Photocatalytic Oxidation of Sulfinates to Vinyl Sulfones with Cyanamide-Functionalised Carbon Nitride

The cyanamide-functionalised carbon nitride (NCN-CNx) can be employed as a photo-redox catalyst for the light-induced sulfonylation of alkenes with sulfinate salts, attaining product yields twice those obtained with the non-functionalised counterpart and comparable to those achieved with the benchmark homogeneous photocatalyst Eosin Y. NCN-CNx as a heterogeneous photocatalyst is easily isolatable and can be re-used for this reaction for over three cycles. This photocatalytic reaction can proceed with various sulfinates (aryl-, alkyl- and thiophene-based) and alkenes with electron-donating and -withdrawing groups, obtaining good to excellent product yields. A reductive quenching route was determined to be the likely mechanism for this photocatalyst.