (4a), (6b) with high optical purity.     

Zur konformation und intramolekularen beweglichkeit von [6]paracyclophan-8,9-dicarbonsäurediethylester)

The title compound 1 prepers the conformations $\text{1a}$/$\text{1b}$ predicted for [6]paracyclophane; the barrier for the intramolecular process $\text{la}$ ? $\text{1b}$ was found to be Δ G⁺ = 13.9 kcal/mol at +4°C.     

Photo-oxygenations of 1H-azepine derivatives isolation and characterization of the [6+2] cycloaddition product

The reactions of 1H-azepine derivatives ($\text{1a-b}$ and $\text{4}$) with singlet oxygen gave the [6+2] cycloadducts ($\text{2a-b}$) and the [4+2] cycloadducts ($\text{3a-b}$ and $\text{5}$). The thermal and base-catalyzed rearrangements of the oxygen-adducts were investigated.     

Cycl[4.2.2]azinium salts

Cycl[4.2.2]azinium salts $\text{3}$, $\text{9}$ and $\text{11}$ have been synthesized and shown to be diatropic.     

Thermolysis of [1,2,4]triazolo[1,5-a]pyrimidine n-ylides

5,7-Dimethyl[1,2,4]triazolo[1,5-a]pyrimidinio-3-phenacylide ($\text{3}$) generated by the reaction of an iminium salt ($\text{2}$) with 1 eq. of triethylamine, underwent a new thermal ring cleavage of the triazole moiety to give the pyrimidine derivative. However reaction of $\text{2}$ with 2 eq. of triethylamine afforded the 2-iminooxazoline derivative. The iminooxazoline reacted with nucleophiles such as alcohols or amines to give imidazoles.     

Aza [3.1.1] propellane durch diels-alder-addition von bicyclo [1.1.0] but-1 (3)-en-derivaten an isoindole

The reaction of the halobicyclobutane derivatives $\text{1}$ and $\text{2}$ with LDA in the presence of isoindoles afforded the azapropellanes $\text{4}$ and $\text{5}$ via the bicyclobutene intermediates $\text{6}$ and $\text{7}$, respectively.     

The [4.4.4.4]Fenestranes and[2.2.2.2]paddlane. Prospects for the realization of planar tetracoordinate carbon?

Semi-empirical (MINDO/3 and UNDO) MO calculations on highly strained planar tetracoordinate carbon candidates indicate the central carbons in $\text{cis}$- [4.4.4.4] fenestrane ($\text{1}$) to have pyramidal ($\text{1a}$) and in trans-[4.4.4.]fenestrane ($\text{2}$) to have distorted tetrahedral ($\text{2a}$) geometries. In [2.2.2.2]paddlane ($\text{3}$), the two central carbons are pentacoordinate. Each is nearly coplanar with four carbon neighbours; additionally, the two bridgehead carbons are connected by a single bond ($\text{3a}$).     

[2+2]-Cycloadditionen von vinylkationen

The vinylbromides $\text{1a}$ and $\text{1b}$ are allowed to react ith AgBF₄ and AgPF₆ in the presence of various olefins in CH₂Cl₂ as the solvent. Except for the reaction of cyclopentene with $\text{1a}$ all other olefins used, react with vinyl cation $\text{2}$ to form the cycloaddition products $\text{7}$, $\text{8a}$ and $\text{8b}$ in high yields.     

The 185-nm photochemistry of 2,3-diazabicyclo[2.2.1]heptene and of its denitrogenation products bicyclo[2.1.0]pentane and cyclopentene

The 185-nm denitrogenation of 2,3-diazabicyclo[2.2.1]heptene ($\text{1}$) afforded bicyclo[2.1.0]-pentane ($\text{2}$) and cyclopentene ($\text{3}$) presumably via a “hot” cyclopentane-1,3-diyl diradical ($\text{8}$); 1,4-pentadiene ($\text{4}$) and methylenecyclobutane ($\text{5}$) were secondary products of the 185-nm photolysis of ($\text{2}$) and ($\text{3}$).     

Synthesis of bicyclo[6.2.2] bridgehead dienes

Bicyclo[6.2.2]dodecadienes ($\text{2}$), ($\text{3a}$), and ($\text{3b}$) having two bridgehead double bonds were synthesized by the pyrolysis of the acetate ($\text{1}$).     

Studies on the formation of [5]metacyclophane

Base induced elimination of HCl from the dichloro[5.3.1]propellane $\text{3a}$ gives a mixture of [5]metacyclophane ($\text{1}$) and tetrahydrocyclopentacyclooctenes ($\text{2}$), while the stereoisomeric $\text{3b}$ affords $\text{1}$ quantitatively.     

Methylated multibridged [2n]cyclophanes. All alternate synthesis of [26](1,2,3,4,5,6) cyclophane (superphane)

A sequence of formylation followed by a carbene insertion reaction has led to the stepwise introduction of additional ethano bridges into 4,5,7,8- tetramethyl [2₂](1,4)cyclophane ($\text{1}$), providing syntheses of 5,7,8-trimethyl- [2₃](l,2,4)cyclophane ($\text{6}$), a mixture of 5,8-dimethyl[2₄(1,2,4,5)cyclophane ($\text{10}$) and 5,7-dimethyl[2₄(1,2,3,5)cyclophane ($\text{11}$, and-4-methyl[2₅](1,2,3,4,5)-cyclophane ($\text{14}$). This route to $\text{14}$ completes a formal eight-step synthesis of [2₆](1,2,3,4,5,6)cyclophane ($\text{15}$, superphane) with an overall yield of 17%. A Birch reduction of $\text{6}$ readily gave 12,15-dihydro-5,7,8-trimethyl[2₃](1,2,4)-cyclophane ($\text{7}$) in 85% yield.     

[4+2]cycloaddition reactions of triarylphosphaalkene

Cycloaddition reactions of mesityl(diphenyliiifithylene)phosphine ($\text{1}$) were Investigated. With several dienes, no Diels-Alder reactions were oEserved. With azides, diphenyidiazomethane and 2,4,6-trimethylbenzonitrile oxide, the corresponding cycloadducts ($\text{4}$$\text{12}$$\text{17}$$\text{12}$were obtained. In the case of phenyl azide, a competing Staudinger reaction occurred leading to $\text{3}$.     

Benzo-separated pyrazolopyrimidines: Expeditious syntheses of [3,4-g]-and [3,4-h]-linked pyrazoloquinazolinones

Syntheses for pyrazolo[3,4-g]quinazolin-8(7H)-one ($\text{8}$) and its [3,4-h]-analog 11 have been developed involving elaboration of aminoindazolcarboxylic acids $\text{15}$ and $\text{30}$ from correspondingly substituted methylnitroindazols, and subsequent anellation of the pyrimidine ring by v. Niementowski cyclization.     

Isomeric [2.2]metaparacyclophane quinhydrones

The two [2.2]metaparacyclophane quinhydrones $\text{1}$ and $\text{2}$ were synthesized. Structure, stereochemistry and charge-transfer absorptions are discussed.     

Formation and trapping of 6-azabicyclo[3.2.2]non-5-ene,a strained bridgehead imine

Photolysis or flash vacuum pyrolysis of 1-bicyclo[3.2.1]octylazide $\text{9}$ yields 6-azabicyclo[3.2.2]non-5-ene $\text{10}$, a strained bridgehead imine, which could not be isolated but was trapped with methanol.