Sulfide oxidation catalyzed vanadyl complexes of N-salicylidene α-amino acids at low catalyst loading

► Vanadyl complexes of N-salicylidene α-amino acids used for sulfoxidation. ► Only 0.03 (mol)% catalysts fulfill sulfide oxidation with high yields. ► The process is green, low catalyst amount, solvent-free and easy-operated. ► Vanadyl complexes of N-salicylidene α-amino acids are stable to H2O2. ► Useful for designing high efficient catalysts with H2O2 as an oxidant.