Oxygenation of olefin, N-dealkylation of tertiary amine, oxidation of sulfide, and oxidative cleavage of ether bond were conducted with tetraphenylporphyrinatoiron(III) (Fe³⁺TPPCl), NaBH₄, Me₄N·OH, and molecular dioxygen in benzene-methanol solution. Fe³⁺TPPCl, NaBH₄, and molecular dioxygen were essential for these reactions and the yields were decreased when Me₄N·OH was absent. Olefins were converted to alcohols, which were not produced from the corresponding epoxides under the same conditions. In styrene oxygenation, an electron-donating substituent on the substrate decreased the reactivity, whereas in N, N-dimethylaniline demethylation, it enhanced the reactivity. Despite the use of the same reagents, the key intermediates of these two reactions are different. Fe²⁺TPP-σ-alkyl complexes produced from Fe³⁺TPPCl, olefin, and NaBH₄ were identified as intermediates under anaerobic conditions. Fe²⁺TPP-σ-alkyl complex reacted with molecular dioxygen to give oxygenated products.Examination of the relative reactivities of p-substituted N, N-dimethylanilines in the NaBH₄ reaction system revealed first, that the demethylation proceeded via one-electron abstraction, and second, that the reactive species of the demethylation reactions seems to be an iron-oxenoid.