A novel oxidation system in which magnesium nitrate [Mg(NO3)2] is used as an oxidant in the presence of diphenylphosphine oxide [HP(O)Ph2] permits the C(sp3)–H hydroxylation of fluorenes, oxindoles, and benzofuranones. This method features high efficiency, good functional group tolerance, and operational simplicity. Its synthetic utility is highlighted by further transformations to valuable organic materials.
