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.     

Generation and reactions of two new functionalized tricyclo[3.3.0.0 3,7]oct-1(5)-ene derivatives

The generation of the new functionalized and highly pyramidalized alkenes, 3,7-(2,2'-biphenylene)tricyclo[3.3.0.0(3,7)]oct-1(5)-ene (20) and 3,7-sulfonyldioxytricyclo[3.3.0.0(3,7)]oct-1(5)-ene (39), and their trapping with 1,3-diphenylisobenzofuran and 11,12-dimethylene-9,10-dihydro-9,10-ethanoanthracene are described. While both alkenes 20 and 39 failed to give the expected cyclobutane or diene dimers, 20 was reacted with 3,7-dimethyltricyclo[3.3.0.0(3,7)]oct-1(5)-ene (1b) to give the cross-coupled product 4,5-(2,2')-biphenylene-10,11-dimethylpentacyclo[8.2.1.1(2,5).1(4,7).1(8,11)]hexadeca-1,7-diene (33). DFT calculations [B3LYP/6-31G(d)] on compound 20 gave important parameters of this pyramidalized alkene, such as the pyramidalization angle (61.7 degrees), the strain energy (72.9 kcal/mol), and the HOMO/LUMO gap (3.79 eV).     

Alternative syntheses of the new D2d symmetric tetramethyl tricyclo- [3.3.0.0(3,7)]octane-1,3,5,7-tetracarboxylate

Two alternative syntheses of the new D2d symmetric tetramethyl tricyclo[3.3.0.0(3,7)]octane-1,3,5,7-tetracarboxylate from the known dimethyl 3,7-dioxo-cis-bicyclo[3.3.0]octane-1,5-dicarboxylate and 1,5-(2,2'-biphenylene)-cis-bicyclo[3.3.0]octane-3,7-dione are described.     

Alternative syntheses of the D2d symmetric 1,3,5,7-tetraiodotricyclo[3.3.0.0]octane

Three alternative syntheses of 1,3,5,7-tetraiodotricyclo[3.3.0.0^3,7]octane are described. Reaction of this tetraiodide with sodium amalgam in the presence of dienes or with molten sodium in boiling 1,4-dioxane in the absence of trapping agents led to very complex mixtures of products, presumably due to competitive 1,2- and 1,3-deiodination reactions.     

The role of the intersection space in the photochemistry of tricyclo[3.3.0.0(2,6)]octa-3,7-diene

CASSCF and CASPT2 methods were used to study the photochemistry of tricyclo[3.3.0.0(2,6)]octa-3,7-diene (TOD). The analysis of different S1 reaction paths as well as the topology of the S1/S0 intersection space allows us to establish two novel properties associated with the photochemical behavior of this compound: (i) simple low-lying intersection space domains can mediate different photoproducts, and (ii) TOD photochemistry is probably mediated by two disconnected intersection space domains, related to the formation of cyclooctatetraene and semibulvalene in different time-scales. It is shown that these domains are chemically distinct since the first, leading to COT, mediates barrierless pericyclic reactions while the second, leading to SBV, is accessed through the formation of an excited-state biradical intermediate. To the best of our knowledge, in the domain of single molecule photochemistry, TOD represents the first example where a different chemical role of distinct low-lying intersection spaces has been computationally documented. The observed photoproducts can be rationalized in terms of branching space diagrams, constructed by determining the branching space (derivative coupling and gradient difference vectors) for each conical intersection involved in the photochemical process.     

Facile Preparation of 3,7-Diazabicyclo[3.3.0]octane and 3,7,10-Triheterocyclic [3.3.3]Propellane Ring Systems from 1,5-Diazacyclooctane 3,7-Derivatives(1)

The cyclodimerization of p-toluenesulfonamide and 3-chloro-2-(chloromethyl)-1-propene to prepare N,N'-bis(p-toluenesulfonyl)-3,7-bis(methylene)-1,5-diazacyclooctane (1a) and its ozonation to the corresponding 3,7-dione 2a are reported. Unusual transannular cyclizations initiated by lithium aluminum hydride treatment or bromination of 1a and oxidative coupling of the dioxime derived from 2a are described. These reactions lead, respectively, to the following derivatives of the little-studied 3,7-diazabicyclo[3.3.0]octane ring system: 1,5-dimethyl-3,7-diazabicyclo[3.3.0]octane (5), N,N'-bis(p-toluenesulfonyl)-1,5-bis(bromomethyl)-3,7-diazabicyclo[3.3.0]octane (8), and N,N'-bis(p-toluenesulfonyl)-1,5-dinitro-3,7-diazabicyclo[3.3.0]octane, (12). Acid-catalyzed hydration of 1a, in contrast, gives the expected 5-methyl-3,7-diazabicyclo[3.3.1]nonan-1-ol (10). Reaction of the dibromide 8 with the nucleophiles, sodium sulfide, sodium oxide, and sodium p-toluenesulfonamide conveniently delivers the corresponding novel 3,7,10-triheterocyclic [3.3.3]propellanes.     

