Sulfinic esters: Novel and versatile sulfenylating agents for biologically important thioethers synthesis

Thioethers are one of the most important family of organosulfur compounds that have shown lots of applications in pharmaceuticals, agrochemicals, polymeric materials and organic dyes. Interestingly, over 30 FDA-approved drugs contain at least one thioether motif in their structures and are used to treat a wide range of diseases, from depression to rheumatoid arthritis to acute coronary syndrome. Therefore, looking for novel, efficient, and straightforward methodologies for their synthesis from low cost, readily available, and non-toxic starting materials is very important in organic chemistry. In this context, the reactions between various electrophiles and sulfenylating agents has recently attracted more and more attention as a general and straightforward route for their synthesis. However, most of the existing sulfenylating agents had some disadvantages, such as a foul smell, high cost and being unstable to air and moisture. Recently, sulfinic esters have emerged as odor-less, easily accessible, stable and easy to handle sulfenylating agents and successfully applied in the synthesis of various aliphatic and aromatic thioethers, mainly through the site-selective functionalization of C–H bonds. The purpose of this review is to provide an overview of the available literature on the synthesis of thioethers using sulfinic esters as sulfenylating agents, with special emphasis on the mechanistic features of the reactions. Literature has been surveyed from 2016 to the end of 2022.