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 NaBrO3, 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 NaBrO3. These ratios correspond to the theoretical requirement of NaBrO3. The reactions were conducted at 0-30 degrees C, depending upon Substrate, and were initiated with catalytic amounts of H+ and Br- (initial Br-/BrO3- = 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.