Diels-Alder reactions of highly pyramidalized tricyclo[3.3.0.0]oct-1(5)-ene derivatives: further chemistry of pentacyclo[6.4.0.0.0.0]dodeca-5,8,11-triene

A study of the trapping of highly pyramidalized tricyclo[3.3.0.0^3,7]oct-1(5)-ene derivatives (generated from a 1,2-diiodo precursor on reaction with t-BuLi, 0.45% sodium amalgam and molten sodium) with different dienes (11,12-dimethylene-9,10-dihydro-9,10-ethanoanthracene, 1,3-diphenylisobenzofuran, 2,5-dimethylfuran and furan) is presented. Byproducts from the trapping of pentacyclo[6.4.0.0^2,10.0^3,7.0^4,9]dodeca-5,8,11-triene with 1,3-diphenylisobenzofuran have been synthesized and fully characterized, including an X-ray diffraction analysis. Also, the above triene has been cross coupled with 3,7-dimethyltricyclo[3.3.0.0^3,7]oct-1(5)ene to give a tetrasecododecahedratetraene derivative.     

Gold(I)-catalyzed cycloisomerization of alkynyl hydroxyallyl tosylamides to 4-oxa-6-azatricyclo[3.3.0.0(2,8)]octanes

Reaction of alkyne allyl alcohols tethered with N-(p-tolylsulfonamide) in the presence of a cationic gold(I) catalyst gave new cycloisomerization products, 4-oxa-6-azatricyclo[3.3.0.0(2,8)]octanes.     

Synthesis and structure of 2,4,6,8-tetramethyl-3,7-dithia-2,4,6,8-tetraazabicyclo[3.3.0]octane 3,3,7,7-tetraoxide

Condensation of N,N′-dimethylsulfamide with glyoxal gave 2,4,6,8-tetramethyl-3,7-dithia-2,4,6,8-tetraazabicyclo[3.3.0]octane 3,3,7,7-tetraoxide, a sulfur-containing analog of 2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione (Mebicar). The product structure was studied by X-ray analysis.     

Corner Bromination of 2-Methyl-endo-tricyclo[3.2.1.0(2,4)]octane and -oct-6-ene

Reaction of 2-methyl-endo-tricyclo[3.2.1.0(2,4)]octane (1) with bromine in CCl(4) gave 2-exo,3-endo-dibromo-2-endo-methylbicyclo[3.2.1]octane (3) which rearranges on silica to 2-exo,6-endo-dibromo-1-methylbicyclo[2.2.2]octane (4). Reaction in methanol gave 4-endo-bromo-2-exo-methoxy-2-endo-methylbicyclo[3.2.1]octane (10) and 4-endo-bromo-2-endo-methoxy-2-exo-methylbicyclo[3.2.1]octane (11) formed by corner attack of the bromine electrophile with C2-C4 bond rupture and inversion of configuration at the site of electrophilic attack. Reaction of 2-methyl-endo-tricyclo[3.2.1.0(2,4)]oct-6-ene (2) with bromine in CCl(4) and methanol gave products of reaction at the alkene site.     

Quantum chemical study of the structure of tricyclic saturated hexafluoro-1,3-butadiene dimers

Results of a quantum-chemical study of the molecular structure of dimerization products of saturated 1,3-butadiene and hexafluoro-1,3-butadiene (tricyclo[3.3.0.0^2.6]octane, dodecafluorotricyclo[4.2.0.0^2.5]octane (I), and dodecafluorotricyclo[3.3.0.0^2.6]octane (II)) are presented. The calculated symmetry of the molecule of I in vacuum (C ₂) differs from its symmetry in the single crystal (C _b , XRD). The most stable of dimers (II) contains C-C bonds with a length of up to 1.573 Å and a four-atom cycle with angles of 82.3°.     

Generation and trapping of tricyclo[3.3.0.0]oct-1(5)-ene derivatives containing carbonyl functionalities

Two new functionalized highly pyramidalized tricyclo[3.3.0.0^3,7]oct-1(5)-ene derivatives containing carbonyl functionalities have been trapped as Diels-Alder adducts, although they failed to dimerize. An interesting fragmentation of the bisnoradamantane skeleton to norbornane derivatives has also been observed.     

A general strategy for the diastereoselective synthesis of 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane lignans

A strategy for the stereoselective synthesis of all the possible diastereoisomers of the 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane (furofuran) lignans from a single dihydrofuran precursor is described. The key steps involve a diastereocontrolled templated cationic cyclization followed by stereoselective reduction of the resulting methyl glycoside.     

Stereospecificity of the reaction of (+)-(4S, 5S)-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3.3.0]octane with methyl iodide

The MINDO3, MNDO, AM1, and PM3 methods have been used to optimize the geometries of (+)-(4S,5S)-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3.3.0]octane and (+)-(4S,5S)-4-phenyl-1-aza-3,7-dioxabicyclo-[3.3.0]octane. It has been shown that the stereospecificity, of the reaction of the former with methyl iodide is due to the high stability of one of the possible conformers. Pharmacy Faculty 28, University of the Auvergne, Henri Dunant Place, Clermont-Ferrand, France; Samara State University, Samara 443011, Russia; Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1424–1427, October, 1999.     

