Iron‐Mediated Oxidation of Thiolates with Dioxygen – Speciation, Autoxidation, and Selectivity

The results of an investigation on the reactivity of thiolates RS‒ (R = phenyl, mesityl, tert‐butyl, iso‐propyl, n‐propyl, n‐octyl, ethyl, (CH2)2NHBoc) towards O2, in the presence or absence of iron ions, revealed, that under conditions typically employed to test bioinspired model complexes with regard to their potential to act as functional models for thiol dioxygenases, thiophenolate and other thiolates with electron rich residues R can undergo autoxidation. This, in the absence of Fe, gives high yields of the corresponding sulfinates. The case is different for aliphatic primary R: here the presence of iron ions can be helpful and studies concerning the development of iron‐based dioxygenation catalysts should aim at such substrates. The proceedings during the reactions in the presence of Fe2+ were followed more closely for the case of R = Ph as well as for n‐Pr and t‐Bu by Mössbauer studies.