Stannic Chloride–Iodine: An Efficient Reagent for Regioselective Synthesis of Furan–Fused Heterocycles

Abstract

SnCl₄‐I₂‐mediated cyclization of ortho‐cyclohexenyl phenol and ortho‐cyclohexenyl enol derivatives of coumarin, uracil, dimedone, and pyrone at room temperature for 1 h give the linear cyclized products in 78–90% yield, which, on treatment with 10% Pd‐C at 250°C for 1–2 h, afford corresponding aromatized products in 80–84% yield.

Keywords:

• coumarin
• dimedone
• 5‐exo‐cyclization
• iodine
• pyrone
• stannic chloride
• uracil

Acknowledgments

We thank the Council of Scientific and Industrial Research (CSIR, New Delhi) for financial assistance. Two of us (A. B. and P. P. M.) are thankful to CSIR (New Delhi) for senior research fellowships. We also thank the Department of Science and Technology (DST, New Delhi) for providing a UV‐VIS spectrophotometer and a FT‐IR spectrometer under the DST‐FIST program.