An environmentally benign synthesis of 1-benzyl-4-aza-1-azonia-bicyclo[2.2. 2]octane tribromide and its application as an efficient and selective reagent for oxidation of sulfides to sulfoxides in solution and solvent-free conditions

Abstract

Stable crystalline 1-Benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane tribromide (BABOT), can be readily synthesized from the reaction of the corresponding bromide with HNO3 and aqueous KBr. Selective Oxidation of a variety of dialkyl and alkyl Aryl sulfides to the corresponding sulfoxides in high yield was achieved by this reagent in solution (CH3CN/H2O) and solvent free conditions. The reaction proceeds under neutral and mild conditions and can be carried out easily at room temperature with regeneration of BABOT. In this method purification of products is straightforward and no over oxidation to sulfone was noted.