Sulfur-containing compounds are well known for their frequent occurrence in a large number of natural and synthetic molecules with relevant biological activity. An easy and highly efficient approach to sulfur-containing compounds, by S–H insertion reactions of α-keto esters with thiols, is reported. The substrate scope was remarkably wide, affording the corresponding products in up to 97% yield. Overall, the raw materials were readily available and the reaction conditions were mild in this synthetic method.