SYNTHESIS AND ISOMERIZATION OF 2,5- AND 2,6-SUBSTITUTED F-HEXADIENES AND HEPTADIENES

Article abstract of DOI:10.1016/S0022-1139(00)83065-1

The reaction of 2,2,3,3,4,4-hexafluoro-1,5-diphenylpentane-1,5-dione, 4,4,5,5-tetrafluorooctane-3,6-dione and 4,4,5,5,6,6-hexafluorononane-3,7-dione with excess triphenylphosphine and dibromodifluoromethane in triglyme at 70 deg C gave modest yields (50-60 percent) of the corresponding dienes and enones (10-20 percent).No isomerized olefins were observed.Subsequent treatment of the dienes with tetraethylammonium fluoride gave the internal olefins, and thermal isomerization of 2,6-diphenyl-1,1,3,3,4,4,5,5,7,7-decafluoro-1,6-heptadiene to the internal isomeric olefins was observed at 250 deg C.