Photosensitizer-free synthesis of β-keto sulfones visible-light-induced oxysulfonylation of alkenes with sulfonic acids.

A practical and environment-friendly methodology for the construction of β-keto sulfones through visible-light induced direct oxysulfonylation of alkenes with sulfonic acids at ambient temperature under open-air conditions was developed. Most importantly, the reaction proceeded smoothly without the addition of any photocatalyst or strong oxidant, ultimately minimizing the production of chemical waste.