Rhodium-Catalyzed Relay Carbenoid Functionalization of Aromatic C-H Bonds toward Fused Heteroarenes.

A rhodium-catalyzed annulation between ethyl benzimidates and α- aroyl sulfur ylides was developed, affording a series of pyrano[4,3,2-ij]isoquinoline derivatives in moderate to good yields with good functional group compatibility. The procedure featured dual ortho-C-H functionalization and dual cyclization in one pot. The optoelectronic properties of those fused heteroarenes were tested by UV/vis and fluorescence spectrometers.