Photocatalytic Decarboxylative Alkylation of the C2-Position of 3-Haloindoles with Aliphatic Carboxylic Acids

Indole is one of the most prevalent structural frameworks. Notably, C2-substituted indoles bearing an unsubstituted C3-position are recognized as privileged structural motifs in pharmaceutical synthesis. Here, we report a transition-metal-free photocatalytic decarboxylative coupling strategy employing 4CzIPN as the photocatalyst, enabling efficient and dehalogenative C2 functionalization of 3-haloindoles under mild conditions. Moreover, the one-step direct functionalization protocol exhibits excellent scalability, highlighting the synthetic utility of this methodology.