Synthesis of 1,10-phenanthrolines fused with bicyclo[3.3.0]octane and bicyclo[3.3.1]nonane frameworks

Reactions of bicyclo[3.3.1]nonane-2,6-dione and bicyclo[3.3.0]octane-3,7-dione with 8-amino-7-quino-linecarbaldehyde under basic conditions led to fused nonplanar compounds with one or two 1,10-phenanthroline moieties. The novel heterocyclic systems bicyclo[3.3.1]nonano[2,3-b]bis[1,10]-phenanthroline, cis-bicyclo[3.3.0]octano[3,2-b:7,6-b']bis[1,10]phenanthroline, bicyclo[3.3.1]nona-no[2,3-b:6,7-b']bis[1,10]phenanthroline, and 8H-9,16-methanoindolo[2',3':5,6]cycloocta[1,2-b]bis-[1,10]-phenanthroline have been synthesized and characterized.     

Bicyclo[3.3.1]nonane and its derivatives—IV : Reactions of some carbonyl derivatives of bicyclo[3.3.1]nonane with diazomethane

The reaction of bicyclo[3.3.1]nonane-2,6-dione with diazomethane in situ does not lead to the homologous bicyclo[4.3.1]decane-2,7-dione, but mainly to tricyclo[4.4.0.0^2,9]decan-9-ol-5-one. The structure of the latter was confirmed by the proton NMR spectra measured with an addition of Eu(DPM)₃, A mixture of tricyclo[4,4.0.0^2,9]decan-9-ol-5-one and bicyclo[4.3.1]decane-2,7-dione results when solutions of diazomethane are used. The reaction of bicyclo[3.3.1]nonane-2,6-dione monoethyleneacetal with diazomethane in situ yields predominantly bicyclo[4.3.1]decane-2,7-dione. Under the same conditions bicyclo[3.3.1]nonan-2-one gives with diazomethane in situ only bicyclo[4.3.1]decan-2-one.     

The quinones of bicyclo[3.1.0]hexatriene: A computational study of their chemistry and thermochemistry

Quinones of bicyclo[3.1.0]hexa-1,3,5-triene were examined computationally. The six compounds considered were the five possible classical and one non-classical quinone: bicyclo[3.1.0]hexa-1(6),4-diene-2,3-dione (and its monocyclic isomer with a long trans-annular bond), bicyclo[3.1.0]hexa-1(5),3-diene-2,6-dione, bicyclo[3.1.0]hexa-1,4-diene-3,6-dione (and its monocyclic isomer with a long trans-annular bond), and bicyclo[3.1.0]hexa-1(5),4-diene-2,4-dione-3,6-diyl, a non-classical (non-Kekulé) zwitterion. The two long trans-annular bond structures are akin to that found for m-benzyne. Geometries were calculated (BLYP/6-31G¹, CASSCF(2,2)/6-31G¹, MP2/6-31G¹) and electronic structural inferences were made from the geometries. Also calculated were relative energies and heats of formation (CBS-QB3), singlet and triplet energies (BLYP/6-31G¹), and ionization energies and electron affinities (HF/6-311+G⁷//BLYP/6-31G¹). The NICS(1) calculations were performed as a probe of the aromaticity of the diverse quinones.     

Eleuthesides and Their Analogs: XIII. Synthesis of Bicyclo[6.2.1]undecane System from Cyclohex-2-en-1-one

A short synthetic route to bicyclo[6.2.1]undec-9-ene-2,6-dione has been developed on the basis of retro-aldol reaction of 7-hydroxytricyclo[6.2.1.0^2,7]undec-9-en-3-one obtained from the Diels–Alder adducts of 3-tosylcyclohex-2-en-1-one with cyclopentadiene.     

Control of photoreactions of eight membered ring di- and trienones in a crystalline inclusion complex with optically active 1,6-DI(o-Chlorophenyl)-1,6-diphenylhexa-2,4-diyne-1,6-diol

By complexing with the title host compound, flipping equilibrium of cycloocta-2,4,6-trien-1-one was frozen in one optical conformer as a 2:1 complex, which upon irradiation gave optically active bicyclo [4.2.0] octa-4,7-dien-2-one. Irradiation of a 1:2 complex of cycloocta-2,4-dien-1-one and the same host compound gave an optically active dimer, anti-tricyclo [8.6.0.0^2,9] hexadeca-7, 11-diene-3, 16-dione.     

