Die Cyclopropylcarbinyl-Cyclobutyl-Homoallyl-Umlagerung. I. Teil. Synthese von Tricyclo[3.2.1.02,7]octan-3-ol,endo- und exo-Tricyclo[3.2.1.03,6]octan-4-ol und exo-Bicyclo[3.2.1]-oct-2-en-7-ol

Tricyclo[3.2.1.0^2,7]octan-3-ol ( 1 ) and its 4-isomer 7 were obtained by hydroboration of tricyclo[3.2.1.0^2,7]oct-3-ene ( 5 ). The former alcohol 1 is quantitatively converted to the isomeric alcohol exo-bicyclo[3.2.1]oct-2-en-7-ol ( 3 ) by treatment with aqueous acid. Photolysis of 1-diazo-3-(cyclopent-3-enyl)-propan-2-one ( 12c ) gave a high yield of tricyclo[3.2.1.0^3,6]octan-4-one ( 10a ). Reduction of the latter ketone produced a mixture of endo- and exo-tricyclo[3.2.1.0^3,6]octan-4-ol 2 and 9 , respectively. Oxidation of these secondary alcohols with silver carbonate in benzene furnished a mixture of the ketone 10a and the lactone 14 of 6-hydroxy-bicyclo[2.1.1]heptane-2-carboxylic acid. The latter is thought to be formed by oxydation of the hydrate of the strained ketone 10a .     

Regiochemical Trends in Intramolecular [2 + 2] Photocycloadditions of 6-(prop-2-enyl)cyclohex-2-enones and 5-(prop-2-enyl)cyclopent-2-enones

The effect of substituents (X ? H, Me, or F at C(6), R ? H or Me at C(2′) of the allyl side chain) on the photoisomerization (λ = 350 nm) of 6-allylcyclohex-2-enones 1 in MeCN is studied. Substituents X control the overall efficiency of intramolecular [2 + 2] photocycloadduct formation (Φ: Me > F > H) but do not exercise an influence on the orientation of addition of the exocyclic double bond to the enone C?C bond. In contrast, replacement of the prop-2-enyl (R ? H) by a 2-methylprop-2-enyl (R ? Me) side chain causes a change in the tricyclo[3.3.1.0^2,7]nonan-6-one 4 vs. tricyclo[4.2,1.0^3,8]nonan-7-one ( 5 ) product ratio from 100:0 (R ? H) to roughly 2:1 (R ? Me) but has almost no bearing on the relative rates of conversion of 1 to products. For C(6)-unsubstituted enones 1aa and 1ba (X ? H), the efficiency of cyclization becomes low enough so that lumiketone rearrangement to bicyclohexanones 6 and 3-isopropylcyclopent-2-enones 9 becomes competitive. Enones 9 undergo consecutive intramolecular [2 + 2] photocycloaddition to tricyclo[3.2.1.0^3,6]octan-2-ones 7 and to tricyclo[3.2.1.0^3,6]octan-7-ones 8 , compounds 8 only being formed when R ? Me.     

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.     

A unified synthetic approach to trachylobane-, beyerane-, atisane- and kaurane-type diterpenes

A general synthetic approach to the polycyclic carbon skeleton of biogenetically related trachylobane, beyerane, atisane, and kaurane diterpenes from carvone is described. The skeleton of these diterpenes is prepared from a common intermediate, that is, 25, readily prepared from carvone using an IMDA reaction and an intramolecular diazo ketone cyclopropanation of an unsaturated ketone as key steps. The tetracyclic diterpene ring systems are obtained from this key trachylobane-type intermediate through the regioselective reductive cleavage of the cyclopropane ring, after adequate modification of the functionalization around the tricyclo[3.2.1.0^2,7]octane moiety.     

Intramolekulare [2π + 2σ]-Thermo-cycloadditionen Synthese von Bis-homo-cyclopentadien-Derivaten Vorläufige Mitteilung

Intramolecular thermal [2π + 2σ]-cycloaddition reactions in the tricyclo[3.2.1.0^2,4]-oct-6-ene system are described. Within a certain set of conditions no [2π + 2σ]-additions within some tricyclo[5.1.0.0^3,5]octane derivatives could be achieved.     

Intramolecular Diels-Alder reactions of 5-vinyl-1,3-cyclohexadienes

[reaction: see text] The intramolecular Diels-Alder reaction of 5-vinyl-1,3-cyclohexadienes affording substituted tricyclo[3.2.1.0(2,7)]oct-3-enes is studied.     

Domino pericyclic reactions of acyclic conjugated (E,Z,E,E)-tetraenes

Acyclic conjugated (E,Z,E,E)-tetraenes, upon thermolysis, undergo a domino pericyclic process involving 6π electrocyclisation of the (E,Z,E)-triene moiety to give the corresponding cis-disubstituted 5-vinyl-1,3-cyclohexadienes, followed by an intramolecular Diels-Alder reaction with the vinyl side chain to give tricyclo[3.2.1.0^2,7]oct-3-enes.     

