Sequential cascade of pyranose 2-oxidase and sodium tungstate for selective sulfoxidation of thioethers.

Sulfoxides, as essential structural scaffolds, are commonly found in pharmaceuticals and bulk chemicals. We report a practical enzymatic approach for the selective oxidation of thioethers to sulfoxides. Under an oxygen atmosphere, using D-glucose as the substrate and flavin adenine dinucleotide (FAD) as a cofactor, this system relies on the sequential cascade of pyranose 2-oxidase (P2OX) and sodium tungstate dihydrate (Na2WO4·2H2O) to accomplish selective thioether oxidation under mild and environmentally friendly conditions. It provides a sustainable, robust and operationally simple route for sulfoxide synthesis.