Michael reaction on example of unsaturated ketones of bicyclo[3.3.1]nonane series

Conclusions The reaction of bicyclo[3.3.1]-3,7-nonadiene-2,6-dione with nitromethane under the conditions of the Michael reaction in ether solution proceeds with the formation of 2,6-bis(nitromethyl)bicyclo[3.3.1]-nonane-4,8-dione, while in methanol this reaction leads to the formation of a derivative with the bicyclo[2.2.2]octane structure, specifically 3-carbomethoxymethyl-2-nitrobicyclo[2.2.2]-5-octanone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2624–2626, November, 1981.The authors thank Yu. T. Struchkova, A. I. Akhmedova, and A. I. Yanovskii for running the x-ray structure analysis.     

On the Dual Mode of Aldol Cyclization of Bicyclo-[4.3.1] Decane-3,8-Dione: A Novel,Efficient Entry into the Isotwistanone System

Isotwistanones have been highlighted since their use in the sesquiterpene syntheses.¹ Begley and coworkers reported a new access to this system via the postulated aldol cyclization of bicyclo [4.3.1]decane-2, 7-dione.² We have found another novel path of a similar mode.     

Reactions of α,β-unsaturated ketones of the bicyclo[3.3.1]nonane series with nitro alkanes

Reaction of bicyclo[3.3.1]nona-3,7-diene-2,6-dione with nitroform in boiling methanol occurs with involvement of the solvent and results in 2,6-dimethoxy-4,8-bis(trinitromethyl)-bicyclo[3.3.1]nona-2,6-diene, while the reaction in tert-butyl alcohol affords 4,8-bis(trinitromethyl)bicyclo[3.3.1]nona-2,6-dione.     

Synthesis of indoles condensed with a bicyclo[3.3.1]nonane skeleton

Derivatives of mono- and bisindoles condensed with a bicyclo[3.3.1]nonane skeleton were synthesized from bicyclo[3.3.1]nonane-2,6-dione and 6-hydroxybicyclo[3.3.1]nonan-2-one by means of the Fischer reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 315–318, March, 1979.     

13C NMR spectra of bicyclo[3.3.1]nonanones and their derivatives

Conclusions An assignment was made of the lines in the¹³C NMR spectra of the mono- and diketones of the bicyclo[3.3.1]nonane series, and of the hydrolysis products of bicyclo[3.3.1]nonane-2,9-dione and its 7-benzoyloxy derivative.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2386–2389, October, 1979.     

Autocatalytic domino Michael reaction leading to bicyclo[2.2.2]octane-2,5-dione derivatives

In the presence of a catalytic amount of lithium amide, the reaction of oxophorone with electron-deficient olefins afforded bicyclo[2.2.2]octane-2,5-dione derivatives in high yields. The reaction proceeds autocatalytically by an enolate of bicyclo[2.2.2]octane-2,5-dione, generated by an initial domino Michael reaction.     

Synthesis of 1-hydroxy-2-(N-substituted) azatwistanes

The reductive amination of bicyclo[3.3.1]nonane-2,6-dione with benzylamine or isopropylamine in the presence of sodium borohydride proceeds with the formation of 1-hydroxy-2-(N-substituted)azatwistanes. When 1-hydroxy-2-benzyl-2-azatwistane is refluxed with acetic anhydride, the ring is opened to give 2-acetoxy-6-acetylbenzylaminobicyclo[3.3.1] nonane. The structures of the synthesized compounds were proved by means of the IR and PMR spectra and the results of elementary analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 940–942, July, 1980.     

Synthesis and chiroptical properties of Methanocycloocta

The synthesis of chiral methanocyclocta[b]indoles, the fused structures obtained from enantiomeric bicyclo[3.3.1]nonanones via Fisher indolization reaction, is reported. The starting optically active bicyclo[3.3.1]nonane-2,6-dione (1) was obtained by a chiral HPLC enantiomer separation on a swollen microcrystalline triacetylcellulose column and by the enzymatic resolution of the racemic dione. The circular dichroism (CD) spectra of the chiral structures 4, 5, and 7 were recorded, and the absolute configuration for the indole compounds was assigned. The theoretical calculations of the CD spectrum of diindole 4 reproduce the (1)B(b) couplet at 229 nm but predict wrong signs for the (1)L(a) and (1)L(b) bands using standard polarization directions. The CD spectrum of indole ketone 5 is reproduced correctly.     

