The formation and decomposition of Δ2-triazolines derived from bicyclo [2,2,1] hept-2-enes.

Abstract

The 1,3-dipolar cycloadditions of phenyl azide with a series of substituted bicyclo [2,2,1] hept-2-enes, were observed to afford the exclusive formation of the exo-Δ2 -triazolines in accord with the Alder "exo-addition rule". As expected, photochemical decomposition of all the exo-Δ2 -triazolines examined, was shown to lead to the stereospecific formation of the corresponding exo-aziridines. Pyrolysis of the 8exo, 9endo -dichloro-(72), the 8endo, 9exo -dichloro-(73) and the unsubstituted (2), Δ -triazolines led to the formation of at least five products. Thermal decomposition of cis, endo-dichloro-(74), and tetrachloro-(75), Δ2 -triazolines resulted in the loss of nitrogen and the formation of at least two products, while pyrolysis of tetracyano-Δ2-triazoline (76) gave predominantly the corresponding exo-aziridine.