GENERATION AND DIELS–ALDER REACTION OF 1-SILOXY-3-ARYLISOBENZOFURANS FROM 3-ARYLPHTHALIDES

Abstract
1-t-Butyldimethylsiloxy-3-arylisobenzofurans, a new type of isobenzofurans, were generated from 3-arylphthalides by sequential treatment with LDA and TBDMSCl. The isobenzofurans, thus formed, were intercepted in situ by dimethyl fumarate to give stable Diels–Alder adducts in good yields. These adducts were converted into 4-aryl-1-naphthols by acid treatment. This new route for the preparation of naphthols was applied to the synthesis of natural arylnaphthalide lignan, diphyllin.