Thianthrene 5‐Oxide as Mechanistic Probe in Oxygen Transfer Reactions: The Nucleophilic Character of Carbonyl Oxides

The charge distribution in carbonyl oxides 1 can be studied with thianthrene 5-oxide 2: Compound 2 is oxidized at the sulfoxide sulfur by strongly nucleophilic oxidizing agents, and at the sulfide sulfur by strongly electrophilic oxidizing agents. According to experimental findings with twelve carbonyl oxides the resonance structure 1 largely contributes to the description of the bonding situation in these intermediates.