Cascade cycloaddition reactions involving dimethylhydrazones of alpha-substituted acroleins

摘要

Unusual cascade cycloaddition reactions with dimethylhydrazones of alpha-trimethylsilyloxy-alkylacroleins acting as azadienes were found. Depending on the nature of the dienophile, the reactions give either fused heterocyclic compounds (when two consecutive Diels-Alder reactions take place) or azabicyclic compounds, resulting from the [2+4]-and [2+3]-cycloaddition cascade.