Cobaloxime-Catalyzed Radical Allylic C–H Sulfonylation Through Synergistic XAT/HAT Processes

Allyl sulfones represent crucial structural scaffolds in diverse natural products and pharmaceuticals. Direct allylic C–H sulfonylation of readily accessible alkenes is an attractive synthetic route to access these motifs, driving intense research efforts toward the development of mild and efficient catalytic strategies. However, achieving selective sulfonylation remains a formidable challenge, as competing alkene difunctionalization and off-target sulfonylation pathways often compromise chemo- and regioselectivity, hampering the practical synthesis of allyl sulfones. Herein, we report a cobaloxime-catalyzed radical strategy that capitalizes on the synergistic interplay of halogen atom transfer (XAT) and hydrogen atom transfer (HAT) processes. This protocol enables the conversion of readily available olefins and sulfonyl chlorides into allyl sulfones under operationally simple conditions. The reaction proceeds efficiently on a gram scale with >20:1 regioselectivity, offering a robust protocol for allyl sulfone synthesis.