Konformation und Bromierung von Bicyclo[3.3.1]nonan‐2,6‐dion sowie Dehydrobromierung der Bromketone. – Verbesserte Synthese von Bicyclo[3.3.1]nona‐3,7‐dien‐2,6‐dion

Quast, Helmut; Becker, Christian F. W.; Geissler, E.; Knoll, Katja; Peters, E.‐M.; Peters, Karl

doi:10.1002/jlac.199419940203

Cited by 12 publications

(12 citation statements)

References 40 publications

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“…The topological representation of the 3-connected 2D net in the crystal structure of rac-1 is shown in Figure 7. For further discussion it will be important to note that in this case a racemic solution of rac-1 crystallises as a racemate, 10 whereas rac-5 and rac-6 both crystallise as conglomerates.…”

Section: Rac-bicyclo[331]nona-37-diene-endo-2endo-6-diol Rac-1mentioning

confidence: 99%

“…The following examination was made more or less independently of the classical analysis in the preceding section and we can therefore briefly comment on the added value of the Hirshfeld approach. 10 Bicyclo[3.3.1]nona-3,7-diene-endo-2,endo-6-diol, rac-1. In this analysis we use the fingerprint option in CrystalExplorer TM that for each point on the Hirshfeld surface plots the closest distance to an atom outside the surface (d e ) against the closest distance to an atom inside the surface (d i ).…”

Section: Hirshfeld Surface Analysismentioning

confidence: 99%

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confidence: 94%

“…We furthermore explore what effect the potential, weak, 5 hydrogen bonds introduced by the unsaturation, will have on the solid state structure of the so formed compounds rac-1, rac-2, rac-3, rac-4, and (+)-4. It is worth noticing that the introduction of a bromine atom in the unsaturated BCN skeleton, rac-3, also introduces another intermolecular force, 10 the halogen-halogen interaction (not to be confused with the halogen bond). In addition to the network analysis of the crystal structures of compounds 1-4, a traditional analysis, by inspection of intermolecular atom-atom geometries, is compared to an independent approach based on Hirshfeld 15 surfaces.…”

Section: Introductionmentioning

confidence: 99%

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Synthetic and crystallographic studies of bicyclo[3.3.1]nonane derivatives: from strong to weak hydrogen bonds and the stereochemistry of network formation

et al. 2012

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The syntheses and crystal structures of four unsaturated bicyclo[3.3.1]nonane derivatives containing various functionalities are presented and their intermolecular interactions examined. 10 The impact of unsaturation on crystal structures and intermolecular networks of the six membered rings were found to be significant compared to the saturated analogues. Thus, unsaturated diol rac-1, in striking contrast to its saturated analogue rac-6, does not crystallise with spontaneous resolution. The hydrogen bonds in the starting bicyclononane diene diol rac-1, and the weaker hydrogen bonds in the dienone rac-2, and the bromo and nitrile derivatives, rac-3, rac-4 and (+)-15 4 respectively, were found significant for the overall structure. The two bromine atoms in rac-3 have significant halogen-halogen interactions. In several structures 2D nets can be identified and overall structures can be interpreted as close packing of these layers. The crystal structures were also subject to independent analysis by Hirshfeld surfaces, and this method provided additional insights, especially for the structural role of the unsaturation. The possible relation between chiral 20 networks and conglomerate formation is discussed.

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Section: Rac-bicyclo[331]nona-37-diene-endo-2endo-6-diol Rac-1mentioning

confidence: 99%

Section: Hirshfeld Surface Analysismentioning

confidence: 99%

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mentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Synthetic and crystallographic studies of bicyclo[3.3.1]nonane derivatives: from strong to weak hydrogen bonds and the stereochemistry of network formation

et al. 2012

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“…Relying on these results, we ascribed di-exo-configuration to the halogen atoms in dibromo-and dichlorodiketones 2a,h (cfi Ref. 8).…”

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confidence: 94%

Formation of 2-oxatricyclo[4.3.1.03,8]decanes in intramolecular cyclization of α-halobicyclo[3.3.1]nonanones

