Neighboring Group Participation in Organic Redox Reactions. 11. Anchimeric Assistance by the Carboxylate Anion in Aqueous Iodine Oxidations of 3-(Alkylthio)propanoates

Article abstract of DOI:10.1021/jo00357a015

The kinetics and mechanism of the aqueous iodine oxidation of three 3-(alkylthio)propanoates has been examined in detail.All the oxidations are essentially independent of external buffer and proceed via anchimeric assistance by the carboxylate anion.The reaction of aqueous iodine with both 3,3'-thiodipropanoate and 3-(methylthio)propanoate are enhanced a millionfold over that of simple thioethers, making these thioethers among the most easily oxidized of any reported.The degree of anchimeric assistance is considerably less with N-acetyl-S-methylcysteinate and is attributable to the lowered basicity of its carboxylate group.