Sulfoxides are important intermediates in the synthesis of various natural products [1,2]. Syntheses of sulfoxides are usually achieved by oxidation of their corresponding sulfides. During the last years, various procedures for H2O2 oxidation of sulfides including the use of various heterogeneous catalyst systems have been reported [3-5]. The application of this oxidant has been developed due to its effective oxygen content, ecofriendly nature, low cost, and also safety in storage and operation [6,7]. Although, many reagents have been employed for the oxidation of sulfides to sulfoxides, the most common problem encountered during the reaction is the over-oxidation of sulfoxides to their corresponding sulfones [8]. Prompted by these reports and due to the potential oxidation of sulfur-containing compounds by H2O2, in the presence of catalysts, in this study we wish to report on a new and efficient method for selective oxidation of sulfides to sulfoxides by H2O2 as oxidant and in the presence of DBUH-Br3 as catalyst. Chemoselectivity, easy and clean work-up, green oxidant, high yields and the easy preparation of the catalyst were the remarks of this method which could be the priority of the other existing methodologies.

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