Regioselective Synthesis of Coumarin‐Annulated Polyheterocycles by [3,3] Sigmatropic Rearrangement

Abstract

Several coumarin‐annulated polyheterocycles have been regioselectively synthesized in 82–90% yield by anhydrous AlCl₃‐catalyzed charge‐accelerated Claisen rearrangement of 4‐aryloxymethyl [3,2‐c] pyrano benzopyran‐5‐ones in dichloromethane at rt for 0.5 h.

Keywords:

• Anhydrous aluminium chloride
• charge‐accelerated Claisen rearrangement
• coumarin derivatives
• polyheterocycles
• tandem cyclization

Acknowledgment

We are thankful to the Council of Scientific and Industrial Research (CSIR) (New Delhi) for financial assistance and one of us (B. C.) is thankful to the CSIR (New Delhi) for a junior research fellowship. We also thank the Department of Science and Technology (DST) (New Delhi) for providing a UV‐Vis spectrometer under the Department of Science and Technology‐Financial Assistance for Infurastructral Development of Science and Technology (DST‐FIST) program.