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.     

First synthesis of nitro-substituted bicyclo[1.1.0]butane derivatives and new method for generation of tricyclo[4.1.0.0<Superscript>2,7</Superscript>]hept-1(7)-ene

Successive treatment of 1-phenylsulfonyltricyclo[4.1.0.0^2,7]heptane with butyllithium and ethyl nitrate leads to the formation of 7-nitro-7′-phenylsulfonyl-1,1′-bi(tricyclo[4.1.0.0^2,7]heptane) through intermediate tricyclo[4.1.0.0^2,7]hept-1(7)-ene which is generated by 1,2-elimination of benzenesulfinic acid from the initial compound. Analogous treatment of 1-phenyltricyclo[4.1.0.0^2,7]heptane gives 1-nitro-7-phenyltricyclo[4.1.0.0^2,7]heptane.     

Zur Photochemie von (Z,Z)-2,7-Cyclodecadien-1-on und 4,8-Cyclododecadien-1-on. Synthese und Eigenschaften von Tricyclo[5.3.0.02,8]decan-Systemen

On the Photochemistry of (Z,Z)-2,7-Cyclodecadien-1-one and 4,8-Cyclododecadien-1-one. Synthesis and Properties of Tricyclo[5.3.0.0^2,8]decane Systems Irradiation of (Z,Z)-2,7-cyclodecadien-1-one ( 3 ) yields (Z,Z)-3,7-cyclodecadien-1-one ( 12 ) or tricyclo-[5.3.0.0^2,8]decan-4-one ( 16 ), depending on the reaction conditions. Irradiation of 4,8-cyclododecadien-1-one ( 28 ) results also in a light-induced transannular [2 + 2] cycloaddition, yielding tetracyclo[7.3.0.0^2,100^3,6]dodecan-1-one ( 30 ). Starting from 16 , the preparation of tricyclo[5.3.0.0^2,8]dec-4-ene ( 19 ), tricyclo[5.3.0.0^2,8]dec-4-ene ( 21 ) and tricyclo[5.3.0.0^2,8]deca-3,5-diene ( 24 ) is described. The ¹H-NMR and ¹³C? NMR spectra of the newly prepared compounds are discussed. In the case of 19, 21 , and 24 , the electronic structure is discussed on hand of their PE spectra.     

Stereoselective synthesis of substituted bicyclo[3.1.1]heptanes: II.* Synthesis of all diastereoisomers of 7-methyl-and 7-phenylbicyclo[3.1.1]hept-6-yl phenyl sulfones from tricyclo[4.1.0.02,7]heptane precursors

All four possible diastereoisomers of 7-methyl-and 7-phenylbicyclo[3.1.1]hept-6-yl phenyl sulfones were intentionally synthesized from tricyclo[4.1.0.0^2,7]heptane and 1-phenyltricyclo[4.1.0.0^2,7]heptane, respectively. The key stage in the synthesis was regio-and stereoselective cleavage of the central bicyclobutane C¹-C⁷ bond in the tricycloheptane precursors by the action of radical, nucleophilic, and electrophilic reagents. The NMR spectra of the diastereoisomers were compared.     

Carbon-13 n.m.r. studies. 65—13C spectra of some tricyclo[3.2.1.02,4]octane derivatives

The ¹³C n.m.r. spectra of 18 derivatives of the tricyclo[3.2.1.0^2,4]octanes have been determined. This series includes methyl, hydroxyl and oxo substituted examples to compare the effects of these substituents on the skeletal carbon shieldings with those observed for the corresponding norbornanes and bicyclo[3.2.1]octanes. In general, the trends are similar and the perturbations associated with closely neighboring groups follow a consistent pattern. The shielding data for the exo–exo and exo–endo isomers of tetracyclo[3.3.1.0^2,40^6,8]nonane are also reported.     

Nitrochlorination of methyl tricyclo[4.1.0.02,7]heptane-1-carboxylate and phenyl tricyclo[4.1.0.02,7]hept-1-yl sulfone

Treatment of methyl tricyclo[4.1.0.0^2,7]heptane-1-carboxylate and phenyl tricyclo[4.1.0.0^2,7]hept-1-yl sulfone with a ～1:8 mixture of N₂O₄ and NOCl in diethyl ether at ?5 to 0°C gave products of formal anti-addition of NO₂Cl at the central C¹-C⁷ bond. In the reaction with phenyl tricyclo[4.1.0.0^2,7]hept-1-yl sulfone nitryl chloride acts as an effective chlorinating agent; as a result, a mixture of diastereoisomeric syn- and anti-6,7-dichlorobicyclo[3.1.1]hept-6-yl phenyl sulfones at a ratio of 7.5:1 is formed.     

