Synthesis of 3-Alkylcatechols via Intramolecular Cyclization

The intramolecular cyclization of 2-alkanoyl-2,5-dimethoxytetrahydrofurans 4 with aqueous acid is described. 3-Alkylcatechols 7 were prepared in generally good yields by boiling the dioxane solution of compounds 4 in the presence of 1M hydrochloric acid. In addition, 4,5-dioxoalkanals 6 were obtained in good to high yields when the dioxane solution of compounds 4 was treated with 0.1 M hydrochloric acid.