Synthetic utility of 3-(perfluoro-1,1-dimethylbutyl)prop-1-ene. Part VI. A free-radical addition of CCl4 and CBr4 and dehydrohalogenation of the adducts

Article abstract of DOI:10.1016/0022-1139(94)03125-J

Heating the title compound 1 in excess CCl4 and in the presence of a free-radical initiator (t-butyl peroxide) at 120 deg C afforded 1,1,1,3-tetrachloro-4-(perfluoro-1,1-dimethylbutyl)butane (2) as the main product together with considerable amounts of cyclic dimer, 1,4-bis(perfluoro-1,1-dimethylbutyl)cyclohexane (3).Reaction of 1 with CBr4 at 120 deg C gave 1,1,1,3-tetrabromo-4-(perfluoro-1,1-dimethylbutyl)butane (4) as the sole product while at 220 deg C a mixture of 1,2-dibromo-3-(perfluoro-1,1-dimethylbutyl)propane (5) and 1,1-dibromo-4-(perfluoro-1,1-dimethylbutyl)buta-1,3-diene (6) was formed.Treatment of adducts 2 and 4 with methanolic potassium hydroxide at ambient temperature gave mixtures of 1,1,3-trihalo-4-(perfluoro-1,1-dimethylbutyl)but-1-enes (7) or (8) and 1,1-dihalo-4-(perfluoro-1,1-dimethylbutyl)buta-1,3-dienes (9) or (6) in ratios depending on the adduct to base ratio and on the reaction conditions.Using an excess of the base and reflux temperature, adduct 4 and diene 6 were converted into methyl 4-(perfluoro-1,1-dimethylbutyl)buten-3-oate (10). - Keywords: Synthetic utility; Free-radical addition; Perfluorodimethylbutylprop-1-ene; Dehydrohalogenation; Adduct formation; Carbon tetrachloride; Carbon tetrabromide; Reaction mechanism; NMR spectroscopy; IR spectroscopy; Mass spectrometry