878-43-3Relevant academic research and scientific papers
POLYFLUORO-COMPOUNDS BASED ON THE CYCLOHEPTANE RING SYSTEM. PART 5. OCTAFLUOROCYCLOHEPTA-1,3,5-TRIENE AND HEXAFLUOROTROPONE
Dodsworth, D. J.,Jenkins, C. M.,Stephens, R.,Tatlow, J. C.
, p. 41 - 60 (2007/10/02)
Decafluorocyclohepta-1,3-diene underwent reductive addition-elimination with sodium borohydride to give mainly 1H-nonafluorocyclohepta-1,3-diene, together with minor products, the 1H,4H-octafluoro-analogue and, most significantly, 5H-nonafluorocyclohepta-1,3-diene.Decafluorocyclohepta-1,4-diene, together with some 6H-nonafluorocyclohepta-1,4-diene and a trace of the 5H-1,3-diene.These last two dienes were important products, having hydrogen on allylic carbons.They could be dehydrofluorinated, either by bubbling through molten potassium hydroxide or, better, with powdered alkali in an inert medium.Unless special precautions were taken, such reactions yielded hexafluorotropone.With care however the primary product, octafluorocyclohepta-1,3,5-triene, could be isolated, but it was hydrolysewd rapidly, even by water, to give the tropone.Isomerizations and pyrolytic dehydrofluorinations of the major reduction products were carried out, but none yielded the triene or the tropone.It seemed that the triene was probably formed but decomposed to give perfluoroarenes.An interesting defluorination pathway was also operating, to give pentafluorobenzene. 2H-Nonafluorocyclohepta-1,3-diene was an isomerization product.Hexafluorotropone reacted with sodium methoxide in methanol to give 3,6-dimethoxytetrafluorotropone.
THE THERMAL ISOMERIZATION OF HEPTAFLUOROCYCLOHEXADIENES
Feast, W. J.,Morland, J. B.
, p. 57 - 74 (2007/10/02)
The evidence for the involvement of sigmatropic fluorine migrations in the isomerizations of fluorinated polyenes is reviewed and the difficulties inherent in providing satisfactory rationalizations are discussed.The thermal isomerizations of heptafluorocyclohexadienes under various reaction conditions are described.It is established that such isomerizations occur by a mechanism which does not involve catalysis by fluoride ion, however the exact mechanistic pathway remains uncertain.
THE SIGMATROPIC MIGRATION OF FLUORINE
Burdon, J.,Childs, A.,Parsons, I. W.,Rimmington, T. W.
, p. 75 - 86 (2007/10/02)
Pyrolysis of polyfluorocyclohexadienes at 475-480 deg C over new quartz or Pyrex glass gave products derived from 1,5-sigmatropic migrations of fluorine; 1,3-migrations occurred to only a small degree.As the quartz or glass aged, other processes - 1,3-migrations and defluorinations to aromatics - began to occur; these appear to be due in some way to fluoride ion, since pyrolysis over sodium fluoride gave similar products.