The Configuration of Tricyclo [7.1.1.02,7]undecanes and the Stereochemistry of the Reduction of Tricyclone

A full discussion of the configuration of tricyclo [7.1.1.0^2,7]undecanes related to cis-10, 10-dimethyltricyclo [7.1.1.0^2,7]undec-2-en-4-one (2) , the Robinson annelation product from norpinone 1 and 3-buten-2-one is given, based on 360-MHz-NMR. spectra. Nuclear Overhauser effects confirm the cis configuration of 2 , and show that the saturated ketone 10 , obtained by catalytic hydrogenation, is also all-cis with the cyclohexanone ring in the boat conformation. The parent hydrocarbon, cis-10, 10-dimethyltricyclo[7.1.1.0^2,7]undecane is compared with one of the corresponding trans isomers prepared from pinocarvone (14) . The stereochemistry of metal hydride reduction and Grignard reaction of 2 is examined.     

Catalytic syntheses of polycyclic compounds based on norbornadiene in the presence of nickel complexes: VI. Heterogenized catalyst for isomerization reactions of norbornene derivatives

The kinetics and mechanism of the thermal izomerization of 5-exo-methyl-tricyclo[3.2.1.0^5,7]octene-2 into 2-methyl-tetracyclo[3.2.1.0^2,7.0^4,6]octane are reported. The use of catalysts based on nickel compounds is demonstrated. As compared to the other catalytic systems, the heterogenized nickel catalyst obtained by thermal treatment of nickel norbornadiene complexes shows much better performance characteristics (selectivity, specific activity, and service life).     

The effect of the α-cyano moiety on neighboring group participation by the cyclopropyl group

H/α-CN rate ratios have been derived for the solvolysis of sulfonate esters of endo-tricyclo[3.2.1.0^2,4]octan-anti-8-ol and tricyclo[2.2.1.0^2,6]heptan-3-ol. The role of the α-cyano moiety in the stabilization of highly delocalized cations has been evaluated.     

Reactions of azinium ions. 4. Reactions of quinoxalinium salts with nitroalkanes — Single-stage path to tetraazaheterocycles with bridged and framework structures

The addition of the carbanions of nitroalkanes of N-alkylquinoxalinium salts in an alcohol medium leads to dibenzo [d,k]-1,3,6,10-tetrasubstituted tricyclo[7.3.1.0^2,7]-and tetracyclo[7.3.1.0^2,70^6,13]tridecanes.For Communication 3, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 389–399, March, 1986.     

Coupling-isomerization-Claisen sequences - mechanistic dichotomies in hetero domino reactions

A new coupling-isomerization-Claisen domino reaction starting from electron deficient halides and 1-(hetero)aryl propargyl trityl ethers dichotomizes in the concluding steps of the sequence and gives rise to the formation of tricyclo[3.2.1.0(2,7)]oct-3-enes, enones, 1H-isochromenes, or indans as a consequence of minute differences of substituent effects.     

Dichotomies in microwave-assisted propargyl-isomerization-Claisen domino sequences dependent on base strengths

Microwave-assisted unimolecular isomerization-Claisen domino reactions of 1,3-di(hetero)aryl propargyl trityl ethers lead, depending on the basicity of the amine, either to the formation of tricyclo[3.2.1.0(2,7)]oct-3-enes (with triethylamine) or to indanes (with DBU). Based upon product analyses and computations, this base dependent dichotomy can be rationalized as a sequel of pericyclic reactions with intermediate protonation and deprotonation.     

The preparation and reactions of 1,3,4,5,6,7,8-heptafluoro-2-naphthyl prop-2-enyl ether: Formation of 1,3,4,5,6,7,8-heptafluoro-1-(prop-2-enyl)naphthalen-2-one and the photolysis and pyrolysis of this ketone [1].

1,3,4,5,6,7,8-Heptafluoro-2-naphthyl prop-2-enyl ether (8) was isomerised in boiling xylene to 1,3,4,5,6,7,8-heptafluoro- 1-(prop-2-enyl)naphthalen-2-one (9). Photolysis of (9) gave 2,5,7-trifluoro-3,4-(tetrafluorobenzo)tricyclo[3.3.1.O^2,7]non-3- en-6-one (11) (by a [2 + 2] addition) and 1,2,7-trifluoro-3,4- (tetrafluorobenzo) tricyclo [3.3.1.O^2,7]non-3-en-8-one (12) (via an initial [3,5] photochemically-allowed sigmatropic shift). Pyrolysis of (9) at 455° also gave (11), while at 490°, both (9) and (11) gave 1-fluorovinyl 4,5,6,7,8-pentafluoro-1-naphthyl ketone (19).