A metal-free approach to highly functionalized 3-substituted-3-arylbenzofuran-2(3H)-ones

Abstract

A novel metal-free approach to the synthesis of a variety of 3-substituted-3-arylbenzofuran-2(3H)-ones is developed via H₂SO₄-mediated dehydrative substitution of 3-hydroxy-3-phenylbenzofuran-2(3H)-ones with electron-rich arenes/1,3-diones/alcohols/thiols as nucleophiles in moderate to good yields. Mechanistically, the substitution with the alkoxy group proceeds via a phenolic–hydroxyester intermediate, and forms the desired product via cascade dehydration–relactonization steps.