Silver-Catalyzed Cascade Reactions for the Synthesis of Indopyran Pseudo-Natural Products as Potent Anti-tumor Agents.

Herein, we reported a silver-catalyzed chemoselective cascade reaction that enables the synthesis of pyran-fused indoles in an efficient manner (41 examples, 3 unique scaffolds, up to 93% yield). Compound 3t demonstrated potent antiproliferative activity against various tumor cells, including MGC-803, KYSE-30, and MCF-7, with the IC50 values of 5.25, 6.31, and 5.53 μM. The mechanistic studies revealed that compound 3t effectively arrested cells in the G2/M phase, induced apoptosis, and suppressed cell migration.