Synthesis and conformation of some 2,4-dioxa- and 2,4-dioxa-3-silabicyclo[3.3.1]nonanes

The conformation of the title compounds established by ¹³C and ¹H NMR spectroscopy shows that replacement of the 2- and 4-methylene groups in bicyclo[3.3.1]nonane by ether oxygen atoms strongly destablizes the cc conformation: in 2-oxabicyclo[3.3.1]-nonane the cc and the bc conformers are about equally populated, whereas in 2,4-dioxabicyclo[3.3.1]nonane the bc conformation predominates. The 2,4-dioxa-3-silabicyclo[3.3.1]nonanes also occur predominantly inthe bc conformation. As in the carbocyclic bicyclo[3.3.1]nonanes both wings are strongly flattened. A stereoselective synthesis of 3-methylbicyclo[3.3.1]nonane, an important model compound in this study, is described.     

5-Hydroxy-1-phosphabicyclo[3.3.1]nonan

5-Hydroxy-1-phosphabicyclo[3.3.1]nonane A new approach to 1-phosphabicyclo[3.3.1]nonane compounds involves free-radical cyclization of 4-trimethylsilyloxy-4-phosphinomethyl-hepta-1.6-diene synthesized by the reaction of 2.2-diallyl-oxirane with KPH₂ followed by trimethylsilylation. Trimethylsilyl groups are easily cleaved in boiling methanol forming 5-hydroxy-1-phosphabicyclo[3.3.1]nonanes. Silylated and desilylated bicyclic compounds are characterized by n.m.r. and i.r. data.     

Conformational analysis of 3-borabicyclo[3.3.1]nonane derivatives

Conformations of 3-borabicyclo[3.3.1]nonane derivatives have been studied by means of ¹H and ¹³C NMR spectroscopy. With the aid of the coupling constants ³J(HH) and ¹³C chemical shifts it has been shown that all the derivatives of 3-borabicyclo[3.3.1]nonane with the trigonal boron atom studied are in a flattened double-chair conformation. In 3-borabicyclo[3.3.1]nonane derivatives with the tetra-coordinated boron atom and substituents at the 7α-position, the chair-boat conformation predominates, the boat conformation being characteristic of the cyclohexane ring; exceptions are the compounds with the internal donor—acceptor bond between the boron atom an 7α-substituent.     

VI. Synthesis of Heterocyclic Analogs of γ-Aminobutyric Acid from 3,5-Dinitrobenzoic Acid

A series of 7-carboxy-3-R-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes was synthesized by reduction of 3,5-dinitrobenzoic acid with sodium borohydride followed by Mannich reaction with formaldehyde and primary amines. The mechanism of decomposition under electron impact of the 3-azabicyclo[3.3.1]nonane was established. Enthalpies of formation of compounds synthesized were calculated by semiempirical PM3 method.     

The "hockey sticks" effect revisited: the conformational and electronic properties of 3,7-dithia-1,5-diazabicyclo[3.3.1]nonane from the QTAIM perspective

The conformational effects in bicyclo[3.3.1]nonanes, while thoroughly studied, have not yet received the full theoretical explanation. R. F. W. Bader's quantum theory of atoms in molecules presents unique opportunities for studying the stereoelectronic interactions (SEI) and weak intramolecular bonding leading to these effects. Here, we report the study of 3,7-dithia-1,5-diazabicyclo[3.3.1]nonane by means of the topological analysis of the calculated (MP2(full)/6-311++G**) and experimental (X-ray derived) charge density to reveal the origins of the so-called "hockey sticks" effect observed in similar compounds. A new explanation of the relative stability of bicyclo[3.3.1]nonane conformers based on the analysis of the QTAIM atomic energies is given. The H···H and S···S interactions in bicyclo[3.3.1]nonane and its dithia derivatives are shown to be significant factors contributing to the differences in the relative stability of the conformers.     

Synthesis of 1,3,5,7-tetraazacyclooctane derivatives

Tetraazaadamantane was converted under mild conditions into 1,3,5,7-tetraazabicyclo[3.3.1]nonane derivatives. The latter were transformed selectively into 1,3,5,7-tetraazacyclooctane derivatives avoiding the formation of 1,3,5-triazacyclohexane compounds.     

