Abstract The [Cu (acac) 2]-catalyzed reactions of α, β-unsaturated carboxamides with dimethyl diazomalonate yielded dihydrofuran derivatives by a 1, 5-electrocyclic reaction at C (β), and butadiene derivatives by carbene addition reaction at C (α)(Schemes 4 and 5; Table). Phenyl substituents at the N-atom of the amides seem to be effective on the reaction pathways (Table).
