We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham e-Theses
You are in:

The synthesis and reactions of some fluorinated polycyclic polyenes

Preston, William Edward (1972) The synthesis and reactions of some fluorinated polycyclic polyenes. Doctoral thesis, Durham University.



Perfluorocyclohexa-l,3-diene gave the expected 1,4-adducts with cyclohexene, cyclopentene,1,2H-octafluorocyclohexene, 1H,2H-hexafluorocyclopenteneand lH,2H-tetrafIuorocyclobutene; reaction with 1H,2H-tetrafluorocyclobutene also yielded two 2,2-difluorovinyldecafluorobicyclo[4,2,0]oct-2-enes and the dimer 3,3,4,4,7,7,8,8-octafluorotricyclo[3,3,0,0(^2,4)]octane. Dehydrofluorinatlon of the adducts from 1H,2H-octafluorocyclohexene and 1H,2H-hexafluorocyclopentene gave the trienes, perfluorotricyclo[5,2,2,0(^2,7)]dodeca-2,6,9-triene and perfluorotricyclo[5,2,2,0(^2.6)]undeca-2,5,8-triene respectively. Perfluorotricyclo[5,2,2,0(^2,6)]undeca-2,5,8-triene reacted as a diene in Diels-Alder reactions with ethylene, propyne and but-2-yne. The 1,4-adducts with alkynes could be pyrolysed selectively to either polyfluorobenzobicyclo-[2,2,2]octa-2,5-dienes or 2,3-disubstituted hexafluoronaphthalenes. Irradiation of perfluorotricyclo[6,2,2,0(^2,7)]dodeca-2,6,9-triene and perfluorotricyclo[5,2,2,0 (^2,6)]undeca-2,5,8-triene in the vapour phase with UV radiation resulted in their isomerisation to perfluorotetracyclo[6,2,2,0(^2,7)0(^5,7)]-dodeca-2,9-dienes and perfluorotricyclo[5,2,2,0(^2,6)]undeca-2,3,8-triene respectively. Arguments presented support the latter isomerisation being a photochemical 1,5-sigmatropic migration of a fluorine atom. Vacuum pyrolysis of perfluorotricyclo[5,2,2,0(^2.6)]undeca-2,5,8-triene provides perfluoroindene in good yield. Irradiation of 2H-heptafluorocyclohexa-1,3-diene in the vapour phase with UV radiation yielded 2H-heptafluorobicyclo[2,2,0]hex-2-ene, the isomerisation proceeding in the reverse direction on pyrolysis; the photoisomer was of the same order of dienophilicity as perfluorobicyclo[2,2,0]-hex-2-ene towards furan. Perfluoroindene reacted readily with the nucleophiles sodium borohydride, sodium methoxide and lithium methyl replacing initially one of the vinylic fluorines in the five-membered ring. Its olefinic character was evident from the formation of a mixture of hydrazones on reaction with hydrazine hydrate and the isolation of l,l,3,4,5,6,7-heptafluoroindan-2-one from its reaction with oleum; intermediate unstable compounds formed in the latter transformation suggest that the initial stage in the reaction is the formation of the β sultone of perfluoroindene.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:1972
Copyright:Copyright of this thesis is held by the author
Deposited On:13 Nov 2013 16:07

Social bookmarking: del.icio.usConnoteaBibSonomyCiteULikeFacebookTwitter