Synthèse facile de dérivés du diphényl-2,4-aza-3-bicyclo[3.3.1]nonane et du diphényl-7,8-aza-8-bicyclo[4.3.1]décane

Facile synthesis of derivatives of 2,4-diphenyl-3-azabicyclo[3.3.1]nonane and 7,9-diphenyl-8-azabicyclo[4.3.1]decane The facile synthesis of hydantoins, cyanhydrins and aminonitriles derived from 2,4-diphenyl-3-azabicyclo[3.3.1]nonanone and 7,9-diphenyl-8-azabicyclo[4.3.1]decanone is described. Configurations at C(9) or C(10) of the new compounds wth pharmaceutical and synthetical utility is deduced from their spectral properties.     

Efficient Synthesis of a New Family of 2,6-Disulfanyl-9-selenabicyclo[3.3.1]nonanes

The efficient synthesis of a new family of 2,6-disulfanyl-9-selenabicyclo[3.3.1]nonanes in high yields has been developed based on 9-selenabicyclo[3.3.1]nonane-2,6-dithiolate anion generated from bis-isothiouronium salt of 2,6-dibromo-9-selenabicyclo[3.3.1]nonane. The derivatives of 2,6-disulfanyl-9-selenabicyclo[3.3.1]nonane containing alkyl, allyl and benzyl moieties have been prepared in 90–99% yields by nucleophilic substitution of 9-selenabicyclo[3.3.1]nonane-2,6-dithiolate anion with alkyl, allyl and benzyl halides. The reaction of nucleophilic addition of 9-selenabicyclo[3.3.1]nonane-2,6-dithiolate anion to alkyl propiolates afforded 2,6-di(vinylsulfanyl)-9-selenabicyclo[3.3.1]nonanes. The conditions for regio- and stereoselective addition of 9-selenabicyclo[3.3.1]nonane-2,6-dithiolate anion to a triple bond of alkyl propiolates have been found. To date, not a single representative of 2,6-disulfanyl-9-selenabicyclo[3.3.1]nonanes has been described in the literature.     

Solvolysis of 2-Bicyclo

The solvolysis rate of 2-bicyclo[3.2.2]nonyl p-toluenesulfonate (6-OTs) was nearly equal to that of cycloheptyl p-toluenesulfonate in 2,2,2-trifluoroethanol (TFE). This indicates that the ethylene bridge in 6-OTs does not significantly enhance the rate and that 6-OTs ionizes without anchimeric assistance. The solvolysis of [1-(13)C]-2-bicyclo[3.2.2]nonyl p-toluenesulfonate in methanol or TFE gave 2-substituted bicyclo[3.2.2]nonane, exo-2-substituted bicyclo[3.3.1]nonane, 2-bicyclo[3.2.2]nonene (10), and 2-bicyclo[3.3.1]nonene (11), whose distributions of (13)C labels were determined by quantitative (13)C NMR analysis using a relaxation reagent. The (13)C labels were exclusively placed at only two positions, the ratios of them were not unity, and the labels in 10 were less extensively scrambled than those in other products. These results indicate that the 2-bicyclo[3.2.2]nonyl cation is classical and that 10 is formed at a former ionization stage than 2-substituted bicyclo[3.2.2]nonane. The (13)C redistributions for both exo-2-substituted bicyclo[3.3.1]nonane and 11, which are yielded via 1,3-hydride shift, were similar to that of 2-substituted bicyclo[3.2.2]nonane, suggesting that 1,3-hydride shift occurs mainly at the solvent-separated ion pair.     

2-Oxo-9C(3)-hydroxy- und 2-Oxo-9C(7)-hydroxy-bicyclo[3.3.1]nonan

A synthesis of the two C(9) epimers 14 and 15 of 2-oxo-9-hydroxy-bicyclo[3.3.1]nonane is described starting from the two C(2) epimers 3 and 4 of 2-hydroxy-9-oxo-bicyclo[3.3.1]nonane.     

