Reactions involving fluoride ion. Part 38. New fluorinated dienes by defluorination

Abstract
The oligomers 2, 4 and 6, 6a, derived from tetrafluoroethene, octafluorocyclopentene, and hexafluorocyclobutene respectively, are converted into their corresponding dienes 7–9 by defluorination, using sodium amalgam. An alternative route using tetrakis(dimethylamino)ethene (TDAE) is also described and forms a fluoride salt of TDAE. The diene 7 shows a remarkably low extinction coefficient for UV absorption.