Hydrocarbon-Involved Sulfoxide Deoxygenation via Bifunctional Iron-Enabled Electron Buffering and Ligand-to-Metal Charge Transfer.

Sulfur-containing compounds are essential motifs of natural molecules. We herein report a photoinduced iron-catalyzed strategy for efficient sulfoxide deoxygenation under mild conditions. The iron catalyst as the sole additive acts dually: it activates hydrocarbon reductants (also as a solvent) via a ligand-to-metal charge transfer pathway and serves as an "electron buffer" to regulate subsequent electron transfer. This unique mechanism enables a non-chromatography protocol with high efficiency (majority at >95%, up to 99%) and selectivity. The operationally simple method exhibits broad functional group tolerance and wide application in late-stage transformation of drug-derived sulfoxides into bioactive sulfides.