Synthesis and Properties of 1,5-Dimethyltricyclo[3.3.0.02,8]octane- and 1,5-Dimethyltetracyclo[3.3.0.02,804,6]octane Derivatives

The synthesis of 1,5-dimethyltricyclo[3.3.0.0^2,8]octane-3,7-dione ( 2 ), 1,5-dimethyltetracyclo[3.3.0.0^2,80^4,6]-octane-3,7-dione ( 3 ), the corresponding dienes 5 and 6 as well as the mixed enones 13 – 15 is reported. Using He( I ) photoelectron spectroscopy (PE) as a tool, a considerable interaction between the n orbitals on the O-atoms and the σ frame in 2 and 3 as well as of the double bonds in 5 and 6 and the σ frame is found. These interactions are also traced back by the electronic absorption spectra of these compounds. The molecular structures of 2 and 3 have been investigated by X-ray analysis.     

One-step synthesis of substituted 3,5-dinitropiperidines and 1,5-dinitro-3,7-diazabicyclo[3.3.1]nonanes from 1,3-dinitropropanes

1,5-Dinitro-3,7-diazabicyclo[3.3.1]nonane derivatives were synthesized in up to 83%yields by the Mannich reaction of 1,3-dinitropropanes with excess formaldehyde and primary amines. In some cases, for instance, when 2,2-dimethyl-1,3-dinitropropane and benzylamine or monoethanolamine are used, the reaction occurs with low yields or stops at the step of formation of 3,5-dinitropiperidines. The influence of the structure of the starting compounds and reaction conditions on the yields of 1,5-dinitro-3,7-diazabicyclo[3.3.1]nonanes and 3,5-dinitropiperidines was studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 405–411, February, 2005.     

Stereospecific synthesis of endo-endo-3,7-dioxabicyclo[3.3.0]octane lignans using 1,6-bis(dipropylboryl)-2,4-hexadiene

A general methodology for the stereoselective synthesis of compounds of the 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane series was developed. The strategy includes allylboration of aromatic aldehydes with 1,6-bis(dialkylboryl)-2,4-hexadiene, ozonolysis of the thus obtained 1,4-diaryl-2,3-divinyl-1,4-diols, and subsequent intramolecular cyclization. This methodology was used for obtaining the naturally occurring lignans of the furofuran series, viz., diaeudesmin, diayangambin, epiasarinin, epieudesmin, epiyangambin, and asarinin.     

Electrocyclic rearrangement of pentamethylcyclooctapyrimidine-2,4-diones: reaction pathway into a 9,11-diazapentacyclo-[6.4.0.0(1,3).0(2,5).0(4,8)]dodecane system and a 9,11-diazapentacyclo [6.4.0.0(1,3).0(2,6).0(4,8)]dodecane system

Photolysis of 6-chloro-1,3-dimethyluracil and mesitylene in the presence of trifluoroacetic acid (TFA) at low temperature gave 1,3,5,7,9- and 1,3,6,8,10-pentamethylcyclooctapyrimidine-2,4-diones (1b, 1c). Sequential photoreaction of the former (1b) resulted in the formation of 9,11-diazapentacyclo[6.4.0.0(1,3).0(2,5).0(4,8)]dodecane-2,4-dione (2b) by way of 9-exo-methylene derivative (7b) and cyclobutaquinazoline (8b). On the other hand, UV-irradiation of 1c led to the bond shift isomer (5c) whose photolysis in the presence of TFA gave rise to the formation of the [6.4.0.0(1,3).0(2,6).0(4,8)]dodecane isomer (3c).     

Synthesis of highly functionalised enantiopure bicyclo[3.2.1]- octane systems from carvone

The commercially available monoterpene carvone has been efficiently converted into the tricyclo[3.2.1.0(2.7)]octane and bicyclo[3.2.1]octane systems characteristic of some biologically active compounds. The sequence used for this transformation involves as key features an intramolecular Diels-Alder reaction of a 5-vinyl-1,3-cyclohexadiene and a cyclopropane ring opening.     

Anodic electrochemical polymerization of complexes [Ni(Salpn-1,3)] and [Cu(Salpn-1,3)]

New experimental data characterizing the conditions of electrochemical synthesis of stable electrically conducting electrochromic polymeric film systems based on the complexes [Ni(Salpn-1,3)] and [Cu(Salpn-1,3)] [Salpn-1,3 is N,N-propylenebis(salicylidenimine)] in a 0.1 M Bu₄NClO₄/CH₂Cl₂ solution are presented. The redox conductivity of the new polymers is characterized by the charge diffusion coefficient. The electrochemical stability of the polymeric films is analyzed in relation to the potential and time of accumulation, and also to the range of potential sweeping.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 12, 2004, pp. 1985–1989.Original Russian Text Copyright © 2004 by Ardasheva, Vovk, Pchelova, Shagisultanova.