Silver-Catalyzed Cascade Approach to Access Fused Pyrazolo-naphthyridine and -isoquinoline Backbones and Investigation of Their Photophysical Properties

We describe a novel approach for synthesizing diverse fused heterocyclic compounds by utilizing a sequential silver(I) catalyzed reaction between readily obtainable <i>N</i>-amidonaphthyridin ylide and dialkyl acetylenedicarboxylates. This method provides an efficient approach for the selective synthesis of tetracyclic ring-fused 1,6-naphthyridine and isoquinoline derivatives, offering exceptional structural diversity. In addition, the title compounds constitute an interesting class of luminophores with tunable emission solvatochromicity.