Amine-mediated tandem conjugative isomerization-bridging Michael addition: concise synthesis of 1-azabicyclo[3.3.1]nonanes

To reach densely functionalized 1-azabicyclo[3.3.1]nonane frameworks synthesis, a stereocontrolled bridging Michael addition involving an unexplored C-5/C-6 disconnection strategy was studied. 1-Azabicyclo[3.3.1]nonane scaffolds have been diastereoselectively elaborated in fairly good yields by two concise pathways implying pyrrolidine derivative organocatalyst or enantiopure 1-phenylethylamine.     

Selective reduction of 6-substituted 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes

Reduction of 6-substituted 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes gives either saturated 1,5-diamino-3-azabicyclo[3.3.1]nonane or unsaturated 1,5-diamino-3-azabicyclo[3.3.1]non-6-enes, depending on the conditions and nature of substituent in the substrate.     

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.     

Heteroadamantanes and their derivatives. 9. Synthesis of 1,5-dinitro-3,7-diazabicyclo[3.3.1]nonane and derived 2,2-disubstituted 5,7-dinitro-1,3-diazaadamantanes

Heating 1,5-dinitro-3,7-di(tert-butyl)-3,7-diazabicyclo[3.3.1]-nonane with concentrated hydrobromic acid gives 1,5-dinitro-3,7-diazabicyclo[3.3.1]nonane. Cyclization of the latter with various aldehydes and ketones gave a series of 2,2-disubstituted 5,7-dinitro-1,3-diazaadamantanes. The behavior of the synthesized compounds under electron impact has been studied.For Communication 8 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 538–542, April, 1990.     

Construction of the adamantane core of plukenetione-type polycyclic polyprenylated acylphloroglucinols

The construction of a highly functionalized adamantane core of plukenetione-type polycyclic polyprenylated acylphloroglucinols (PPAPs) is described. The method features the construction of the bicyclo[3.3.1]nonane core (3) by successive Michael reactions and the construction of the adamantane core of plukenetione-type PPAPs by acid-catalyzed cyclization of a bicyclo[3.3.1]nonane precursor (2).     

13C NMR spectroscopy of some 3- and 7-substituted bicyclo[3.3.1]nonanes

The ¹³C NMR spectra of a series of 3,7-substituted bicyclo[3.3.1]nonane derivatives are examined. Taken into account substituent influences, the ¹³C chemical shifts appear to be diagnostic for the conformation of the bicyclo[3.3.1]nonane derivative.     

Substituierte 9-Oxabicyclo[4.2.1]- und 9-Oxabicyclo[3.3.1]nonane IV. endo,endo-2,5-Dihydroxy-9-oxabicyclo[4.2.1]nonan,endo, endo-, endo,exo- und exo,exo-2,6-Dihydroxy sowie endo,exo-2,7-Dihydroxy-9-oxabicyclo[3.3.1]nonan; Darstellung und Umwandlungsprodukte

The synthesis of the following compounds and reaction products thereof are described: endo, endo-2,5-dihydroxy-9-oxabicyclo[4.2.1]nonane ( 3–5 ), epimeric 2,6-dihydroxy-9-oxabicyclo[3.3.1]nonanes (endo, endo: 6–8 , exo, exo: 29–32 , and endo, exo: 43–45 ), and endo, exo 2,7-dihydroxy-9-oxabicyclo[3.3.1]nonane ( 46–50 ).     

Lone pairs vs. covalent bonds: conformational effects in bicyclo[3.3.1]nonane derivatives

Structural Chemistry - Investigations on the relative energy of two least-strain conformers for bicyclo[3.3.1]nonane 1, bicyclo[3.3.1]nonan-9-one 2, and their heteroanalogues:...     

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.     

Nitrogen is a requirement for the photochemical induced 3-azabicyclo[3.3.1]nonane skeletal rearrangement!

Specific 3-azabicyclo[3.3.1]nonane derivatives undergo skeletal cleavage when subjected to light or Lewis acidic conditions affording novel heterotricycles, which is in stark contrast to 3-oxabicyclo[3.3.1]nonanes.