Efficient and Short Route for the Regioselective Synthesis of Highly Substituted, Angularly Fused Furano-, Pyrano-, and Pyrrolocoumarin/Quinolone Derivatives by Metal-Mediated Cyclization

Abstract

A one-step efficacious method for the construction of a variety of substituted furano-, pyrano-, and pyrrolocoumarins and pyrroloquinolones in good to excellent yields has been developed.

Keywords:

• Claisen rearrangement
• heterocycle
• Lewis acid
• palladium catalyst
• regioselective cyclization

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Corrigendum

ACKNOWLEDGMENTS

We thank the Department of Science and Technology (DST), New Delhi and the Council for Scientific and Industrial Research (CSIR), New Delhi, for financial assistance. S. M. and B. C. are thankful to the CSIR (New Delhi) for their fellowships.

Notes

^a Overall yield.

dp – deallylated product.

nr – no reaction.

A = PdCl₂ (4 mol %), Cu(acac)₂·H₂O (3 equiv), LiCl (3 equiv), DMF-water (9:1), rt, 3 h.

B = Pd(acac)₂ (20 mol%), (0-tolyl)₃P (40 mol %), acetic acid (10 equiv), CH₃CN, 110 °C, 1 h.

C = AlCl₃ (1.5 equiv), dichlorobenzene, reflux, 1 h.