Novel synthesis and regiospecific cycloaddition reactions of perfluoro-3-methylbut-1-yne

Vacuum pyrolysis of a perfluorodialkyl-1,2,3-triazine (1) gives a route to a fluoro-alkyne derivative (2), which undergoes novel stereospecific 2π+ 2π cycloadditions to (E)- and (Z)-pentene.