Abstract
Carbonyl-containing dihydrobenzofurans/dihydrobenzopyrans were prepared from carbonyl-containing ortho-allyl/prenylphenols by activation of phenolic oxygen atom using polyphosphoric acid (PPA). Various substrates were investigated, and the corresponding dihydrobenzofurans/dihydrobenzopyrans were obtained in good to excellent yields.
Graphical Abstract
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Acknowledgments
The authors are grateful for the staff at the Key Laboratory of Chemistry for Natural Products of Guizhou Province and the Chinese Academy of Sciences.