The Favorskii Rearrangement

Akhrem, A. A.; Ustynyuk, T. K.; Titov, Yu. A.

doi:10.1070/rc1970v039n09abeh002019

Cited by 74 publications

(30 citation statements)

References 150 publications

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“…Verwandt ist die von uns beschriebene Kohlenstoff-Extrusion/Cluster-Kontraktion, wenn auch mechanistisch unterschiedlich, mit der Favorskii-Umlagerung, bei der a-Halogenketone in Carbonsäuren oder Carbonsäurederivate umgewandelt werden (Schema 3). [19,20] Die in geringen Mengen im Startmaterial vorhandenen Anionen [1-H 2 N-closo-CB 11 [28] In K 2 [3-NC-closo-B 11 F 10 ], das in der monoklinen Raumgruppe C2/c kristallisiert, [29] ist die CN-Gruppe an das BAtom in der 3-Position des B 11 -Oktadecaeders gebunden (Abbildung 2). Diese Beobachtung ist in Übereinstimmung mit Ergebnissen aus DFT-Rechnungen, [30] die zeigen, dass es sich bei diesem Isomer um das stabilste der fünf möglichen handelt (siehe Hintergrundinformationen).…”

Section: Maik Finze*unclassified

Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K₂[3‐NC‐closo‐B₁₁F₁₀]

Finze

2007

Angewandte Chemie

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Section: Maik Finze*unclassified

Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K₂[3‐NC‐closo‐B₁₁F₁₀]

Finze

2007

Angewandte Chemie

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“…In the 19 F NMR spectrum of the [NC-closo-B 11 F 10 ] 2À ion, only one signal is observed for all ten F atoms, which is due to fast rearrangement of the cluster in solution; such behavior is typical of undecaborate anions. [2,32,33] The signal is split into a quartet because of coupling to the 11 B nuclei (Table 1; see also the Supporting Information).…”

mentioning

confidence: 91%

“…Example of a Favorskii rearrangement. [19,20] cluster contraction reaction presented herein. Furthermore, salts of the [NC-closo-B 11 F 10 ] 2À anion are promising precursors for the synthesis of fluorinated and alkylated boron clusters.…”

mentioning

confidence: 95%

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Carbon Extrusion/Cluster Contraction: Synthesis of the Fluorinated Cyano‐closo‐Undecaborate K₂[3‐NC‐closo‐B₁₁F₁₀]

Finze

2007

Angew Chem Int Ed

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“…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.…”

mentioning

confidence: 98%

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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The Favorskii Rearrangement

Cited by 74 publications

References 150 publications

Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K₂[3‐NC‐closo‐B₁₁F₁₀]

Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K₂[3‐NC‐closo‐B₁₁F₁₀]

Carbon Extrusion/Cluster Contraction: Synthesis of the Fluorinated Cyano‐closo‐Undecaborate K₂[3‐NC‐closo‐B₁₁F₁₀]

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

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The Favorskii Rearrangement

Cited by 74 publications

References 150 publications

Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K2[3‐NC‐closo‐B11F10]

Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K2[3‐NC‐closo‐B11F10]

Carbon Extrusion/Cluster Contraction: Synthesis of the Fluorinated Cyano‐closo‐Undecaborate K2[3‐NC‐closo‐B11F10]

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

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Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K₂[3‐NC‐closo‐B₁₁F₁₀]

Kohlenstoff‐Extrusion/Cluster‐Kontraktion: Synthese des fluorierten Cyano‐closo‐undecaborats K₂[3‐NC‐closo‐B₁₁F₁₀]

Carbon Extrusion/Cluster Contraction: Synthesis of the Fluorinated Cyano‐closo‐Undecaborate K₂[3‐NC‐closo‐B₁₁F₁₀]