Solvent-mediated switching between oxidative addition and addition–oxidation: access to β-hydroxysulfides and β-arylsulfones by the addition of thiols to olefins in the presence of Oxone

Abstract

The reaction between aryl olefins and thiols in the presence of Oxone in toluene–water (9 : 1, v/v) affords β-hydroxy-2-arylethyl aryl sulfides smoothly by the interception of intermediary thiyl radicals with aryl olefins; the former are generated by the oxidation of thiols with Oxone in a biphasic medium. However, the change of the solvent system to acetonitrile–water facilitates a nonradical and concerted pathway leading to 2-arylethyl aryl sulfones exclusively via a tandem click reaction followed by oxidation. In essence, ‘oxidative addition’ is facilitated in a toluene–water medium, while ‘addition–oxidation’ is promoted in acetonitrile–water. Given that Oxone is readily available, environmentally benign, and cheap, solvent-mediated switching constitutes facile and direct access to two disparate products, namely, β-hydroxy-2-arylethyl aryl sulfides and 2-arylethyl aryl sulfones.