Oxidation of organosulfur compounds promoted by continuous-flow chemistry

Abstract

Organosulfur compounds are important moieties found in several medicinal drugs used in the therapy of arthritis, cancer, depression, diabetes or immune deficiency syndrome. Furthermore, organosulfur compounds are intermediates in many organic reactions with a key role as ligands or chiral auxiliaries. Due to their importance in various areas as pharmaceutical chemistry, synthetic organic chemistry, as well as materials science, the development of new and more sustainable synthetic protocols to provide access to different organosulfur compounds, has a high impact on the broader chemistry community. Many interesting transformations of organosulfur compounds involve an oxidation reaction to access to organosulfur derivatives such as disulfide, sulfinyl or sulfones. Organosulfur oxidation is typically carried out using different oxidant agents such as peroxides, peracids or using atmosphere oxygen under photocatalysis. Despite the numerous procedures reported in the academia, the developments of oxidation of organosulfur compounds with an industrial interest has been limited in regard to the scaling-up, sustainable and safer process. In this context, the use of continuous-flow technology has allowed overcome the disadvantaged of batch approach and is a bridge to connect the academia with the industry. The aim of this review is to highlight the importance of applying flow chemistry methodology as a greener and scalable process in the oxidation of organosulfur compounds. Additionally, a critical view of the different developed methodologies and a future view in the employ of organosulfur oxidation are discussed.