Iron-photocatalyzed desulfurizing chlorination with seawater

A method for the iron-photocatalyzed desulfurizing chlorination of aryl thioethers was established by harvesting chloride from seawater at room temperature. Various aryl thioether derivatives with diverse functional groups were compatible to afford the corresponding aryl chlorides with high efficiency and selectivity. Control experiments and density functional theory calculations suggested that the formation of a chlorine radical-thioether and a subsequent homolytic aromatic substitution process “on water” were the key steps in the selective C(sp²)-S bond cleavage. Furthermore, the utilization of natural seawater and gram-scale experiment demonstrated the practicability of this protocol.