Chemodivergent Temperature Controlled Switchable Iron Catalysed Annulation of o-vinylaniline with Isatin Derivatives

Chemo-divergent approach enables to achieve regioselective and site-divergent transformations of multiple products by changing the parameter from identical, readily accessible starting materials are ideal but challenging due to the complexity of precisely controlling the chemo-diversity. Herein, we reported a novel FeCl₃-catalyzed one-pot strategy enabling the selective synthesis of 5-methyl-7-phenyldibenzo[b,h][1,6] naphthyridin-6(5H)-one or 3-phenyl-1H-indole from o-vinylaniline and N-substituted isatin by switching the temperature. Notably, the reaction exhibits temperature-controlled chemo-divergence, selectively yielding either intramolecular or intermolecular products. This approach demonstrates wide substrate, affording structurally diverse scaffolds under mild conditions. Furthermore, it provides an efficient route for synthesis of symmetrical urea derivatives and offers a potential pathway for the direct synthesis of tryptanthrin and related bioactive molecules.