et al. 1997

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Transformations of c~-chlovo-and a-bromobicyclo[3.3.1lnonanones under conditions of the Favorskii reaction were studied. The interaction of dihalodiketones with MeONa gives 2-oxatricyclo{4.3.1.03.SJdecane (oxaprotoadamantane) derivatives as a result of intramolecular cyclization, whereas 3-bromobicyc!ononanone undergoes only nucleophilic substitution of bromine.Key words: c~-halobicyclo[3.3.1Jnonanones, 2-oxatricyclo[4.3.1.03.SJdecane.Interconversion of bridged bicyclic and cage tricyclic organic structures is of considerable interest as regards the design of organic molecules I as well as studies dealing with stereochemistry and reaction mechanisms, z In this work, we report on a quite unexpected intramolecular cyclization of dihalo-derivatives of bicyclo[3.3.1]nonane-2,6-dione under conditions of the Favorskii reaction.The Favorskii rearrangement of ct-haloketones is a relatively convenient method for the synthesis of carboxylic acids. 3 The use of this reaction in the series of bridged bicyclic structures for the synthesis of the corresponding bicyclic acids has been reported. 4,5 In order to continue the studies dealing with the Favorskii rearrangement of bicyclic cc-haloketones, in the present work, we studied transformations of dichloro-and dibromobicyclo[3.3.1]nonane-2,6-diones under the action of MeONa. The halo-substituted diketones were prepared by halogenation of bicyclo[3.3.11nonane-2,6--dione (1) with 2 equiv, of Br 2 or CIr.It should be noted that the melting point of dibromoderivative 2a that we prepared (171--172 ~ differs substantially from that of the compound described previously (cf The main distinction between the synthetic procedures was duration of the reaction: in our study, the product was isolated 10 min after the addition of Br 2, whereas in the previous paper, the reaction was carried out for 3 h. Apparently, prolonged keeping of the reaction mixture led to epimerization of dibromoketone 2a to give a mixture of diastereomers. This follows from the IH NMR spectrum in which the signals at ~5 4.6 corresponding to the protons at C(3) and C(7) transform into a complex multiplet some time after the beginning of the reaction. In the I H NMR spectrum of dichlorodiketone 2b, the signal at 5 5.2 shows up as a doublet of doublets, and the t3C NMR spectrum contains signals for five carbon atoms of the bicyclic skeleton, in conformity with the symmetry of the molecule. To determine the configuration of the halogen atoms in the bicyclic molecule, we carried out bromination of ketone lb and found that under these conditions, the reaction yields the previously described 7 exo-bromoketone 2c. Relying on these results, we ascribed di-exo-configuration to the halogen atoms in dibromo-and dichlorodiketones 2a,h (cfi Ref. 8).Dibromo-and dichlorodiketones 2a,b react with MeONa under the conditions of the Favorskii reaction to give one product in each case (GLC); based on the spectral data, these products were identified as 4-halo-3-methoxy-2-oxatricyclo[4.3.1. OLS]decan -10-ones (3a,b) (oxaprotoadamantanon...

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ChemInform Abstract: Conformation and Bromination of Bicyclo(3.3.1)nonane‐2,6‐dione (I) and Dehydrobromination of the Bromo Ketones. Improved Synthesis of Bicyclo( 3.3.1)nona‐3,7‐diene‐2,6‐dione (IV).

et al. 1994

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Conformation and Bromination of Bicyclo(3.3.1)nonane-2,6-dione (I) and Dehydrobromination of the Bromo Ketones. Improved Synthesis of Bicyclo( 3.3.1)nona-3,7-diene-2,6-dione (IV). -The title reactions are described and the conformations of (I) (space group C2/c with Z = 4) (V) (space group P212121 with Z = 4) and (VII) ( space group P21/c with Z = 4) determined by X-ray diffractions analyses. From torsional angles, vicinal proton coupling constants are calculated with the aid of the Karplus equation and compared with those determined from solutions by high-field NMR spectroscopy. -(QUAST, H.; BECKER, C.; GEISSLER, E.; KNOLL, K.; PETERS, E.-M.; PETERS, K.; VON SCHNERING, H. G.; Liebigs Ann. Chem. (1994) 2, 109-120; Inst. Org.

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Konformation und Bromierung von Bicyclo[3.3.1]nonan‐2,6‐dion sowie Dehydrobromierung der Bromketone. – Verbesserte Synthese von Bicyclo[3.3.1]nona‐3,7‐dien‐2,6‐dion

Cited by 12 publications

References 40 publications

Synthetic and crystallographic studies of bicyclo[3.3.1]nonane derivatives: from strong to weak hydrogen bonds and the stereochemistry of network formation

Synthetic and crystallographic studies of bicyclo[3.3.1]nonane derivatives: from strong to weak hydrogen bonds and the stereochemistry of network formation

Formation of 2-oxatricyclo[4.3.1.03,8]decanes in intramolecular cyclization of α-halobicyclo[3.3.1]nonanones

ChemInform Abstract: Conformation and Bromination of Bicyclo(3.3.1)nonane‐2,6‐dione (I) and Dehydrobromination of the Bromo Ketones. Improved Synthesis of Bicyclo( 3.3.1)nona‐3,7‐diene‐2,6‐dione (IV).

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