Acetylenes hexafluoroacetone azine

Hexafluoroacetone azine reacts with 2 equivalents of terminal olefins [194] and acetylenes [182] to give 1,5-diazabicyclo[3.3.0]octanes and 1,5-diazahicy-clo[3 3 0]octa-2,6-dienes, respectively (equation 44). 

An unusual 1,4-migration of a trifluoromethyl group was observed when azomethine imines were synthesized from hexafluoroacetone azine and alkoxy-acetylenes The rearrangement, which occurs at temperatures as low as 0 "C, results in the formation of A-(perfluoro-ferf-butyl)pyrazoles [207] (equation 46)... 

What is the product C10H4FI2N2 of the reaction of hexafluoroacetone azine with two molecules of acetylene ... 

The reaction shown above is a bizarre example of a crisscross cycloaddition. It starts as a (2 + 3) cycloaddition of one molecule of acetylene to positions 1 and 3 of the hexafluoroacetone azine to form an intermediate that by another (2 + 3) addition of another molecule of acetylene across the remaining nitrogen-carbon double bond forms another five-membered ring. In this way, a bicyclic system of two five-membered rings is formed to yield the final product [124, 125]. 

Fluoroalkylketenimines may be obtained from fluorinated alkenes and 60 undergoes a series of cycloaddition reactions, including formation of the quinoline derivative 61.Hexafluoroacetone azine (62) also reacts with acetylenes and the formation of pyrazoles (63) has been formulated as involving the quite novel migration of a trifluoromethyl group. 

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