Making Full Use of the Oxidizing Equivalents in Bromate in the Selective Oxidation of Thiols, Sulfides, and Benzylic/Secondary Alcohols into Disulfides, Sulfoxides, and Aldehydes/Ketones

The oxidation of thiols to disulfides was achieved in high yields with 6:1 mol ratio of thiol to NaBrO 3, while the oxidation of sulfides and benzylic/secondary alcohols to the corresponding sulfoxides and aldehydes/ketones was successfully undertaken with 3:1 mol ratio of substrate to NaBrO 3 . These ratios correspond to the minimum theoretical requirement of NaBrO 3 . The reactions were conducted at 0−30 °C, depending upon substrate, and were initiated with catalytic amounts of H + and Br − (initial Br − /BrO 3 − = 1:3.5 for thiol oxidation and 1:8 for sulfide and alcohol oxidation). Further, regeneration and reuse of the spent reagent in the aqueous effluent was demonstrated.