Efficient Generation of ortho-Naphthoquinone Methides from 1,4-Epoxy-1,4-dihydronaphthalenes and Their Annulation with Allyl Silanes


  • This research was partially supported by a Grant-in-Aid for Young Scientists (B) from the Japan Society for the Promotion of Science (JSPS) and by the Ritsumeikan Global Innovation Research Organization (R-GIRO) project.


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Pharmaceutically useful dihydronaphthopyran derivatives were obtained in good yield by the regio- and stereoselective annulation of ortho-naphthoquinone methides with allyl silanes. The ortho-naphthoquinone methides were generated in situ from 1-siloxymethyl-1,4-epoxy-1,4-dihydronaphthalenes under FeCl3 catalysis (see scheme; allyl-TMS=allyltrimethylsilane, TBS=tert-butyldimethylsilyl, TMS=trimethylsilyl).