Pentafluorophenol (C6F5OH) catalyzed Regioselective annulation for the synthesis of tetracyclic Dihydrochromeno indoles

Abstract

A regioselective pentafluorophenol (PFP)-catalyzed annulation of 2-(1H-indol-2-yl)phenols with aromatic aldehydes has been developed, enabling the efficient synthesis of tetracyclic dihydrochromeno indoles. These heterocyclic frameworks are pivotal in synthetic and medicinal chemistry as scaffolds for biologically active molecules and advanced materials. The method features a broad substrate scope, excellent regioselectivity, and scalability. The synthesized compounds were characterized using ¹H, ¹³C NMR, IR, and mass spectrometry, confirming the reliability of the methodology. This approach highlights pentafluorophenol's utility in constructing complex heterocyclic architectures with potential applications in synthetic and medicinal chemistry.