Unsaturated nitrogen compounds containing fluorine. Part I. The thermal and photochemical reactions of hexafluoroacetone azine with acetylene and with hydrocarbon terminal olefins

Hexafluoroacetone azine reacts with ethylene, with propene, and with but-1-ene at 160—180° to give high yields of the corresponding 1 : 2 adducts, 1,5-diazabicyclo[3,3,0]octanes. Acetylene reacts similarly to give the corresponding 1,5-diazabicyclo[3,3,0]octa-2,6-diene. The olefins also react under photochemical conditions to give the same products, but acetylene does not react. The azine does not react with electron-deficient olefins or acetylenes under comparable conditions. Pyrolysis of the ethylene or propene adducts affords 3,3,3-trifluoro-2-trifluoromethylpropene in high yield; the acetylene adduct gives mainly a mixture of hexafluoroethane and 3,3,3-trifluoropropyne, together with 1,1,1,6,6,6-hexafluoro-2,5-bistrifluoromethylhexa-2,4-diene.