Catalytic Synthesis of Allylic Sulfones Directly From Secondary Alcohols

Allylic sulfones are valuable structures in bioactive compounds and serve as versatile intermediates in organic synthesis. A selective method for the C-C coupling of aryl sulfones with secondary alcohols has been developed using a Ru-SNS pincer catalyst. This transformation enables efficient access to allylic sulfones under mild conditions with broad functional group tolerance. Sensitive moieties, including olefins and pharmaceutically relevant piperazine-substituted aryl sulfones, are well tolerated. The method demonstrates wide synthetic utility, converting natural product-derived alcohols such as geraniol, nopol, and perillyl alcohol into corresponding sulfone products in high yield. Mechanistic studies suggest the reaction proceeds via initial dehydrogenation of the secondary alcohol to generate a carbonyl intermediate, followed by nucleophilic addition of a sulfone-derived carbanion. A subsequent isomerization step furnishes the allylic sulfone. DFT calculations support this pathway and reveal a key role for the water generated during alcohol oxidation. This in situ formed water facilitates both catalyst regeneration and the final isomerization step, functioning as an essential component in the catalytic cycle. This method provides a practical, atom-economical approach to allylic sulfones with high chemo- and regioselectivity, expanding the toolbox for sulfone chemistry in synthesis and medicinal chemistry applications.