Direct access to 1,4-dihydroxyanthraquinones: The Hauser annulation reexamined with p-quinones

摘要

3-Phenylsulfanylphthalides (e.g. 8a) readily react with p-benzoquinones in the presence of (LiOBu)-Bu-t in THF to furnish 1,4-dihydroxyanthraquinones in good yields and one-pot operations.