Elimination Reactions of 1,2-Dihalo-2,3,3-trifluorocyclobutanes

Elimination reactions on isomeric mixtures of cis and trans 1,2-dihalo-2,3,3-trifluorocyclobutanes are reported. In zinc-promoted dehalogenations a steady decrease in the relative amount of the trans isomers compared to the cis isomers occured, with 2,3,3-trifluorocyclobutene as the sole product. The cis isomers reacted at a faster rate in potassium hydroxide induced eliminations to yield a slight predominance of 1-halo-2,3,3-trifluorocyclobutenes over 3-halo-3,4,4-trifluorocyclobutenes. However, with triethylamine as the inducing base, an increased rate of elimination from the trans isomers was noted along with almost exclusive formation of 3-halo-3,4,4-trifluorocyclobutenes.