Substrate- and Catalyst-Controlled C-H Bond Activation/Annulation for Construction of Pyrido[2,3,4-de]quinazolinones and Indolo[1,2-c]quinazolinones

A substrate and catalyst-controlled synthetic strategy was employed to construct two distinct types of fused polycyclic heterocycles, namely pyrido[2,3,4-de]quinazolinones and indolo[1,2-c]quinazolinones. The most notable advantage of this method is its ability to rapidly generate two different polycyclic scaffolds via a simple C-H activation and subsequent cyclization cascade pathway. Specifically, sulfoxonium ylides played a crucial role in both transformations, serving as a two-carbon synthon and a one-carbon synthon, to independently construct the two fused polycyclic scaffolds through [4+2] and [4+1] annulation pathways, respectively.