Abstract
This study presents an efficient strategy for synthesizing ring-fused indoles through Rh-(III)-catalyzed C-H activation of N-arylpyrimidin-2-amines with maleimides, utilizing a pyrimidinyl directing group. The reaction proceeds via a formal [3 + 2] annulation, forming new C-C and C-N bonds and facilitating the streamlined construction of diversely functionalized pyrimidinyl-incorporated pyrrolo-[3,4-b]-indolediones. Furthermore, in the pursuit of potential metal-ion chemosensors, a new ring-fused indole-based fluorescent probe was identified, exhibiting high selectivity and sensitivity for Fe(3+) detection.