Multivicinal fluorine substitution of the cyclohexane ring

Fluorination;Cyclohexane

Durie, Alastair J. ; Engineering and Physical Sciences Research Council (EPSRC) ; Engineering and Physical Sciences Research Council (EPSRC)

University:University of St Andrews

Department:Chemistry (School of)

关键词: Fluorination;    Cyclohexane;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/8080/TheFullTextOfThisDocumentIsNotAvailable.pdf?sequence=1&isAllowed=y

来源: DR-NTU

【 摘 要 】

Highly polar organic fluorinated motifs are of interest in materials chemistry, forexample, in liquid crystal applications. Cyclohexane is an important and widely usedstructural motif within organic chemistry. Work has been carried out to preparesingle stereoisomers of multivicinal fluorinated cyclohexanes, a class of compoundsthat has not been previously produced. A synthesis of the all-syn-1,2,3,4-tetrafluorocyclohexane, in 9 steps from cyclohexa-1,3-diene will be presented. The¹⁹F NMR spectra of the all-syn-1,2,3,4-tetrafluorocyclohexane shows interestingdynamic conformational effects. This is a small polar organic molecule, which wascrystalline at room temperature. The structure of the compound was confirmed bysingle crystal X-ray diffraction studies.The synthesis of the all-syn-1,2,4,5-tetrafluorocyclohexane from cyclohexa-1,4-diene is also presented. The synthesis of a single diastereoisomer of 1,2,3,4,5,6-hexafluorocyclohexane, derived from benzene in 5 steps, is presented. As with the tetrafluoro compounds, the ¹⁹F NMR spectra of this compound shows dynamic conformational effects. Thestructure of the compound was confirmed by single crystal X-ray diffractionstudies. The 1,2,4,5-tetrafluorocyclohexane motif was elaborated to contain a phenylgroup, producing “rod-like” molecules. This motif was synthesised in view ofpotential applications for liquid crystalline materials.