Preparation of Geminal Diflourodienes

This report discusses research involving the preparation of germinal difluorodienes. Free radical addition of dibromodifluoromethane to 1-hexene and cyclohexene was performed, followed by a double dehydrohalogenation to yield 1,1-difluoro-1,3-heptadiene and 3-(difluoromethylene)cyclohexene, respectively. NMR, IR, and mass spectral data were obtained and presented as groundwork for further research. A study comparing the free radical initiators, benzoyl peroxide and 2,2’-azobis-(2-methyl)proprionitrile (AIBN) was included, showing neither as ideal initiators for the free radical additions performed. The relative stabilities of the bromodifluoromethyl and the difluoroiodomethyl radicals were approximated. A Diels-Alder reaction of 1,1-difluoro-1,3-heptadiene with 4-phenyl-1,2,4-triazoline-3,5-dione produced the expected [4 + 2] cycloadduct in good yield