[4+2]- and [2+4]-cycloaddition processes of 4,5-dicyanopyridazine with 2,3-dimethylbuta-1,3-diene
作者:Rodolfo Nesi、Donatella Giomi、Stefania Turchi、Paola Paoli
DOI:10.1016/s0040-4020(01)85385-0
日期:1994.1
The title compounds afforded under relatively mild conditions the polycyclic systems 3a, 4, and 5 through alternative concomitant cycloadditions; the reactivity of the dicyanopyridazine system was critically influenced by the presence of methyl groups at the 3 and 6 positions. The skeleton of 3a and the stereochemistry of 5 were established by X-ray experiments.