Diastereoselective oxidation of hydroxysulfides with TBHP:a comparative study of titanocenes and Ti(OiPr)4, as catalysts

Titanocene dichlorides and Ti(Oi-Pr)(4) have been used as catalysts for the oxidation with t-butyl hydroperoxide of racemic beta-hydroxysulfides having a stereogenic carbon centre in alpha- or beta- position with respect to the sulfur atom. beta-Hydroxysulfides were oxidized in high yields to the corresponding sulfoxides, titanocenes being more chemo- and generally more diastereoselective than Ti(Oi-Pr)(4). A divergent stereochemical outcome has been observed when using titanocenes or Ti(Oi-Pr)(4) in the oxidation of protected beta-hydroxy sulfides