The Diels-Alder reaction of 1-azadienes is a valuable methodology for synthesis of nitrogen heterocycles1 bearing endocyclic enamine moieties that are key intermediates in the preparation of complicated heterocycles2a and natural products. 2b The 4π participation of simple 1-azadienes is rarely observed in normal [4+ 2] cycloaddition reactions; however, this problem could be circumvented by introducing either electron-withdrawing1, 3 or ...