Visible light-promoted selective oxidation of sulfides to sulfoxides catalyzed by ruthenium porphyrins with iodobenzene diacetate

• We report a new highly selective catalytic sulfoxidations using ruthenium porphyrins and iodobenzene diacetate.
• We examine the reaction conditions and explore the substrate scope.
• We propose a mechanism in light of detecting the key oxidizing intermediate.

Under visible light irradiation, the carbonyl ruthenium(II) porphyrin complexes efficiently catalyze the selective oxidation of sulfides to sulfoxides with iodobenzene diacetate [PhI(OAc)2] as the oxygen source. Various thioanisoles and allylic sulfides were oxidized to the corresponding sulfoxides without overoxidation to sulfones. The high selectivity of this unprecedented oxygen-transfer process is mechanistically rationalized by a low-reactivity ruthenium(IV)-oxo species which can be detected in the reaction of carbonyl ruthenium(II) porphyrin with iodobenzene diacetate. To the best of our knowledge, this is the first demonstration of a mild and high-yield method for the highly selective sulfoxidations by ruthenium porphyrins and PhI(OAc)2.

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