Photo-Promoted Decarboxylative Arylation of 3-Indoleacetic Acids for the Synthesis of Indole-Containing Diarylmethanes

A visible-light-driven, photocatalyst-free C-C bond formation strategy is reported, enabling the decarboxylative arylation of 3-indoleacetic acid with (hetero)aromatic nitriles via electron donor-acceptor (EDA) complex activation. In addition, this strategy is also applicable to the coupling reaction between 3-indoleacetic acids and 2-sulfonylated benzothiazoles. Diverse indole-containing diarylmethanes were afforded in moderate to excellent yields. Moreover, biological evaluation revealed that several products exhibited antiproliferative activity against B16, HCT116, and HepG2 cancer cell lines. This protocol features mild conditions and a broad substrate scope and avoids external photocatalysts, offering a practical approach for constructing indole-based bioactive scaffolds.