Samarium(II) Diiodide-Mediated Deoxygenation of Sulfoxides

Samarium diiodide-mediated deoxygenative activation of sulfoxides by selective S-O cleavage to construct thioethers under mild room temperature conditions has been achieved. A broad variety of sulfoxides, including aryl-aryl, aryl-alkyl, aryl-alkenyl, and alkyl-alkyl sulfoxides, can be readily converted to the corresponding thioethers using the highly chemoselective, operationally simple, and benign SmI₂/Et₃N reagent system. Extensive studies on the effect of additives indicate that typical samarium(II) iodide additives, such as water, alcohols, HMPA or nickel, have a negative impact on this valuable deoxygenation, while triethylamine promotes the deoxygenation in a versatile manner to afford synthetically useful thioether products.