Unusual Reactivity of Isoquinolinones Generated by Silver-Catalyzed Cycloisomerizations of Imines Derived from ortho-Alkynylsalicylaldehydes.

8-Isoquinolinones derived from a silver-catalyzed cycloisomerization of in situ formed ortho-alkynylsalicylaldimines react with 1 equiv of acetylenedicarboxylate derivatives to give pyrano[2,3,4- ij]isoquinolines through a [4 + 2]-cycloaddition reaction. When 2 equiv of the alkyne are used, structurally complex benzo[ de]chromenes are obtained through an intricate cascade process comprising unusual formal [4 + 2]- and [2 + 2]-cycloadditions followed by several ring-opening and ring-closing processes.