Transition-metal-free synthesis of thiazolidin-2-ones and 1,3-thiazinan-2-ones from arylamines, elemental sulfur and CO2

Transfering waste to treasure is highly important in green chemistry. However, it is difficult to realize it efficiently due to the low reactivity, especially the simultaneous utilization of two unreactive feedstocks in one reaction. Herein, we report the first utilization of both elemental sulfur and CO2 in a multi-component reaction to generate valuable thiazolidin-2-ones and 1,3-thiazinan-2-ones. Under transition-metal-free reaction conditions, a variety of easily available arylamines react with elemental sulfur and CO2 (1 atm) to give functional thiazolidin-2-ones and 1,3-thiazinan-2-ones in moderate to good yields via C-H bond functionalization. This strategy is highlighted by high step economy with generation of three bonds in one reaction and good functional groups tolerance.