OXYGEN-TRANSFER REACTIONS .2. A COMPARISON OF THE REACTIONS OF RUTHENIUM TETROXIDE, CHROMYL CHLORIDE, AND PERMANGANATE WITH THIANTHRENE 5-OXIDE

Products obtained from the oxidation of thianthrene 5-oxide, SSO, have been used to compare oxygen transfer mechanisms for three high-valent transition metals. Oxidation of SSO by benzyltriethylammonium permang anate in methylene chloride gives the corresponding sulfone, thianthre ne 5,5-dioxide (SSO2), as the exclusive product. Oxidation of SSO by r uthenium tetroxide also gives SSO2 as the predominant product along wi th minor amounts of the disulfoxide, thianthrene 5,10-dioxide (SOSO). However, the converse is observed when chromyl chloride is used as the oxidant; SOSO is the major product. It is suggested that oxygen trans fers from permanganate and ruthenium tetroxide are initiated by comple xation between the central metal atom and the oxygen end of the S = O dipole, while oxidation by chromyl chloride is likely initiated by an alternative mechanism, possibly a single electron transfer.