Degradation of sulfur hexafluoride and its application in the synthesis of esters and amides

Abstract

To meet the increasing demand for degrading the greenhouse gas sulfur hexafluoride (SF₆) used in the electric power industry, which causes growing environmental pressure, utilizing it in practical organic synthesis could offer an ideal solution. Despite various reported methods for activating inert SF₆ in recent years, its utilization remains limited, mainly due to the lack of understanding of the degradation products of SF₆. Here, we introduce the findings on the multistage degradation products, sulfur tetrafluoride (SF₄) and thionyl fluoride (SOF₂), generated from the photoredox catalytic reduction of SF₆, and the reactions utilizing them to facilitate the thionylation of alcohols, esterification and amidation of carboxylic acids. SF₆ shows excellent reactivity compared with traditional condensation reagents in the synthesis of esters and amides. Both batch and stop-flow micro-tubing reactions have been successfully implemented, underscoring the potential for large-scale utilization of SF₆. Detailed discussions on the mechanisms, involving varied intermediates produced by SOF₂ and SF₄, are provided based on comprehensive mechanistic experiments.