Synthesis of quinoline derivatives by palladium-catalyzed isocyanide insertion/undirected C(sp2)–H functionalization/[4 + 1] cyclization reactions involving aryl isocyanide†

This study reports a novel strategy for palladium-catalyzed aryl isocyanide insertion, offering a brand-new route for the efficient synthesis of quinoline derivatives. The remarkable features of this method are reflected in two aspects. On the one hand, it ingeniously utilizes a palladium catalyst to directly and highly selectively activate the C(sp²)–H bonds of aromatic substrates, demonstrating excellent chemoselectivity. On the other hand, by integrating C(sp²)–H functionalization with [4 + 1] cyclization within a single reaction system, this approach significantly streamlines the synthesis process. It enables the direct construction of quinoline derivatives via a one-step operation starting from simple and easily accessible raw materials, achieving remarkable synthetic efficiency.