Photoredox- or Metal-Catalyzed in Situ SO ₂ -Capture Reactions: Synthesis of β-Ketosulfones and Allylsulfones

The first report of the in situ capture of the SO ₂ fragment of the trifluoromethylsulfonyl radical is described here. With cyclobutanone oximes as representative alkyl radical precursors, vinyl triflates and allyl trifluoromethylsulfones were employed as radical acceptors and SO ₂ sources to provide various β-ketosulfones and allylsulfones, known to be significant building blocks. Without the use of any additives including external SO ₂ gas, the reaction was performed under mild photoredox- or metal-catalytic conditions while tolerating various functional groups.