Preparation of C2-symmetric bicyclo[2.2.2]octa-2,5-diene ligands and their use for rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids

[reaction: see text] C2-symmetric bicyclo[2.2.2]octa-2,5-dienes containing benzyl, phenyl, and substituted phenyl groups at 2 and 5 positions were prepared enantiomerically pure by way of bicyclo[2.2.2]octane-2,5-dione as a key intermediate. These chiral diene ligands were successfully applied to rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to alpha,beta-unsaturated ketones. High enantioselectivity (up to 99% ee) as well as high catalytic activity was observed in the addition to both cyclic and linear substrates.     

Reaction of dicobalt octacarbonyl with acetylene and carbon monoxide at low temperature and pressure: Formation of cyclic enone products

Dicobalt octacarbonyl is shown to react with acetylene and carbon monoxide under mild conditions in dimethoxyethane or benzene to produce, in low yields, bicyclo[3.3.0]octa-3,7-diene-2,6-dione, benzoquinone, and the cyclopentadienone-derived products 3a,4,7,7a-tetrahydro-2,7-methanoindene-1,10-dione, 1-indanone, tetracyclo[5.5.2.0^2,60^8,12]tetradeca-4,10,13-triene-3,9-dione, and tetracyclo[5.5.2.0^2,60^8,12]tetradeca-4,9,13-triene-3,11-dione. Possible mechanisms for the formation of these products are discussed.     

A Facile Entry into Bicyclo[3.3.0] Octene System Via Anionic Oxy-Cope Rearrangement

The bicyclo[3.3.0] octene system has been synthesised from the readily available starting material 2-methyl-cyclohexane-1,3-dione, utilizing the base catalysed oxy-Cope rearrangement as a key step.     

13C-NMR-spektren von bicyclo[n.1.0]alkenen

The ¹³C-NMR spectra of some bicyclo[3.1.0]hex-3-en-2-ols and of some bicyclo[3.1.0]hex-3-en-2-ones are described. The bond parameters of bicyclo[3.1.0]hex-3-en-2-one are derived from a structure determination of endo-6-methoxy-1,3,6-triphenylbicyclo[3.1.0]hex-3-en-2-one. The electron density is calculated by the EHT method, and correlated with the ¹³C NMR shifts. For comparison the ¹³C NMR spectrum of a bicyclo[4.1.0]hepta-1,5-dione derivative is analysed. The influence of a cyclopropane system attached to a five-membered and to a six-membered ring is elucidated. Whereas the five-membered ring shows conjugation between the carbonyl group and the cyclopropane system, the same effect is not observed in the six-membered ring analogue. This is explained by the highly rigid structure of the five-membered ring.     

Expanding the C2-symmetric bicyclo[2.2.1]hepta-2,5-diene ligand family: concise synthesis and catalytic activity in rhodium-catalyzed asymmetric addition

New C2-symmetric bicyclo[2.2.1]hepta-2,5-dienes bearing methyl and phenyl substituents at the 2 and 5 positions were prepared enantiomerically pure through a two-step sequence starting from the readily available bicyclo[2.2.1]hepta-2,5-dione. Due to the instability or volatility of these dienes, their isolation was achieved through the formation of the corresponding stable [RhCl(diene)]2 complexes. These chiral rhodium complexes displayed high activity and enantioselectivity (up to 99% ee) in the rhodium-catalyzed 1,4-addition and 1,2-addition of phenylboronic acid to cyclic enones and N-sulfonylimines, respectively.     

Synthesis of optically active 1,2,3-substituted-1,4,5,6-tetrahydro-7H-indolones

Trisubstituted 1,4,5,6,-tetrahydro-7H-indolones are obtained in a one-pot synthesis from conjugated nitroolefins and α-ketoenamines derived from α-amino esters and cyclohexane-1,2-dione. In some cases bicyclo[3.2.1]octan-8-one and 1,2-oxazine N-oxide derivatives are isolated.     

Photoisomerization of quinolin-2-yl derivatives of β-tropolone

Photolysis of hexane solutions of quinolin-2-yl-β-tropolones is accompanied by the photo-induced proton transfer O-H...N → O...H-N followed by the disrotatory electrocyclic rearrangement giving rise to 3-(1H-quinolin-2-ylidene)bicyclo[3.2.0]hept-6-ene-2,4-dione derivatives. The molecular and crystal structure of one of the compounds isolated preparatively, viz., 1,6-di(tert-butyl)-3-(4-chloro-8-methyl-1H-quinolin-2-ylidene)bicyclo[3.2.0]hept-6-ene-2,4-dione, was established by X-ray diffraction. The structures, tautomeric transformations, and the structural dynamics of the resulting compounds were studied by ab initio quantum chemical methods, absorption and fluorescence spectroscopy, and dynamic NMR spectroscopy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 467–474, March, 2006.